CN114888059B - Risk management and control method based on safe utilization of polluted site - Google Patents

Abstract

The invention provides a risk management and control method based on safe utilization of a polluted site, which comprises a construction planning method, wherein the construction planning method comprises the following steps: s101, acquiring pollution condition information of a pollution site, wherein the pollution condition information comprises pollutant types, pollutant contents and pollutant ranges; s102, formulating that the target ground elevation of the polluted site is at least 30-50 centimeters higher than that of a surrounding road according to the surrounding road elevation of the polluted site; s103, setting a water collecting ditch around the polluted site; s104, setting earthwork allocation planning according to pollution conditions, pollution ranges and future planning purposes of places. The invention provides a method for combining management and control of risks of heavy (quasi) metal pollution sites with development and construction according to land development planning, so as to achieve the purposes of greatly shortening the safety utilization period and reducing the engineering energy consumption, carbon emission and cost.

Description

Risk management and control method based on safe utilization of polluted site

Technical Field

The invention relates to a method for controlling risks of heavy (quasi) metal polluted sites, in particular to a method for controlling risks of pollution for a long time combined with a land redevelopment construction scheme, which is suitable for land redevelopment safety utilization without volatile heavy (quasi) metal pollution and with high geological background value.

Background

For large-scale heavy (metal-like) polluted sites, soil and groundwater remediation often involves the processes of large-area deep foundation pit excavation, polluted soil transportation and transfer, solidification/stabilization, safe landfill and the like, and engineering cost, energy consumption and carbon emission are large. More importantly, the site repair engineering consumes longer time, seriously affects the development and construction progress of the land block, and is not beneficial to urban updating in economic developed areas such as Jingjin Ji, yangtze river delta, guangdong and Australian Dawan areas and the like. According to main urban data of a large bay area, the average time required for polluted land blocks from investigation to repair is more than 800 days, and the development and utilization process is often delayed from planning requirements, so that urban function upgrading is severely restricted. On the other hand, heavy metal(s) pollutants cannot be degraded and are difficult to volatilize (except individual elements such as mercury), particularly heavy metal(s) pollution caused by geological reasons, the form of the pollutants is generally stable and has poor mobility, and the exposure route to human health under the condition of no disturbance is mainly imported and ingested by dust-raising particles. Therefore, the method can be considered to be combined with a later development and construction scheme, and the building bottom plate of a building structure, a road and the like is utilized as a control surface to cut off the exposure path. After the risk management and control engineering is finished, the service life of the building is generally 70 years, and the building has long service life and stable structure. In the region with low geological activity, on the premise of effective management, the risk management and control measures can effectively cut off the exposure way of the risk source, and ensure the health of the crowd using the land parcel. Meanwhile, the organic combination of risk management and control and development and construction engineering can obtain beneficial results of shortening engineering time, reducing engineering energy consumption, reducing carbon emission and the like.

Disclosure of Invention

The invention provides a risk management and control method based on safe utilization of a polluted site, which is used for improving the treatment efficiency of the polluted site.

The invention provides a risk management and control method based on safe utilization of a polluted site, which comprises a construction planning method, wherein the construction planning method comprises the following steps:

s101, acquiring pollution condition information of a pollution site;

s102, determining pollution condition range distribution and pollution site planning purposes, and making a pollution site target ground elevation which is at least 30-50 centimeters higher than that of a surrounding road according to the surrounding road elevation of the pollution site;

s103, setting a water collecting ditch around the polluted site;

s104, setting earthwork allocation planning according to pollution conditions, pollution ranges and future planning purposes of places.

Further, the step 101 of obtaining pollution condition information of the polluted site includes:

and partitioning and fixing the pollution range according to the heavy metal type, the pollution degree and the depth of the super-screening value according to the land soil pollution condition investigation result, and determining the inflection point coordinates of each region range.

Further, the determining pollution extent distribution and pollution site planning uses include:

the low-pollution area in the pollution site is set as a sensitive application area, and the high-pollution area in the pollution site is set as a non-sensitive application area.

Further, the low-pollution area is an excavated heavy metal non-standard exceeding area; the high pollution area is an excavated heavy metal exceeding area; the sensitive application area is used for sensitive application of living and children parks, and the non-sensitive application area is used for greening and public facilities.

Further, the step s103 of setting a water collection ditch around the contaminated site further includes:

designing a waterproof curtain based on the water collecting ditch, and setting the depth of the waterproof curtain to reach a groundwater waterproof layer if no underground facilities exist; if underground facilities exist, setting a waterproof curtain to reach the upper part of the underground facilities.

Further, the step s104 of setting an earthwork deployment plan according to the pollution condition, the pollution range and the future planning purpose of the site includes:

s1041, determining the area of an excavation area required by the construction of the polluted site building according to the planning purpose of the polluted site;

s1042 fits the area of the excavated area with the distribution of the pollution condition range, and determines the change condition of the earthwork volume at the area of the excavated area in the construction process.

Still further, the variation includes at least an amount of earth excavation and an amount of earth backfill.

Further, the step s104 of setting an earthwork deployment plan according to the pollution condition, the pollution range and the future planning purpose of the site further comprises:

S1043, taking the area with the insensitive application as a polluted earthwork backfill area, and if the amount of the backfill earthwork which can be contained in the polluted earthwork backfill area is smaller than the earth excavation amount of the polluted soil, carrying the redundant polluted soil out for disposal.

Further, the step S1043 of using the area with the insensitive usage as the contaminated soil backfill area specifically includes:

s201, setting a polluted site as a polluted soil excavation area by taking the position of the polluted soil backfill area as a starting point, and determining the distance between the polluted soil excavation area and the starting point;

s202, determining the type and the pollution degree of pollutants in the earthwork excavated by the polluted site;

s203, dividing the polluted soil backfill area into a plurality of polluted soil backfill positions according to the same pollutant type and pollution degree.

Further, the step S203 of dividing the contaminated soil backfill area into a plurality of contaminated soil backfill positions according to the same type of contaminant and the same degree of contamination includes: and backfilling the polluted soil with the same pollutant type and similar pollution degree at the backfill position of the same polluted soil.

Compared with the prior art, the invention provides a method for combining management and control of risks of heavy (quasi) metal pollution sites with development and construction according to land development planning, so as to achieve the purposes of greatly shortening the safety utilization period and reducing the engineering energy consumption, carbon emission and cost. The risk management and control method mainly comprises a series of treatments of cutting off the exposure path of pollutants, such as constructing a waterproof curtain at the boundary of a pollution site to prevent the horizontal diffusion of the pollutants, constructing a totally-enclosed barrier layer on the ground to prevent the diffusion of the pollutants to the atmosphere, and the like, in combination with development and construction schemes; the method combined with development and construction not only utilizes the construction structures and the road bottom plate as a part of the barrier layer, but also reasonably distributes earthwork through the super risk screening value earthwork overall distribution system in the site construction process, ensures that polluted earthwork cannot go out of site, realizes land leveling, utilizes static pressure piles to construct to prevent heavy metal-containing dust from diffusing and the like, constructs underground pipeline galleries and the like to prevent municipal construction from disturbing polluted soil and the like, ensures that all possible exposure ways are cut off, and does not influence the normal use function of the land. Through calculation of the risk assessment model, the method can realize land block redevelopment and safe utilization, reduce carbon emission and energy consumption, shorten development time by 60%, reduce repair cost and ensure land value.

Drawings

FIG. 1 is a schematic view of a large earth excavation range according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a cross-section of a green area and municipal road pipeline laying according to an embodiment of the invention;

FIG. 3 is a schematic view of earth excavation of structures such as a bearing platform according to an embodiment of the present invention;

fig. 4 is a schematic diagram of excavation of heavy metal contaminated earthwork deployment according to an embodiment of the present invention.

Detailed Description

In order that those skilled in the art will better understand the present invention, a technical solution of the embodiments of the present invention will be clearly and completely described below, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments.

Examples

The embodiment of the invention discloses a risk management and control method based on safe utilization of a polluted site, which comprises a construction planning method, wherein the construction planning method comprises the following steps:

s101, acquiring pollution condition information of a pollution site;

taking fig. 1 as an example, according to the investigation result of the soil pollution condition of the land block, partitioning and fixing the pollution range according to the metal type, pollution degree, depth and the like of the super-screening value, determining the inflection point coordinates of each region range, and inputting the processed soil block into a super-risk screening value land block overall allocation system;

S102, determining pollution condition range distribution and pollution site planning purposes, and making a pollution site target ground elevation which is at least 30-50 centimeters higher than that of a surrounding road according to the surrounding road elevation of the pollution site;

and according to the distribution and planning purposes of each range, combining the elevation of surrounding roads, and formulating the constructability planning of land block construction buildings, municipal facilities and the like, so that the elevation of the ground is at least 30-50 cm higher than one of the surrounding municipal roads after the construction of land block construction and roads and the like is completed, and the ground has a certain gradient (2-3 degrees are suitable) so as to facilitate drainage. The planning principle is as follows: (1) The areas with lighter pollution and lower risk are used for sensitive applications such as living, children parks and the like, and the areas with heavier pollution and higher risk are used for non-sensitive applications such as greening, public facilities and the like; (2) After the construction, the whole land is designed to be gentle, so that the earth excavation depth is reduced, and unnecessary artificial landscaping such as artificial lakes, artificial mountains and the like is avoided; (3) If deeper underground facilities must be provided, the low-lying places are prioritized.

S103, setting a water collecting ditch around the polluted site;

the method comprises the steps of constructing a water collecting ditch on a red line (the red line mainly refers to a black line at the edge due to a gray scale drawing) of a land block so as to collect construction wastewater, and reinforcing the construction wastewater into a permanent underground drainage pipe network after engineering is finished; and constructing a waterproof curtain, and if underground structures such as subways or air-raid shelters exist in the ground, the construction depth of the waterproof curtain can be properly modified in principle.

S104, setting earthwork allocation planning according to pollution conditions, pollution ranges and future planning purposes of places.

And carrying out earthwork allocation by combining elevation of each place of the land according to pollution range distribution and constructive planning. The earthwork blending principle comprises: (1) Preferentially blending the pollutant types with the same super risk screening value and the soil with the same super screening degree; (2) nearby blending, reducing earthwork transportation; (3) The precise excavation and allocation are implemented, random dumping is forbidden, and all polluted earthwork cannot leave the red line (mainly the black line of the edge due to the gray scale of the drawing) range of the land in principle.

Optionally, the determining the pollution condition range distribution and the pollution site planning use includes:

the low-pollution area in the pollution site is set as a sensitive application area, and the high-pollution area in the pollution site is set as a non-sensitive application area.

Optionally, the low-pollution area is an excavated heavy metal non-standard exceeding area; the high pollution area is an excavated heavy metal exceeding area; the sensitive application area is used for sensitive application of living and children parks, and the non-sensitive application area is used for greening and public facilities.

The distinguishing standard of the middle-low pollution area and the middle-high pollution area is the conventional environment protection construction standard. The sensitive application areas and the non-sensitive application areas are distinguished by human exposure and the like, for example, areas such as residence, children parks and the like, the areas belong to the sensitive application areas due to long contact time between people and soil environments, and the landscape environments such as parks and the like belong to the non-sensitive application areas due to short contact time of human bodies.

Optionally, the s103, setting a water collection ditch around the contaminated site further includes:

designing a waterproof curtain based on the water collecting ditch, and setting the depth of the waterproof curtain to reach a groundwater waterproof layer if no underground facilities exist; if underground facilities exist, setting a waterproof curtain to reach the upper part of the underground facilities.

The water curtain stopping method is characterized in that a double-row phi 600 single-shaft stirring pile (with the lap joint of 200mm and the cement content of 90kg/m, and the pile bottom at least enters a water impermeable layer of 1.5 m) is adopted to construct a water curtain stopping curtain, a temporary water guide channel is excavated along a red line of a land according to the potential, and after the engineering is completed, the water guide channel is trimmed, a control surface is paved and then is used as a permanent underground drainage pipe network. The collected construction wastewater, flushing rainwater and the like mainly contain various heavy metals. And pumping the wastewater to an adjusting tank for treatment through a pipe network, and pumping the wastewater to a reaction tank of integrated treatment equipment for flocculation sedimentation mixing reaction after adjustment. And the water in the reaction tank flows to the inclined tube sedimentation tank, and the water in the upper part of the inclined tube sedimentation tank flows to the reuse water tank from the end, and is ready for detection. The bottom of the inclined tube sedimentation tank is provided with a conical mud outlet, the mud is dried in the sun, the generated mud is transported to a qualification unit for disposal, and a water filtering pump is returned to the regulating tank. The sedimentation aid can be added with proper amount of Polyacrylamide (PAM) and polyaluminum chloride (PAC). If the construction wastewater contains organic pollutants such as petroleum hydrocarbon and polycyclic aromatic hydrocarbon, fenton reagent and the like are added for chemical oxidation treatment. After the water quality reaches the standard of urban sewage recycling-urban miscellaneous water quality (GB/T18920-2002), the water quality can be used as construction dust fall or vehicle equipment flushing water.

In particular, the step s104 of setting an earthwork deployment plan according to the pollution condition, the pollution range and the future planning purpose of the site includes:

s1041, determining the area of an excavation area required by the construction of the polluted site building according to the planning purpose of the polluted site;

s1042 fits the area of the excavated area with the distribution of the pollution condition range, and determines the change condition of the earthwork volume at the area of the excavated area in the construction process.

In particular, the variation includes at least an amount of earth excavation and an amount of earth backfill.

Taking fig. 1 as an example, it can be seen that a plurality of areas in the map have excessive heavy metals and various metal pollution types exist in the map. In construction, the excavated area is the entire field and the backfill area is the small annular area within the excavated area, as shown in fig. 3. The earthwork excavation amount and the earthwork backfill amount can be obtained through calculation of the excavation area and the backfill area.

In particular, the step s104 of setting an earthwork deployment plan according to the pollution condition, the pollution range and the future planning use of the site further comprises:

s1043, taking the area with the insensitive application as a polluted earthwork backfill area, and if the amount of the backfill earthwork which can be contained in the polluted earthwork backfill area is smaller than the earth excavation amount of the polluted soil, carrying the redundant polluted soil out for disposal.

In principle, the polluted soil backfill area should contain polluted soil to the maximum extent, such as a rockery and the like.

In particular, the step S1043 of using the area with the insensitive usage as the contaminated soil backfill area specifically includes:

s201, setting a polluted site as a polluted land excavation area by taking the position of the polluted land backfill area as a starting point, and determining the distance between the polluted land excavation area and the starting point;

s202, determining the type and the pollution degree of pollutants in the earthwork excavated by the polluted site;

s203, dividing the polluted soil backfill area into a plurality of polluted soil backfill positions according to the same pollutant type and pollution degree.

In particular, the step S203 includes, according to the same type of pollutant and the same pollution level, dividing the polluted soil backfill area into a plurality of polluted soil backfill positions: and backfilling the polluted soil with the same pollutant type and similar pollution degree at the backfill position of the same polluted soil.

As shown in fig. 4 (the starting point of the arrow is the original contaminated soil position, the key point of the arrow is the contaminated soil backfill position), the three contaminated soil backfill positions are divided into seven contaminated soil backfill positions of T1, T2, T3, T4, T5, T6 and T7 according to the type and the pollution degree of the pollutant, the T1 is the arsenic contaminated soil backfill position, the T2 and T3 are the cobalt contaminated soil backfill position, the T4 is the arsenic and cobalt mixed contaminated soil backfill position, the T5 is the antimony contaminated soil backfill position, the T6 is the lead contaminated soil backfill position, and the T7 is the cadmium zinc nickel barium+antimony+cobalt+lead mixed contaminated soil backfill position. T1, T2, T3, T4, T5, T6, T7 are all at planned locations in a mall or public park.

During implementation, non-soil-discharging piles such as static pressure piles are utilized for constructing building piles, dust-proof measures such as dust screens, spray water and the like are adopted, and pollution soil is prevented from diffusing along with the atmosphere. Before construction, rolling is carried out after the surface layer is cleaned, the compaction coefficient K is 1.0 within the depth range of not less than 0.5m of the foundation surface layer and is more than the planned value of 0.80, and tubular pile construction is carried out after the requirement is met. The construction of the support pile adopts a 500mm static pressure prestress high-strength concrete pipe pile for construction, and mainly aims at controlling the risk of the matched polluted soil, the pipe pile is a non-soil-discharging pile, and the polluted soil is not required to be discharged in the construction process, so that the pipe pile is adopted in the construction process, and the constructed pipe pile can be integrally formed with a control surface to prevent the problems of cracking of the follow-up control surface and the like. After the earthwork preparation and pile construction are completed, the whole area of the land is covered with clean soil with the thickness of about 50cm, and the land is compacted and leveled.

In addition, in order to further isolate the polluted soil, the earthwork of underground facilities such as a water collecting well, a septic tank, an elevator shaft, a reservoir, a pipeline corridor and the like can be excavated according to the constructability planning, the height of about 50cm is reserved for covering the clean soil, and the earthwork allocation is carried out according to the principle of S104 and the overall allocation system.

And after the inspection is qualified, performing barrier layer construction. The soil barrier layer needs to be built under the building. Pipeline burying is needed below building bottom boards of shops, kindergartens and the like, and a soil barrier layer bottom board is established below the pipeline of the building bottom boards; paving pipelines at the bottoms of structural layers such as gardens, district roads and the like, and making a soil barrier layer bottom plate at the bottoms of the pipelines; the reinforced concrete bottom plate of the bottom parking garage can be directly used as a bottom plate of the soil barrier layer. The structural specification of the surface covering barrier layer refers to the structural design requirement of the barrier landfill body, and the surface covering barrier landfill body needs to comprise a barrier layer and a barrier layer, wherein the thickness of the concrete of the barrier layer is not less than 20cm, and a building bottom plate is used as the barrier layer in the range of combining with the site planning and selecting (1) the parking garage; (2) and (5) taking a concrete layer as a barrier layer outside the range of the parking garage, and paving a pipeline on the barrier layer.

The specific implementation mode of the embodiment of the invention is as follows:

taking the industrial plot of fig. 1 as an example, the industrial plot is planned to be developed and built again as a type of living land compatible with commercial, business, recreational health land and urban road land. The land occupation area is 112573.21m ² According to the soil pollution condition investigation and risk assessment results, the 8-item (metal) (arsenic, antimony, cadmium, lead, zinc, nickel, cobalt and barium) human health risk of the land is unacceptable, and the range exceeding the risk screening value is 94472m ² Accounting for 85 percent of the total land mass. The phenomenon of arsenic oversieveling of soil commonly exists in land parcels, and the area of the oversieveling reaches 86437m ² The maximum super-sieve multiple is 49.8, and the arsenic exceeding depth reaches 29m. The pollution characteristics and the cause analysis result show that the activity of most heavy (quasi) metals is low, the stable forms such as the iron-manganese combined state, the residue state and the like are mainly used, and the super-risk screening value is related to artificial filling and high geological background. In the groundwater environment investigation, 22 groundwater monitoring wells are distributed in total, 22 groundwater samples are collected, wherein 17 super-sieve samples are provided, 7 super-sieve pollutants are provided, the super-sieve pollutants comprise heavy (class) metals such as nickel, zinc, lead, arsenic, manganese and beryllium, and the super-sieve multiple range is 0.98 (nickel) -56 (arsenic).

In order to realize the safe utilization of land parcel redevelopment, risk management and control or treatment and repair are needed, and construction is carried out according to the method by taking energy conservation, emission reduction and cost reduction as priority conditions. The method with low energy consumption and low cost is considered as much as possible under the possible condition so as to prevent secondary pollution and reduce the influence on residents.

As the heavy (quasi) metal super-risk screening value soil such as arsenic is treated by adopting the technology of covering and blocking the surface layer and sealing the periphery. The surface layer covering and blocking is to cover a blocking layer on the top of soil in an ultra-standard area which is not excavated, completely isolate the top of a polluted area from the surrounding, cut off the direct contact of a receptor and the ultra-standard soil, accidental ingestion of the ultra-standard soil, prevent soil particles from entering air in a dust-raising mode and the like. The soil surface covering barrier is usually formed by combining one or more layers of clay layers, artificial synthetic material liners, sand layers and the like, and is determined according to the field pollution type and future planning. Therefore, the project is covered and blocked after the heavy metal (like) polluted soil is backfilled by combining the construction scheme and the high requirement of municipal road sign and the earth balance in the construction process. Meanwhile, in order to prevent the horizontal migration of pollutants, a waterproof curtain is built at the boundary of the land block, a blocking system with surface coverage and four closed sides is formed, long-term peripheral monitoring is enhanced, and pollution diffusion risks are prevented.

Description of an implementation procedure

(1) Pile foundation construction

The pile foundation adopts a construction technology of undisturbed lower layer exceeding soil. The project building foundation planning adopts static pressure prestressed pipe piles. Static pile is a pile sinking technology for pressing precast pile into soil by using pile pressing mechanism of static pile pressing machine and counter force provided by dead weight of pile pressing machine and counter weight on machine frame. The static pile pressing construction process has the advantages of low noise, no pollution and high construction speed, and soil is not required to be excavated in the construction process, so that the lower layer exceeding soil is not disturbed.

(2) Earthwork blending with heavy metal pollution

And combining the pollution ranges of different depths of heavy metals in the land and the excavation ranges of development and construction, carrying out layered classification excavation on heavy metal polluted soil according to the investigation depth division principle (0-0.5 m, 0.5-1.0m, 1.0-2.0m, 2.0-3.0m, 3.0-4.0m, 4.0-5.0m and 5.0-6.0 m), wherein the total excavation range is shown in figure 3, and the excavation ranges of the polluted soil of structures such as a bearing platform, a water collecting well, a septic tank and the like are shown in figure 3. Through measurement and calculation, excavation range of about 21340m related to heavy metal pollution in land ² The excavation pollution soil volume is 20708m ³ The contaminated earthwork and clean earthwork estimates for each layer are detailed in table 1.

Shallow excavation of heavy metal contaminated soil needs to be allocated to the site Above the pollutant-like material, the polluted soil filling area is shown in fig. 3. The fill area is divided into 7 areas (T1-T7) according to the pollutant type, and the total area is 21340m ² The required soil volume (after compaction) is approximately 21334m, calculated as engineering compaction factor (compacted earth/original earth) 0.9 ³ Can accommodate the amount of excavated polluted soil (original soil) of about 23705m ³ . Thus, the set fill area is sufficient to accommodate the excavated heavy metal contaminated soil.

According to the construction plan, the earthwork balancing process is as follows:

a. before excavation, measuring and positioning are carried out, an excavation range and an exceeding soil range are determined, and the excavation is carried out according to paying-off partition and layering;

b. marking the range of structures such as a bearing platform, a water collecting well, a septic tank and the like, and avoiding secondary excavation;

c. carrying out large earth balance on a bench, excavating a cutting area to a designed elevation, wherein heavy metal exceeding soil is excavated in a layered and classified mode according to the types of pollutants and allocated to a designated area above similar pollutants, clean soil is allocated to a filling area nearby, and the filling area needs to be covered with soil and backfilled to the designed elevation;

d. and carrying out small earth balance on structures such as a bearing platform, a water collecting well, a septic tank and the like, wherein the allocation principle is consistent with the large earth balance.

(3) Non-pollution earth excavation filling balance

According to the requirements of local block development and construction engineering, the requirement of the engineering tamping coefficient (tamping earthwork/original earthwork) of the development and construction unit is 0.9, namely 0.9m through field test ³ The original soil needed by the filling area of (2) is 1m ³ Through measurement and calculation, the total excavated area in the land is 37315.65m ² The total square excavation is 83736m ³ While the required earthwork of the filling area is 83772m ³ The earth is about 75395m after being compacted ³ . Therefore, according to the development and construction scheme, the earthwork excavated in the land block can be automatically consumed in the field, and the earthwork outward transportation condition can not be generated. After the contaminated earthwork is allocated, the non-contaminated earthwork is excavated and allocated to the area adjacent to the filled earthwork, and the non-contaminated earthwork is allocated to 56814.22m ³ 。

TABLE 1 statistics of the amount of excavated earth at different depths (unit: m) ³ )

* : the positions of the filling areas T1-T7 are shown in FIG. 4.

(4) In situ covering barrier

After the earthwork is balanced, full-field in-situ covering and blocking are carried out, and the laying area of the blocking layer is 112573.21m of the land area ² . Wherein the floor parking garage area uses the building floor as a barrier layer, and other areas (41650.37 m ² ) The barrier layer is paved first, and the pipeline is buried in the covering soil above the barrier layer.

The barrier layer consists of two parts, namely an impermeable layer and a rigid barrier layer, wherein the impermeable layer adopts two cloth films (a non-woven protective layer- -an HDPE film (1.5 mm) - -a non-woven protective layer), the rigid barrier layer comprises a plain concrete cushion layer of 100mm and a reinforced concrete slab of 200-300mm (internally provided with a single layer of phi 6@150×150 double-layer bidirectional reinforcing steel bars), and the barrier layer of the bottom layer parking garage is additionally provided with waterproof paint of 50 mm. The barrier layer is thus, from top to bottom, reinforced concrete-waterproof paint (bottom parking garage) -plain concrete cushion-non-woven protective layer-HDPE film (1.5 mm) -non-woven protective layer.

(5) Construction of waterproof curtain

In order to prevent the exceeding soil from affecting the surrounding environment by the diffusion of groundwater, a waterproof curtain is built along the red line of the land block, and double rows are adopted

The total length of the single-shaft cement mixing piles is 15365m of the circumference of the red line, the diameter of each mixing pile is 600mm, the front and back overlap joint is 200mm, the cement content of 42.5R is 90kg/m, and the water-cement ratio is 0.6-0.8. According to the requirements of the technical Specification for controlling groundwater in construction and municipal engineering (JGJ 111-2016), the depth of the waterproof curtain is not less than 1.5m when the waterproof curtain enters a weakly permeable layer, and is 3-17m unequal and the average depth is 8m in combination with the land exploration condition and the soil layer condition disclosed in the investigation process.

Two-risk management and control part energy consumption condition

According to pollution risk management and development and utilization schemes, the energy consumption condition of the whole project can be calculated. Because the rigid original steric barrier layer in the range of the pile foundation construction and the bottom layer parking garage belongs to a part of the construction scheme, the energy consumption in the process is not calculated for the convenience of comparison with a comparative example. The barrier layer is paved and then the pipeline is buried outside the range of the parking garage, and the original barrier layer does not belong to a part of a construction scheme, so that the energy consumption of earth balance allocation, full-field in-situ barrier impermeable layer, rigid barrier layer in the outer region of the parking garage and surrounding waterproof curtain construction is calculated.

(1) And (5) earthwork blending. Excavating and mixing the polluted earthwork quantity of 20708m ³ The soil volume of the non-pollution soil is 56814.22m ³ Aggregate 77,522.22m ³ . Because the excavation area and depth are small, and the layer-by-layer excavation and layer-by-layer allocation are carried out, high-strength support is basically not needed. The equipment in the process of excavation and deployment mainly comprises an excavator, a forklift, a transport vehicle, a soil rammer and the like, and mainly uses fuel which is diesel oil per m ³ Soil (dummy) consumed 0.45L diesel, totaling 34885.0L.

(2) And (5) paving a flexible impermeable layer. The seepage-proof area is the land area 112573.21m ² The plane paving is mainly adopted, so that only about 10 percent of the connecting area is needed to be increased, namely the area of paving material is 123830.53m ² Aggregate required geotextile 247661.06m ² HDPE film 123830.53m ² . Therefore, geotextile 148.60t and HDPE film 176.46t are required to be laid. The unit energy consumption of the diesel oil was 0.35L/t of material, which was 130022.06L in total.

(3) The rigid barrier layer is laid. Outdoor area (41650.37 m) ² ) The method is equivalent to paving two layers of rigid cement baffle plates, wherein one layer is paved in the building process, and the energy consumption is not calculated. And the other layer serves for risk management and control and is included in the accounting range. The thickness of the baffle plate is 30cm, wherein 20cm is C30P6 impervious concrete, 10cm is C15 concrete cushion, and phi 6@150×150 double-layer bidirectional reinforcing steel bars are internally arranged. Thus, C30 concrete 21250.02t, C15 concrete 9996.09t, and rebar 14.06t are required. The unit energy consumption of the diesel oil was 0.35L/t of material, which was 10941.06L in total.

(4) And (5) building a waterproof curtain. The total construction length of the waterproof curtain is 15365m of the circumference of the red line, the diameter of each stirring pile is 600mm, the front and rear overlapping is 200mm, double-row single-shaft curtains are built together, 76826 curtains are required to be poured, the average construction depth is 8m, and the actual cement consumption is 5531.48t according to the cement content of 90kg/m of 42.5R. The pouring work mainly uses stirring machinery, cement pulping, pouring machinery and other equipment, and the unit energy consumption of fuel diesel is 0.5L/t and is 2765.74L in total.

The total energy consumption of the whole process is 216.01t of standard coal, and the conditions of the whole process are summarized in the following table.

TABLE 2 direct energy consumption for target land parcel risk management and control process ¹

Note that: 1, only calculating the energy consumption condition of field engineering, and not calculating the energy consumption conditions of energy sources and processes of material production, transportation, abandonment and the like; the reference index coefficient of the 2 diesel oil is 1.4571 ton of standard coal/ton of diesel oil, and the diesel oil density meter is 0.83kg/L.

Three-risk control part carbon emission

Similarly, the carbon emission condition of the whole project can be calculated according to pollution risk management and development and utilization schemes. Because the pile foundation construction and the rigid original steric barrier layer are part of the construction scheme, the carbon emission in the process is not calculated for the convenience of comparison with the comparative example, and only the carbon emission in the earthwork balance allocation, the in-situ barrier impermeable layer and the surrounding waterproof curtain construction are calculated.

(1) Energy consumption and carbon emission.

According to IPCC data, 1L diesel combustion CO ₂ Emission coefficient of 2.63kg CO _2e The process uses diesel oil as main energy source to discharge 469.75t CO _2e 。

(2) Carbon emissions from material production.

Estimation of carbon emission of materials according to the building carbon emission calculation Standard (GB/T51366-2019)See table 3. Therefore, the carbon emission of the engineering due to the use of materials is 8076.15t CO _2e 。

TABLE 3 carbon emissions resulting from target plot "Risk management" process Material usage ¹

Note that: 1, only the carbon emission condition of material consumption is calculated, and the carbon emission conditions of the processes of slow release of cement, material transportation, waste and the like are not calculated.

(3) Other processes carbon emissions.

Besides the process, the construction of field leveling and repairing facilities is required in the early stage of the engineering, foundation pit drainage and the like are required to be treated in the engineering, clean soil is required to be covered and related facilities are required to be removed in the later stage of the engineering, and certain energy consumption and carbon emission are provided. But this part is also involved in the control example and therefore no additional calculation is performed.

In conclusion, the carbon emission of the 'risk management' part of the project is 8545.90t CO _2e 。

Four engineering cost

The general repair engineering comprises an engineering early preparation stage, repair engineering fees, supervision fees, checking and accepting evaluation fees and the like. The comparison example also relates to the cost of the engineering early preparation stage, supervision cost, checking and accepting evaluation cost and the like, so the comparison example only calculates the cost of the risk management engineering per se, and the cost is 6511.904 ten thousand yuan, and the concrete calculation is as follows.

TABLE 4 target plot "Risk management" engineering expense

After repair, the whole area of the land is 112573.21m ² Can meet the development and use requirements. The city was monitored according to 2021 to average 13450 yuan/m for the total ground ² The total price of the land after repair is 151,410.97 ten thousand yuan.

Time consuming five projects

The engineering construction deployment is generally divided into three stages: project preparation stage, project implementation stage, acceptance and completion withdrawal stage. The project is all-land pile foundation construction, heavy metal contaminated soil allocation and baffle pouring completion planning period is about 150 days.

Comparative example

And if the polluted land is repaired by adopting a traditional method, the soil with the super-screening value is excavated, solidified/stabilized and then buried in situ. According to measurement and calculation, the total excavation area is 94472m ² If only 0-8m depth soil is treated, the soil volume is about 766224m ³ 。

Introduction of a repair procedure

The main implementation process of the curing/stabilizing technology repair is as follows:

(1) Pit excavation

Excavating soil layer by fixed point by using an excavator, wherein the super-screening value range is 94472m ² The area of the excavated foundation pit is 95778m according to the site topography ² . In the excavation process, secondary pollution prevention measures such as removing soil while covering HDPE film are adopted to avoid the influence of the diffusion of pollutants on the periphery and the atmospheric environment, and the covered area is 1.2 times of the excavation area.

And after the excavation is completed, supporting the side wall of the foundation pit in a net-weaving and spraying construction mode. The thickness of the sprayed concrete on the slope surface of the foundation pit is 10cm, the strength is not lower than 20Mp, and the section steel bars are adopted

Slope surface implanted with L=1000mm steel bar

The surface layer is provided with a water drain hole. The anchor spraying area is 7821870 square meters, and the used concrete square quantity is 6387861m ³ ，/>

Reinforcing bars 522356646m, < >>

The steel bars 2932161973m and the maintenance days are 1 day. And collecting foundation pit water generated by excavating a foundation pit through a water collecting pipe, and then treating the collected foundation pit water, wherein the generated treated sludge is subjected to solidification/stabilization treatment.

(2) Reduction in crushing screening and treatment

The soil is screened and crushed by the screening crushing hopper, and the particle size of the crushed soil is smaller than 5cm. In order to promote the thorough mixing of the soil and the medicament at the later stage, the number of times of crushing and sieving of the soil in each batch is not less than 8. The soil mechanical composition obtained according to the analysis data of 4 random sampling points is shown in Table 5, the particle size components of 500-2000 μm and 75-150 μm are relatively high in content, and the mass fraction average values are 35.80% and 24.98%, respectively; the particle size content of 250-500 mu m is relatively low, and the mass fraction average value is 15.73%. The arsenic content in each particle size is shown in Table 6, and exceeds the soil risk screening value (60 mg/kg). As can be seen, the curing/stabilization is required in each particle size range, so the soil volume to be cured and stabilized in the present process is 766224m ³ The reduction process cannot be performed.

TABLE 5 mass fraction of each particle size of target plot soil samples (unit:%)

Particle size (mum)	Point location 1	Point location 2	Point location 3	Point location 4	Average value of
						500-2000	39.35	40.25	35.95	27.65	35.80
250-500	14.83	18.15	16.30	13.65	15.73
						150-250	18.73	21.45	27.30	26.03	23.38
75-150	27.08	19.90	20.45	32.48	24.98

TABLE 6 As content (unit: mg/kg, dry weight) for each particle size of target plot soil samples

Particle size (mum)	Point location 1	Point location 2	Point location 3	Average value of
					500-2000	1230	493	173	632.00
250-500	1650	431	138	739.67
					150-250	2210	682	286	1059.33
75-150	1570	481	159	736.67

(3) Contaminated soil stabilization by solidification

The polluted soil is piled up after being screened and crushed by a screening and crushing device (A Lu Dou). On average 2% of the iron-containing silicate solidification stabilizer is added, and the total amount is 33.84t; the water content is regulated to about 20-40%. Because the adding proportion of the medicament is lower, the medicament is uniformly mixed step by step, so as to ensure the uniform mixing effect of stirring.

(4) Post-repair management maintenance

Delivering the solidified/stabilized repaired soil to a curing area for curing, wherein the usage amount of the covering material is 0.5m per cubic meter of soil (virtual square) ² In total, 48846.78m ² Dust-proof net with density of 120g/m ³ And 5.86t. The water content of the soil is kept to be about 20-30%, and the soil is maintained for 3 days.

(5) Soil backfill after repair

According to the development scheme, the soil after maintenance is buried. Because of the large area, the foundation pit is selected to be buried in the original foundation pit. The bottom and side walls are smooth and concrete construction is carried out, geotextile, HDPE film and geotextile are paved in sequence, soil after solidification, stabilization and repair is backfilled and compacted in layers, reinforced concrete construction is carried out at the top, geotextile (600 g/m) is paved at the top in sequence ² Long fiber nonwoven geotextile), HDPE film (1.5 mm thick), geotextile, clean soil backfill, compaction. Super-screening value range is 94472m ² The construction area of the foundation pit is 95778m ² The coverage area of the membrane cloth is at least 200332.63m ² The connection area is increased by about 15%, and the engineering required membrane cloth area is at least 230382.5m ² The method comprises the steps of carrying out a first treatment on the surface of the The construction area of the reinforced concrete is 200332.63m ² 。

(6) Operation maintenance and subsequent development

(1) Soil excavation safety: and (3) fence sealing operation, namely setting up a warning sign and avoiding underground hidden facilities. (2) Safety protection: workers should pay attention to labor protection. (3) Preventing secondary diffusion: measures are taken to prevent rainwater from entering the soil, prevent the rainfall from flushing the soil to carry pollutants into the surrounding environment, and prevent wind and dust from flying up to cause secondary diffusion. (4) Long-term monitoring: according to domestic and foreign experiences, at least 1 monitoring well needs to be arranged at the downstream of groundwater for the soil subjected to backfill treatment after solidification/stabilization, and the monitoring is carried out once in a quarter for 2 years, so that no leakage is ensured. (5) In the subsequent development process, the solidification/stabilization area is ensured not to be disturbed, and the landfill area is not developed as much as possible.Thus, the area of the local block that can actually be developed is only 15%, i.e. 16885.98m ² The method comprises the steps of carrying out a first treatment on the surface of the The landfill range can only be used as green land and the like, and the land value is greatly reduced.

Two energy consumption conditions

If the repairing and developing are carried out according to the scheme, the energy consumption condition of the whole project is calculated as follows.

(1) The excavation of the foundation pit consumes 7243849L of diesel oil and 8760660kg of standard coal. The specific measurement and calculation are as follows:

the earthwork volume is about 766224m ³ The equipment in the excavation process is mainly an excavator, a forklift, a transport vehicle and the like, and mainly uses fuel which is diesel oil, and the fuel is used for every m ³ Soil (dummy) consumed 0.35L of diesel oil, totaling 268178.4L.

After the cleaning is completed, the deep foundation pit needs to be supported, and the working procedures comprise slope repairing, reinforcement cage installation, reinforcement cage hanging on the slope, concrete spraying and maintenance. Diesel oil is mainly used as fuel for lifting, transportation and the like. The weights of materials such as steel bars, cement and the like are 766903.13t and 19163583t respectively, and the total weight is 19930486.13t; each t of material consumed 0.35L of diesel, which totaled 6975670.147L.

(2) Crushing and screening consumed 268178.4L of diesel oil, 324333.1kg of standard coal. The specific measurement and calculation are as follows:

the earthwork volume is about 766224m ³ A Lu Dou uses diesel oil as fuel with energy consumption of 0.35L/m ³ Soil, total 268178.4L. (3) Contaminated soil stabilization consumed 272126.60L of diesel fuel, 329108.0052kg of standard coal. The specific measurement and calculation are as follows:

The earthwork volume is about 766224m ³ The earthwork volume is increased to 777504.5m after adding 2 percent of iron-containing silicate material ³ A Lu Dou uses diesel oil as fuel with energy consumption of 0.35L/m ³ Soil, total 272126.60L.

(4) The dust screen is paved and the water content is regulated in the repairing and management maintenance process mainly by using manpower, so that the energy consumption is negligible.

(5) The restored soil backfill consumed 528051.54L of diesel oil, and 363774.7kg of standard coal was counted. The specific measurement and calculation are as follows:

according to the development scheme, the soil after maintenance is fedAnd (5) performing row landfill. Because of the large area, the foundation pit is selected to be buried in the original foundation pit. The bottom and side walls are smooth and concrete construction is carried out, geotextile, HDPE film and geotextile are paved in sequence, soil after solidification, stabilization and repair is backfilled and compacted in layers, reinforced concrete construction is carried out at the top, geotextile (600 g/m) is paved at the top in sequence ² Long fiber nonwoven geotextile), HDPE film (1.5 mm thick), geotextile, clean soil backfill, compaction. The foundation pit area meter is 95778m ² The coverage area of the membrane cloth is at least 201459.37m ² The connection area is increased by about 15%, and the engineering required membrane cloth area is at least 200332.63m ² Aggregate required geotextile 463356.54m ² HDPE film 231678.27m ² The method comprises the steps of carrying out a first treatment on the surface of the The construction area of the reinforced concrete is 200332.63m ² The thickness was 20cm.

In conclusion, the foundation pit construction needs geotechnical cloth 276.46t, HDPE film 328.30t and reinforced concrete 102209.71t, and the total soil amount after maintenance is 777504.5m ³ . The unit energy consumption of diesel oil is 0.35L/m ³ Soil, 0.35L/t of other materials, and total 528051.54L.

The total energy consumption of the whole process is 9777.88t of standard coal, and the conditions of the whole process are summarized in the following table. It can be seen that the energy consumption of the process is large due to the large area of the excavated foundation pit.

TABLE 7 direct energy consumption during solidification/stabilization of target plots ¹

Note that: 1, only calculating the energy consumption condition of field engineering, and not calculating the energy consumption conditions of energy sources and processes of material production, transportation, abandonment and the like; the reference index coefficient of the 2 diesel oil is 1.4571 ton of standard coal/ton of diesel oil, and the diesel oil density meter is 0.83kg/L.

Three carbon emissions

According to the energy consumption and material consumption, the engineering carbon emission can be calculated initially.

(1) Energy consumption and carbon emission.

According to IPCC data, 1L diesel combustion CO ₂ Emission coefficient of 2.63kg CO _2e The process uses diesel oil as main energy source to discharge 1388.78t CO _2e 。

(2) Carbon emissions from material production.

The carbon emission estimates for each material are shown in Table 8, according to the building carbon emission calculation Standard (GB/T51366-2019). Therefore, the carbon emission of the engineering due to the use of materials is 15889823.10t CO _2e 。

TABLE 8 target carbon emissions resulting from the use of materials during solidification/stabilization of plots ¹

Note that: 1, only the carbon emission condition of material consumption is calculated, and the carbon emission conditions of the processes of slow release of cement, material transportation, waste and the like are not calculated.

(3) Other processes carbon emissions.

Besides the process, the construction of field leveling and repairing facilities is required in the early stage of the engineering, foundation pit drainage and the like are required to be treated in the engineering, clean soil is required to be covered and related facilities are required to be removed in the later stage of the engineering, and certain energy consumption and carbon emission are provided. But this part is also involved in the embodiment and therefore no extra calculation is made.

In conclusion, the carbon emission of the project is at least 15891211.88t CO _2e 。

Four engineering cost

The general repair engineering comprises an engineering early preparation stage, repair engineering fees, supervision fees, checking and accepting evaluation fees and the like. The embodiment also relates to the cost of the engineering early preparation stage, supervision cost, checking and accepting evaluation cost and the like, so the method only calculates the cost of the repair engineering per se, and calculates 73707.504 ten thousand yuan, and the specific calculation is as follows.

TABLE 9 target parcel cure/stabilization repair engineering costs

Project name	Unit (B)	Engineering quantity	Unit price (Yuan)	Budget closing price (ten thousand yuan)
					Repair engineering fee				73707.504
Earthwork excavation transportation landfill	m 3	766224	100	7662.240
					Stabilization treatment of soil solidification	m 3	766224	860	65895.264
Construction environment monitoring	/	/	/	150

After repair, 85% of the area is used as a landfill area, so that the area cannot be developed and utilized according to the existing management requirements; thus, the land has only 15% of its area, i.e. 16885.98m ² Can be used for development. The city was monitored according to 2021 to average 13450 yuan/m for the total ground ² The total price of the land after repair is 22711.64 ten thousand yuan, which is not enough for repair engineering.

Time consuming five projects

The engineering construction deployment is generally divided into three stages: project preparation stage, project implementation stage, acceptance and completion withdrawal stage. The project is scheduled for about 240 days, and the specific scheduling is as follows:

(1) Construction preparation, temporary power utilization line, temporary water supply and drainage engineering: and 5, on a calendar day, the main construction contents comprise office area construction, hydropower access, temporary road arrangement, solidification/stabilization area construction, negative pressure airtight greenhouse construction, waste water treatment temporary facility construction and drainage pipeline construction, and the construction progress is ensured, more labor force is input at the stage, and multi-stage simultaneous construction is carried out.

(2) And (3) equipment installation and debugging: and 5, on a calendar day, the main construction content is the entrance and the debugging of screening and crushing equipment and soil stirring equipment, the debugging of the equipment is responsible for a professional engineer, and the qualified debugging can be used for the solidification/stabilization treatment of the polluted soil.

(3) Cleaning and digging contaminated soil: 60 calendar days, this stage mainly involves the excavation and transportation of the in-situ ex-situ solidification/stabilization treatment soil; the construction period is partially overlapped with (4).

(4) In-situ curing/stabilization treatment: the solidification/stabilization repair is batch repair, and the total amount of the repaired earthwork is 766224m ³ The total repair period was 150 calendar days (including maintenance and inspection time). The main working content of the part is solidification/stabilization treatment of polluted soilThe solidification/stabilization treatment of the soil is started 5 days after the soil is excavated, the process is connected with the soil excavation working procedures of each polluted area block, the soil excavation working procedures are arranged in an overall mode, the foundation pit generated after excavation can be subjected to sampling acceptance check at the stage, and the foundation pit is backfilled with clean soil generated after acceptance check is qualified.

(5) And (5) acceptance checking: the main content of the part is sampling analysis, detection data arrangement, evaluation report preparation and the like.

(6) Backfilling: and backfilling the treated soil after acceptance, wherein the total construction period is 85 calendar days. The method comprises the steps of foundation pit arrangement and laying, and earth backfilling, and can be synchronously carried out with the above-mentioned processes.

(7) And (3) a refund: 2 calendar days.

From the above analysis, it can be seen that the embodiment of the present invention has greater advantages (see table 10 for details) in terms of energy consumption, carbon emission, construction cost, time-consuming construction and land value guarantee, and particularly has a great reduction in terms of energy consumption and carbon emission, and can realize low-carbon green.

Table 10 comparison of examples with comparative examples ^*

Sequence number	Category(s)	Unit (B)	Examples	Comparative example	Multiple of lifting
						1	Engineering ofEnergy consumption	t standard coal	216.01	9777.88	44.27
2	Carbon emission	t CO 2e	8545.90	15891212	1858.5
						3	Engineering cost	Wan Yuan	6511.90	73707.5	10.3
4	Land value	Wan Yuan	151410.97	22711.64	0.85
						5	Engineering is time-consuming	Tiantian (Chinese character of 'Tian')	150	240	0.6

Note that: neither the early nor late engineering conditions were calculated.

In summary, the embodiment of the invention can perform targeted risk management and control according to the actual pollution condition of the pollution site, and can realize the purposes of greatly shortening the safety utilization period and reducing the engineering energy consumption, carbon emission and cost by combining development and construction. Meanwhile, the risk management and control method of the embodiment of the invention constructs a waterproof curtain at the boundary of the pollution site to prevent the horizontal diffusion of pollutants, and is combined with the development and construction scheme, constructs a totally-enclosed barrier layer on the ground to prevent the diffusion of the pollutants to the atmosphere and the like for a series of treatments for cutting off the exposure path of the pollutants; the method has the advantages that when a building structure and a road bottom plate are used as a part of a barrier layer, earthwork is reasonably allocated through the 'super risk screening value earthwork overall allocation system' in the site construction process, so that the polluted earthwork is prevented from leaving the site, the land leveling is realized, the static pile construction is utilized to prevent heavy metal-containing dust from diffusing and the like, the underground pipeline corridor and the like are constructed to prevent municipal construction from disturbing polluted soil and the like, all possible exposure paths are ensured to be cut off, meanwhile, the normal use function of the land is not influenced, the land re-development and the safety utilization can be realized, the carbon emission and the energy consumption are reduced, the development time of 60% is shortened, the repair cost is reduced, and the land value is ensured.

Finally, it should be noted that the above-mentioned embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above-mentioned embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made to the specific embodiments of the present invention after reading the present specification, and these modifications and variations do not depart from the scope of the invention as claimed in the pending claims.

Claims (2)

1. The risk management and control method based on the safe utilization of the polluted site is characterized by comprising a construction planning method, wherein the construction planning method comprises the following steps of:

s101, acquiring pollution condition information of a pollution site;

s102, determining pollution condition range distribution and pollution site planning purposes, and making a pollution site target ground elevation which is at least 30-50 centimeters higher than that of a surrounding road according to the surrounding road elevation of the pollution site;

s103, setting a water collecting ditch around the polluted site;

s104, setting earthwork allocation planning according to pollution conditions, pollution ranges and future planning purposes of places;

s101, acquiring pollution condition information of a pollution site comprises the following steps:

Partitioning and fixing the pollution range according to the investigation result of the soil pollution condition of the land parcels and the heavy metal type, the pollution degree and the depth of the super-screening value, and determining the inflection point coordinates of each region range;

the determining pollution condition range distribution and pollution site planning purposes comprise:

setting a low-pollution area in a pollution site as a sensitive application area, and setting a high-pollution area in the pollution site as a non-sensitive application area;

the low pollution area is an excavated heavy metal non-standard exceeding area; the high pollution area is an excavated heavy metal exceeding area; the sensitive application area is used for living and children park sensitive application, and the non-sensitive application area is used for greening and public facilities;

s104, setting an earthwork deployment plan according to pollution conditions, pollution ranges and future planning purposes of a site, wherein the earthwork deployment plan comprises the following steps:

s1041, determining the area of an excavation area required by the construction of the polluted site building according to the planning purpose of the polluted site;

s1042, fitting the area of the excavated area and the distribution of the pollution condition range, and determining the change condition of the earthwork quantity at the area of the excavated area in the construction process;

the change condition at least comprises an earthwork excavation amount and an earthwork backfill amount;

s104, setting an earthwork deployment plan according to pollution conditions, pollution ranges and future planning purposes of a site, wherein the earthwork deployment plan further comprises:

S1043, taking a non-sensitive use area as a polluted earthwork backfill area, and carrying out extra polluted soil if the amount of the backfill earthwork which can be contained in the polluted earthwork backfill area is smaller than the earth excavation amount of the polluted soil;

the step S1043 of using the area with the non-sensitive use as the contaminated earth backfill area specifically includes:

s201, setting a polluted site as a polluted soil excavation area by taking the position of the polluted soil backfill area as a starting point, and determining the distance between the polluted soil excavation area and the starting point;

s202, determining the type and the pollution degree of pollutants in the earthwork excavated by the polluted site;

s203, dividing a polluted soil backfill area into a plurality of polluted soil backfill positions according to the same pollutant type and pollution degree;

the step S203, according to the same type of pollutant and the same pollution degree, is to divide the polluted soil backfill area into a plurality of polluted soil backfill positions, and includes: and backfilling the polluted soil with the same pollutant type and similar pollution degree at the backfill position of the same polluted soil.

2. The risk management and control method based on safe utilization of a contaminated site according to claim 1, wherein said s103. Setting a water collection ditch around the contaminated site further comprises:

designing a waterproof curtain based on the water collecting ditch, and setting the depth of the waterproof curtain to reach a groundwater waterproof layer if no underground facilities exist; if underground facilities exist, setting a waterproof curtain to reach the upper part of the underground facilities.

Images