CN109653240B - Urban residual mud and slag mound in ecological restoration project and its construction method - Google Patents

Abstract

The invention provides an urban residual mud and slag piling body and a construction method thereof in an ecological restoration project. The piling body comprises: a piling body body arranged on a base, a drainage blind pipe arranged in the piling body body, A retaining wall assembly arranged on at least one side of the stack body and a geogrid disposed above the retaining wall assembly, wherein, from bottom to top, between the fine round gravel soil layer and the base layer sequentially includes: geotextile Layer and cushion, the thickness of the cushion is 0.4-0.8m, and the cushion from bottom to top is: medium-coarse sand layer, sand and gravel layer and gravel layer, of which the longitudinal and transverse tensile fracture strength of geotextile layer is ≥12KN /m, longitudinal and transverse tearing strength ≥0.4KN, CBR bursting strength ≥1.5KN, gradient ratio GR≤3. According to the urban residual mud and slag pile in the ecological restoration project of the present invention, the stability of the entire pile is greatly improved, and the construction residual soil is reasonably used for the construction of the pile, which facilitates the more effective reconstruction of the ecological environment. , has a good application prospect.

Description

Urban residual mud and slag mound in ecological restoration project and its construction method

technical field

The invention relates to the technical field of garden architecture, in particular, to an urban residual mud and slag mound in an ecological restoration project and a construction method thereof

Background technique

With the rapid development of the economy and the continuous expansion of the city scale, the shortage of urban land and other problems have become prominent, and the development of urban underground space has been paid more and more attention. The continuous construction of underground buildings, structures, municipal transportation projects, etc., is accompanied by more and more residual construction waste. "Scum siege" has become a pain point in many cities, restricting the sustainable development of cities. Nowadays, the transformation of the ecological environment and the improvement of the living environment are increasingly being valued by the government. With the continuous development of the concept of urban construction in the future, how to "turn waste into treasure" and use the residual soil of urban construction to artificially build mountain mass engineering will have more and more extensive application prospects.

SUMMARY OF THE INVENTION

The present invention aims to solve one of the above-mentioned technical problems in the prior art at least to a certain extent. In view of this, one aspect of the present invention provides an urban residual mud and slag mound in an ecological restoration project that is easy to implement and has high reliability. Another aspect of the present invention provides a construction method for an urban residual mud and slag mound in an ecological restoration project.

According to the ecological restoration project of the present invention, the urban residual mud and slag soil stack includes: a stack body body arranged on the base, a drainage blind pipe arranged in the stack body body, and a stack body body arranged in the stack body body. At least one side retaining wall assembly and a geogrid disposed above the retaining wall assembly, the retaining wall assembly comprising: a Panax notoginseng lime soil layer with a thickness of 0.8m-1.2m, The modular reinforced soil retaining wall above the layer, the pebble flood intercepting ditch located on the Panax notoginseng soil layer and located outside the modular reinforced soil retaining wall, and the modular reinforced soil retaining wall and the The fine round gravel soil layer between the body of the stacking body, the permeable geotextile arranged above the fine round gravel soil layer, and the thick bagged bag set between the fine round gravel soil layer and the body of the stacking body Sand and gravel filter layer, wherein, from bottom to top, between the fine round gravel soil layer and the base layer sequentially includes: a geotextile layer and a cushion layer, the thickness of the cushion layer is 0.4-0.8m, the The cushion layers from bottom to top are: medium-coarse sand layer, sand sandwiched gravel layer and crushed stone layer, wherein the longitudinal and transverse tensile breaking strength of the geotextile layer is ≥12KN/m, and the longitudinal and transverse tearing strength is ≥0.4KN, CBR bursting strength≥1.5KN, gradient ratio GR≤3.

In the ecological restoration project according to the embodiment of the present invention, the stability of the entire piled body is greatly improved, and the residual construction soil is reasonably used for the construction of the piled body, which is convenient for more effective ecological restoration. The environment is transformed, and it has a good application prospect.

In addition, in the ecological restoration project according to the above-mentioned embodiment of the present invention, the urban residual mud and slag mound may also have the following additional technical features:

According to an embodiment of the present invention, a plurality of earth pressure cells are arranged in the fine round gravel soil layer, and displacement monitoring piles are arranged on the geogrid.

According to an embodiment of the present invention, the modular reinforced soil retaining wall includes a first modular reinforced soil retaining wall with a first predetermined height and a second modular reinforced soil retaining wall with a second predetermined height, The first modular reinforced soil retaining wall and the second modular reinforced soil retaining wall are constructed in a stepped shape to form a first-level retaining wall on one side of the first modular reinforced soil retaining wall assembly and forming a secondary retaining wall assembly on one side of the second modular reinforced earth retaining wall.

According to an embodiment of the present invention, a settling plate for monitoring the settlement of the base is provided in the stack body.

According to an embodiment of the present invention, the cushion layer is provided in a stepped shape.

According to the construction method of the urban residual mud and slag mound in the above-mentioned ecological restoration project, the following steps are included:

S1: The surface of the base is treated, and steps with a height of less than 0.6m and a width of greater than 1.0m are arranged on the base, and the steps correspond to the steep slope of the body of the stack;

S2: Compact the soil layer at the base of the body of the stack, replace with notoginseng lime soil at the base of the modular reinforced soil retaining wall and compact it, and lay it first within 20m-25m of the slope foot of the base A layer of geotextile, and then lay a cushion;

S3: Filling and compacting the body of the stacked body in different zones and layers, and the body of the stacked body is filled with silt, and the surrounding of the main peak of the stacked body is filled with clay, wherein the silt is filled with clay. The compaction coefficient K is not less than 0.9, the foundation coefficient K30 is not less than 80MPa/m; the thickness of the clay is 0.4m-0.6m, the compaction coefficient K is not less than 0.9, the foundation coefficient K30 is not less than 80MPa/m, and the layer thickness is 0.3m layer after compaction, after each layer of compaction, the compaction coefficient K and foundation coefficient K30 of the foundation shall be inspected, and the number of inspections shall not be less than ⁴ per 2000m2;

S4: Use the modular reinforced soil retaining wall for slope closing, and the height of the modular reinforced soil retaining wall used is 2.83m-7.02m;

S5: Use side slope inclusions to reinforce the side slopes of the stacked body that are steeper than 1:4, and set up gravel and mortar rubble foundations below the side slope inclusions;

S6: A drainage dead pipe is arranged at the lower part of the modular reinforced earth retaining wall, and a composite geomembrane is laid on the bottom of the drainage dead pipe.

According to the construction method of the urban residual mud and slag pile in the ecological restoration project according to the embodiment of the present invention, the stability of the whole pile is greatly improved, and the construction of the pile can be reasonably made use of the construction residual soil, which is convenient for a more effective It has a good application prospect for the transformation of the ecological environment.

In addition, the construction method of the urban residual mud and slag pile in the ecological restoration project according to the above-mentioned embodiment of the present invention may also have the following additional technical features:

According to an embodiment of the present invention, it further includes the following steps: S7: Determine the dimensions of the stacking body in the three directions of X, Y, and Z according to the project overview, establish a three-dimensional model, and divide the three-dimensional model by meshing the three-dimensional model. Multiple displacement monitoring points and multiple stress monitoring points are set in the model to analyze the stress, deformation and stability of the highest section of the modular reinforced soil retaining wall.

According to an embodiment of the present invention, settlement observation and horizontal displacement observation are carried out on the stack, so as to issue an alarm when at least one of the following conditions occurs:

The maximum horizontal displacement of the slope top of the slope supporting structure has been greater than 1/500 or 20mm of the fill height, and the horizontal displacement rate has been greater than 2mm/d for 3 consecutive days;

During the filling period, the surface settlement rate is greater than 10mm/d;

Signs that may lead to shear failure or other signs that may affect safety at the bottom of the slope or in the surrounding soil;

New cracks appear near the top of the slope;

Judging from experience, other situations have occurred that must be reported to the police.

According to an embodiment of the present invention, in S4, prefabricated concrete modules are arranged on the surface layer of the modular reinforced earth retaining wall, and expansion joints are provided between the adjacent prefabricated concrete blocks.

According to an embodiment of the present invention, in S5: the slope inclusion includes a biaxially oriented geogrid and a geotextile, and the biaxially oriented geogrid is filled with polypropylene with an amount of carbon black greater than 2%: the The blind drainage pipes are arranged in a plum blossom shape, and the composite geomembrane is made of non-woven geotextiles pasted with a high-density polyethylene film with carbon black added, and the film thickness of the high-density polyethylene film is greater than 0.3 mm.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

FIG. 1 is a schematic structural diagram of an urban residual mud and slag pile in an ecological restoration project according to an embodiment of the present invention.

2 is a schematic structural diagram of an urban residual mud and slag pile in an ecological restoration project according to another embodiment of the present invention;

FIG. 3 is an enlarged schematic view of A in FIG. 2 .

Fig. 4 is a flow chart of a construction method of an urban residual mud and slag pile in an ecological restoration project according to an embodiment of the present invention.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. The relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore It should not be construed as a limitation of the present invention.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of the two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may include the first and second features in direct contact, or may include the first and second features Not directly but through additional features between them. Also, the first feature being "above", "over" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature is "below", "below" and "below" the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature has a lower level than the second feature.

As shown in FIGS. 1-3 , the urban residual mud and slag soil stack 100 in the ecological restoration project according to the embodiment of the present invention includes: a stack body 10 provided on the base 200 , a stack body 10 provided on the stack body 10 The inner drainage blind pipe 11 , the retaining wall assembly arranged on at least one side of the stack body 10 , and the geogrid 30 disposed above the retaining wall assembly.

The retaining wall assembly may include: a Panax notoginseng lime soil layer 21 with a thickness of 0.8m-1.2m, a modular reinforced soil retaining wall 22 provided above the Panax notoginseng soil layer 21, a modular reinforced soil retaining wall 22 provided on the Panax notoginseng soil layer 21 and located in a modular The pebble flood intercepting ditch 23 outside the reinforced earth retaining wall 22, the fine round gravel soil layer 24 arranged between the modular reinforced earth retaining wall 22 and the stack body 10, the fine round gravel soil layer 24 arranged above the fine round gravel soil layer 24. The permeable geotextile 25 and the thick bagged sand and gravel filter layer 26 arranged between the fine round gravel soil layer 24 and the body 10 of the stacking body.

Among them, between the fine round gravel soil layer 24 and the base 200, from bottom to top, it includes: a geotextile layer 27 and a cushion layer 28, the thickness of the cushion layer 28 is 0.4-0.8m, and the cushion layer 28 from bottom to top is: Coarse sand layer, sand sandwiched gravel layer and gravel layer, of which the geotextile layer 27 has longitudinal and transverse tensile fracture strength ≥12KN/m, longitudinal and transverse tearing strength ≥0.4KN, CBR bursting strength ≥1.5KN, gradient ratio GR≤3.

As shown in FIG. 3 , the modular reinforced earth retaining wall 22 may include a first modular reinforced earth retaining wall 221 having a first predetermined height and a second modular reinforced earth retaining wall 222 having a second predetermined height, The first modular reinforced earth retaining wall 221 and the second modular reinforced earth retaining wall 222 are constructed in a stepped shape, so as to form the first-level retaining wall assembly 201 on one side of the first modular reinforced earth retaining wall and on the other side. One side of the second modular reinforced earth retaining wall 222 forms the secondary retaining wall assembly 202 .

According to the embodiment of the present invention, compared with the single-stage reinforced soil retaining wall, the two-stage reinforced soil retaining wall mainly has structural differences and damage model differences by setting the first-stage retaining wall assembly 201 and the second-stage retaining wall assembly 202 and three aspects of the design method.

Structural difference: The steps between the two-level reinforced earth retaining wall and the lower and lower walls interact with the reinforcement, the reinforcement and the wall panel filler, and together form the structure of the two-level reinforced earth retaining wall. Under the action of the step, the lower wall will be greatly affected by the load stress diffusion on the upper part of the retaining wall. For example, when the step width is large, the step effect is more obvious; when the step width is small, the two-stage retaining wall can also be regarded as a single-stage retaining wall. Step retaining walls are used for design, and the influence of steps is ignored.

Differences in failure models: The failures of two-level reinforced earth retaining walls are both independent and interrelated. Since the foundation of the upper wall is set on the wall of the lower wall, the bearing capacity and stability of the lower wall are directly related to the stability and safety of the upper wall. Less affected.

Referring to FIGS. 1-3 , it can be understood that during the construction of the stack body 100 , a modular reinforced soil retaining wall 22 may be set on one side of the stack body 10 to close the slope. The wall height of the wall 22 may be 2.83m-7.02m. The slope ratio of the reinforced soil retaining wall between the chest and the back is 1:0.05. The reinforcement material of the modular reinforced earth retaining wall 22 should be uniaxially stretched polyethylene plastic geogrid, the amount of carbon black is ≥2% and evenly distributed, the longitudinal ultimate tensile strength of the geogrid is ≥120KN/m, and the longitudinal standard is ≥120KN/m. Said elongation ≤ 11.5%. The length of the geogrid is 7m-9m, and the vertical spacing Sy=0.3m. The folded length of the geogrid shall not be less than 1.5m, the overlap between the panels shall be 0.1m, and the backfill shall be fixed on the filling soil with a distance of 1m by using saddle tacks. Reinforced earth retaining wall fill is clean and well-graded fine round gravel soil.

Further, under heavy rainfall conditions, the mountain seepage has a greater impact on the stability of the mountain. In order to reduce the impact, it is advisable to reduce the surface water seepage on the mountain and strengthen the discharge of groundwater in the mountain.

The maximum filling height within the main peak range has the lowest safety and stability, and requires key design. Therefore, an anti-seepage clay layer is added to reduce surface water infiltration and lead it to a safe area. The modular reinforced soil retaining wall 22 is made of fine round gravel soil, and the plumb-shaped drainage blind pipes are laid in the back of the wall to enhance the drainage of groundwater. Drainage cushions are set up in the range of 20m-30m from the foot of the slope around the mountain to the mountain to speed up the drainage of groundwater.

The blind drainage pipe 11 is suitable for being arranged at a position 3m above the cushion layer on the right side of the bagged sand and gravel filter layer. The composite geomembrane at the bottom of the blind ditch adopts a non-woven composite geomembrane, with two fabrics and one membrane structure. Composite geomembrane longitudinal and transverse tensile breaking strength ≥ 20KN/m, CBR bursting strength ≥ 2.5KN, vertical permeability coefficient ≤ 1.0×10-11cm/s, the membrane material is high-density polyethylene with carbon black added, and the film thickness ≥ 0.3mm.

The earth pressure of retaining wall, internal force of tie bars and mountain settlement and deformation (including foundation and body) can be continuously monitored during and after the filling of the stack. Through systematic observation, analysis and evaluation of the earth pressure of the retaining wall, the tensile force of the geogrid and the settlement deformation, the filling rate is guided and controlled during the filling process. Specifically, according to some embodiments of the present invention, a plurality of earth pressure cells 41 are provided in the fine round gravel soil layer 24 , and displacement monitoring piles 42 are provided on the geogrid 30 . A settling plate 43 for monitoring the settlement of the base 200 is provided in the stack body 10 .

According to an embodiment of the present invention, in order to facilitate construction, the cushion layer 28 may be provided in a stepped shape.

In the ecological restoration project according to the embodiment of the present invention, the urban residual mud and slag pile 100 has high stability of the entire pile, and the construction waste can be reasonably used for the construction of the pile, which is convenient for more effective ecological restoration. The environment is transformed, and it has a good application prospect.

The following describes the construction method of the urban residual mud and slag pile in the ecological restoration project according to the embodiment of the present invention with reference to FIG. 4 . The construction method is characterized in that, it includes the following steps:

S1: The surface of the base is treated, and steps with a height of less than 0.6m and a width of greater than 1.0m are arranged on the base, and the steps correspond to the steep slope of the body of the stack;

S2: Compact the soil layer at the base of the body of the stack, replace with notoginseng lime soil at the base of the modular reinforced soil retaining wall and compact it, and lay it first within 20m-25m of the slope foot of the base A layer of geotextile, and then lay a cushion;

S3: Filling and compacting the body of the stacked body in different zones and layers, and the body of the stacked body is filled with silt, and the surrounding of the main peak of the stacked body is filled with clay, wherein the silt is filled with clay. The compaction coefficient K is not less than 0.9, the foundation coefficient K30 is not less than 80MPa/m; the thickness of the clay is 0.4m-0.6m, the compaction coefficient K is not less than 0.9, the foundation coefficient K30 is not less than 80MPa/m, and the layer thickness is 0.3m layer after compaction, after each layer of compaction, the compaction coefficient K and foundation coefficient K30 of the foundation shall be inspected, and the number of inspections shall not be less than ⁴ per 2000m2;

S4: Use the modular reinforced soil retaining wall for slope closing, and the height of the modular reinforced soil retaining wall used is 2.83m-7.02m;

S5: Use side slope inclusions to reinforce the side slopes of the stacked body that are steeper than 1:4, and set up gravel and mortar rubble foundations below the side slope inclusions;

S6: A drainage dead pipe is arranged at the lower part of the modular reinforced earth retaining wall, and a composite geomembrane is laid on the bottom of the drainage dead pipe.

It is understandable that, before construction, the substrate (foundation) needs to be surface treated and reinforced, specifically:

Ground surface treatment:

1) Before the construction of mountain filling, drain the ground and level the ground; remove the topsoil from the original ground, backfill and compact according to the regulations, and the standards are the same as the mountain requirements;

2) The horizontal and vertical slopes of the mountain foundation are steeper than 1:10, and the base is dug with steps. The height of the steps is not more than 0.6m, the width of the steps is not less than 1.0m, and the bottom of the steps is set with a slope of 4% inclined outward.

Ground reinforcement treatment:

1) Set up a 300m two-level reinforced retaining wall along the mountain slope of the provincial road, and excavate and replace the base of the first-level reinforced soil retaining wall with not less than 1.0m thick Panax notoginseng soil + heavy rolling. Panax notoginseng lime soil adopts excavated original foundation soil, and after removing broken bricks, 30% (proportion by volume) ash is added on the spot to improve. The compaction standard of Panax notoginseng lime soil adopts the compaction coefficient K of not less than 0.90, and the 7d saturated unconfined compressive strength of not less than 300kPa. The characteristic value of the foundation bearing capacity of the foundation after replacement of Panax notoginseng lime soil reaches 180kPa.

2) The mountain base fill layer shall be compacted. The base of the section with the fill layer thickness greater than 2.5m shall be compacted by impact rolling, and the other sections shall be compacted by heavy rolling. The compaction coefficient of the foundation after rolling shall not be less than 0.9.

3) Above the original ground on the southern slope of the mountain, lay a layer of geotextile + 0.6m thick cushion (0.15m thick medium and coarse sand + 0.15m thick sand with gravel + 0.3m thick gravel) within 20~25m of the foot of the slope, Steep sections need to be treated with stepped cushion.

When filling the body 10 of the stack, the filling can be divided into two parts, the mountain body silt filling and the mountain surface clay filling; the water content of the filling should be strictly controlled before construction, and when the water content of the filling is greater than the maximum When the water content is excellent, measures such as loosening, drying, air-drying or soil replacement and backfilling, and evenly mixing dry soil are used to reduce the water content. Refill when there is water. If the water content is low, it can be moistened with pre-sprinkling water. Strictly control the water content of the filler to ensure the quality of earthwork filling in the mountain; the mountain mass is mainly built by impact rolling, and heavy rolling is used locally; the mountain body is filled with silt, the compaction coefficient K is not less than 0.9, and the foundation coefficient K30 is not less than 80MPa/m; the surface of the mountain is filled with 0.5m thick clay, the compaction coefficient K is not less than 0.9, and the foundation coefficient K30 is not less than 80MPa/m; For compaction, the layer thickness is 0.3m after compaction. After each compaction layer, the compaction coefficient K and the foundation coefficient K30 of the foundation are tested for the compaction quality, and the number of inspections is not less than ⁴ per 2000m2. The surface of the mountain is filled with 0.5m of clay according to the design requirements. The filling method is that each section of 15m-20m of mountain silt is filled and rolled, and then trimmed by an excavator, and then laid with clay for leveling (divided into two layers of soil and rolling). Pressing), and finally use the road roller to compact along the contour line (when the road roller is inclined not more than 10 degrees), and when it is more than 10 degrees, it is rolled up and down.

When protecting the slope of the stack, the slope of the mountain is reinforced with geogrids with a width of 6.0m and a layer spacing of 0.6m. The geogrid adopts biaxially stretched plastic geogrid, the material is polypropylene with carbon black added, the carbon black content is ≥2% and evenly distributed, the longitudinal and transverse tensile strengths are not less than 50kN/m, and the longitudinal/horizontal standard Said elongation ≤ 15/13%.

The surface of the mountain is covered with easily degradable three-dimensional geonet mats, the width of the mats is not less than 5.0m, and the basic properties of the materials meet the relevant requirements. Vertically and horizontally every 1m or so, use bamboo nails no shorter than 15cm to vertically drive into the slope to fix the mesh pad; the overlap width of the mesh pad is not less than 2cm, and the overlapping parts are properly encrypted with bamboo nails. After the laying is completed, it is necessary to ram the slope surface once, so that the mesh pad is closely attached to the slope surface, and grass seeds are sown on the mountain surface for greening.

排水管，山体雨水能顺利排入截洪沟内。Reinforcement at the foot of the slope: the east, west and south slopes of the mountain are set with pebble flood intercepting ditch and the retaining wall at the foot of the slope, and the retaining wall at the foot of the slope is set

Drainage pipes, the rainwater from the mountain can be smoothly discharged into the flood intercepting ditch.

For the setting of drainage blind pipes, vertical drainage blind pipes are set at suitable positions 3m above the right cushion of the bagged sand and gravel filter layer. The composite geomembrane at the bottom of the blind ditch adopts a non-woven composite geomembrane, with two fabrics and one membrane structure. Composite geomembrane longitudinal and transverse tensile breaking strength ≥ 20KN/m, CBR bursting strength ≥ 2.5KN, vertical permeability coefficient ≤ 1.0×10-11cm/s, the membrane material is high-density polyethylene with carbon black added, and the film thickness ≥ 0.3mm. A layer of drainage cushion with a thickness of 0.6m shall be laid within the range of 20-25m above the slope foot of the mountain slope, which shall be discharged into the pebble flood interception ditch through the PVC drainage pipe.

When testing the stack, a layer of 0.6m-thick drainage cushion should be laid within 20-25m above the ground on the west and south slopes of the mountain, and then drained into the pebble flood interception ditch through PVC drainage pipes. The horizontal and vertical displacement observation piles at the top of the slope are made of pine logs with a diameter of 100 mm and a length of 1 m. A small steel nail is embedded in the center of the top of the pile. The displacement observation piles at the toe of the slope and the outer side of the retaining wall can be laid out after the construction starts. The displacement observation piles at the toe of the slope and the top of the retaining wall shall be buried after the construction reaches the corresponding elevation, and the initial readings shall be tested.

The foundation settlement and slope top displacement of this project shall be measured according to the requirements of the third-level displacement monitoring network. The crack measurement was used to measure the development of surface cracks within the range of 1.5H (H is the height of the slope) at the top of the retaining wall. The monitoring accuracy is not less than 1mm.

The earth pressure sensor should be calibrated before installation. When installing, put the stress-bearing membrane (pressure-bearing membrane) of the earth pressure box facing up, fill the bottom of the earth pressure box with about 5cm of medium-fine sand to compact it, and use a level ruler to control the earth pressure. The box is installed horizontally. After the earth pressure box is installed, cover it with 10cm thick medium-fine sand and compact it. The accuracy of the pressure monitoring sensor (earth pressure box) should not be greater than 5% FS (full scale);

The flexible displacement meter should be calibrated before installation. When the lower layer of the geogrid is filled and compacted, the geogrid should be laid on the flat surface after the filling and rolling according to the design length, and the flexible displacement meter should be firmly installed. The bottom of the meter is flat and dense. Cover it with 20cm of fine or medium sand for compaction. The test accuracy of the flexible displacement meter should not be greater than 0.01m.

Monitor the frequency and period. After all components are buried, the initial reading must be tested. Before the mountain is officially filled, all components must be re-tested as the official initial reading. The frequency of monitoring engineering observation should meet the requirements of the construction stage, and should be observed in time when the external environmental conditions (weather, construction, etc.) change. The settlement and deformation observation period shall be no less than 6 months after the filling is completed, and a rainy season shall pass.

Monitoring technical standards and warning values, working datum points shall be accurately measured according to the requirements of the second-class leveling survey, and settlement observation and horizontal displacement observation shall be accurately measured according to the requirements of the third-level leveling survey. If you encounter one of the following situations that may affect the safety of the foundation pit, you should immediately call the police:

The maximum horizontal displacement of the slope top of the slope supporting structure has been greater than 1/500 or 20mm of the fill height, and the horizontal displacement rate has been greater than 2mm/d for 3 consecutive days;

During the filling period, the surface settlement rate is greater than 10mm/d;

The bottom of the slope or the surrounding soil shows signs that may lead to shear failure or other signs that may affect safety (such as a small amount of quicksand, soil gushing, uplift, collapse, etc.);

New cracks appear near the top of the slope;

Judging from experience, other situations have occurred that must be reported to the police.

According to an embodiment of the present invention, the construction method of the urban residual mud and slag mound in the ecological restoration project further includes the following steps: S7: Determine the dimensions of the mound in the three directions of X, Y, and Z according to the general situation of the project, and establish Three-dimensional model, after dividing the three-dimensional model into a grid, by setting multiple displacement monitoring points and multiple stress monitoring points in the three-dimensional model, the stress, deformation and stability of the highest section of the modular reinforced soil retaining wall are sex analysis.

According to an embodiment of the present invention, in S4, prefabricated concrete modules are arranged on the surface layer of the modular reinforced earth retaining wall, and expansion joints are provided between the adjacent prefabricated concrete blocks.

According to an embodiment of the present invention, in S5: the slope inclusion includes a biaxially oriented geogrid and a geotextile, and the biaxially oriented geogrid is filled with polypropylene with an amount of carbon black greater than 2%: the The blind drainage pipes are arranged in a plum blossom shape, and the composite geomembrane is made of non-woven geotextiles pasted with a high-density polyethylene film with carbon black added, and the film thickness of the high-density polyethylene film is greater than 0.3 mm.

It can be understood that, in S1, the surface of the base is processed, and steps are provided on the base, and the steps correspond to the steep slope of the stack. S1 can be understood as: the steps of treating the surface of the foundation. Specifically, before the filling construction of a stacked body, such as a mountain, the surface should be drained and the ground should be leveled; , compaction, its standards are the same as the mountain requirements. The lateral and longitudinal slopes of the mountain foundation are steeper than 1:10, and the base should be dug with steps. The height of the steps should be less than 0.6m, the width of the steps should be greater than 1.0m, and the bottom of the steps should have a slope of 4% inclined outward.

In S2, compaction is carried out on the base fill layer of the stacking body, and the base of the modular reinforced soil retaining wall is replaced with Panax notoginseng lime soil and compacted, and the base is first laid within the range of 20m-25m from the slope foot of the base. A layer of geotextile, and then laying a cushion, the cushion can be set into a step shape. S2 can be understood as the step of reinforcing the foundation. Specifically, the replaced Panax notoginseng lime soil can be excavated at the base of the modular reinforced soil retaining wall and heavy-duty rolling is used. Notoginseng lime soil was improved by mixing ash with the excavated original foundation soil. The characteristic value of the foundation bearing capacity of the foundation soil on the bottom surface of Panax notoginseng lime soil after rolling is required to reach 150kPa, and the characteristic value of the foundation bearing capacity of the foundation after replacement with notoginseng lime soil is required to reach 180kPa. The mountain base fill layer shall be compacted. The base of the section with the fill layer thickness greater than 2.5m shall be compacted by impact rolling, and the other sections shall be compacted by heavy rolling. The compaction coefficient of the foundation after rolling shall not be less than 0.9.

In S3, the stacked body is filled and compacted in layers, and the stacked body is filled with silt, and the surrounding of the main peak of the stacked body is filled with clay. S3 can be understood as: the step of filling the stack. Specifically, the stack can be understood as a mountain. The main peak of the mountain is filled with clay with a thickness of more than 0.6m, the compaction coefficient K is not less than 0.9, and the foundation coefficient K30 is not recommended. less than 80MPa/m. The mountain can be filled with silt, the compaction coefficient K is not less than 0.9, and the foundation coefficient K30 is recommended not to be less than 80MPa/m. The mountain filling needs to be filled in different layers and compacted. The compaction standard of the packing adopts the combination of the compaction coefficient and the foundation coefficient as the control index.

In S4, the modular reinforced soil retaining wall is used for slope closing, and the height of the adopted modular reinforced soil retaining wall is 2.83m-7.02m.

In S5, slope inclusions are used to reinforce the side slopes of the stacked body that are steeper than 1:4, and gravel and mortar rubble foundations are set under the slope inclusions; S5 can be understood as: slope protection Steps, specifically, the slope of the mountain body steeper than 1:4 is reinforced with inclusions, and every 0.3m layer is wrapped with geogrid and geotextile, and the width is not less than 4.0m.

In S6, a drainage blind pipe is set at the lower part of the modular reinforced earth retaining wall, and a composite geomembrane is laid at the bottom of the drainage blind pipe. S5 can be understood as: the steps of the mountain drainage project.

According to the construction method of the stack body according to the embodiment of the present invention, the stability of the whole stack body is greatly improved, the residual construction soil is reasonably used for the stack body construction, the ecological environment can be transformed more effectively, and the application prospects.

According to an embodiment of the present invention, in S2, the mountain base is laid with a layer of cushion within the range of 20m-25m at the foot of the slope, wherein the thickness of medium and coarse sand can be 0.15m, and the thickness of thick sand with gravel can be 0.15m , The thickness of the thick gravel can be 0.3m, a layer of geotextile is laid on the surface of the cushion, and the steeper section needs to be treated with a stepped cushion.

According to one embodiment of the present invention, for example, according to the project overview, the height of the reinforced earth retaining wall is 2.83-7.02m. Choose a thicker fill. The width of the entire model (X direction) is 60m, and the width outside the bottom of the retaining wall is 10.8m; the vertical (Z direction) is zero to the bottom of the model; the horizontal thickness (Y direction) is 0.5m.

This numerical calculation can use the FLAC3D fast Lagrangian difference analysis software. According to the above model and the size of each geological element, a fake 3D model was established with the help of ansys software, and after dividing the mesh, it was imported into FLAC3D for calculation and post-processing. The built model is shown in Figure 2. The element type is hexahedral element, and the model has a total of 7836 nodes and 3796 elements.

According to the characteristics of the slope and the reinforced soil retaining wall, three displacement monitoring points 1, 2 and 3 are set up, which are located at the top of the fill, the middle of the slope, and the top of the reinforced soil retaining wall. , the depth is 10m; a total of 3 stress monitoring points 4, 5 and 6 are set, which are located at the contact interface between the concrete panel and the filler. The No. 4 measuring point is located 2.5m down from the top of the reinforced soil retaining wall, and the No. 5 measuring point is located in the reinforced soil. The top of the retaining wall is 5m down, and the No. 6 measuring point is located at the junction of the bottom of the concrete panel and the filling of the reinforced soil retaining wall. Geogrid is a structural unit, and monitoring points cannot be arranged in it, and its stress can be displayed by calculation results.

Using the FLAC3D fast Lagrangian differential analysis software, the following work is carried out with the above model and material parameters:

First, the initial stress field calculation. In this state, the elastic model is used to calculate the initial stress field in the natural state, and the formation is consolidated under the self-weight stress field. Through the calculation results, namely stress field and displacement field, it can be judged whether the model is normal or not.

Second, the calculation of the reinforced earth retaining wall. Clear the displacement field generated in the previous stage to prepare for the calculation of this stage. This state activates the geogrid structural element geogrid. The deformation and stability of retaining walls and slopes were calculated using the Moore-Coulomb model.

Third, the calculation is carried out in the following cases.

(1) Elastic modulus of different geogrids: 10GPa, 26GPa, 52GPa, 78GPa.

(2) Different geogrid spacing: 30cm, 45cm, 60cm, 75cm.

(3) Cohesion of different reinforced soil retaining wall fillers: 0, 0.1kPa, 1kPa, 10kPa.

(4) Elastic modulus of different reinforced soil retaining wall fillers: 1MPa, 10MPa, 50MPa, 100MPa.

(5) Friction angles of different reinforced soil retaining wall fillers: 20°, 25°, 30°, 35°.

According to an embodiment of the present invention, the numerical simulation calculation mainly analyzes the highest section of the reinforced soil retaining wall, which is the most dangerous section of the slope of the entire reinforced soil retaining wall. As long as the deformation and stability of the modified section meet the safety requirements, the entire reinforced earth retaining wall slope meets the safety requirements. In addition, considering different geogrid strength parameters, different geogrid spacing, and different reinforced soil retaining wall filler strength parameters, the influence of these parameters on the deformation and stability of the reinforced soil retaining wall was analyzed. Due to the long calculation time of the strength reduction iterative method used in the calculation of the stability safety factor, this numerical calculation only calculates and analyzes the stability safety factor of the most unfavorable section under the adopted state parameters.

Because the numerical calculation cannot accurately calculate the construction deformation of the soil layer in the process of stratified rolling, the elastic model is used in this numerical calculation to clear the displacement field after equilibrium, and then the Moore-Coulomb model is used to calculate the final deformation and stability. In view of the purpose and effect of numerical calculation, the displacement field can qualitatively reflect the deformation trend, but quantitatively there may be some errors with the actual deformation, especially when considering the load. Compared with the design calculation, the numerical calculation stability safety factor calculation process adopts the strength reduction method, so it can better reflect the actual failure process of the slope, and the stability analysis is more reliable than the design calculation. The most unfavorable section analysis: Calculate the initial stress field in the natural state. If the stress field is uniformly distributed in layers, there is no abnormal state, and the stress increases with the deeper the formation. It shows that the numerical calculation model has no mesh division error, and the next calculation can be carried out.

No overload condition:

Displacement analysis shows that the larger displacement area is within about 30m of the reinforced earth retaining wall and the slope behind it. The total displacement of the reinforced soil retaining wall is in the range of 16mm-28mm. Due to the thrust of the retaining wall, the soil displacement of the back pressure in front of the bottom corner of the retaining wall is the largest, which is manifested as uplift, and the maximum uplift is about 35mm; The largest position of soil displacement is on the slope surface layer behind the top of the reinforced earth retaining wall, the maximum horizontal displacement is about 12mm, and the maximum settlement is about 20mm. The displacement of the reinforced soil retaining wall is smaller than that of the soil behind the wall, and the difference between the upper and lower displacements of the retaining wall is small. The displacement vector field shows that the displacement vector field of the slope and retaining wall is relatively uniform, and there is no region with sudden displacement. If the displacement curves of the retaining wall and the slope body are similar with the calculation process, they are both increasing with the calculation process. The displacements are very close. At the beginning, the settlement of the top of the reinforced earth retaining wall is very slow, the settlement of the slope is relatively sudden, and the settlement rate of the retaining wall becomes larger after a certain period of time. This is because the deformation of the concrete structure of the retaining wall itself is very small. Deformation of the retaining wall occurs only after the soil is deformed. Finally, the settlement of the top of the wall is smaller than that of the slope, and the settlement of the monitoring points is less than 9mm.

The stress analysis shows that the maximum principal stress concentration occurs at the bottom of the reinforced soil retaining wall and the filling in the middle and lower parts of the retaining wall. The stress concentration at the bottom of the wall is caused by the thrust of the retaining wall, and the stress concentration of the retaining wall filling is due to the sliding force of the slope acting on the rear of the entire reinforced soil filling, indicating that the reinforced soil retaining wall plays a good role in blocking the slope. Effect. The panel of the reinforced soil retaining wall is a small principal stress concentration area. Due to the thrust of the soil behind the retaining wall, the retaining wall handles the tension trend and appears tensile stress, but the value of the tensile stress is small.

Stability analysis shows that the shear strain rate of the reinforced soil retaining wall and the slope does not appear to increase significantly, and the shear strain between the retaining wall layer and the filling increases due to the extrusion effect. The ground shear strain rate at the front edge of the bottom of the retaining wall is relatively large, which is caused by the excessive ground uplift there, so gravity backpressure measures should be taken.

According to an embodiment of the present invention, the sand and gravel are packed with inclusions, the inclusions are plastic woven bags, and the ballast width of the inclusions is greater than 0.5 m. Thereby, the construction can be facilitated and the construction cost can be reduced.

According to an embodiment of the present invention, in S4, the modular reinforced earth retaining wall includes a geogrid made of uniaxially stretched polyethylene plastic with a carbon black content of ≥2%, and the geogrid is 7m-9m long, The vertical spacing is greater than 0.3m, the folded length of the geogrid is greater than 1.5m, and the overlap between the panels is greater than 0.1m. Preferably, the filler in the modular reinforced earth retaining wall adopts fine round gravel soil. Preferably, in S4, prefabricated concrete modules are arranged on the surface layer of the modular reinforced earth retaining wall, and expansion joints are provided between the adjacent prefabricated concrete blocks. The geogrid adopts biaxially stretched plastic geogrid, the material is polypropylene with carbon black added, the carbon black content is greater than or equal to 2% and evenly distributed, the longitudinal and transverse tensile strength is not less than 50kN/m, the longitudinal/transverse The nominal elongation is less than or equal to 15/13%. The geotextile is made of non-woven geotextile. The longitudinal and transverse tensile breaking strength of the geotextile is greater than or equal to 12KN/m, the longitudinal and transverse tearing strength is greater than or equal to 0.4KN, the bursting strength of CBR is greater than or equal to 1.5KN, and the gradient ratio GR is less than or equal to 3. The gravel and mortar rubble foundations are set below the inclusions. The section size of the gravel foundation is 1.4*0.15m, and the section size of the mortar rubble foundation is 1.6*0.15m. It can be understood that the scheme of modular reinforced soil retaining wall is a relatively simple process technology and construction equipment, and consumes less material, the construction period is short and the impact on pipeline engineering is small. Therefore, the stability of the structure of the stack can be effectively ensured, and this structure is more conducive to promotion and use.

It is understandable that under heavy rainfall conditions, the mountain seepage has a great influence on the stability of the mountain. In order to reduce the impact, it is advisable to reduce the infiltration of the surface water on the mountain and strengthen the drainage of groundwater in the mountain.

The maximum filling height within the main peak range has the lowest safety and stability, and requires key design. Therefore, an anti-seepage clay layer is added to reduce surface water infiltration and lead it to a safe area. The modular reinforced soil retaining wall is made of fine round gravel soil, and the back of the wall is laid with a plum-shaped blind pipe in the mountain to enhance the drainage of groundwater. Drainage cushions are set up in the 20-30m range from the foot of the slope around the mountain to the mountain to speed up the drainage of groundwater.

According to an embodiment of the present invention, in S5: the slope inclusion includes a biaxially oriented geogrid and a geotextile, and the biaxially oriented geogrid is filled with polypropylene with a carbon black content greater than 2%. Specifically, the geogrid is made of biaxially stretched plastic geogrid, the material is polypropylene with carbon black added, the carbon black content is greater than 2% and is evenly distributed, the longitudinal and transverse tensile strength / The nominal elongation in transverse direction is less than or equal to 15/13%. The geotextile is made of non-woven geotextile. The longitudinal and transverse tensile breaking strength of the geotextile is greater than or equal to 12KN/m, the longitudinal and transverse tearing strength is greater than or equal to 0.4KN, the bursting strength of CBR is greater than or equal to 1.5KN, and the gradient ratio GR is less than or equal to 3. The gravel and mortar rubble foundations are set below the inclusions. The section size of the gravel foundation is 1.4*0.15m, and the section size of the mortar rubble foundation is 1.6*0.15m. Thereby, the overall stability of the stack can be improved.

According to an embodiment of the present invention, in S6: the drainage blind pipes are arranged in a plum blossom shape, and the composite geomembrane is made of non-woven geotextiles pasted with a high-density polyethylene film with carbon black added. The film thickness is greater than 0.3mm. Specifically, a vertical drainage blind pipe is set at a suitable position 3m above the cushion on the right side of the bagged sand and gravel filter layer. The section of the blind ditch is 0.3m*0.3m, and the longitudinal spacing is 5m, which is arranged in a plum blossom shape. The composite geomembrane at the bottom of the blind ditch adopts a non-woven composite geomembrane, with two fabrics and one membrane structure. The longitudinal and transverse tensile breaking strength of composite geomembrane is greater than or equal to 20KN/m, the bursting strength of CBR is greater than or equal to 2.5KN, and the vertical permeability coefficient is less than or equal to 1.0×10-11cm/s. The film thickness is greater than or equal to 0.3mm. Geotextile specifications are the same as non-woven geotextiles in slope protection.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims (10)

1. an urban residual mud and slag mound in an ecological restoration project is characterized in that, comprising: the mound body that is arranged on the base, the drainage blind pipe that is positioned in the described mound body, the The retaining wall assembly on the side of at least one side of the stack body and the geogrid arranged above the retaining wall assembly, the retaining wall assembly includes: a Panax notoginseng lime soil layer with a thickness of 0.8m-1.2m, a The modular reinforced soil retaining wall above the Panax notoginseng soil layer, the pebble flood intercepting ditch located on the Panax notoginseng soil layer and located outside the modular reinforced soil retaining wall, and the The fine round gravel soil layer between the reinforced soil retaining wall and the body of the stack body, the permeable geotextile arranged above the fine round gravel soil layer, and the permeable geotextile provided between the fine round gravel soil layer and the body of the stack body The thick bagged sand and gravel filter layer between the layers, wherein, between the fine round gravel soil layer and the base layer, from bottom to top, it includes: a geotextile layer and a cushion layer, and the thickness of the cushion layer is 0.4- 0.8m, the cushion layers from bottom to top are: medium-coarse sand layer, sand sandwiched gravel layer and crushed stone layer, wherein the longitudinal and transverse tensile fracture strength of the geotextile layer is ≥12KN/m, and the longitudinal and transverse tearing Strength ≥0.4KN, CBR bursting strength ≥1.5KN, gradient ratio GR≤3. 2 . The urban residual mud and slag soil stack in the ecological restoration project according to claim 1 , wherein a plurality of earth pressure cells are arranged in the fine round gravel soil layer, and a plurality of earth pressure cells are arranged on the geogrid. Equipped with displacement monitoring piles. 3 . The urban residual mud and slag building body in the ecological restoration project according to claim 1 , wherein the modular reinforced soil retaining wall comprises a first modular reinforced soil retaining wall with a first predetermined height. 4 . wall and a second modular reinforced earth retaining wall having a second predetermined height, the first modular reinforced earth retaining wall and the second modular reinforced earth retaining wall are configured in a stepped shape to A primary retaining wall assembly is formed on one side of the first modular reinforced earth retaining wall and a secondary retaining wall assembly is formed on one side of the second modular reinforced earth retaining wall. 4 . The urban residual mud and slag soil stack in an ecological restoration project according to claim 1 , wherein a settlement plate for monitoring the settlement of the base is provided in the body of the stack. 5 . 5 . The urban residual mud and slag pile in the ecological restoration project according to claim 1 , wherein the cushion layer is arranged in a stepped shape. 6 . 6. according to the construction method of urban residual mud and slag mound in the ecological restoration project according to any one of claims 1-5, it is characterized in that, comprising the following steps: S1: The surface of the base is treated, and steps with a height of less than 0.6m and a width of greater than 1.0m are arranged on the base, and the steps correspond to the steep slope of the body of the stack; S2: Compact the soil layer at the base of the body of the stack, replace with notoginseng lime soil at the base of the modular reinforced soil retaining wall and compact it, and lay it first within 20m-25m of the slope foot of the base A layer of geotextile, and then lay a cushion; S3: Filling and compacting the body of the stacked body in different zones and layers, and the body of the stacked body is filled with silt, and the surrounding of the main peak of the stacked body is filled with clay, wherein the silt is filled with clay. The compaction coefficient K is not less than 0.9, the foundation coefficient K30 is not less than 80MPa/m; the thickness of the clay is 0.4m-0.6m, the compaction coefficient K is not less than 0.9, the foundation coefficient K30 is not less than 80MPa/m, and the layer thickness is 0.3m layer after compaction, after each layer of compaction, the compaction coefficient K and foundation coefficient K30 of the foundation shall be inspected, and the number of inspections shall not be less than ⁴ per 2000m2; S4: Use the modular reinforced soil retaining wall for slope closing, and the height of the modular reinforced soil retaining wall used is 2.83m-7.02m; S5: Use side slope inclusions to reinforce the side slopes of the stacked body that are steeper than 1:4, and set up gravel and mortar rubble foundations below the side slope inclusions; S6: A drainage dead pipe is arranged at the lower part of the modular reinforced earth retaining wall, and a composite geomembrane is laid on the bottom of the drainage dead pipe. 7. The construction method of the urban residual mud and slag pile in the ecological restoration project according to claim 6, it is characterized in that, further comprises the following steps: S7: determine three piles X, Y, Z according to the general situation of the project The size of the direction, establish a three-dimensional model, after dividing the three-dimensional model into a grid, by setting a plurality of displacement monitoring points and a plurality of stress monitoring points in the three-dimensional model, the maximum section of the modular reinforced soil retaining wall is subjected to stress. Force, deformation and stability are analyzed. 8. the construction method of the urban residual mud and slag mound in the ecological restoration project according to claim 6, is characterized in that, carry out settlement observation and horizontal displacement observation to the mound, so that when the following at least one situation occurs Send an alarm: The maximum horizontal displacement of the slope top of the slope supporting structure has been greater than 1/500 or 20mm of the fill height, and the horizontal displacement rate has been greater than 2mm/d for 3 consecutive days; During the filling period, the surface settlement rate is greater than 10mm/d; Signs that may lead to shear failure or other signs that may affect safety at the bottom of the slope or in the surrounding soil; New cracks appear near the top of the slope; Judging from experience, other situations have occurred that must be reported to the police. 9. The construction method of the urban residual mud and slag pile in the ecological restoration project according to claim 6, wherein in S4, prefabricated concrete modules are arranged on the surface layer of the modular reinforced soil retaining wall, And expansion joints are arranged between the adjacent concrete prefabricated blocks. 10. The construction method of the urban residual mud and slag pile in the ecological restoration project according to claim 6, wherein in S5: the side slope inclusion comprises a biaxially stretched geogrid and a geotextile, so the The biaxially oriented geogrid is filled with polypropylene with a carbon black content of more than 2%: the drainage blind pipes are arranged in a plum blossom shape, and the composite geomembrane is made of non-woven geotextiles pasted with high-density polyethylene film with carbon black added , the film thickness of high-density polyethylene film is greater than 0.3mm.

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