CN108129080A - A kind of cement bonded sand cream suitable for rich water karst large-cavity strata anti-seepage reinforcing is starched - Google Patents

Abstract

The invention discloses a cement mortar slurry suitable for anti-seepage and reinforcement of water-rich karst large-pore formations. The composition of the anti-seepage and reinforcement cement mortar slurry includes: water, cement, sand and modifiers. The cement 1. The weight ratio of sand and modifying agent is 1:0.4-0.75:0.01-0.0125, and the modifying agent component is a mineral additive, and the mineral additive is mainly sodium aluminate. The product of the present invention has stable slurry basic properties in the application of water-rich karst large-pore formation anti-seepage reinforcement, the setting time and fluidity of the slurry can be adjusted, the anti-water flow flushing performance is good, the stone rate and strength are high, and the cost of slurry materials is low. It is equivalent to ordinary cement paste, but its superior stability and erosion resistance greatly reduce slurry consumption, reduce engineering costs, and have social benefits such as environmental protection.

Description

A cement mortar slurry suitable for anti-seepage and reinforcement of water-rich karst large-porosity strata

technical field

The invention relates to the fields of grouting such as geotechnical engineering and water conservancy engineering foundation treatment, and in particular to a cement mortar slurry suitable for anti-seepage and reinforcement of water-rich karst large-pore formations.

Background technique

In geotechnical engineering and foundation treatment of water conservancy engineering, the filling, anti-seepage and reinforcement of water-rich karst strata with large pores are often encountered problems. For example, in the basic engineering treatment of karst caves in dam foundations, underground powerhouses, karst around tunnels, and anti-seepage reinforcement of embankments of rivers and lakes, most of the research results are on the level of ordinary cement mortar and quick-setting slurry materials. Although ordinary cement mortar has certain advantages in technology, economy and ecology, it has disadvantages such as low plastic viscosity and yield stress in the early stage, long setting time of slurry material, and weak resistance to water flow erosion. Quick-setting slurry materials have the advantages of controllable setting time and good resistance to water flow erosion, but the range of cut-off seepage channels is limited, and the seepage flow cannot be effectively controlled, and the cost of quick-setting slurry materials is high, and for water-rich karst large The foundation treatment of porous strata requires a large amount of slurry material for pouring.

Therefore, there is an urgent need to study a cement mortar slurry with adjustable setting time and fluidity, good water flow resistance and low price, so as to meet the actual needs.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology, and provide a kind of slurry with stable basic properties, adjustable slurry setting time and fluidity, good anti-flushing performance of water flow, high calculus rate and It has higher strength and the cost of slurry materials is equivalent to that of ordinary cement slurry, but its superior stability and erosion resistance greatly reduce slurry consumption and project costs, and it has social benefits such as environmental protection. Cement mortar slurry.

In order to solve the problems of the technologies described above, the technical solution proposed by the present invention is:

A cement mortar slurry suitable for anti-seepage and reinforcement of water-rich karst macroporous formations, the composition of the anti-seepage and reinforcement cement mortar slurry includes: water, cement, sand and modifier, and the cement, sand and modified The weight ratio of the modifier is 1:0.4-0.75:0.01-0.0125, and the modifying agent component is a mineral additive, and the mineral additive includes sodium aluminate.

For the above-mentioned anti-seepage and reinforced cement mortar slurry, preferably, the weight ratio of the water, cement, sand and modifier is 1:1:0.4-0.75:0.01-0.0125.

For the above-mentioned anti-seepage and reinforced cement mortar slurry, preferably, the ratio of the total mass of cement and sand to the mass of water is (1.4-1.75):1.

For the above-mentioned anti-seepage and reinforced cement mortar slurry, preferably, the ratio of the total mass of the cement, sand and modifier to the mass of water is (1.41-1.762):1.

For the above-mentioned anti-seepage and reinforced cement mortar slurry, preferably, the sand is natural river sand, the fineness modulus after screening is 2.4-2.6, the mud content is 1.5-1.7%, and the bulk density is 1400-1500kg/m ³ , the table The apparent density is 2600-2700kg/m ³ , and the moisture content is 1.9-2.0%.

For the above-mentioned anti-seepage and reinforcement cement mortar slurry, preferably, the slurry specific gravity of the anti-seepage and reinforcement cement mortar slurry is 1.64g/cm ³ -1.72g/cm ³ . Appropriate slurry specific gravity can minimize the unit consumption of materials.

For the above-mentioned anti-seepage and reinforced cement mortar slurry, preferably, the 28-day unconfined compressive strength of the stone body of the anti-seepage and reinforced cement mortar slurry can reach 5.75MPa-9.75MPa.

For the above-mentioned anti-seepage and reinforced cement mortar slurry, preferably, the initial setting time of the anti-seepage and reinforced cement mortar slurry is 2 minutes to 30 minutes. The initial setting time affects the impact resistance of the material. The initial setting time of the existing ordinary cement mortar is more than 2 hours and 40 minutes, compared with that, the present invention greatly shortens the initial setting time and improves the initial strength of the material.

For the above-mentioned anti-seepage and reinforced cement mortar slurry, preferably, the fluidity of the anti-seepage and reinforced cement mortar slurry is 10 cm to 50 cm. Mobility affects the diffusion radius of a material. The fluidity of the existing common cement mortar is more than 60cm. In contrast, the invention effectively controls the diffusion range of the slurry material and provides parameters for on-site construction.

The above-mentioned anti-seepage and reinforced cement mortar slurry, preferably, the initial yield stress of the anti-seepage and reinforced cement mortar slurry is 4.678Pa～767.786Pa, and the viscosity of the anti-seepage and reinforced cement mortar slurry is 0.136Pa ·s～2.962Pa·s. Initial yield stress and viscosity affect the rheological properties of a material. Compared with the existing common cement mortar, the invention effectively increases the initial yield stress and viscosity, and improves the strength of the material.

An application of cement mortar slurry suitable for anti-seepage and reinforcement of water-rich karst large-pore formations, the cement mortar slurry for anti-seepage reinforcement is applied to the specific gravity and 28-day compressive strength of the cement mortar slurry for anti-seepage reinforcement In the construction process with different requirements for strength, initial setting time, viscosity, and water flow resistance, the specific method is to increase the amount of sand in the anti-seepage and reinforced cement mortar slurry to make the anti-seepage and reinforced cement mortar slurry Proportion gradually increases; After the sand dosage is set, the 28-day compressive strength of the cement mortar slurry of the anti-seepage reinforcement is gradually increased by increasing the modifier dosage in the cement mortar slurry of the anti-seepage reinforcement; After the sand dosage is set, the initial setting time of the cement mortar slurry of the anti-seepage reinforcement is gradually reduced by increasing the modifier dosage in the cement mortar slurry of the anti-seepage reinforcement; after the sand dosage is set, When modifier dosage is less than 0.01, the viscosity of the cement mortar slurry of described anti-seepage reinforcement is gradually increased by increasing the modifier dosage in the cement mortar slurry of anti-seepage reinforcement, when modifier dosage is greater than When 0.01, by increasing the modifier dosage in the cement mortar slurry of anti-seepage reinforcement, the viscosity of the cement mortar slurry of described anti-seepage reinforcement is gradually reduced; after the modifier dosage is set, when the sand content When it is less than 0.5, the viscosity of the cement mortar slurry for the anti-seepage reinforcement is gradually increased by increasing the sand content in the cement mortar slurry for the anti-seepage reinforcement; when the sand content is greater than 0.5, the cement sand for the anti-seepage reinforcement is The amount of sand in the paste makes the viscosity of the anti-seepage and reinforced cement mortar gradually decrease; after the amount of sand is set, when the amount of modifier is less than 0.01, the cement sand strengthened by increasing the amount of anti-seepage The amount of modifying agent in the paste makes the water flow resistance of the anti-seepage and reinforced cement mortar slurry gradually increase. When the amount of modifier is greater than 0.01, by increasing The amount of modifier added gradually reduces the water flow resistance of the anti-seepage and reinforced cement mortar slurry. By adjusting the content ratio of the modifier and the sand, the stability of the anti-seepage reinforced cement mortar slurry, the anti-water flow wash-out performance and the performance of the stone body can be adjusted, and the on-site construction adaptability is strong. Foundation anti-seepage reinforcement specification requirements.

The principle of the above-mentioned technical scheme of the present invention is as follows: the mineral additive sodium aluminate of the present invention ^is hydrolyzed at first, generates a large amount of AlO ^2- , SO ₄ ^2- , OH ^- , and the Ca( OH) ₂ dissolved Ca ²⁺ reacts to form hydrated 3CaO·Al ₂ O ₃ , which reduces the concentration of Ca ²⁺ in the solution and increases the strength of the slurry; and the hydrated 3CaO·Al ₂ O ₃ crystals become the subsequent reaction The crystal nuclei for the growth of material crystals accelerate the growth of various hydration product crystals, thereby accelerating the hydration reaction of cement, improving the early strength and shortening the initial setting time. Adding a certain amount of sand can increase the cohesion, effective cohesion, internal friction angle, and effective internal friction angle, so that it has the effect of perfecting the particle filling effect, can effectively reduce the number of pores in the cement slurry, and can Play the role of sand particle replacement and cement hydrate cementation. Cement particles wrap the aggregate structure centered on sand particles through hydrate bonding, thereby improving the strength of cement slurry. In addition, mixing sand in cement slurry will also bring negative effects. Sand is a granular material and has a certain dispersion effect. It needs to be used in conjunction with modifiers to solve this problem.

Compared with the existing water-rich karst macroporous formation anti-seepage reinforcement foundation treatment technology, the present invention has the following advantages: (1) by adding the mineral additive sodium metaaluminate and adjusting the modifier in the cement mortar slurry of the present invention Proportioning can realize the control of the specific gravity, water separation rate, initial setting time, consistency, fluidity, shear yield strength, viscosity and other indicators of cement mortar slurry, and the stone formation rate and strength of the stone body can be adjusted. The stability, thixotropy, water flow resistance and impermeability of cement mortar are improved, so that it meets the requirements of engineering design. It solves the problems that the plastic viscosity and yield stress of the existing cement mortar are small in the early stage, the setting time of the slurry material is long, and the resistance to water flow is weak; (2) in addition, by mixing a certain amount of sand in the cement mortar slurry of the present invention , using the characteristics of larger volume and higher hardness of sand relative to cement, it can be used as the coarse aggregate of cement, which can play a supporting role in the overall structure of cement, and can effectively reduce the number of pores in cement slurry and play a role in particle replacement. The effect of cement hydrate and the cementation effect of cement hydrate, and then improve the strength of cement slurry material; sand also has certain technical, economic and ecological advantages, which solves the problem of high cost of ordinary quick-setting slurry material and the problem of water-rich karst large-pore formation. Ground treatment requires a lot of consumables.

In summary, the new controllable cement mortar grouting material suitable for grouting filling of water-rich karst large-pore formations of the present invention fully utilizes the advantages of mineral additives and sand, and is a kind of grout with good slurry stability and adjustable It is the preferred grouting material with material controllability, strong water flow resistance, high stone body strength, environmental protection and low price. In geotechnical engineering and water conservancy engineering foundation treatment projects, such as karst caves in dam foundations, underground powerhouses, karst around tunnels, and water-rich karst large-pore formations such as embankments of rivers and lakes, the new controllable cement mortar grouting material can be used according to According to actual engineering needs, adjust the corresponding modifier and the amount of sand to meet the requirements of the design specification.

Description of drawings

Fig. 1 is a trend chart of specific gravity variation of anti-seepage and reinforcement controllable cement mortar slurry added with different modifiers and sand content in Example 1 of the present invention.

Fig. 2 is a trend chart of the initial setting time of the anti-seepage reinforcement controllable cement mortar slurry added with different modifiers and sand content in Example 1 of the present invention.

Fig. 3 is a trend diagram of the viscosity change of the anti-seepage reinforcement controllable cement mortar slurry added with different modifiers and sand content in Example 1 of the present invention.

Fig. 4 is a 28-day unconfined compressive strength change trend diagram of the anti-seepage reinforcement controllable cement mortar slurry added with different modifiers and sand content in Example 1 of the present invention.

Fig. 5 is a graph showing the change trend of water flow erosion resistance of anti-seepage reinforcement controllable cement mortar slurry with different modifiers and sand content added in Example 1 of the present invention.

Fig. 6 is a diagram of the anti-seepage reinforcement controllable cement mortar slurry material with different modifiers and sand content added in Example 1 of the present invention.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully and in detail below in conjunction with the accompanying drawings and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

Unless otherwise defined, all technical terms used hereinafter have the same meanings as commonly understood by those skilled in the art. The terminology used herein is only for the purpose of describing specific embodiments, and is not intended to limit the protection scope of the present invention.

Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

Example 1:

A cement mortar slurry suitable for anti-seepage and reinforcement of water-rich karst macroporous formations, the composition of which includes water, cement, sand and a modifier, and the weight ratio of the water, cement, sand and modifier is 1: 1: 0.4～0.75: 0.01～0.0125, the modifier components are mineral additives. In this example, eight groups of proportioning schemes in the following table 1 are selected, among which A1-A6 are schemes with modifiers added, and A7-A8 are Comparative experiment without adding modifier.

Table 1: The mass ratio of main materials and comparative experiments of a controllable cement mortar slurry suitable for anti-seepage reinforcement of water-rich karst macroporous formations

After testing, the specific gravity (measured by a 1002 type hydrometer) of the anti-seepage reinforcement controllable cement mortar slurry of the number A1-A6 of this embodiment is in the range of 1.64g/cm ³ ~ 1.71g/cm ³ , and the number A7-A8 does not add The specific gravity of the modifier-based cement mortar is in the range of 1.64g/cm ³ to 1.65g/cm ³ , and its specific trend of change is shown in Figure 1 .

The initial setting time (measured by Vicat instrument) of the anti-seepage reinforcement controllable cement mortar of the present embodiment numbering A1-A6 is in the range of 5min～13min, and the initial setting time of the cement mortar of the numbering A7-A8 without modifier In the range of 160min to 180min, the specific change trend is shown in Figure 2.

The viscosity of the anti-seepage reinforcement controllable cement mortar slurry of present embodiment number A1-A6 (adopting the R/S-SST Plus ^TM rheometer measurement of U.S. Brookfield company) is in the scope of 0.420Pa s～2.962Pa s, number A7-A8 The viscosity of the cement mortar without modifiers is in the range of 0.054Pa·s～0.109Pa·s, and the specific change trend is shown in Figure 3.

The 28-day unconfined compressive strength (measured by a universal material testing machine) of the anti-seepage reinforcement and controllable cement mortar slurry of the number A1-A6 of this embodiment is in the range of 5.75MPa～9.2MPa, and the number A7-A8 has no added modification The 28-day unconfined compressive strength of the cement mortar prepared with additives is in the range of 14MPa to 18MPa, and its specific change trend is shown in Figure 4.

The anti-seepage and reinforcement controllable cement mortar slurry in this embodiment is measured by the weight difference retained after the slurry is eroded by the water flow. When the flow rate is 0.4-0.6m/s, the specific change trend is shown in the figure 5.

The material of the anti-seepage reinforcement controllable cement mortar slurry in this embodiment is shown in FIG. 6 .

It can be seen from Figures 1 to 3 that, compared with cement mortar without modifier, the present invention effectively increases the specific gravity of the slurry material, shortens the setting time of the slurry, and increases the viscosity of the slurry.

It can be seen from Figure 4 that compared with the cement mortar without modifier, the 28d compressive strength has been improved to a certain extent. When the amount of sand is constant, the 28-day compressive strength of the anti-seepage reinforced cement mortar increases with the increase of the amount of modifier.

It can be seen from Figure 5 that the water flow resistance of cement mortar increases first and then decreases with the increase of modifier content. When the amount of the modifying agent is 0.01, the anti-flushing performance of the slurry reaches the best, and the retention rate reaches more than 85%.

It can be seen from the above that in this embodiment, through the regulation of modifiers and the ratio of different components of sand content, the various indicators of the stability of the anti-seepage reinforcement, the stability of the cement mortar slurry, the resistance to water flow and the performance of the stone body can be controlled. It can be adjusted, has strong adaptability to on-site construction, and meets the requirements of foundation anti-seepage and reinforcement specifications.

The above descriptions are only preferred implementations of the present invention, and the scope of protection of the present invention is not limited to the above examples. For those skilled in the art, improvements and transformations obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims (10)

1. a kind of cement bonded sand cream suitable for rich water karst large-cavity strata anti-seepage reinforcing is starched, which is characterized in that the anti-seepage reinforcing Cement bonded sand cream slurry composition include：Water, cement, sand and modifying agent, the weight proportion of the cement, sand and modifying agent is 1： 0.4~0.75：0.01~0.0125, the modifier component is mineral additive, and the mineral additive includes sodium aluminate.

2. the cement bonded sand cream according to claim 1 suitable for rich water karst large-cavity strata anti-seepage reinforcing is starched, feature exists In the cement bonded sand cream slurry of, the anti-seepage reinforcing water, cement, sand and modifying agent weight proportion be 1：1：0.4~0.75：0.01 ~0.0125.

3. the cement bonded sand cream according to claim 1 suitable for rich water karst large-cavity strata anti-seepage reinforcing is starched, feature exists In cement and the gross mass of sand and the mass ratio of water in the cement bonded sand cream slurry of the anti-seepage reinforcing are (1.4~1.75)：1.

4. the cement bonded sand cream according to claim 1 suitable for rich water karst large-cavity strata anti-seepage reinforcing is starched, feature exists In cement, three's gross mass of sand and modifying agent and the mass ratio of water in the cement bonded sand cream slurry of the anti-seepage reinforcing are (1.41~1.762)：1.

5. the cement bonded sand cream for being suitable for rich water karst large-cavity strata anti-seepage reinforcing according to claim 1-4 any one of them is starched, It is characterized in that, sand uses natural river sand, fineness modulus 2.4-2.6 after screening, clay content 1.5-1.7%, bulk density 1400-1500kg/m³, apparent density 2600-2700kg/m³, moisture content 1.9-2.0%.

6. the cement bonded sand cream for being suitable for rich water karst large-cavity strata anti-seepage reinforcing according to claim 1-4 any one of them is starched, It is characterized in that, the slurry specific gravity of the cement bonded sand cream slurry of the anti-seepage reinforcing is 1.64g/cm³~1.72g/cm³；The antiseepage adds Solid cement bonded sand cream slurry 28 days unconfined compressive strengths of Seed harvest up to 5.75MPa~9.75MPa.

7. the cement bonded sand cream for being suitable for rich water karst large-cavity strata anti-seepage reinforcing according to claim 1-4 any one of them is starched, It is characterized in that, the presetting period of the cement bonded sand cream slurry of the anti-seepage reinforcing is 2min~30min.

8. the cement bonded sand cream for being suitable for rich water karst large-cavity strata anti-seepage reinforcing according to claim 1-4 any one of them is starched, It is characterized in that, the fluidity of the cement bonded sand cream slurry of the anti-seepage reinforcing is 10cm~50cm.

9. the cement bonded sand cream for being suitable for rich water karst large-cavity strata anti-seepage reinforcing according to claim 1-4 any one of them is starched, It is characterized in that, the initial yield stress of the cement bonded sand cream slurry of the anti-seepage reinforcing is 4.678Pa~767.786Pa, it is described anti- The viscosity for oozing the cement bonded sand cream slurry of reinforcing is 0.136Pas~2.962Pas.

10. a kind of cement bonded sand suitable for rich water karst large-cavity strata anti-seepage reinforcing as described in any one of claim 1-4 The application of cream slurry, which is characterized in that be applied to starch the cement bonded sand cream of anti-seepage reinforcing by the cement bonded sand cream slurry of the anti-seepage reinforcing Proportion, 28 days compression strength, the presetting period, viscosity, water resistant stream punching release in the work progress that ability has different requirements, specifically The proportion that sand volume in being starched by the cement bonded sand cream for increasing anti-seepage reinforcing starches the cement bonded sand cream of the anti-seepage reinforcing gradually increases Add；

After the setting of sand volume, the content of modifier in being starched by the cement bonded sand cream for increasing anti-seepage reinforcing makes the anti-seepage reinforcing Cement bonded sand cream slurry 28 days compression strength be stepped up；

After the setting of sand volume, the content of modifier in being starched by the cement bonded sand cream for increasing anti-seepage reinforcing makes the anti-seepage reinforcing Cement bonded sand cream slurry presetting period gradually reduce；

After the setting of sand volume, when content of modifier is less than 0.01, in being starched by the cement bonded sand cream for increasing anti-seepage reinforcing The viscosity that content of modifier starches the cement bonded sand cream of the anti-seepage reinforcing is stepped up；When content of modifier is more than 0.01, lead to The content of modifier crossed in the cement bonded sand cream slurry for increasing anti-seepage reinforcing makes viscosity that the cement bonded sand cream of the anti-seepage reinforcing starches gradually Reduce；

After content of modifier setting, when sand content is less than 0.5, the sand in being starched by the cement bonded sand cream for increasing anti-seepage reinforcing The viscosity that volume starches the cement bonded sand cream of the anti-seepage reinforcing is stepped up；When sand content is more than 0.5, added by increasing antiseepage Solid cement bonded sand cream slurry in the sand volume viscosity that starches the cement bonded sand cream of the anti-seepage reinforcing gradually reduce；

After the setting of sand volume, when content of modifier is less than 0.01, in being starched by the cement bonded sand cream for increasing anti-seepage reinforcing The water resistant stream punching that content of modifier starches the cement bonded sand cream of the anti-seepage reinforcing is released ability and is stepped up；When content of modifier is more than When 0.01, the content of modifier in being starched by the cement bonded sand cream for increasing anti-seepage reinforcing makes what the cement bonded sand cream of the anti-seepage reinforcing was starched The punching of water resistant stream is released ability and is gradually reduced.