WO2021013186A1

WO2021013186A1 - Test device and test method for simulating earth-filling and grouting

Info

Publication number: WO2021013186A1
Application number: PCT/CN2020/103556
Authority: WO
Inventors: 牛建东; 古炜恒; 张波涛; 周柱; 刘建新; 陈红飞; 谭旭亮; 邱亮亮; 李艳鸽; 刘文杰; 李泽玮
Original assignee: 中南大学; 长沙恒德岩土工程技术有限公司
Priority date: 2019-07-24
Filing date: 2020-07-22
Publication date: 2021-01-28
Also published as: CN110529148A

Abstract

A test device for simulating earth-filling and grouting, comprising a grouting system (1), a test bench cavity (2), a bottom plate (3), and an information monitoring device (4). The grouting system (1) is connected to the test bench cavity (2), and the information monitoring device (4) is disposed between the grouting system (1) and the test bench cavity (2). The test bench cavity (2) comprises at least two cavities (21) stacked together, and each cavity (21) comprises at least two portions. The cavities (21) are connected to each other in a detachable manner, and the portions of each cavity (21) are also connected to each other in a detachable manner. The bottom plate (3) is disposed at the bottom of the test bench cavity (2). Further disclosed is a corresponding test method. The device and method help to evacuate grouting-reinforced portions and facilitates subsequent detailed research.

Description

Experimental device and method for simulating soil filling and grouting

Cross references to related applications

This application claims the priority of the Chinese patent application 201910672357.7 entitled "An Experimental Device and Experimental Method for Simulating Fill Grouting", which was filed on July 24, 2019. The entire content of this application is incorporated by reference. In this article.

Technical field

The invention belongs to the technical field of underground engineering construction, and specifically relates to an experimental device and an experimental method for simulating soil filling and grouting.

Background technique

In the field of underground engineering construction, the application of grouting technology is becoming more and more extensive. Because the stratum conditions involved in grouting engineering are complex and changeable, and the uncertainty is large, the existing theoretical research work seriously lags behind the application and is difficult to guide scientifically Design, construction, and evaluation work mostly rely on manual experience for evaluation, which often results in grouting effects that are difficult to meet engineering requirements or waste of grouting materials during use. Moreover, the effect of grouting and the law of grout diffusion before construction are often difficult to be seen intuitively. The grouting simulation test can truly, comprehensively and intuitively reflect the mechanical behavior of rock and soil under external force disturbance and the law of grout diffusion. Therefore, under specific engineering geological conditions, it is extremely important to develop relevant experimental devices under compound conditions to carry out simulation tests. At present, the simulation experiment device in the prior art has problems that are not conducive to the excavation of grouting and solidification and subsequent detailed research.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art, and provide an experimental device and an experimental method for simulating soil filling grouting which is convenient for grouting and solid excavation, and subsequent detailed research.

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

An experimental device used for simulating soil filling and grouting includes a grouting system, a laboratory bench cavity, a bottom plate and an information monitoring device. Among them, the grouting system is connected to the test bench cavity, and the information monitoring device is arranged between the grouting system and the test bench cavity. The laboratory bench cavity includes at least two layers of cavities superimposed, each layer of cavities includes at least two parts, and each layer of cavities and the parts of each layer of cavities are connected in a detachable manner. The bottom plate is arranged at the bottom of the test bench cavity.

According to the experimental device for simulating soil filling and grouting of the present invention, the cavity of the test bench is composed of multiple layers of cavities and a bottom plate superimposed and spliced, and the detachable way is adopted between the layers of the cavities and the parts of each layer of the cavity The connection, installation and disassembly are convenient, which is conducive to the excavation sampling of grouting and solidification and the follow-up detailed research on grouting and solidification. Through the information monitoring device, the working condition of the grouting system can be monitored in real time to ensure that the grouting process is stable and meets the test requirements.

For the above technical solutions, further improvements can be made as described below.

According to the experimental device for simulating filling and grouting of the present invention, in a preferred embodiment, the cavities of each layer and the parts of the cavities of each layer are connected by welding wings and bolts.

Through the welding of the wings and the high-strength bolt connection, on the one hand, the installation and disassembly of the entire test bench cavity can be more convenient and tight, and on the other hand, the structure of the entire experimental device can be simplified and the cost can be reduced.

Further, in a preferred embodiment, a sealing ring is provided between the welding wings on each layer of the cavity, so that the sealing of the cavity of the test bench can be further increased, thereby avoiding leakage during the grouting process.

Further, in a preferred embodiment, a pressure relief hole is provided on the cavity, and a pressure relief valve is provided at the pressure relief hole.

By setting pressure relief holes and high-strength pressure relief valves, the grouting pressure can be flexibly controlled, which can prevent the grout and fill from emerging during the grouting process, and strictly simulate the on-site grouting situation, which is more in line with engineering practice. The result is more precise.

Further, in a preferred embodiment, the top of the cavity of the test bench is connected to the grouting system.

The grouting sequence is set to inject from the top of the test bench cavity down, which is more in line with engineering practice.

The experimental device for simulating fill grouting according to the present invention also includes a detection system.

Through the detection device, the interference to the experimental results due to the accuracy of the test device and the experimental steps can be eliminated.

Specifically, in a preferred embodiment, the detection system includes a light power penetration probe, a soil extractor, an indoor direct shear instrument and a standard ring knife.

Specifically, in a preferred embodiment, the information monitoring device includes a pressure gauge, an electromagnetic flowmeter, and a displacement monitoring device. The pressure gauge and electromagnetic flowmeter can be used to monitor the grouting pressure and flow rate in the grouting process in real time. The displacement monitoring device can realize the observation of the grout filling and compacting the soil during the grouting process, reflecting the spread of the grout in the soil. Morphology and mechanism of action.

Specifically, in a preferred embodiment, the grouting system includes two slurry storage steel drums, a transparent slurry suction pipe, a high pressure pipe, a grouting pipe, and a dual-liquid grouting machine. Among them, two slurry storage steel buckets are respectively used for storing diluted water glass and cement slurry, and the slurry storage buckets are respectively connected with a double-liquid grouting machine through a transparent slurry suction pipe. The high-pressure pipes are respectively connected with a double-liquid grouting machine, and a three-way pipe is arranged on the high-pressure pipe, and the grouting pipe is connected with the three-way pipe.

The water glass and the cement slurry are respectively placed in two slurry storage steel buckets through dilution. The cement slurry and water glass placed in the two slurry storage steel buckets are respectively connected to the two-fluid grouting machine through a transparent slurry suction pipe. The grouting machine is merged into the high-pressure pipe, and the cement slurry and water glass are mixed through the tee on the high-pressure pipe, and then connected to the grouting pipe on the upper part of the test bench cavity through the information monitoring device, and the grouting pipe is inserted into the grouting soil Body. The grouting system of this structure can provide a stable two-liquid slurry. By setting a ball valve 17 at the inlet of the water glass, it is convenient to control the ratio of cement slurry and water glass.

Further, in a preferred embodiment, the grouting system further includes a screen, which is arranged on the slurry storage steel drum.

By placing the screen on the slurry storage steel drum, it can prevent the agglomerated cement block from entering the grouting machine and causing the grouting efficiency to drop.

The experimental method according to the second aspect of the present invention includes:

Step 1: Take soil and screen: First, screen the filled soil retrieved from the construction site to remove large particles of rocks, plants and garbage, and then stir the soil to make its properties more uniform and random Take soil samples for indoor tests to determine particle size, density, liquid limit and plastic limit, moisture content, cohesion and internal friction angle. Step 2: Install the aforementioned experimental device for simulating filling and grouting. Step 3: Shovel the soil into the cavity of the experiment bench, first step on the soil with your feet, and then use a tamping machine to evenly ram the soil from the inside to the outside. Subsequently, in each layer of the cavity, a standard ring knife is used to take soil samples for a compactness test to ensure that the difference in compactness of the soil samples is less than 10%, until the filling in the cavity of the test bench is completely compacted. Step 4. Perform a light dynamic penetration test on the fill before grouting, and record the number of times the hammer falls each time the instrument is hit, and then backfill and compact the holes produced during the test. Step 5: Configure slurry and water glass. The slurry uses cement slurry with a water-cement ratio of 1:1, and the water glass concentration is 25 Baume. Step 6. Pre-grouting and opening preparation: First, use a water mill electric drill to make a hole on the flat ground near the laboratory, insert the grouting pipe, and connect the grouting supporting pressure pipe to the grouting pipe for pre-grouting to ensure it is used for simulation The experimental device for filling and grouting is in normal use. The soil sampler is used to sample at the center of the test bench cavity, and then the soil samples are tested for density, particle grading curve, liquid-plastic limit, water content, and direct shear test. Step 7. Grouting: Before starting grouting, drain the clear water in the grouting pipe. When thick grout appears in the pressure relief hole, close the pressure relief hole, then start grouting and record the top soil during the grouting process Change data, slurry flow rate, grouting pressure change data, and pay attention to whether the slurry overflows from the periphery of the test bench cavity. Step 8. Seven days after the grouting is completed, a light dynamic penetration test is performed on the top of the cavity of the test bench, and the number of drops of the hammer of the instrument in each probe hole is recorded. Step 9: Sampling from the soil extractor after grouting: Use a drilling instrument to take the core, and then perform soil density, moisture content, and direct shear tests. Step 10. Excavation and detailed study of grouting and solidification: Remove the outer shell of the test bench cavity, sweep away the loose soil, leave the grouting and solidification, check the shape of the slurry vein and measure the size.

According to the experimental method of the second aspect of the present invention, due to the use of the above-mentioned experimental device for simulating filling grouting, the excavation of grouting and solidification and the subsequent detailed research are very convenient, and the detection system And the information monitoring device can ensure that the entire experimental project is more in line with engineering practice, and the results obtained by the simulation test are more accurate.

According to the experimental method of the second aspect of the present invention, in a preferred embodiment, in step 6, a bag containing cement is set in the middle of the grouting pipe before the grouting pipe is lowered, and the grouting pipe is lowered to a certain depth. The hole in the center of the cavity of the test bench is sealed and stepped firmly, a fixed pipe is set on the top of the slurry storage steel drum, and the pressure relief device at the outlet of the grouting pipe is fixed on the fixed pipe.

By setting a bag filled with cement in the middle of the grouting pipe, the borrow hole can be blocked and the grout can be prevented from overflowing from the borrow hole. A fixed pipe is set on the top of the slurry storage steel drum, and the pressure relief device at the outlet of the grouting pipe is fixed on the fixed pipe, which can prevent the grouting pipe from popping out due to excessive pressure in the cavity of the test bench during grouting.

Compared with the prior art, the present invention has the advantages of facilitating the excavation of grouting and solidification, and subsequent detailed research.

Description of the drawings

Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the drawings. among them:

Figure 1 schematically shows the front view structure of a test bench cavity of an embodiment of the present invention;

Figure 2 schematically shows the top view structure of the test bench cavity of the embodiment of the present invention;

Figure 3 schematically shows the overall frame structure of the grouting system of the embodiment of the present invention;

Figure 4 schematically shows the overall frame structure of the test device for simulating filling and grouting according to an embodiment of the present invention;

Figure 5 schematically shows the sampling test density of the ring knife in an embodiment of the present invention;

Figure 6 schematically shows the light dynamic penetration detection point before grouting according to an embodiment of the present invention;

Figure 7 schematically shows the light dynamic penetration detection point after grouting in an embodiment of the present invention;

Fig. 8 schematically shows sampling points for indoor tests of soil after grouting in an embodiment of the present invention;

Fig. 9 schematically shows the flow of the test method of the embodiment of the present invention.

In the drawings, the same components use the same reference signs. The drawings are not drawn to actual scale.

Detailed ways

The present invention will be further described in detail below with reference to the drawings and specific embodiments, but the protection scope of the present invention will not be limited thereby.

Fig. 1 schematically shows the front view structure of a test bench cavity 2 according to an embodiment of the present invention. FIG. 2 schematically shows the top view structure of the test bench cavity 2 of the embodiment of the present invention. Fig. 3 schematically shows the overall frame structure of the grouting system 1 of the embodiment of the present invention. FIG. 4 schematically shows the overall frame structure of the test device 10 for simulating fill grouting according to an embodiment of the present invention. Fig. 5 schematically shows the sampling test density of the ring knife in an embodiment of the present invention. Fig. 6 schematically shows the light dynamic penetration detection point before grouting in an embodiment of the present invention. Fig. 7 schematically shows the light dynamic penetration detection point after grouting in an embodiment of the present invention. Fig. 8 schematically shows sampling points for indoor tests of soil after grouting in an embodiment of the present invention. Fig. 9 schematically shows the flow of the test method of the embodiment of the present invention.

As shown in FIGS. 1 to 4, the experimental device 10 for simulating filling grouting according to the embodiment of the present invention includes a grouting system 1, a laboratory bench cavity 2, a bottom plate 3 and an information monitoring device 4. Among them, the grouting system 1 is connected to the test bench cavity 2, and the information monitoring device 4 is arranged between the grouting system 1 and the test bench cavity 2. The laboratory bench cavity 2 includes at least two layers of cavities 21 superimposed, each layer of cavities 21 includes at least two parts, and each layer of cavities 21 and each part of each layer of cavities 21 are connected in a detachable manner. The bottom plate 3 is arranged at the bottom of the cavity 21 of the test bench. According to the experimental device for simulating soil filling and grouting according to the embodiment of the present invention, the cavity of the test bench is composed of multi-layer cavities and bottom plate superimposed and spliced, and detachable is adopted between each layer of cavities and between each part of each layer of cavities. The method of connection, installation and disassembly is convenient, which is conducive to the excavation and sampling of grouting and solids and subsequent detailed research on grouting and solids. Through the information monitoring device, the working condition of the grouting system can be monitored in real time to ensure that the grouting process is stable and meets the test requirements.

Further, in this embodiment, as shown in FIG. 1, a supporting base 24 is provided at the bottom of the laboratory bench cavity 2. By setting up a supporting base, the structural stability and structural strength of the entire experimental device can be ensured, thereby further ensuring the stability and accuracy of the experimental structure. Preferably, a bearing plate 25 is provided between the supporting base 24 and the bottom plate 3. By providing the bearing plate, the structural strength and structural stability of the entire experimental device can be further increased.

Specifically, in this embodiment, as shown in FIGS. 2 and 4, the information monitoring device 4 includes a pressure gauge 41, an electromagnetic flow meter 42 and a displacement monitoring device 43. The pressure gauge and electromagnetic flowmeter can be used to monitor the grouting pressure and flow rate in the grouting process in real time. The displacement monitoring device can realize the observation of the grout filling and compacting the soil during the grouting process, reflecting the spread of the grout in the soil. Morphology and mechanism of action. Specifically, in this embodiment, the displacement monitoring device 43 includes a flat wooden board 431 and a displacement strain gauge 432 arranged on the flat wooden board 431 and a sensing line 433 connected with the displacement strain gauge 432.

As shown in FIG. 3, specifically, in this embodiment, the grouting system 1 includes two slurry storage steel drums 11, a transparent slurry suction pipe 12, a high pressure pipe 13, a grouting pipe 14 and a two-liquid grouting machine 15. Among them, two slurry storage steel barrels 11 are used to store diluted water glass and cement slurry, respectively, and the slurry storage barrel 11 is connected to a double-liquid grouting machine 15 through a transparent slurry suction pipe 12 respectively. The high-pressure pipes 13 are respectively connected with the double-liquid grouting machine 15, and the three-way pipe 16 is provided on the high-pressure pipe 13, and the grouting pipe 14 is connected with the three-way pipe 16. The water glass and the cement slurry are respectively placed in two slurry storage steel buckets through dilution. The cement slurry and water glass placed in the two slurry storage steel buckets are respectively connected to the two-fluid grouting machine through a transparent slurry suction pipe. The grouting machine is merged into the high-pressure pipe, and the cement slurry and water glass are mixed through the tee on the high-pressure pipe, and then connected to the grouting pipe on the upper part of the test bench cavity through the information monitoring device, and the grouting pipe is inserted into the grouting soil Body. The grouting system of this structure can provide a stable two-liquid slurry. By setting a ball valve at the inlet of the water glass, it is convenient to control the ratio of cement slurry and water glass.

Further, in this embodiment, the grouting system 1 further includes a screen, and the screen is arranged on the slurry storage steel drum 11 for storing cement slurry. By placing the screen on the slurry storage steel drum, it can prevent the agglomerated cement block from entering the grouting machine and causing the grouting efficiency to drop.

According to the embodiment of the present invention, the experimental device 10 for simulating filling and grouting is preferably, as shown in FIG. 1, the wing plates 5 and bolts are welded between the cavities 21 of each layer and between the parts of the cavities 21 of each layer. 6Connect. Through the welding of the wings and the high-strength bolt connection, on the one hand, the installation and disassembly of the entire test bench cavity can be more convenient and tight, and on the other hand, the structure of the entire experimental device can be simplified and the cost can be reduced. Further, in this embodiment, a sealing ring 7 is provided between the welding wing plates 5 on each layer of the cavity 21, so that the sealing of the cavity of the test bench can be further increased, thereby avoiding leakage during the grouting process.

Further, in this embodiment, as shown in FIG. 1, the cavity 21 is provided with a pressure relief hole 22, and the pressure relief hole 22 is provided with a high-strength pressure relief valve 23. Specifically, in this embodiment, the pressure relief valve 23 is a ball valve. By setting pressure relief holes and high-strength pressure relief valves, the grouting pressure can be flexibly controlled, which can prevent the grout and fill from emerging during the grouting process, and strictly simulate the on-site grouting situation, which is more in line with engineering practice. The result is more precise. Preferably, in this embodiment, the top of the test bench cavity 2 is connected to the grouting system 1. The grouting sequence is set to inject from the top of the test bench cavity down, which is more in line with engineering practice.

In a specific operation example, the test bench cavity 2 is a 5-layer circular cavity formed by superimposing and splicing 10 semicircular iron rings and a bottom plate. The three-layer cavity near the bottom of the circular cavity is arranged with 6 layers. There are two pressure relief holes 22, and a high-strength pressure relief valve 23 is installed during the test to prevent the slurry and the fill from coming out. The cavity layer and the layer and the two semicircular iron rings on the same layer are connected by high-strength bolts 6 by welding wing plates 5, and 3mm thick rubber gaskets are used to seal the joints. The top of the test bench cavity 2 is connected with the grouting system 1.

As shown in FIGS. 3 and 4, the experimental device 10 for simulating fill grouting according to the embodiment of the present invention further includes a detection system. Through the detection device, the interference to the experimental results due to the accuracy of the test device and the experimental steps can be eliminated. Specifically, in this embodiment, the detection system includes a light power penetration probe, a soil extractor, an indoor direct shear instrument and a standard ring knife.

As shown in Figure 9, the experimental method for simulating fill grouting according to the embodiment of the second aspect of the present invention includes:

Step 1: Take soil and screen: First, screen the filled soil retrieved from the construction site to remove large particles of rocks, plants and garbage, and then stir the soil to make its properties more uniform and random Take soil samples for indoor tests to determine particle size, density, liquid limit and plastic limit, moisture content, cohesion and internal friction angle.

Step 2. Install the above-mentioned experimental device 10 for simulating filling and grouting. First, connect the test bench cavity 2 with high-strength bolts 6, and then connect the grouting system 1, the test bench cavity 2, and the information in sequence Monitoring device 4 and detection system 9.

Step 3: Shovel the soil into the cavity 2 of the test bench. First shovel the soil flat with your feet, and then use a tamping machine to evenly ram the soil from the inside to the outside to reduce the large pore pressure in the fill due to the shovel level. Then in each layer of the cavity, as shown in Figure 5, use the standard ring knife to take soil samples at four positions B1 ring knife 750, B2 ring knife 750, B3 ring knife 750, and B4 ring knife 750 for compactness test, where 750 is the distance The distance from the center point is 750mm to ensure that the difference in soil sample density is less than 10%, until the 1.5m high fill of the fifth layer in the cavity 2 of the test bench is completely tamped.

Step 4. Carry out light dynamic penetration test on the fill before grouting, as shown in Figure 6, mark 8 light dynamic penetration points before grouting: C1 light 250, C2 light 250, C3 light 500, C4 Light 500, C5 light 750, C6 light 750, C7 light 900, C8 light 900, the number after the point name is the distance from the center point, as shown in Figure 5. Record in the table the number of times the hammer falls each time the instrument hits 300mm (0mm～300mm, 300mm～600mm, 600mm～900mm). After the light dynamic penetration test is completed, the holes produced during the test are backfilled and compacted.

Step 5: Configure the slurry and water glass. The slurry adopts a cement slurry with a water-cement ratio of 1:1. The same quality water and P.O.42.5 cement ash are mixed and stirred and poured into the slurry storage steel bucket 11 through a 5mm screen 17. The concentration of water glass is 25 Baume, measured by a hydrometer.

Step 6. Pre-grouting and opening preparation: First, use a water mill electric drill to make a hole with a diameter of 70mm and a depth of 1m on the flat ground near the laboratory, and insert a 1m long grouting pipe, and connect the grouting supporting pressure pipe to the grouting pipe. The grouting pipe is pre-grouted to ensure the normal use of the experimental device 10 for simulating filling grouting. After the pre-grouting is completed, the grouting pipe is cleaned by suction pipe. A 70mm diameter soil extractor was used to sample at the center of chamber 2 of the test bench with a total sampling depth of 1050mm, and the soil samples were wrapped and recorded. Then the soil samples were tested for density, particle grading curve, liquid-plastic limit, water content, and direct shear test.

Step 7. Grouting: Before starting grouting, drain the clear water in the grouting pipe. When thick grout appears in the pressure relief hole, close the pressure relief hole, then start grouting and record the top soil during the grouting process Change data, slurry flow rate, grouting pressure change data, and pay attention to whether the slurry overflows from the periphery of the test bench cavity.

Step 8. Seven days after the grouting is completed, perform a light dynamic penetration test on the top of the chamber 2 of the test bench, and test the 8 light dynamic penetration points marked in Figure 7: E1 light 250, E2 light 250, E3 light 500 , E4 light 500, E5 light 750, E6 light 750, E7 light 900, E8 light 900, where the number after the point name is the distance from the center point. Record each 300mm drop of the instrument in each probe in the table ( 0mm～300mm, 300mm～600mm, 600mm～900mm) the number of times the hammer falls.

Step 9: Take samples from the soil extractor after grouting: Use a 70mm drilling instrument to take a core of 1050mm. As shown in Figure 8, the soil sampling positions are marked as F1 for 250, F2 for 500, F3 for 750, F4 for 900, and the middle point The number after the name is the distance from the center point. Then carry out soil density, moisture content, and direct shear tests.

Step 10. Excavation and detailed study of grouting and solidification: Remove the outer shell of the test bench cavity 2, sweep away the loose soil, leave the grouting and solidification, check the shape of the slurry vein and measure the size.

Step 11. Cleaning: Put the slurry inlet hose (grouting pipe) into clean water, open the valve, drain the remaining slurry with water, and clean it, while cleaning the slurry storage steel drum and other equipment.

According to the experimental method of the embodiment of the second aspect of the present invention, preferably, in step 6, before lowering the grouting pipe, wrap a bag containing cement in the middle of the grouting pipe, and tie it with a transparent tape so that it can block the borrow hole. To prevent the grout from overflowing from the 70mm borrow hole, lower the grouting pipe to a depth of 950mm, and plug the hole in the center of the test bench cavity with soil. In order to prevent the grouting pipe from emerging due to excessive pressure during grouting in the test bench cavity 2, three steel pipes were tied on the top of the grouting steel drum, and the pressure relief device at the outlet of the grouting pipe was fixed on the steel pipe.

According to the above-mentioned embodiments, it can be seen that the experimental device and experimental method for simulating fill grouting according to the present invention are convenient for the excavation of grouting and solidification and subsequent detailed research.

Although the present invention has been described with reference to the preferred embodiments, without departing from the scope of the present invention, various modifications can be made thereto and the components therein can be replaced with equivalents. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any manner. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

An experimental device for simulating soil filling and grouting, which is characterized in that it comprises a grouting system, a laboratory bench cavity, a bottom plate and an information monitoring device; wherein,

The grouting system is connected to the cavity of the test bench, and the information monitoring device is arranged between the grouting system and the cavity of the test bench;

The laboratory bench cavity includes at least two layers of cavities superimposed, each layer of cavities includes at least two parts, and the cavities of the layers and the parts of the cavities of each layer are detachably connected;

The bottom plate is arranged at the bottom of the test bench cavity.
The experimental device for simulating filling and grouting according to claim 1, wherein the cavity is provided with a pressure relief hole, and a pressure relief valve is provided at the pressure relief hole.
The experimental device for simulating soil filling grouting according to claim 1 or 2, wherein the top of the cavity of the test bench is connected to the grouting system.
The experimental device for simulating fill grouting according to any one of claims 1 to 3, wherein the experimental device for simulating fill grouting further comprises a detection system.
The experimental device for simulating soil filling and grouting according to claim 4, characterized in that the detection system includes a light dynamic penetrometer, a soil extractor, an indoor direct shear instrument and a standard ring knife.
The experimental device for simulating filling and grouting according to any one of claims 1 to 5, wherein the information monitoring device includes a pressure gauge, an electromagnetic flowmeter and a displacement monitoring device.
The experimental device for simulating filling grouting according to any one of claims 1 to 6, wherein the grouting system includes two grouting steel barrels, a transparent slurry suction pipe, a high pressure pipe, and Grouting pipe and two-fluid grouting machine; among them,

The two slurry storage steel barrels are respectively used for storing diluted water glass and cement slurry, and the slurry storage barrels are respectively connected to the dual-liquid grouting machine through the transparent slurry suction pipe;

The high-pressure pipes are respectively connected with the two-liquid grouting machine, and a three-way pipe is provided on the high-pressure pipe, and the grouting pipe is connected with the three-way pipe.
The experimental device for simulating soil filling grouting according to claim 7, wherein the grouting system further comprises a screen, and the screen is arranged on the storage steel drum.
An experimental method, characterized in that it includes:

Step 1. Take soil and sieving, then stir the soil, randomly take soil samples for indoor tests to determine particle size distribution, density, liquid limit and plastic limit, moisture content, cohesion and internal friction angle;

Step 2: Install the experimental device for simulating filling and grouting according to any one of claims 1 to 9;

Step 3: Shovel the soil into the cavity of the test bench, and use a tamping machine to evenly ram the soil from the inside to the outside until the filling in the cavity of the test bench is completely compacted;

Step 4. Perform a light dynamic penetration test on the fill before grouting, record the number of times the hammer falls each time the instrument is hit, and then backfill and compact the holes produced during the test;

Step 5: Configure slurry and water glass. The slurry uses cement slurry with a water-cement ratio of 1:1, and the water glass concentration is 25 Baume degrees;

Step 6: Pre-grouting and opening preparations, using a soil extractor to sample at the center of the test bench cavity, and then conduct density, particle grading curve, liquid-plastic limit, moisture content, direct shear test and other tests on the soil sample;

Step seven, grouting;

Step 8. Seven days after the grouting is completed, perform a light dynamic penetration test on the top of the cavity of the test bench, and record the number of drops of the hammer of the instrument in each probe hole;

Step 9: Sampling from the soil extractor after grouting: use a drilling instrument to take the core, and then perform soil density, moisture content, and direct shear tests;

Step 10. Excavation and detailed study of grouting and solidification: Remove the outer shell of the test bench cavity, sweep away the loose soil, leave the grouting and solidification, check the shape of the slurry vein and measure the size.
The experimental method for simulating soil fill grouting according to claim 9, characterized in that, in the sixth step, a bag containing cement is set in the middle of the grouting pipe before the grouting pipe is lowered. When the grouting pipe reaches a certain depth, the hole in the center of the cavity of the test bench is sealed and compacted by taking soil, a fixed pipe is set on the top of the grouting steel barrel, and the The pressure relief device is fixed on the fixed pipe.