Experimental device and method for studying water-blocking effect of double-liquid grouting under dynamic water conditions

Abstract

This invention relates to an experimental apparatus and method for studying the water-blocking effect of two-component grouting under dynamic water conditions, belonging to the field of indoor testing in geotechnical engineering. It mainly includes a test chamber, a sealing cover, an air compressor, an automatic water supply machine, intelligent grouting equipment, a seepage pressure monitoring system, a wastewater collection tank, and grouting perforated pipes. Using this experimental apparatus, by changing the seepage velocity, soil porosity, grouting pressure, and the ratio of the two-component grout, the effects of different factors on the grouting volume, water-blocking effect, grouting time, grout diffusion range, and diffusion morphology can be compared. Through comprehensive analysis of the experimental results, the most suitable two-component grouting parameters for specific working conditions can be found, providing a reference for two-component grouting in dynamic water control projects.

Description

Technical Field

[0001] This invention relates to an experimental device and method for studying the water-blocking effect of dual-liquid grouting under dynamic water conditions, belonging to the field of indoor testing in geotechnical engineering. Background Technology

[0002] In underground engineering construction such as mines, tunnels, and foundation pit support, the disturbance caused by excavation and unloading often leads to excessive deformation and water leakage in the surrounding soil. In severe cases, this can even result in sudden water and mudflows, endangering the safety of workers and causing significant economic losses to companies. With the continuous updating of grouting materials and the improvement of grouting equipment, grouting technology has been widely applied in various fields. Among them, dual-liquid grouting technology plays a crucial role in the treatment of dynamic water. Dual-liquid grouting for water plugging mainly involves injecting two grouting materials in a specific ratio into the soil layer under certain pressure using grouting equipment, allowing them to solidify rapidly and reducing the permeability of the in-situ soil, thereby achieving the purpose of seepage prevention and plugging. Due to the complexity of the underground environment, current dual-liquid grouting construction largely relies on engineering experience to determine parameters such as grouting pressure, material ratio, and grouting flow rate. However, indiscriminate grouting often leads to excessive waste of grouting materials, and the water plugging effect cannot be evaluated. Therefore, in order to improve the efficiency and accuracy of grouting, research on the effectiveness of dual-liquid grouting for water plugging under dynamic water conditions is particularly important. Laboratory testing is an important method in geotechnical engineering. For dynamic water control, scholars both domestically and internationally have developed a series of testing devices and conducted numerous laboratory experiments, which have promoted the development of geotechnical grouting theory to some extent, but also have certain shortcomings:

[0003] (1) The hydrogeological conditions are simple and cannot simulate different soil layer parameters, resulting in a low degree of consistency with actual engineering conditions.

[0004] (2) It is impossible to simultaneously meet the research requirements of water blocking effect of slurry under various working conditions such as different porosities, dynamic water pressure and dynamic water flow rate.

[0005] (3) Most studies only simulate the effect of dynamic water treatment under single flat plate cracks or cross cracks.

[0006] (4) Grouting parameters such as grouting pressure and flow rate fluctuate greatly, and the grout density and two-component grout ratio are simple, making it impossible to monitor and control grouting parameters in real time. Patents such as a grouting flow rate and pressure synchronous control device (authorization publication number: CN216286332U) and an automatic control device and method for two-component grouting (application publication number: CN114661076A) have achieved precise control of grouting pressure and flow rate and automated configuration of grouts of different densities and two-component grout ratios, but they have not yet been applied to the field of geotechnical engineering laboratory testing.

[0007] (5) The test apparatus is subject to the sidewall effect.

[0008] Based on the above problems, this invention proposes an experimental device and method for studying the water plugging effect of dual-liquid grouting under dynamic water conditions. Summary of the Invention

[0009] To overcome the shortcomings of the traditional grouting and water-blocking test devices and methods, this invention proposes a test device and method for studying the water-blocking effect of dual-liquid grouting under dynamic water conditions, which can provide a reference for dual-liquid grouting dynamic water treatment projects.

[0010] To achieve the above objectives, the present invention is implemented through the following technical solution: an experimental device and method for studying the water-blocking effect of dual-liquid grouting under dynamic water conditions, which mainly includes a test chamber, a sealing cover, an air compressor, an automatic water supply machine, an intelligent grouting equipment, a seepage pressure monitoring system, a wastewater collection tank, and a grouting perforated pipe; the test chamber includes two slots, a hole for fixing the sealing cover, and sawtooth protrusions and guide holes on the bottom and sides of the chamber; the sealing cover includes an installation hole, sawtooth protrusions of the sealing cover, a grouting hole, and a sealing rubber gasket; the air compressor is connected to the test chamber through a transmission pipeline. The system includes a pressure gauge installed on the transmission pipeline; an automatic water supply machine connected to the test chamber via a water supply pipeline, on which a flow meter No. 1 is installed; an intelligent grouting equipment connected to the grouting perforated pipe via a threaded connection through a dual-liquid grouting pipe, with a mixer installed at the end of the dual-liquid grouting pipe; a pressure monitoring system including a pressure gauge No. 1, a pressure gauge No. 2, and a transmission line; a wastewater collection tank connected to a flow guide hole via a guide pipe, on which a flow meter No. 2 is installed; and a grouting perforated pipe is divided into two parts along the longitudinal centerline, with threads at the ends and grouting holes on the pipe, the lower end of which is connected to the tip of the perforated pipe via a threaded connection. During the test, the permeable devices were first placed into the slots inside the test chamber. Test soil was then added between the two permeable devices and compacted. Simultaneously, piezometers No. 1 and No. 2 were buried in the test soil. The sealing cap and test chamber were connected with fixing bolts. The orifice sealer was connected to the grouting hole of the sealing cap via threads. After the orifice sealer was installed, the grouting pipe was wrapped with tape to seal the grouting holes, and the grouting pipe was connected to its tip via threads. The grouting pipe was then driven into the test soil along the orifice sealer. The intelligent grouting equipment was installed, and the dual-liquid grouting pipe was connected to the grouting pipe port via threads. An automatic water supply machine supplied water to the test chamber, ensuring the water level was higher than the test soil and maintaining the water level within a certain range. An air compressor provided pressure to increase the seepage velocity of the water in the test soil. The water was then fed through flow meter No. 2. Once the wastewater flow rate stabilizes or the piezometer reading stabilizes, the intelligent grouting equipment is activated. A certain grouting pressure is maintained, and a specific grout ratio is injected into the grouting pipe through a mixer, breaking through the tape on the grouting hole, thus initiating dual-liquid grouting. The wastewater flow rate is monitored in real-time using flowmeter #2, while the pressure change of piezometer #1 is monitored simultaneously to assess the water-blocking effect. When the wastewater flow rate gradually decreases and approaches zero, and the pressure of piezometer #1 gradually decreases and approaches constant, it indicates a good water-blocking effect, and grouting is stopped. During the grouting process, the intelligent grouting equipment records the grouting pressure, grout volume, and grouting time. After grouting is completed, water supply and pressurization are stopped, the grouting pipe is promptly removed, the tip is unscrewed, the grouting pipe is separated, and residual grout is cleaned for reuse. The sealing cap is removed, and the test soil is excavated to observe the diffusion range and morphology of the grout within the test soil.

[0011] Due to the adoption of the above technical solutions, the present invention has the following technical advantages:

[0012] (1) This test device can change the seepage velocity, the porosity of the test soil, the grouting pressure, and the two-liquid grout ratio, and compare and analyze the effects of the above factors on the grouting volume, water plugging effect, grouting time, grout diffusion range and diffusion morphology. It has multiple test functions and a wide research scope.

[0013] (2) The bottom and sides of the test chamber are provided with serrated protrusions, and the sealing cover is provided with serrated protrusions. The positions are relatively matched, which can eliminate the side wall effect and improve the authenticity of the test results.

[0014] (3) The grouting pipe can be divided into two parts along the longitudinal centerline, which facilitates separation and demolding after the double-liquid grouting and plugging, and improves the reusability of the grouting pipe;

[0015] (4) The grouting equipment is an intelligent grouting equipment, which can accurately control the grouting pressure and flow rate, automatically adjust the two-liquid grout ratio, reduce manual intervention, and increase the accuracy of test results. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the pre-grouting test device of the present invention;

[0017] Figure 2 This is a three-dimensional view of the sealing cap of the present invention;

[0018] Figure 3 This is a diagram of the internal structure of the test chamber of the present invention;

[0019] Figure 4 This invention relates to a grouting pipe;

[0020] Figure 5 This invention relates to an orifice sealer;

[0021] Among them, 1 is the test chamber, 11 is the slot, 12 is the fixed sealing cover hole, 13 is the serrated protrusion inside the chamber, 14 is the guide hole, 15 is the water permeation device, and 16 is the test soil; 2 is the sealing cover, 21 is the installation hole, 22 is the serrated protrusion of the sealing cover, 23 is the grouting hole, and 24 is the sealing rubber gasket; 3 is the air compressor, 31 is the transmission pipe, and 32 is the pressure gauge; 4 is the automatic water supply machine, 41 is the water delivery pipe, and 42 is the No. 1 flow meter; 5 is the intelligent grouting equipment, 51 is the dual-liquid grouting pipe, and 52 is the mixer; 6 is the seepage pressure monitoring system, 61 is the No. 1 piezometer, 62 is the No. 2 piezometer, and 63 is the transmission line; 7 is the wastewater collection tank, 71 is the guide pipe, and 72 is the No. 2 flow meter; 8 is the grouting perforated pipe, 81 is the grouting eye, and 82 is the tip of the perforated pipe; 9 is the fixing bolt; and 10 is the orifice sealer. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings. The specific embodiments are further illustrations of the present invention and are not intended to limit the invention in any way. Any techniques identical or similar to the present invention do not exceed the scope of protection of the present invention.

[0023] Attached Figure

[0024] An experimental apparatus and method for studying the water-blocking effect of dual-liquid grouting under dynamic water conditions are disclosed. The experimental apparatus mainly includes a test chamber 1, a sealing cover 2, an air compressor 3, an automatic water supply machine 4, an intelligent grouting device 5, a seepage pressure monitoring system 6, a wastewater collection tank 7, and a grouting perforated pipe 8. The test chamber 1 is used to place test soil 16, the sealing cover 2 is used to seal the test chamber 1, the grouting perforated pipe 8 is buried in the test soil 16 and is connected to the intelligent grouting device 5 by threads. The intelligent grouting device 5 can realize controllable dual-liquid grouting, the automatic water supply machine 4 can supply water to the test chamber and maintain the liquid level within a certain height range, the air compressor 3 can provide pressure to the test chamber and change the seepage rate of water in the test soil 16, the seepage pressure monitoring system 6 is used to monitor the seepage pressure during the test, and the wastewater collection tank 7 can collect the wastewater that has seeped through the test soil 16.

[0025] The test chamber 1 includes two slots 11 for fixing the permeable device 15, a fixing sealing cover hole 12, and a guide hole 14. The bottom and sides are respectively provided with serrated protrusions 13 inside the chamber. The sealing cover 2 includes an installation hole 21, a serrated protrusion 22, a grouting hole 23, and a sealing rubber gasket 24. The fixing sealing cover hole 12 and the installation hole 21 are fixed by fixing bolts 9. The serrated protrusion 13 inside the chamber and the serrated protrusion 22 of the sealing cover are matched in relative position. Sealing rubber gaskets 24 are installed around the sealing cover 2 and at the contact position with the permeable device 15.

[0026] The grouting pipe 8 is divided into two parts along the longitudinal centerline. The lower end of the grouting pipe 8 is connected to the tip 82 of the pipe by a thread, and the upper end is fixed by the orifice sealer 10.

[0027] The experimental method includes the following implementation steps:

[0028] Step 1: Prepare test soils of different types and permeability coefficients according to the experimental requirements;

[0029] Step 2: Place the permeable device 15 into the two slots 11 inside the test chamber 1 respectively;

[0030] Step 3: Add test soil 16 between the two permeable devices 15, and pre-bury piezometers 61 and 62 into the test soil 16; at the same time, ensure that the permeability of the permeable device 15 is always higher than that of the test soil 16 to eliminate the influence of the permeable device 15 on the seepage rate.

[0031] Step 4: Align the mounting hole 21 on the sealing cover 2 with the fixing hole 12 on the sealing cover 1 of the test chamber, and connect and fix it with the fixing bolt 9;

[0032] Step 5: Use tape to wrap the grouting pipe 8 to seal the grouting hole 81. The grouting pipe 8 and the tip 82 of the pipe are connected by threads. The grouting pipe 8 is installed into the test soil 16 along the grouting hole 23. The hole sealer 10 is connected to the grouting hole 23 of the sealing cover 2 by threads.

[0033] Step 6: Install the intelligent grouting equipment 5 and connect the dual-liquid grouting pipe 51. The dual-liquid grouting pipe 51 and the grouting flower pipe 8 are connected by threads. A mixer 52 is installed at the end of the dual-liquid grouting pipe 51.

[0034] Step 7: Connect the automatic water supply machine 4 to the test chamber 1 through the water supply pipe 41. The automatic water supply machine 4 supplies water to the test chamber 1 so that the water level is higher than the test soil 16 and the water level is kept constant. A flow meter 42 is installed on the water supply pipe 41 to record the flow rate. The air compressor 3 is connected to the test chamber 1 through the transmission pipe 31 and provides a certain pressure. The pressure can be changed according to the test needs, that is, the seepage rate of water in the test soil 16 can be changed. A pressure gauge 32 is installed on the transmission pipe 31.

[0035] Step 8: Monitor the osmotic pressure using the osmotic pressure monitoring system 6. Once the wastewater flow rate through flow meter 2 72 stabilizes and the monitoring values ​​of osmotic gauges 1 and 2 62 tend to stabilize, start the intelligent grouting equipment 5. Maintain a certain grouting pressure and a certain two-liquid grout ratio. Mix the grout evenly through mixer 10 and inject it into the grouting perforated pipe 8. The grout breaks through the tape on the grouting hole 81, and the two-liquid grouting begins. The intelligent grouting equipment 5 can accurately control the grouting pressure and flow rate, and automatically adjust the two-liquid grout ratio to meet different test requirements.

[0036] Step 9: Monitor the wastewater flow rate in real time using flow meter 72 (No. 2) and pressure change of piezometer 61 (No. 1) to determine the water blocking effect. When the wastewater flow rate gradually decreases and approaches 0 and the pressure of piezometer 61 gradually decreases and stabilizes, it indicates that the water blocking effect is good, and grouting is stopped. During the grouting process, the intelligent grouting equipment 5 records the grouting pressure, grouting volume, and grouting time.

[0037] Step 10: After grouting is completed, stop water supply and pressurization, pull out the grouting tube 8 in time, unscrew the tip 82 of the tube, separate the grouting tube 8, clean up the residual grout, and reuse it.

[0038] Step 11: Remove the sealing cap 2, excavate the test soil 16, and observe the diffusion range and diffusion pattern of the slurry in the test soil 16.

Claims

1. An experimental apparatus for studying the water-stopping effect of dual-liquid grouting under dynamic water conditions, comprising a test chamber, a sealing cover, an air compressor, an automatic water supply machine, an intelligent grouting device, a seepage pressure monitoring system, a wastewater collection tank, and grouting perforated pipes; the test chamber is used to hold test soil, the sealing cover is used to seal the test chamber, the grouting perforated pipes are buried in the test soil and connected to the intelligent grouting device via threads, the intelligent grouting device can realize controllable dual-liquid grouting, the automatic water supply machine can supply water to the test chamber and maintain the liquid level within a certain height range, the air compressor can provide pressure to the test chamber to change the seepage velocity of water in the test soil, the seepage pressure monitoring system is used to monitor the seepage pressure during the test, and the wastewater collection tank can collect wastewater that has permeated through the test soil; the test chamber includes a fixed sealing cover hole, a guide hole, and two slots for fixing the permeable device, and the bottom and sides of the test chamber are respectively... The test chamber is equipped with serrated protrusions inside the chamber. The sealing cover includes an installation hole, serrated protrusions on the sealing cover, a grouting hole, and a sealing rubber gasket. The sealing cover hole is fixed to the installation hole by fixing bolts. The relative positions of the serrated protrusions inside the chamber and the serrated protrusions on the sealing cover are matched, which can eliminate the sidewall effect when water flows in the test chamber and improve the authenticity of the test results. Sealing rubber gaskets are installed around the sealing cover and at the contact position between the sealing cover and the water-permeable device to prevent water leakage during the test. At the same time, the sealing rubber gaskets can protect the transmission line of the seepage pressure monitoring system from being crushed. The grouting perforated pipe is divided into two parts along the longitudinal centerline, which facilitates separation and demolding after the double-liquid grouting and plugging, and improves the reusability of the grouting perforated pipe. The lower end of the grouting perforated pipe is connected to the tip of the perforated pipe by threads, and the upper end is fixed by the orifice sealer, which increases the integrity of the grouting perforated pipe and prevents separation due to grouting pressure during grouting, thus preventing uneven grouting.

2. The experimental apparatus for studying the water-blocking effect of dual-liquid grouting under dynamic water conditions according to claim 1, characterized in that: The use of intelligent grouting equipment can precisely control grouting pressure and flow rate, automatically adjust the two-component grout ratio, reduce manual intervention, and increase the accuracy of test results.

3. The test method for the experimental apparatus for studying the water-blocking effect of dual-liquid grouting under dynamic water conditions according to any one of claims 1-2, characterized in that: The experimental method includes the following implementation steps: Step 1: Prepare test soils of different types and permeability coefficients according to the experimental requirements; Step 2: Place the permeable devices into the two slots inside the test chamber; Step 3: Add test soil between the two permeable devices, and pre-bury piezometers No. 1 and No. 2 in the test soil; at the same time, ensure that the permeability of the permeable device is always higher than that of the test soil to eliminate the influence of the permeable device on the seepage velocity. Step 4: Align the mounting holes on the sealing cap with the fixing holes on the test chamber, and secure them with fixing bolts; Step 5: Use tape to wrap the grouting pipe and seal the grouting hole. Connect the grouting pipe to the tip of the pipe with threads. Drive the grouting pipe into the test soil along the grouting hole. Connect the hole sealer to the grouting hole of the sealing cap with threads. Step Six: Install the intelligent grouting equipment and connect the dual-liquid grouting pipe. The dual-liquid grouting pipe and the grouting perforated pipe are connected by threads. A mixer is installed at the end of the dual-liquid grouting pipe. Step 7: Connect the automatic water supply machine to the test chamber through the water supply pipeline. The automatic water supply machine supplies water into the test chamber, making the water level higher than the test soil and keeping the water level constant. A flow meter No. 1 is installed on the water supply pipeline to record the flow rate. The air compressor is connected to the test chamber through the transmission pipeline and provides a certain pressure. The pressure can be changed according to the test needs, that is, the seepage rate of water in the test soil can be changed. A pressure gauge is installed on the transmission pipeline. Step 8: Monitor the osmotic pressure using the osmotic pressure monitoring system. Once the wastewater flow rate through flowmeter No. 2 stabilizes and the monitoring values ​​of osmometers No. 1 and No. 2 tend to stabilize, start the intelligent grouting equipment. Maintain a certain grouting pressure and a certain two-liquid grout ratio. Mix the grout evenly through the mixer and inject it into the grouting pipe. The grout breaks through the tape on the grouting hole, and the two-liquid grouting begins. The intelligent grouting equipment can accurately control the grouting pressure and flow rate, and automatically adjust the two-liquid grout ratio to meet different test requirements. Step 9: Monitor the wastewater flow rate in real time using flow meter No. 2, and simultaneously monitor the pressure change of piezometer No. 1 to determine the water blocking effect; when the wastewater flow rate gradually decreases and approaches 0 and the pressure of piezometer No. 1 gradually decreases and approaches stability, it indicates that the water blocking effect is good, and grouting is stopped. During the grouting process, use intelligent grouting equipment to record the grouting pressure, grouting volume and grouting time. Step 10: After grouting is completed, stop water supply and pressurization, promptly pull out the grouting pipe, unscrew the tip of the pipe, separate the grouting pipe, clean up any remaining grout, and reuse it. Step 11: Remove the sealing cap, excavate the test soil, and observe the diffusion range and diffusion pattern of the slurry in the test soil.

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