Karst grouting simulation experimental device and karst grouting visualization simulation experimental method based on 3D printing

Abstract

The present invention discloses a karst grouting simulation experimental device, including a confining pressure simulation mechanism, a grouting mechanism, a karst cavity body formed by flexible 3D printing, and a pressurizing mechanism for introducing pressurized water into the karst cavity body, a grouting port is provided at the upper part of the karst cavity body, the grouting mechanism is connected with the grouting port, the confining pressure simulation mechanism includes a rock and soil simulation chamber, a confining pressure pressurizer and a karst external rock and soil body, the karst cavity body is located at the bottom of the rock and soil simulation chamber, the karst external rock and soil body is filled in the rock and soil simulation chamber and surrounds the upper bottom surface and side of the karst cavity body, and the confining pressure pressurizer acts on the karst external rock and soil body; the present invention also includes an experimental method of the above-mentioned karst grouting simulation experimental device. The present invention has the advantages of high repetition rate, good sealing, extensible boundaries and wide adaptability.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering foundation treatment, and in particular to a karst grouting simulation experimental device and an experimental method thereof. Background Art

[0002] Karst is formed by the continuous dissolution of calcium ions from soluble rocks under the long-term action of high water head. It is widely found in the Kashgar area in southwest my country. Its anti-seepage treatment is an important part of ensuring the safe operation of civil engineering in the Kashgar area. The treatment measures mainly include large excavation backfilling and grouting. Grouting has the characteristics of less construction workload, short construction period, and easy quality assurance. It is widely used in karst foundation anti-seepage reinforcement projects at home and abroad. The grouting effect depends to a certain extent on the grouting control parameters, and the acquisition of control parameters is inseparable from a large number of model tests.

[0003] Scholars at home and abroad have developed a series of test devices, which have promoted the development of grouting technology to a certain extent and provided guidance for engineering practice. For example, the China Institute of Water Resources and Hydropower Research spontaneously developed a flat grouting test bench; Zhan Kaiyu and Sui Wanghua independently developed a single fracture grouting simulation test system under dynamic water conditions; Guo Miwen and Sui Wanghua developed a grouting test system that can form a high-pressure environment of more than 5MPa in order to study the seepage and diffusion characteristics of grouting slurry under high-pressure environment conditions; Zhao Honghai, Li Lei and others developed a fracture grouting test device; Jing Xiangdang developed a multifunctional grouting test device; Jiang Maiyong developed a filling type cave anti-seepage grouting simulation experimental device under dynamic water conditions. However, the existing grouting simulation test devices at home and abroad are difficult to simulate the irregularity and boundary ductility of karst, and the consistency of karst grouting tests is poor. Therefore, the development of a karst grouting simulation test system based on 3D printing in order to reasonably determine the control parameters of karst anti-seepage grouting has become an urgent problem for relevant personnel in this field to study and solve. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a karst grouting simulation experimental device and an experimental method thereof, which can customize a karst cavity of any shape through 3D printing, and ensure the boundary ductility by adjusting the material, while ensuring the consistency of the karst cavity in a group of comparative tests, thereby realizing the visualization of grouting to a certain extent.

[0005] In order to solve the above technical problems, the technical solution proposed in the present invention is: a karst grouting simulation experimental device, including a confining pressure simulation mechanism, a grouting mechanism, a karst cavity and a pressurizing mechanism for introducing pressure into the karst cavity, the karst cavity is also provided with a slurry inlet connected to the grouting mechanism, the confining pressure simulation mechanism includes a rock and soil simulation chamber, a confining pressure pressurizer and a karst external rock and soil body, the karst cavity and the karst external rock and soil body are located in the rock and soil simulation chamber, and the karst external rock and soil body wraps the karst cavity body, and the confining pressure pressurizer acts on the karst external rock and soil body.

[0006] The karst grouting simulation experimental device mentioned above is preferably: the karst cavity is a karst cavity simulation module printed by 3D printing. The karst cavity used in the karst grouting simulation experimental device of the present invention is preferably 3D printed, and the consistency of the size and properties of the karst cavity can be achieved through computer control.

[0007] More preferably, the material used for 3D printing is a flexible material, and the flexible material is silicone, silicone rubber, latex, thermoplastic resin material, thermoplastic polyurethane elastic material or photosensitive resin material. The karst cavity body of the karst grouting simulation experimental device of the present invention is 3D printed with a flexible material, which can achieve boundary extension under the action of grouting pressure to a certain extent.

[0008] As a further improvement of the above technical solution: the rock and soil simulation chamber includes a cylindrical transparent tempered glass body and a lower flange. The rock and soil simulation chamber can be closed or open at the top. The tempered glass body is provided with a water inlet and a water outlet. The karst cavity body is provided with a karst water inlet and a karst water outlet. The water inlet is connected to the karst water inlet, and the water outlet is connected to the karst water outlet. The tempered glass body is fixed by a slot provided on the lower flange; the karst cavity body is provided on the lower flange and is not connected to the tempered glass body. The flange connection structure provided at the bottom can ensure that the karst cavity body and the grouting body inside it can be taken out from the rock and soil simulation chamber, thereby greatly improving the repetition rate. By using tempered glass as the outer boundary of the cavity, the visualization of karst grouting can be achieved to a certain extent.

[0009] As a further preference: the pressurizing mechanism includes a pressure gas source and a high-pressure water storage tank, the pressure gas source is connected to the high-pressure water storage tank through an air pipe, and the high-pressure water storage tank is connected to the water inlet of the rock and soil simulation room through a water pipe.

[0010] As a further preference: the grouting mechanism comprises a grouting pump and a grouting pipe connected to the grouting pump, and the grouting pipe is connected to a grouting port on the karst cavity through an orifice pipe penetrating through the external rock and soil body of the karst.

[0011] As a further preference: the karst external rock and soil body is uniformly filled in the lower part of the rock and soil body simulation chamber, the confining pressure pressurizer acts on the upper part of the karst external rock and soil body, and the confining pressure pressurizer includes a rubber sheet, a metal ring, a pressure block, a force transmission rod and a pressure source connected in sequence from bottom to top, and the rubber sheet is in direct contact with the karst external rock and soil body. Further preference: the thickness of the rubber sheet is 10-20mm (for sealing and buffering), the thickness of the metal ring is 5-10mm, and the diameter of the metal ring is 1-4mm smaller than the diameter of the rubber sheet; the pressure block is an isosceles trapezoidal structure.

[0012] As a further preference: on-off valves are respectively installed at the upper end and / or lower end of the orifice pipe, the grouting pipe of the grouting mechanism, the front end of the karst water inlet, and the tail end of the karst water outlet.

[0013] As a general technical concept, the present invention also provides a karst grouting visualization simulation experimental method based on 3D printing, which is operated by the above-mentioned karst grouting simulation experimental device and specifically includes the following steps:

[0014] 1) Install the specimen and the test device: print the karst cavity through flexible 3D printing according to the design, and connect the preset slurry inlet on the karst cavity with the grouting mechanism; place the karst cavity at the bottom of the rock and soil simulation chamber, and connect it with the water inlet and outlet of the rock and soil simulation chamber;

[0015] 2) connecting the pressurizing mechanism to the water inlet of the rock and soil simulation chamber through a water pipe, and filling the karst cavity with water through the pressurizing mechanism to make it expand;

[0016] 3) Applying confining pressure: adding a set number and grade of karst external rock and soil bodies to the rock and soil simulation room so that they wrap around and on the top of the karst cavity, and then placing a confining pressure simulation mechanism above the karst external rock and soil body, applying a certain value of pressure through the confining pressure simulation mechanism, and opening the grouting mechanism after the karst external rock and soil body is completely consolidated and the settlement is stable;

[0017] 4) Anti-seepage grouting simulation: prepare the slurry in proportion and pour it into the grouting mechanism, open the grouting mechanism to start grouting into the karst cavity and squeeze out the excess water until the design end standard is reached, and then close the grouting mechanism;

[0018] 5) Observation of grouting properties: After the grouting is completed and the solidification period has passed, the pressure mechanism is turned off, and the grouting mechanism and the pressure mechanism connected to the karst cavity are disassembled at the connection point. The lower flange at the bottom of the rock and soil simulation room is opened, the karst cavity is taken out and relevant data are measured, and then the grouting stone body in the karst cavity is dissected to observe the grouting properties and obtain relevant experimental data of karst grouting.

[0019] As a further improvement of the above technical solution: the setting time after the grouting in step 5) is 0-60 minutes.

[0020] The working principle of the experimental method of the present invention is: using a 3D printer to generate a flexible karst cavity with consistent size and properties, and simulating the confining pressure through an upper confining pressure device, and then performing a grouting test through a grouting machine, and observing the grouting process through tempered glass. After the grouting is completed, it can be easily disassembled to observe the test conditions of the karst cavity and the external karst rock and soil body.

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] 1. The karst cavity body used in the karst grouting simulation experimental device of the present invention is 3D printed, and the consistency of the size and properties of the karst cavity body can be achieved through computer control;

[0023] 2. The karst cavity of the karst grouting simulation experimental device of the present invention is printed with flexible materials, which can achieve boundary extension under the action of grouting pressure to a certain extent;

[0024] 3. The karst grouting simulation experimental device of the present invention adopts rubber sheets and flexible karst cavities, which can truly simulate different surrounding rock pressures and greatly ensure the sealing of the equipment;

[0025] 4. The karst grouting simulation experimental device of the present invention uses tempered glass as the outer boundary of the cavity, which can realize the visualization of karst grouting to a certain extent.

[0026] In general, the karst grouting simulation experimental device and the experimental method of the present invention are not only simple in structure and easy to operate, but also have intuitive and reliable experimental results and good experimental results. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] Figure 2 This is a physical photo of the grouting stone body obtained in the embodiment of the present invention.

[0029] Legend:

[0030] 1. Confining pressure simulation mechanism; 11. Rock and soil simulation room; 111. Tempered glass body; 1111. Water outlet; 1112. Water inlet; 112. Lower flange; 113. Orifice pipe; 12. Confining pressure booster; 121. Rubber sheet; 122. Metal ring; 123. Pressure block; 124. Force transmission rod; 125. Pressure source; 13. Karst external rock and soil; 2. Grouting mechanism; 21. Grouting pipe; 22. Grouting pump; 3. Karst cavity; 4. Pressurizing mechanism; 41. Pressure gas source; 42. High-pressure water storage tank; 5. On-off valve. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0032] like Figure 1 As shown, a karst grouting simulation experimental device includes a confining pressure simulation mechanism 1, a grouting mechanism 2, a karst cavity body 3 made of flexible (for example, thermoplastic resin material, thermoplastic polyurethane elastic material or photosensitive resin material, etc.) 3D printing, and a pressurizing mechanism 4 for introducing pressurized water into the karst cavity body 3. A slurry inlet is provided on the upper part of the karst cavity body 3, and the grouting mechanism 2 is connected to the slurry inlet. The confining pressure simulation mechanism 1 includes a rock and soil simulation chamber 11, a confining pressure pressurizer 12 and a karst external rock and soil body 13, which can truly simulate the karst surrounding rock pressure. The karst cavity body 3 is located at the bottom of the rock and soil simulation chamber 11, the karst external rock and soil body 13 is filled in the rock and soil simulation chamber 11 and surrounds the upper bottom surface and side surfaces of the karst cavity body 3, and the confining pressure pressurizer 12 acts on the karst external rock and soil body 13.

[0033] In this embodiment, the rock and soil simulation chamber 11 includes a tempered glass body 111, a lower flange 112 and an orifice tube 113. The tempered glass body 111 is provided with a water inlet 1112 and a water outlet 1111. The karst cavity body is provided with a karst water inlet and a karst water outlet. The water inlet 1112 is connected to the karst water inlet, and the water outlet 1111 is connected to the karst water outlet. The two ends of the orifice tube 113 are respectively connected to the grouting port on the karst cavity body 3 and the grouting pipe 21 of the grouting mechanism 2. The tempered glass body 111 is fixed and disassembled by the slot provided in the lower flange 112.

[0034] In this embodiment, on-off valves 5 are respectively installed at the lower end of the orifice pipe 113, the grouting pipe 21 of the grouting mechanism 2, the front end of the karst water inlet, and the tail end of the karst water outlet to control the on-off of the slurry and the moving water.

[0035] In this embodiment, the confining pressure booster 12 includes a rubber sheet 121, a metal ring 122, a pressure block 123, a force transmission rod 124 and a pressure source 125 connected in sequence from bottom to top. The rubber sheet 121 is in direct contact with the karst external rock and soil body 13. A hole consistent with the size of the orifice tube 113 is provided in the middle of the rubber sheet 121 for the orifice tube 113 to pass through.

[0036] In this embodiment, the thickness of the rubber sheet 121 is 15 mm, the thickness of the metal ring 122 is 10 mm, and the diameter of the metal ring 122 is 2 mm smaller than the diameter of the rubber sheet 121; the pressure block 123 is an isosceles trapezoidal structure, which facilitates the high uniformity of the pressure acting on the karst external rock and soil body 13.

[0037] In this embodiment, the pressurizing mechanism 4 includes a pressure gas source 41 and a high-pressure water tank 42. The pressure gas source 41 is connected to the top of the high-pressure water tank 42 through an air pipe, and the bottom of the high-pressure water tank 42 is connected to the water inlet 1112 of the rock and soil simulation chamber 11 through a water pipe. The above-mentioned pressure gas source 41 can use a nitrogen bottle. The use of the pressurizing mechanism 4 can simulate cave leakage.

[0038] In this embodiment, the grouting mechanism 2 includes a grouting pump 22 and a grouting pipe 21 connected to the grouting pump 22. The grouting pipe 21 is connected to the grouting port, which can truly simulate the grouting process of the karst filling.

[0039] In this embodiment, all metal parts used are made of steel materials.

[0040] In this embodiment, various pipelines are connected by flanges, and various non-pipe components are fastened by bolts, which have good sealing properties.

[0041] A karst grouting visualization simulation experimental method based on 3D printing adopts the above-mentioned karst grouting simulation experimental device and includes the following steps:

[0042] 1) Install the sample and the test device: According to the design, the karst cavity 3 is 3D printed, the slurry inlet is connected with the orifice pipe 113, the karst water inlet is connected with the water inlet 1112, the karst water outlet is connected with the water outlet 1111, the on-off valve 5 at the bottom of the orifice pipe 113 and the tail of the karst water outlet is closed, and the on-off valve 5 at the front end of the karst water inlet is opened. When the karst cavity 3 is filled with water, the on-off valve 5 at the front end of the karst water inlet is closed;

[0043] 2) Applying confining pressure: Add a certain amount of karst external rock and soil 13 of a certain grade into the rock and soil simulation chamber 11, then place the rubber sheet 121, the metal ring 122, the pressure block 123 and the force transmission rod 124 in sequence, apply a certain value of pressure through the pressure source 125, and open the on-off valve 5 on the grouting pipe 21 after the karst external rock and soil 13 is completely consolidated and the settlement is stable;

[0044] 3) Anti-seepage grouting simulation: prepare the slurry in proportion and pour it into the grouting pump 22, turn on the grouting pump 22 to start grouting into the karst cavity 3, until the design end standard is reached, and then turn off the grouting pump 22;

[0045] 4) Observation of grouting properties: After the grouting is completed and the solidification time is 30 minutes, the pressure source 125 is turned off, the lower flange 112 of the rock and soil simulation chamber 11 is opened, the orifice pipe 113 and the grout inlet, the water inlet 1112 and the karst water inlet, and the water outlet 1111 and the karst water outlet are disassembled in sequence, the karst cavity 3 is taken out and the relevant data are measured, and then the grouting stone body in the karst cavity 3 is dissected to observe the grouting properties.

[0046] When photosensitive resin material is used as the flexible material, a simulated field condition is measured to measure the grouting stone body (see Figure 2 ) are shown in Table 1 below:

[0047] Table 1: Performance parameter measurement results of the grouting stone body in this embodiment

[0048]

[0049] When thermoplastic polyurethane is used as the flexible material, the performance parameters of the grouting stone body measured under another simulated field condition are shown in Table 2 below:

[0050] Table 2: Performance parameter measurement results of the grouting stone body in this embodiment

[0051]

[0052] The compressive strength test method refers to "Test Method for Cement Mortar Strength (ISO Method)" (GB / T 17671-1999);

[0053] Permeability coefficient test specification DL / T 5150-2001;

[0054] The stone filling rate test method refers to the "Guidelines for Testing Granular Grouting Materials" (2010).

Claims

1. A karst grouting simulation experimental device, characterized in that: The invention comprises a confining pressure simulation mechanism (1), a grouting mechanism (2), a karst cavity body (3) and a pressurizing mechanism (4) for introducing pressure into the karst cavity body (3); the grouting mechanism (2) comprises a grouting pump (22) and a grouting pipe (21) connected to the grouting pump (22); the grouting pipe (21) is connected to a grouting inlet on the karst cavity body (3) through an orifice pipe (113) passing through the karst external rock and soil body (13); the karst cavity body (3) is a karst cavity simulation module printed by 3D printing; the material used for 3D printing is a flexible material, and the flexible material is a silicone, silicone rubber, latex, thermoplastic resin material, thermoplastic The karst cavity (3) is made of a polyurethane elastic material or a photosensitive resin material. A grout inlet connected to the grouting mechanism (2) is also provided on the karst cavity (3). The confining pressure simulation mechanism (1) comprises a rock and soil simulation chamber (11), a confining pressure booster (12) and a karst external rock and soil body (13). The rock and soil simulation chamber (11) comprises a cylindrical transparent tempered glass body (111) and a lower flange (112). The tempered glass body (111) is provided with a water inlet (1112) and a water outlet (1111). The karst cavity (3) is provided with a karst water inlet and a karst water outlet. The water inlet (1112) is connected to the karst water inlet, and the water outlet The karst hollow cavity (3) is arranged on the lower flange (112) and is not connected to the tempered glass body (111). The karst hollow cavity (3) and the karst external rock and soil body (13) are located in the rock and soil body simulation chamber (11), and the karst external rock and soil body (13) wraps the karst hollow cavity (3). The confining pressure booster (12) acts on the karst external rock and soil body (13), and the karst external rock and soil body (13) is uniformly filled in the lower part of the rock and soil body simulation chamber (11). The pressurizer (12) acts on the top of the karst external rock and soil body (13), and the confining pressure pressurizer (12) comprises a rubber sheet (121), a metal ring (122), a pressurizing block (123), a force transmission rod (124) and a pressure source (125) which are connected in sequence from bottom to top, and the rubber sheet (121) is in direct contact with the karst external rock and soil body (13); the pressurizing mechanism (4) comprises a pressure gas source (41) and a high-pressure water storage tank (42), the pressure gas source (41) is connected to the high-pressure water storage tank (42) through an air pipe, and the high-pressure water storage tank (42) is connected to the water inlet (1112) of the rock and soil body simulation chamber (11) through a water pipe.

2. A karst grouting visualization simulation experimental method based on 3D printing, characterized in that: The karst grouting simulation experimental device described in claim 1 is used for operation, and specifically comprises the following steps: 1) Installing the sample and the test device: printing a karst cavity (3) by flexible 3D printing according to the design, and connecting a preset slurry inlet on the karst cavity (3) with a grouting mechanism (2); placing the karst cavity (3) at the bottom of a rock and soil simulation chamber (11), and connecting it with a water inlet (1112) and a water outlet (1111) of the rock and soil simulation chamber (11); 2) connecting the pressurizing mechanism (4) to the water inlet (1112) of the rock and soil simulation chamber (11) through a water pipe, and filling the karst cavity (3) with water through the pressurizing mechanism (4) to cause it to expand; 3) Applying confining pressure: adding a set number of karst external rock and soil bodies (13) of a set grade into the rock and soil body simulation chamber (11) so that the karst external rock and soil bodies (13) are wrapped around the periphery and top surface of the karst cavity body (3), and then placing a confining pressure simulation mechanism (1) above the karst external rock and soil bodies (13). A certain value of pressure is applied through the confining pressure simulation mechanism (1), and after the karst external rock and soil bodies (13) are completely consolidated and the settlement is stable, the grouting mechanism (2) is opened; 4) Anti-seepage grouting simulation: prepare the slurry in proportion and pour it into the grouting mechanism (2), open the grouting mechanism (2) to start grouting into the karst cavity (3) and squeeze out the excess water therein until the design end standard is reached, and then close the grouting mechanism (2); 5) Observation of grouting properties: After the grouting is completed and the solidification period has expired, the pressurizing mechanism (4) is turned off, the grouting mechanism (2) and the pressurizing mechanism (4) connected to the karst cavity (3) are disassembled at the connection, the lower flange (112) at the bottom of the rock and soil simulation chamber (11) is opened, the karst cavity (3) is taken out and relevant data are measured, and then the grouting stone body in the karst cavity (3) is cut open to observe the grouting properties and obtain relevant experimental data of karst grouting.

3. The karst grouting visualization simulation experimental method based on 3D printing according to claim 2, characterized in that: The setting time after the grouting in step 5) is 0-60 minutes.

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