A test device and use method for strengthening soil based on MICP technology

Abstract

The present invention discloses a test device for strengthening soil based on MICP technology and a method for using the same. The device is composed of a sample preparation mold and a liquid injection auxiliary system. The sample preparation mold includes: a semicircular three-dimensional thin-walled groove cylinder, an edge slotted thin-walled round cover, an octagonal prism support rod, and a solid anti-seepage strip; the liquid injection auxiliary system includes: a device base, a three-dimensional hollow side plate, a side plate connecting a fixed plate, a movable hollow upper cover, and a drawer-type waste liquid collection bin. When preparing a sample of microbial solidified aeolian sand, the aeolian sand is filled into the sample preparation mold, and the edge slotted thin-walled round covers are buckled at both ends. The solid anti-seepage strip is embedded in the slot of the mold. The sample preparation mold is fixed in the liquid injection auxiliary system through the octagonal prism support rod. After the liquid is circulated by a peristaltic pump, it is transported to the opening in the groove by a liquid injection hose for injection. The present invention has the characteristics of reducing material loss, avoiding uneven injection due to partial soil consolidation, and significantly improving the injection efficiency and reinforcement effect.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial grouting test, and in particular relates to a test device for reinforcing soil based on MICP technology and a use method thereof. Background Art

[0002] Microbial induced calcium carbonate precipitation (MICP) technology is an emerging soil reinforcement technology in recent years. It has attracted more and more attention in the field of geotechnical engineering for its advantages such as environmental friendliness, cost savings, and simple operation. The bacteria used is a facultative anaerobic Bacillus pasteurianus. If it is cultured in moist soil with urea and liquid containing calcium, it can produce calcium carbonate metabolites between soil particles, which can cement loose soil particles into a whole, thereby improving the mechanical properties of the soil such as strength and permeability. Microbial induced calcium carbonate precipitation soil reinforcement technology has broad prospects for promotion and application.

[0003] Traditional microbial induced calcium carbonate precipitation technology uses Bacillus pasteurianus to migrate in the soil to precipitate calcium carbonate to strengthen the soil. However, since the bacteria do not migrate evenly in the soil and mainly stay on the solidified surface layer of the soil, the soil reinforcement effect is uneven, which is a major limitation of traditional microbial induced calcium carbonate precipitation technology.

[0004] The present invention proposes a test device and a method for solidifying soil based on MICP technology, which focuses on solving the problem of uneven solidification in soil reinforcement. Under this device, the migration ability of Bacillus pasteurianus is significantly improved, and the distribution in the soil is more uniform, not only completing solidification on the surface of the soil, overcoming the uneven problem of soil reinforcement in traditional microbial induced calcium carbonate precipitation technology. Summary of the invention

[0005] The object of the present invention is to provide a test device with simple device, high perfusion efficiency and uniform curing and a use method thereof.

[0006] The present invention is achieved through the following technical solutions:

[0007] A test device for strengthening soil based on MICP technology and a use method thereof include a sample preparation mold and a liquid injection auxiliary system.

[0008] The sample preparation mold comprises: a semicircular three-dimensional thin-wall groove cylinder, an edge-grooved thin-wall round cover, an octagonal column support rod, and a solid anti-seepage strip.

[0009] The liquid injection auxiliary system includes: a three-dimensional hollow side panel, a fixed plate connected to the rear of the side panel, a device base, a fixed plate connected to the front of the side panel, a drawer-type waste liquid collection bin body, a bottom protrusion of the drawer-type waste liquid collection bin, and a movable hollow upper cover.

[0010] A test device for strengthening soil based on MICP technology, comprising the following steps:

[0011] Step 1: After the edge protrusions of the semicircular three-dimensional thin-walled groove cylinder (11) and the semicircular three-dimensional thin-walled groove cylinder (12) are matched and embedded, an edge slotted thin-walled round cover (21) at one end is put on, and soil is poured. After the soil is filled, the edge slotted thin-walled round cover (22) at the other end is put on and the position is adjusted.

[0012] Step 2: After the semicircular three-dimensional thin-walled groove cylinder (1) and the edge slotted thin-walled round cover (2) are tightly fitted, a solid anti-seepage strip (6) is embedded into the groove of the semicircular three-dimensional thin-walled groove cylinder (1), with a total of seven strips embedded, leaving one groove for liquid injection.

[0013] Step 3: Fix the installed sample preparation mold in the liquid injection auxiliary system. When fixing, pass the octagonal column support rod (23) through the three-dimensional hollow side plate (31), and the octagonal column support rod (24) through the three-dimensional hollow side plate (32), adjust the position, and start liquid injection after stabilization.

[0014] Step 4: The bacterial solution and the cementing solution are circulated and transported through the injection hose by a peristaltic pump, and a certain injection frequency and injection speed are set.

[0015] Step 5: After the injection time is reached, the solid anti-seepage strip in the next groove of the semicircular three-dimensional thin-wall groove cylinder (1) is pulled out and embedded into the previous injection groove.

[0016] Step 6: Repeat steps 4 and 5 to pour all the grooves on the semicircular three-dimensional thin-wall groove cylinder (1), and then let it stand for 24 hours.

[0017] Step 7. After the curing reaction is completed, remove the sample mold from the injection auxiliary system, soak the sample in pure water for 24 hours, then demold and dry it, and carry out subsequent tests.

[0018] The beneficial effects of the present invention are:

[0019] This device can realize uniform reinforcement of soil. Through the injection of liquid in this device, the migration ability of Bacillus pasteurianus is significantly improved, and the distribution in the soil is more uniform. It not only completes the solidification on the surface of the soil, but also overcomes the uneven reinforcement problem of soil in traditional microbial induced calcium carbonate precipitation technology. The sample preparation mold in this device is processed by PLA polylactic acid plastic fuse CNC, which has good integrity and is not easy to deform. The surface is endowed with an anti-sticking layer. When the sample is separated from the mold, it is not easy to cause adverse phenomena such as missing corners of the sample. The mold is easy to clean after use and has high efficiency. In the use of this device, no electrical equipment is required, no energy is consumed, and it is safe and environmentally friendly. In general, this device will save time and effort in the process of MICP technology to reinforce the soil, and significantly improve the injection efficiency and reinforcement effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of a test device for strengthening soil based on MICP technology;

[0021] Figure 2 It is a schematic diagram of the structure of the injection auxiliary system;

[0022] Figure 3 This is a structural schematic diagram of a drawer-type waste liquid collection bin;

[0023] Figure 4 It is a schematic diagram of a movable hollow upper cover structure;

[0024] Figure 5 It is a schematic diagram of the overall structure of the sample making mold;

[0025] Figure 6 It is a schematic diagram of the structure of the sample making mold with complete installation;

[0026] Figure 7 It is a schematic diagram of the structure of a solid anti-seepage strip.

[0027] In the figure: 11-semicircular three-dimensional thin-walled groove cylinder, 12-semicircular three-dimensional thin-walled groove cylinder, 21-edge grooved thin-walled round cover, 22-edge grooved thin-walled round cover, 23-octagonal column support rod, 24-octagonal column support rod, 31-three-dimensional hollow side panel, 32-three-dimensional hollow side panel, 33-side panel rear connection fixing plate, 34-device base, 35-side panel front connection fixing plate, 41-drawer type waste liquid collection bin body, 42-drawer type waste liquid collection bin handle, 43-drawer type waste liquid collection bin bottom protrusion, 5-removable hollow upper cover, 6-solid anti-seepage strip. DETAILED DESCRIPTION

[0028] The present invention is further described clearly and completely below in conjunction with the accompanying drawings and specific embodiments. Based on the implementation of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0029] like Figure 1-7 As shown, the present invention relates to a test device for strengthening soil based on MICP technology and a method for using the device, comprising a sample preparation mold and a liquid injection auxiliary system. The sample preparation mold comprises: a semicircular three-dimensional thin-walled groove cylinder (1), an edge-grooved thin-walled round cover (21), an octagonal prism support rod (23), and a solid anti-seepage strip (6); the liquid injection auxiliary system comprises: a three-dimensional hollow side plate (31), a side plate rear connection fixing plate (33), a device base (34), a side plate front connection fixing plate (35), a drawer-type waste liquid collection bin body (41), a drawer-type waste liquid collection bin bottom protrusion (43), and a movable hollow upper cover (5).

[0030] A test device for strengthening soil based on MICP technology, the method comprising the following steps:

[0031] Step 1: Fit the semicircular three-dimensional thin-walled groove cylinder with the edge protrusion of the semicircular three-dimensional thin-walled groove cylinder, and then put on the edge slotted thin-walled round cover at one end, and start pouring soil. After it is full, put on the edge slotted thin-walled round cover at the other end and adjust the position.

[0032] Step 2: After the semicircular three-dimensional thin-walled groove cylinder and the edge slotted thin-walled round cover are tightly fitted, a solid anti-seepage strip is embedded into the groove of the semicircular three-dimensional thin-walled groove cylinder, a total of seven strips are embedded, and the remaining groove is used for liquid injection.

[0033] Step 3: Fix the installed sample preparation mold in the liquid injection auxiliary system. When fixing, pass the octagonal prism support rod through the three-dimensional hollow side plate, adjust the position, and start liquid injection after it is stable.

[0034] Step 4: The bacterial solution and the cementing solution are circulated and transported through the injection hose by a peristaltic pump, and a certain injection frequency and injection speed are set.

[0035] Step 5: After the injection time is reached, the solid anti-seepage strip in the next groove of the semicircular three-dimensional thin-wall groove cylinder is pulled out and embedded into the previous injection groove.

[0036] Step 6: Repeat steps 4 and 5 to pour all the grooves on the semicircular three-dimensional thin-walled groove cylinder, and let it stand for 24 hours.

[0037] Step 7. After the curing reaction is completed, remove the sample mold from the injection auxiliary system, soak the sample in pure water for 24 hours, then demold and dry it, and carry out subsequent tests.

[0038] The present invention provides a test device and a method for using the MICP technology to reinforce soil. This method can not only reduce material loss, but also avoid uneven pouring due to partial soil consolidation, and can significantly improve the pouring efficiency and reinforcement effect.

Claims

1. A test device for strengthening soil based on MICP technology, Features: The device comprises a sample preparation mold and a liquid injection auxiliary system; the sample preparation mold comprises: a semicircular three-dimensional thin-walled groove cylinder (1), an edge-grooved thin-walled round cover (21), an octagonal prism support rod (23), and a solid anti-seepage strip (6); the liquid injection auxiliary system comprises: a three-dimensional hollow side plate (31), a fixed plate (33) connected to the rear of the side plate, a device base (34), a fixed plate (35) connected to the front of the side plate, a drawer-type waste liquid collection bin body (41), a drawer-type waste liquid collection bin bottom protrusion (43), and a movable hollow upper cover (5); The semicircular three-dimensional thin-walled groove cylinder (11) and the semicircular three-dimensional thin-walled groove cylinder (12) are provided with a hollow mesh structure inside the grooves, and the semicircular three-dimensional thin-walled groove cylinder (11) and the semicircular three-dimensional thin-walled groove cylinder (12) are inlaid and connected through a central protruding structure, and the semicircular three-dimensional thin-walled groove cylinder (11) and the semicircular three-dimensional thin-walled groove cylinder (12) are provided with eight grooves in total, and the included angle between the center lines of adjacent grooves is 45°; The inner diameters of the edge grooved thin-walled round cover (21) and the edge grooved thin-walled round cover (22) are slightly larger than the outer diameter of the semicircular three-dimensional thin-walled grooved cylinder (1). The edge grooved thin-walled round cover (21) is inserted into the semicircular three-dimensional thin-walled grooved cylinder (1) and the position is adjusted. After the solid anti-seepage strip (6) is tightly fitted, it is embedded in the groove of the semicircular three-dimensional thin-walled grooved cylinder (1). A total of eight solid anti-seepage strips (6) are required; The semicircular three-dimensional thin-walled groove cylinder (11, 12), the edge slotted thin-walled round cover (21, 22), and the octagonal prism support rod (23, 24) are all made of PLA polylactic acid plastic filaments, and the inner surface of the structure is covered with an anti-sticking layer with low friction. During processing, the edge slotted thin-walled round cover (21) and the octagonal prism support rod (23) are made into one piece, and the edge slotted thin-walled round cover (22) and the octagonal prism support rod (24) are made into one piece. The three-dimensional hollow side panel (31), the three-dimensional hollow side panel (32), the side panel rear connection fixing plate (33), the device base (34), and the side panel front connection fixing plate (35) are made of polymethyl methacrylate material during CNC machining, and the three-dimensional hollow side panel (31), the three-dimensional hollow side panel (32), the side panel rear connection fixing plate (33), the device base (34), and the side panel front connection fixing plate (35) are processed into one piece; The bottom of the drawer-type waste liquid collection bin (41) is provided with a protrusion (43), and the bottom protrusion (43) is embedded in the device base (34), so that the drawer-type waste liquid collection bin (4) is simple and labor-saving during placement, and can not only be pushed and pulled vertically, but also stabilize its position horizontally.

2. A method for using a test device for strengthening soil based on MICP technology according to claim 1, It is characterized in that The following steps are involved: Step 1: fit the edge protrusions of the semicircular three-dimensional thin-walled groove cylinder (11) and the semicircular three-dimensional thin-walled groove cylinder (12) together, and then put on the edge slotted thin-walled round cover (21) at one end, and start pouring soil. After the soil is filled, put on the edge slotted thin-walled round cover (22) at the other end, and adjust the position; Step 2: After the semicircular three-dimensional thin-walled groove cylinder (1) and the edge slotted thin-walled round cover (2) are tightly fitted, a solid anti-seepage strip (6) is embedded into the groove of the semicircular three-dimensional thin-walled groove cylinder (1), with a total of seven strips embedded, leaving one groove for liquid injection; Step 3: Fix the installed sample preparation mold in the liquid injection auxiliary system. When fixing, pass the octagonal prism support rod (23) through the three-dimensional hollow side plate (31), and pass the octagonal prism support rod (24) through the three-dimensional hollow side plate (32), adjust the position, and start liquid injection after stabilization; Step 4: The bacterial solution and the cementing solution are circulated and transported through the injection hose by a peristaltic pump, and a certain injection frequency and injection speed are set; Step 5: After the injection time is reached, the solid anti-seepage strip in the next groove of the semicircular three-dimensional thin-wall groove cylinder (1) is pulled out and inserted into the previous injection groove; Step 6: Repeat steps 4 and 5 to pour all the grooves on the semicircular three-dimensional thin-wall groove cylinder (1), and then let it stand for 24 hours; Step 7. After the curing reaction is completed, remove the sample mold from the injection auxiliary system, soak the sample in pure water for 24 hours, then demold and dry it, and carry out subsequent tests.

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