Micp calcareous sand curing device for ring shear test and use method

Abstract

The invention belongs to the technical field of rock-soil ring shear testing, and particularly relates to a micp solidified calcareous sand device for a ring shear test and a use method.In the micp solidified calcareous sand device for the ring shear test, an upper shear box and a lower shear box are both made of transparent materials, and DIC three-dimensional full-field strain measurement is synchronously conducted through a DIC instrument in the test process; meanwhile, the change condition of the sample can be clearly observed, the upper shear box is communicated with the liquid supply assembly, the lower shear box is communicated with the recovery assembly, and a reagent is poured into the sample from top to bottom, so that the sample reinforcement uniformity is ensured, and the conditions that the surface is intensively cured and the curing uniformity is influenced are avoided; and the whole test process can be directly carried out on the ring shear apparatus, so that the test process is simpler and more convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of rock and soil ring shearing, and in particular relates to a MICP solidified calcareous sand device for ring shearing test and a use method thereof. Background Art

[0002] In the construction of islands and reefs in some areas, calcareous sandstone soil materials are mainly used for filling. However, when such islands and reefs face natural disasters such as landslides and earthquakes, they are prone to significant shear displacement, which in turn leads to the instability or even collapse of buildings. Therefore, it is necessary to measure the mechanical properties of calcareous sand under large shear displacement through ring shear tests.

[0003] At present, microbial reinforcement technology (MICP) is gradually applied to the reinforcement of calcareous sand. Therefore, it is extremely important to clarify the mechanical properties of MICP-reinforced calcareous sand under large shear displacement. However, some existing test devices have poor reinforcement uniformity and cannot intuitively observe the internal changes of the specimens. Therefore, a MICP-reinforced calcareous sand device and a method of use for ring shear test are urgently needed. Summary of the invention

[0004] The object of the present invention is to provide a MICP solidified calcareous sand device for ring shear test and a method of use to solve the above problems.

[0005] To achieve the above object, the present invention provides the following solutions: A MICP solidified calcareous sand device for ring shear test, comprising: A lower shear box is fixedly mounted on the base of the ring shear instrument, and the lower shear box is made of a transparent material; An upper shear box is installed above the lower shear box and communicated with the lower shear box. The upper shear box is made of a transparent material. The sample is filled in the lower shear box and the upper shear box. Ring cutter, placed inside the specimen; A liquid supply assembly, connected to the upper shear box, and used to introduce reagents into the upper shear box; A recovery component, connected to the lower shear box, and used for recovering excess reagent in the lower shear box; A blocking component is detachably connected to the lower shear box and the upper shear box, and the blocking component is used to prevent the reagents in the lower shear box and the upper shear box from flowing out.

[0006] Preferably, the lower shear box comprises: A lower disc, wherein a plurality of lower bolt holes are circumferentially evenly spaced on the lower disc, the plurality of lower bolt holes are circumferentially evenly spaced, the lower bolt holes are close to the outer edge of the lower disc, and the lower disc is bolted to the base of the ring shear instrument through the plurality of lower bolt holes; The lower annular body is coaxially fixed on the top surface of the lower disc. A plurality of outflow holes are circumferentially evenly spaced on the outer wall of the lower annular body. The outflow holes are close to the bottom end of the lower annular body. The lower annular body is connected to the recovery component through the outflow holes.

[0007] Preferably, the upper shear box comprises: An upper circular disk, wherein a plurality of upper bolt holes are circumferentially evenly spaced on the upper circular disk, the upper bolt holes are close to the outer edge of the upper circular disk, and the upper circular disk is bolted to the upper component of the ring shear instrument through the plurality of upper bolt holes; The top end of the upper annular body is circumferentially fixed to the inner edge of the upper annular disk, and a plurality of injection holes are circumferentially evenly spaced on the outer wall of the upper annular body. The upper annular body is connected to the liquid supply assembly through the plurality of injection holes.

[0008] Preferably, the liquid supply assembly comprises: A peristaltic pump, the liquid inlet of which is connected to two conical flasks, wherein the two conical flasks contain bacterial liquid and strengthening liquid respectively; The inlet of the diverter device is connected to the liquid outlet of the peristaltic pump, and the multiple outlets of the diverter device are respectively connected to multiple catheters, and the end of the catheter away from the diverter device is connected to the injection hole, and the multiple catheters are arranged in a one-to-one correspondence with the multiple injection holes.

[0009] Preferably, the recycling component comprises: The other several conduits are arranged one by one corresponding to the several outflow holes, one end of the conduit is connected to the outflow hole, and the other end leads to another conical flask, and the lead liquid flows into the conical flask through the conduit.

[0010] Preferably, the blocking component comprises: A plurality of plugging heads are adapted to the outflow hole and the injection hole and are detachably connected.

[0011] A method for using the MICP solidified calcareous sand device for ring shear test comprises the following steps: The lower shear box is fixedly installed on the base of the ring shear instrument, the upper shear box is placed above the lower shear box, the ring knife is placed in the lower shear box, the upper shear box and the lower shear box are sealed by the sealing assembly, the sample is filled into the upper shear box and the lower shear box by the sand rain method until the set height is reached, the sealing assembly is removed, the upper shear box is connected to the liquid supply assembly, the lower shear box is connected to the recovery assembly, the liquid supply assembly injects the reagent into the upper shear box, and the excess reagent flows into the recovery assembly, after the sample is solidified, the upper shear box is disconnected from the liquid supply assembly and the lower shear box is connected to the recovery assembly, and the upper shear box and the lower shear box are sealed by the sealing assembly, the upper shear box is connected to the upper part of the ring shear instrument, the DIC instrument is set up, the parameters are set and the ring shear test is started, the DIC three-dimensional full-field strain measurement is performed simultaneously, the internal changes of the sample are observed in real time, and the test is terminated when the sample reaches the failure condition.

[0012] Preferably, the sample includes original calcareous sand and calcareous sand with waterproof black coating, and the ratio of original calcareous sand to calcareous sand with waterproof black coating is 2:1.

[0013] Compared with the prior art, the present invention has the following advantages and technical effects: In the present invention, the upper shear box and the lower shear box are both made of transparent materials. The DIC three-dimensional full-field strain measurement is synchronously performed during the test by the DIC instrument, and the changes of the sample can be clearly observed at the same time. The upper shear box is connected to the liquid supply component, and the lower shear box is connected to the recovery component. The reagent is poured into the sample from top to bottom, which ensures the uniformity of sample reinforcement, and there will be no concentrated solidification on the surface, which affects the uniformity of solidification. The entire test process can be directly carried out on the ring shear instrument, and the test process is simpler and more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor: Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of the test steps of the present invention; Figure 3 is a flow chart of the test method of the present invention; Among them, 1. bacterial liquid; 2. reinforcement liquid; 3. conical flask; 4. peristaltic pump; 5. diversion device; 6. catheter; 7. upper shear box; 701. upper annular disk; 702. upper annular body; 703. injection hole; 704. upper bolt hole; 8. lower shear box; 801. lower disk; 802. lower annular body; 803. outflow hole; 804. lower bolt hole; 9. plugging head; 10. outlet liquid; 11. ring knife. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] Reference Figures 1 to 3 The present invention discloses a MICP solidified calcareous sand device for ring shear test, comprising: The lower shear box 8 is fixedly mounted on the base of the ring shear instrument, and the lower shear box 8 is made of transparent material; The upper shear box 7 is installed above the lower shear box 8 and communicated with the lower shear box 8. The upper shear box 7 is made of transparent material. The sample is filled inside the lower shear box 8 and the upper shear box 7. A ring cutter 11 is placed inside the sample; A liquid supply assembly, connected to the upper shear box 7, and used to introduce reagents into the upper shear box 7; A recovery component is connected to the lower shear box 8, and is used to recover excess reagent in the lower shear box 8; The blocking component is detachably connected to the lower shear box 8 and the upper shear box 7 , and is used to prevent the reagents in the lower shear box 8 and the upper shear box 7 from flowing out.

[0018] Further optimizing the scheme, the lower shear box 8 includes: A lower disc 801, wherein a plurality of lower bolt holes 804 are circumferentially evenly spaced on the lower disc 801, and the plurality of lower bolt holes 804 are circumferentially evenly spaced, and the lower bolt holes 804 are close to the outer edge of the lower disc 801, and the lower disc 801 is bolted to the base of the ring shear instrument through the plurality of lower bolt holes 804; The lower annular body 802 is coaxially fixed on the top surface of the lower disc 801. A plurality of outflow holes 803 are circumferentially evenly spaced on the outer wall of the lower annular body 802. The outflow holes 803 are close to the bottom end of the lower annular body 802. The lower annular body 802 is connected to the recovery component through the outflow holes 803.

[0019] Further optimizing the scheme, the upper shear box 7 comprises: An upper circular disk 701, wherein a plurality of upper bolt holes 704 are evenly spaced circumferentially on the upper circular disk 701, and the upper bolt holes 704 are close to the outer edge of the upper circular disk 701, and the upper circular disk 701 is bolted to the upper component of the ring shear instrument through the plurality of upper bolt holes 704; The top end of the upper annular body 702 is circumferentially fixed to the inner edge of the upper annular disk 701 . A plurality of injection holes 703 are circumferentially evenly spaced on the outer wall of the upper annular body 702 . The upper annular body 702 is connected to the liquid supply assembly through the plurality of injection holes 703 .

[0020] To further optimize the solution, the liquid supply components include: A peristaltic pump 4, the liquid inlet of which is connected to two conical flasks 3, wherein the two conical flasks 3 contain a bacterial solution 1 and a reinforcement solution 2 respectively; The inlet of the diverter device 5 is connected to the liquid outlet of the peristaltic pump 4, and the multiple outlets of the diverter device 5 are respectively connected to multiple catheters 6. The end of the catheter 6 away from the diverter device 5 is connected to the injection hole 703, and the multiple catheters 6 are arranged in a one-to-one correspondence with the multiple injection holes 703.

[0021] To further optimize the solution, the recycling components include: Another plurality of conduits 6 are arranged corresponding to the plurality of outflow holes 803 , one end of the conduit 6 is connected to the outflow hole 803 , and the other end leads into another conical flask 3 , and the lead liquid 10 flows into the conical flask 3 through the conduit 6 .

[0022] To further optimize the solution, the plugging components include: A plurality of plugging heads 9 are adapted to the outflow hole 803 and the injection hole 703 and are detachably connected.

[0023] A method for using a MICP solidified calcareous sand device for a ring shear test comprises the following steps: The lower shear box 8 is fixedly installed on the base of the ring shear instrument, the upper shear box 7 is placed above the lower shear box 8, the ring knife 11 is placed in the lower shear box 8, the upper shear box 7 and the lower shear box 8 are sealed by the sealing assembly, the sample is filled into the upper shear box 7 and the lower shear box 8 by the sand rain method until the set height is reached, the sealing assembly is removed, the upper shear box 7 is connected with the liquid supply assembly, and the lower shear box 8 is connected with the recovery assembly, the liquid supply assembly injects the reagent into the upper shear box 7, and the excess reagent flows into the recovery assembly, after the sample is solidified, the connection between the upper shear box 7 and the liquid supply assembly and the connection between the lower shear box 8 and the recovery assembly is disconnected, and the upper shear box 7 and the lower shear box 8 are sealed by the sealing assembly, the upper shear box 7 is connected to the upper part of the ring shear instrument, the DIC instrument is set up, the parameters are set and the ring shear test is started, and the DIC three-dimensional full-field strain measurement is carried out simultaneously, the internal changes of the sample are observed in real time, and the test is terminated when the sample reaches the failure condition.

[0024] The plan was further optimized, and the samples included original calcareous sand and calcareous sand with waterproof black coating, and the ratio of original calcareous sand to calcareous sand with waterproof black coating was 2:1.

[0025] One specific example: There are four injection holes 703, the top of which is 5 mm away from the top of the upper annulus 702, two outflow holes 803, and the bottom of which is 5 mm away from the bottom of the lower annulus 802. The plugging head 9 is preferably made of rubber, and the diameter of the plugging head 9 is 6 mm, which is convenient for plugging the injection hole 703 and the outflow hole 803 without leakage or falling off. There are four upper bolt holes 704 and four lower bolt holes 804, and the upper bolt holes 704 and the lower bolt holes 804 are arranged corresponding to the screw holes on the ring shear instrument. Align the four lower bolt holes 804 on the lower shear box 8 with the screw holes on the ring shear instrument base and fix the lower shear box 8 to the ring shear instrument base by bolts, place the upper shear box 7 on the top of the lower shear box 8 and align them, place the ring cutter 11 in the middle of the lower shear box 8, and block and seal the four injection holes 703 of the upper shear box 7 and the two outflow holes 803 of the lower shear box 8 by the plugging head 9; The sample is divided into two parts, and the ratio of the two parts is 2:1. One part of the sample is evenly sprayed with black waterproof coating to serve as calcareous sand with waterproof black coating. The calcareous sand with waterproof black coating is evenly mixed with the other two parts of original calcareous sand, and then filled into the upper shear box 7 and the lower shear box 8 by the sand rain method. The sample stops when it reaches the set height. Remove the plugging heads 9 on the upper shear box 7 and the lower shear box 8, connect the multiple catheters 6 to the four injection holes 703 and the two outflow holes 803 respectively, the catheters 6 connected to the two outflow holes 803 extend into the empty conical flask 3, the catheters 6 connected to the four injection holes 703 are all connected to the liquid outlet of the diverter device 5, the liquid inlet of the diverter device 5 is connected to the peristaltic pump 4, the peristaltic pump 4 is connected to the conical flask 3 containing the bacterial solution 1 or the reinforcement solution 2 through the catheter 6, firstly, the bacterial solution 1 is injected into the sample in the upper shear box 7 and the lower shear box 8 through the peristaltic pump 4, and then the bacterial solution 1 is injected into the sample in the upper shear box 7 and the lower shear box 8 through the peristaltic pump 4. A certain amount of bacterial liquid 1 flows out through the outflow hole 803 into the empty conical flask 3. When the bacterial liquid 1 flows out through the outflow hole 803, the catheter 6 connected to the inlet of the peristaltic pump 4 is taken out, and the peristaltic pump 4 continues to work until no bacterial liquid flows out of the injection hole 703. One hour later, the catheter 6 connected to the inlet of the peristaltic pump 4 is placed in the conical flask 3 containing the reinforcement liquid 2, and the peristaltic pump 4 is started to inject the reinforcement liquid 2 into the sample. The reinforcement liquid 2 combines with the bacterial liquid in the calcareous sand to solidify the calcareous sand, and the excess reinforcement liquid 2 flows out through the outflow hole 803 into the empty conical flask 3; Remove the catheter 6 on the injection hole 703 and the outflow hole 803, and seal the injection hole 703 and the outflow hole 803 with the sealing head 9, align the four upper bolt holes 704 on the upper shear box 7 with the screw holes on the upper part of the ring shear instrument and fix them with bolts, set up the DIC instrument, adjust the position of the DIC camera so that the DIC camera can shoot the calcareous sand sample through the highly transparent upper shear box 7 and the lower shear box 8 to obtain a clear speckle image, start the ring shear test after setting the parameters, and simultaneously perform DIC three-dimensional full-field strain measurement, and terminate the test when the sample reaches the failure condition.

[0026] The upper shear box 7 and the lower shear box 8 are both made of transparent material, preferably highly transparent polycarbonate, so that the strain and displacement changes of the sample during the shearing process can be tested using a DIC instrument, and the changes of the sample can be clearly observed; The test can be carried out directly on the ring shear apparatus; The arrangement of the peristaltic pump 4 and the diversion device 5 realizes the precise delivery of the bacterial solution 1 and the reinforcement solution 2, thereby improving the accuracy and repeatability of the test; The design of the upper shear box 7 and the lower shear box 8 ensures uniform injection and discharge of reagents, improves the consistency of calcareous sand solidification, and enhances the reliability of the test.

[0027] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0028] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A MICP solidified calcareous sand device for ring shear test, characterized in that: include: A lower shear box (8) is fixedly mounted on the base of the ring shear instrument, and the lower shear box (8) is made of a transparent material; an upper shear box (7) installed above the lower shear box (8) and connected to the lower shear box (8); the upper shear box (7) is made of a transparent material, and the sample is filled inside the lower shear box (8) and the upper shear box (7); A ring cutter (11) is placed inside the sample; A liquid supply component, connected to the upper shear box (7), the liquid supply component being used to introduce reagent into the upper shear box (7); A recovery component, connected to the lower shear box (8), the recovery component being used to recover excess reagent in the lower shear box (8); A blocking component is detachably connected to the lower shear box (8) and the upper shear box (7), and the blocking component is used to prevent the reagents in the lower shear box (8) and the upper shear box (7) from flowing out.

2. A MICP solidified calcareous sand device for ring shear test according to claim 1, characterized in that: The lower shear box (8) comprises: A lower disc (801), wherein a plurality of lower bolt holes (804) are circumferentially evenly spaced on the lower disc (801), the plurality of lower bolt holes (804) are circumferentially evenly spaced, the lower bolt holes (804) are close to the outer edge of the lower disc (801), and the lower disc (801) is bolted to a ring shear instrument base via the plurality of lower bolt holes (804); The lower annular body (802) is coaxially fixed to the top surface of the lower disc (801), and a plurality of outflow holes (803) are circumferentially evenly spaced on the outer wall of the lower annular body (802), wherein the outflow holes (803) are close to the bottom end of the lower annular body (802), and the lower annular body (802) is connected to the recovery component through the outflow holes (803).

3. A MICP solidified calcareous sand device for ring shear test according to claim 2, characterized in that: The upper shear box (7) comprises: An upper circular disk (701), wherein a plurality of upper bolt holes (704) are circumferentially evenly spaced on the upper circular disk (701), wherein the upper bolt holes (704) are close to the outer edge of the upper circular disk (701), and the upper circular disk (701) is bolted to an upper component of the ring shear instrument via the plurality of upper bolt holes (704); The top end of the upper annular body (702) is circumferentially fixed to the inner edge of the upper annular disk (701), and a plurality of injection holes (703) are circumferentially evenly spaced on the outer wall of the upper annular body (702). The upper annular body (702) is connected to the liquid supply assembly through the plurality of injection holes (703).

4. A MICP solidified calcareous sand device for ring shear test according to claim 3, characterized in that: The liquid supply assembly comprises: A peristaltic pump (4), the liquid inlet of which is connected to two conical flasks (3), wherein the two conical flasks (3) contain bacterial liquid (1) and strengthening liquid (2) respectively; The inlet of the flow dividing device (5) is connected to the liquid outlet of the peristaltic pump (4), and the multiple outlets of the flow dividing device (5) are respectively connected to multiple conduits (6), and one end of the conduit (6) away from the flow dividing device (5) is connected to the injection hole (703), and the multiple conduits (6) are arranged in a one-to-one correspondence with the multiple injection holes (703).

5. A MICP solidified calcareous sand device for ring shear test according to claim 4, characterized in that: The recycling assembly comprises: The other plurality of conduits (6) are arranged in one-to-one correspondence with the plurality of outflow holes (803); one end of the conduit (6) is connected to the outflow hole (803), and the other end leads into another conical flask (3); the lead liquid (10) flows into the conical flask (3) through the conduit (6).

6. A MICP solidified calcareous sand device for ring shear test according to claim 3, characterized in that: The blocking component comprises: A plurality of plugging heads (9), wherein the plugging heads (9) are adapted to the outflow hole (803) and the injection hole (703) and are detachably connected.

7. A method for using the MICP solidified calcareous sand device for ring shear test according to any one of claims 1 to 6, characterized in that: The following steps are involved: The lower shear box (8) is fixedly mounted on the base of the ring shear instrument, the upper shear box (7) is placed above the lower shear box (8), the ring knife (11) is placed in the lower shear box (8), the upper shear box (7) and the lower shear box (8) are sealed by a sealing component, the sample is filled into the upper shear box (7) and the lower shear box (8) by a sand rain method until a set height is reached, the sealing component is removed, the upper shear box (7) is connected to the liquid supply component, and the lower shear box (8) is connected to the recovery component, the liquid supply component injects the reagent into the upper shear box (7), and the excess reagent flows into the recovery component, after the sample is solidified, the connection between the upper shear box (7) and the liquid supply component and the connection between the lower shear box (8) and the recovery component is disconnected, and the upper shear box (7) and the lower shear box (8) are sealed by the sealing component, the upper shear box (7) is connected to the upper part of the ring shear instrument, the DIC instrument is set, the parameters are set and the ring shear test is started, the DIC three-dimensional full-field strain measurement is carried out simultaneously, the internal changes of the sample are observed in real time, and the test is terminated when the sample reaches the failure condition.

8. The method for using the MICP solidified calcareous sand device for ring shear test according to claim 7, characterized in that: The sample includes original calcareous sand and calcareous sand with waterproof black coating, and the ratio of the original calcareous sand to the calcareous sand with waterproof black coating is 2:1.

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