Biomineralization radial solidification sand hollow cylinder sample preparation device

Abstract

The invention relates to the technical field of biomineralization, in particular to a biomineralization radial solidification sandy soil hollow cylinder sample preparation device which comprises a base, an inner cylinder and an outer cylinder, the bottoms of the inner cylinder and the outer cylinder are coaxially arranged on the base in a sealed mode, a cover plate is arranged on the tops of the inner cylinder and the outer cylinder in a sealed mode, and a sample preparation cavity is formed between the inner cylinder and the outer cylinder. A plurality of grouting holes are uniformly formed in the side walls, close to the sample preparation cavity, of the inner cylinder and the outer cylinder at intervals in a staggered mode, urease or a bacterial solution and a cementing solution are injected into the grouting holes of the inner cylinder and the outer cylinder respectively, an electroosmosis device is arranged on the cover plate, and the positive electrode and the negative electrode of the electroosmosis device are electrically connected with the inner cylinder and the outer cylinder respectively. The urease or bacteria solution with negative charges moves towards the positive electrode, and the cementing liquid with positive charges moves towards the negative electrode. Slurry is uniformly injected into the hollow cylinder sample, and the soil body reinforcing effect is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomineralization, and particularly relates to a biomineralization radial solidification sand soil hollow cylinder sample preparation device. BACKGROUND

[0002] Biomineralization technology is a technology for inducing calcium carbonate precipitation by using microorganisms or biological enzymes to solidify soil, and the technology promotes urea decomposition by using urease-producing bacteria or urease, and the carbonate ions generated after urea decomposition can combine with free metal cations, especially calcium ions, in the liquid environment to generate crystals with cementation effect, thereby achieving soil reinforcement. Enzyme-induced calcium carbonate precipitation can be divided into animal source enzyme-induced calcium carbonate precipitation and plant source enzyme-induced calcium carbonate precipitation according to different enzyme sources.

[0003] In the process of reinforcing the hollow cylinder sample by using a conventional sample preparation mold, due to the particularity of the cross-sectional shape and size, it is difficult to ensure that the reaction liquid and the cementing liquid are uniformly drip irrigated on the sample cross section, and after the top of the sample is reinforced, the urease or bacteria and the cementing liquid injection pore channel will be blocked, resulting in uneven longitudinal reinforcement of the sample. In the case of less reinforcement times, low activity of urease or bacteria, or both, the special size of the test piece leads to difficulty in demolding, and the demolding process will cause great disturbance to the test piece, thereby reducing the accuracy of the test results.

[0004] The application with the publication number CN117664683A discloses a microbial reinforcement sand soil hollow cylinder sample preparation device and a use method, which comprises a control system electrically connected with a grouting system, and the grouting system is communicated with a sample system; the sample system comprises an outer cylinder and an inner cylinder, both of which are coaxially arranged on a base, and a grouting cavity is left between the outer cylinder and the inner cylinder, and a soil sample is arranged in the grouting cavity; a plurality of first communication hole groups are formed in the outer cylinder and communicated with the grouting cavity, and the first communication hole groups are equally and interval arranged from top to bottom; a plurality of second communication hole groups are formed in the side wall of the inner cylinder and communicated with the grouting cavity, and the second communication hole groups are equally and interval arranged from top to bottom; and the first communication hole groups and the second communication hole groups are communicated with the grouting system. Although the grouting uniformity can be improved to a certain extent by shortening the seepage path, due to the particularity of the sample cross-sectional shape and size, it is difficult to ensure that the reaction liquid and the cementing liquid are uniformly drip irrigated on the sample cross section, thereby leading to uneven sample reinforcement. SUMMARY

[0005] The present application aims to solve the defects in the prior art, and provides a biomineralization radial solidification sand soil hollow cylinder sample preparation device, which can uniformly inject slurry into the hollow cylinder sample and improve the soil reinforcement effect.

[0006] In order to achieve the above object, the present application provides a kind of biological mineralization radial solidification sand soil hollow cylinder sample preparation device, including base, inner tube and outer tube, the bottom of the inner tube and the outer tube is coaxially sealed and arranged on the base, the top of the inner tube and the outer tube is sealed and provided with cover plate, the inner tube and the outer tube are formed sample preparation cavity between, the inner tube and the outer tube are uniformly spaced and staggered and provided with multiple grouting holes on the side wall close to the sample preparation cavity, the grouting hole of the inner tube and the outer tube is used for respectively injecting urease or bacterial solution and cementing fluid, the cover plate is provided with electroosmosis device, the positive and negative poles of the electroosmosis device are electrically connected with the inner tube and the outer tube respectively, to make the urease or bacterial solution with negative charge move to positive electrode, and the cementing fluid with positive charge moves to negative electrode.

[0007] In the present application, the inner tube, the outer tube, the base and the cover plate constitute the sample preparation cavity of the hollow cylinder test piece, due to the special size of the hollow cylinder, the radial thickness is relatively small, and the axial height is relatively large, by setting grouting holes on the side wall of the inner tube and the outer tube, compared with the vertical axial grouting mode, radial reinforcement of the hollow cylinder test sample is realized, which can effectively improve the uniformity of the test piece reinforcement and avoid affecting the accuracy of the hollow cylinder torsion shear test;By connecting the inner tube and the outer tube with the positive and negative poles of the electroosmosis device respectively, the inner tube and the outer tube constitute two electrodes of the electroosmosis device, so as to apply electric field to the soil body at both ends in the sample preparation cavity, so that the urease or bacteria with negative charge can move to the positive electrode, and the calcium ions with positive charge in the cementing fluid can move to the negative electrode, thereby forming seepage to improve the grouting reinforcement effect.

[0008] Optionally, the electroosmosis device includes a direct current power supply, a multimeter and two conductive sheets, the direct current power supply is arranged outside the cover plate, the multimeter is connected in series with the direct current power supply through a wire, and the two conductive sheets are arranged on the cover plate, the outer ends are connected with the positive and negative poles of the direct current power supply respectively, and the inner ends are connected with the side walls of the inner tube and the outer tube close to the sample preparation cavity respectively.

[0009] In the present application, the voltage value of the direct current power supply can be determined according to the test conditions to ensure that the urease or bacteria maintains a certain activity, the multimeter is used to measure the potential difference, by calculating the ratio of potential difference and the spacing of two conductive sheets, the value of potential gradient can be obtained, by adjusting the potential gradient in a suitable range, to ensure the electroosmosis effect.

[0010] Optionally, the base is provided with a liquid injection channel, two ends of the liquid injection channel respectively extend upward and are communicated with a first connector and a second connector, the inner cylinder and the outer cylinder are respectively provided with a third connector and a fourth connector at lower parts of side walls thereof, the third connector and the fourth connector are communicated with the corresponding grouting hole, the first connector is communicated with the third connector through a conduit, and the second connector and the fourth connector are used for connecting a peristaltic pump and respectively sucking the urease or bacterial solution and the cementing liquid.

[0011] In the application, the peristaltic pump is used to inject the urease or bacterial solution and the cementing liquid from opposite sides of the sample preparation cavity through the corresponding grouting hole, the second connector, the liquid injection channel, the first connector, the conduit and the third connector are arranged to realize grouting to the side of the sample preparation cavity close to the inner cylinder, and the fourth connector is connected to realize grouting to the side of the sample preparation cavity close to the outer cylinder, so that the grouting process is not limited by the structure and installation position of the inner cylinder and the outer cylinder, and the smooth grouting process is ensured.

[0012] Optionally, the outer cylinder comprises a plurality of first petals uniformly divided along the radial direction, waterproof adhesive tape is pasted at the joint of adjacent two first petals, and buckles for binding hoops are arranged on the outer wall of the first petals.

[0013] In the application, the outer cylinder is formed by a plurality of first petals, so that the outer cylinder is more simple and quick to disassemble, the disturbance to the test piece is reduced, the maintenance and local replacement of the outer cylinder are facilitated, the reliability of the outer cylinder structure and the accuracy of the test are ensured, the waterproof adhesive tape plays a role in preventing liquid leakage and assisting in adhesion and fixation, the hoops play a further fixation role, and the plurality of first petals are prevented from being deformed by being stretched apart.

[0014] Optionally, the inner cylinder comprises two second petals and two third petals which are divided away from the radial direction, the second petals and the third petals are sequentially and spacedly arranged, waterproof adhesive tape is pasted at the joint of the second petals and the third petals, a fixing rod is arranged between the two second petals in a supporting mode, and the fixing rod abuts and fixes the end faces of the two second petals on the end faces of the two third petals.

[0015] In the application, since the joint of the second petals and the third petals is away from the radial direction, when the second petals and the third petals act on each other through the fixing rod, the contact surfaces of the second petals and the third petals can abut on each other, so that the entire inner cylinder is stably fixed.

[0016] Optionally, it further comprises a cross pressing plate, a threaded rod and a butterfly screw, a first through hole is formed in the middle of the cross pressing plate, a threaded hole is formed in the top center of the base, a second through hole is formed in the fixed rod, the lower end of the threaded rod is sequentially inserted into the first through hole and the second through hole downwards and is threadedly connected with the threaded hole, the butterfly screw is threadedly connected with the upper end of the threaded rod and abuts against the top surface of the cross pressing plate, and the bottom surface of the cross pressing plate is pressed against the cover plate.

[0017] In the application, the lower end of the threaded rod is fixedly connected with the base through the threaded connection of the threaded hole, the cross pressing plate can be pressed tightly on the cover plate by screwing the butterfly screw into the threaded rod downwards, so that the bottom of the cover plate can be tightly attached to the upper ends of the inner cylinder and the outer cylinder, and the butterfly screw has a hand screwing structure, so that the tightening effect can be achieved without the aid of other tools, and the operation is more convenient.

[0018] Optionally, it further comprises an outer cover cylinder coaxially arranged outside the outer cylinder, a first annular groove is formed in the base, the lower end of the outer cover cylinder is sealingly inserted into the first annular groove, and the bottom surface of the cross pressing plate is formed with a second annular groove, and the upper end of the outer cover cylinder is inserted into the second annular groove.

[0019] In the application, the outer cover cylinder is clamped and positioned through the first annular groove and the second annular groove, and the outer cover cylinder can be fixed in the first annular groove and the second annular groove under the pressing action of the cross pressing plate when the butterfly screw is tightened.

[0020] Optionally, a temperature buffer cavity is formed between the outer cover cylinder and the outer cylinder and inside the inner cylinder, clean water can be contained in the temperature buffer cavity, an electric heating wire and a temperature sensor are arranged in the temperature buffer cavity, the temperature sensor is electrically connected with the electric heating wire, the electric heating wire is electrically connected with an external power supply, and a temperature controller is arranged on the outer wall of the outer cover cylinder and electrically connected with the electric heating wire and the temperature sensor.

[0021] In the application, the temperature controller is arranged to control the start and stop of the electric heating wire in the temperature buffer cavity, the contained clean water can be heated, and the temperature of the whole device can be controlled through the joint action of the temperature sensor and the electric heating wire, so that the temperature can be preheated to the required temperature before grouting.

[0022] Optionally, a buffer liquid channel is formed in the base, the two ends of the buffer liquid channel are upwardly inserted out of the top surface of the base and respectively communicate with the temperature buffer cavities between the outer cover cylinder and the outer cylinder and inside the inner cylinder.

[0023] In the present application, the communication between the area surrounded by the inner cylinder and the area surrounded by the outer cylinder and the outer cover is realized through the buffer channel, so that the two sides of the sample preparation cavity can be uniformly preheated by the heated clean water before grouting.

[0024] Optionally, an anti-seepage net is arranged in each of the grouting holes, and filter paper is arranged on the bottom and the side wall of the sample preparation cavity.

[0025] In the present application, by arranging the anti-seepage net in the grouting hole, the soil particles are prevented from entering the grouting hole to cause blockage, and by arranging the filter paper on the inner wall of the sample preparation cavity, the back filtration of the slurry is prevented, so as to improve the uniformity of grouting, and at the same time, the retention time of the chemical liquid and the cementing liquid on one side of the sample preparation cavity during grouting is effectively prevented, so as to avoid the cementing of the sample grouting side too fast, thereby hindering the further penetration of the slurry, and improving the reinforcement effect of the sample. In addition, the adhesion of the soil sample to the mold is also prevented, and the problem of difficult demolding is avoided, thereby improving the uniformity of the overall consolidation of the sample.

[0026] Beneficial effects:

[0027] The inner cylinder, the outer cylinder, the base and the cover plate of the present application constitute the sample preparation cavity of the hollow cylindrical test piece. Due to the special size of the hollow cylinder, the radial thickness is relatively small, and the axial height is relatively large. By arranging the grouting holes on the side walls of the inner cylinder and the outer cylinder, compared with the vertical axial grouting mode, the radial reinforcement of the hollow cylindrical test piece is realized, which can effectively improve the uniformity of the test piece reinforcement and avoid affecting the accuracy of the hollow cylindrical torsional shear test. By connecting the inner cylinder and the outer cylinder with the positive and negative electrodes of the electro-osmotic device respectively, the inner cylinder and the outer cylinder constitute the two electrodes of the electro-osmotic device, so as to apply an electric field to the soil at both ends of the sample preparation cavity, so that the urease or bacteria with negative charge can move to the positive electrode, and the calcium ions with positive charge in the cementing liquid can move to the negative electrode, thereby forming seepage, so as to improve the grouting reinforcement effect. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to the structures shown in the drawings without creative labor.

[0029] Figure 1 It is a sectional view of the biological mineralization radial solidification sand soil hollow cylindrical sample preparation device disclosed by the present application;

[0030] Figure 2 It is a top view of the biological mineralization radial solidification sand soil hollow cylindrical sample preparation device disclosed by the present application;

[0031] Figure 3 Figure 1 is a schematic view of the installation of the inner cylinder and the outer cylinder disclosed in the present application;

[0032] Figure 4 Figure 2 is a schematic view of the grouting of the electroosmosis device disclosed in the present application.

[0033] Reference signs:

[0034] 1, base; 11, liquid injection channel; 12, first joint; 13, second joint; 14, buffer solution channel; 2, inner cylinder; 21, third joint; 22, second flap; 23, third flap; 24, fixing rod; 3, outer cylinder; 31, fourth joint; 32, first flap; 33, buckle; 4, cover plate; 41, liquid discharge hole; 5, electroosmosis device; 51, direct current power supply; 52, multimeter; 53, conductive sheet; 61, grouting hole; 62, sample preparation cavity; 63, catheter; 64, cross pressure plate; 65, threaded rod; 66, butterfly screw; 67, temperature buffer cavity; 7, outer cover cylinder; 81, heating wire; 82, temperature sensor; 83, temperature controller.

[0035] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0037] In the description of the present application, the words such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present application in combination with the specific content of the technical solutions.

[0038] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0039] Reference is made to Figure 1 and Figure 4According to the embodiment of the application, a kind of biological mineralization radial solidification sandy soil hollow cylinder sample preparation device, including base 1, inner cylinder 2 and outer cylinder 3, the bottom of the inner cylinder 2 and the outer cylinder 3 is coaxially sealed and arranged on the base 1, the top of the inner cylinder 2 and the outer cylinder 3 is sealed and provided with cover plate 4, the inner cylinder 2 and the outer cylinder 3 form sample preparation cavity 62 between, the inner cylinder 2 and the outer cylinder 3 are uniformly spaced and staggered and are provided with a plurality of grouting holes 61 on the side wall close to the sample preparation cavity 62, the grouting hole 61 of the inner cylinder 2 and the outer cylinder 3 is used for respectively injecting urease or bacterial solution and cementing fluid, the cover plate 4 is provided with electroosmosis device 5, the positive and negative electrodes of the electroosmosis device 5 are electrically connected with the inner cylinder 2 and the outer cylinder 3 respectively, to make the urease or bacterial solution with negative charge move to positive electrode, and the cementing fluid with positive charge moves to negative electrode.

[0040] In the application, the inner cylinder 2, the outer cylinder 3, the base 1 and the cover plate 4 form the sample preparation cavity 62 of the hollow cylinder test piece, due to the special size of the hollow cylinder, the radial thickness is relatively small, and the axial height is relatively large, by arranging the grouting hole 61 on the side wall of the inner cylinder 2 and the outer cylinder 3, compared with the vertical axial grouting mode, the radial reinforcement of the hollow cylinder test piece is realized, the uniformity of the test piece reinforcement can be effectively improved, and the accuracy of the hollow cylinder torsion shear test is avoided to be affected; by connecting the inner cylinder 2 and the outer cylinder 3 with the positive and negative electrodes of the electroosmosis device 5 respectively, the inner cylinder 2 and the outer cylinder 3 form two electrodes of the electroosmosis device 5, so as to apply electric field to the soil body at both ends in the sample preparation cavity 62, so that the urease or bacteria with negative charge can move to the positive electrode, and the calcium ion with positive charge in the cementing fluid can move to the negative electrode, thereby forming seepage flow, to improve the grouting reinforcement effect.

[0041] Specifically, in one embodiment of the application, the urease or bacterial solution is specifically soybean urease, and the extraction of urease from soybeans for reinforcing soil is soybean urease induced calcium carbonate precipitation. Compared with the technology of microbial induced calcium carbonate precipitation, the soybean source is wide and the cost is low, which has high economic value, and the culture step of microorganism is reduced, the technology is easy to operate, the small size of free urease is used, which is more easily to penetrate the soil of fine particles, relatively difficult to cause biological blockage in the soil, and the urease is harmless to the environment, which reduces the possibility of biological pollution.

[0042] Specifically, a plurality of drainage holes 41 are also provided through the cover plate 4, the plurality of drainage holes 41 are uniformly spaced and arranged in an annular array and are communicated with the sample preparation cavity 62, to ensure that the overflow liquid is removed and collected during the reinforcement process, and the grouting effect is improved.

[0043] Referring to Figure 1In some embodiments of the present application, the electroosmosis device 5 comprises a direct current power supply 51, a multimeter 52 and two conductive sheets 53. The direct current power supply 51 is arranged outside the cover plate 4. The multimeter 52 is connected in series with the direct current power supply 51 through a wire. The two conductive sheets 53 are arranged on the cover plate 4. The outer ends of the two conductive sheets 53 are connected to the positive and negative poles of the direct current power supply 51 respectively. The inner ends of the two conductive sheets 53 are connected to the inner cylinder 2 and the outer cylinder 3 respectively.

[0044] In the present application, the voltage value of the direct current power supply 51 can be determined according to the test conditions to ensure that the urease of soybean maintains a certain activity. The multimeter 52 is used to measure the potential difference. By calculating the ratio of the potential difference to the distance between the two conductive sheets 53, the value of the potential gradient can be obtained. The potential gradient is adjusted to be 0.2-1.5 V / cm to ensure the electroosmosis effect.

[0045] Referring to Figure 1 In some embodiments of the present application, the base 1 is provided with a liquid injection channel 11. The two ends of the liquid injection channel 11 extend upward and are connected to a first joint 12 and a second joint 13 respectively. The side walls of the inner cylinder 2 and the outer cylinder 3 are provided with a third joint 21 and a fourth joint 31 respectively. The third joint 21 and the fourth joint 31 are connected to the corresponding grouting holes 61. The first joint 12 is connected to the third joint 21 through a conduit 63. The second joint 13 and the fourth joint 31 are used to connect a peristaltic pump and to suck the soybean urease solution and the cementing liquid respectively.

[0046] In the present application, the peristaltic pump is used to inject the soybean urease solution and the cementing liquid from the opposite sides of the sample preparation cavity 62 through the corresponding grouting holes 61. The second joint 13, the liquid injection channel 11, the first joint 12, the conduit 63 and the third joint 21 are arranged to realize grouting to the side of the sample preparation cavity 62 close to the inner cylinder 2. By connecting the fourth joint 31, grouting to the side of the sample preparation cavity 62 close to the outer cylinder 3 is realized. The grouting process is not limited by the structure and installation position of the inner cylinder 2 and the outer cylinder 3, ensuring the smooth progress of the grouting process.

[0047] Specifically, the side walls of the inner cylinder 2 and the outer cylinder 3 are vertically provided with grouting channels. The outer ends of the grouting holes 61 are connected to the sample preparation cavity 62. The inner ends of the grouting holes 61 are connected to the grouting channels. The third joint 21 and the fourth joint 31 are also connected to the grouting channels. When the slurry is injected into the corresponding grouting channels from the third joint 21 and the fourth joint 31, part of the slurry enters the sample preparation cavity 62 through the lower grouting holes 61. The other part of the slurry moves upward along the grouting channels and enters the sample preparation cavity 62 through the upper grouting holes 61. Until the soil sample in the sample preparation cavity 62 is grouted through the multiple grouting holes 61 from bottom to top, uniform radial grouting effect is realized.

[0048] Specifically, the peristaltic pump not only has a function of sucking slurry and being capable of injecting slurry into the sample preparation cavity 62, but also has a function of pumping slurry and being capable of pumping out waste liquid in the injection channel 11, the first joint 12, the second joint 13, the third joint 21 and the fourth joint 31 when the motor of the peristaltic pump is reversed, so as to prevent the next injection of slurry from being affected by blockage caused in the maintenance process.

[0049] Referring to Figure 1 and Figure 3 In some embodiments of the present application, the outer cylinder 3 comprises a plurality of first petals 32 which are uniformly divided along the radial direction, the joints of two adjacent first petals 32 are pasted with waterproof tape, and buckles 33 for binding hoops are arranged on the outer wall of the first petals 32.

[0050] In the present application, the outer cylinder 3 is formed by a plurality of first petals 32, which makes the disassembly of the outer cylinder 3 more simple and fast, reduces the disturbance to the test piece, facilitates the maintenance and local replacement of the outer cylinder 3, ensures the reliability of the structure of the outer cylinder 3 and the accuracy of the test, and the waterproof tape plays a role in preventing liquid leakage and assisting in adhesion and fixation, and the hoops play a further fixing role to avoid deformation of the plurality of first petals 32 caused by being stretched apart.

[0051] Referring to Figure 1 and Figure 3 In some embodiments of the present application, the inner cylinder 2 comprises two second petals 22 and two third petals 23 which are divided away from the radial direction, the second petals 22 and the third petals 23 are arranged in sequence with a spacing therebetween, and the joints are pasted with waterproof tape, a fixing rod 24 is arranged between the two second petals 22 in a supporting manner, and the end faces of the two second petals 22 are abutted and fixed on the end faces of the two third petals 23 by the fixing rod 24.

[0052] In the present application, since the joints of the second petals 22 and the third petals 23 are offset from the radial direction, when the second petals 22 and the third petals 23 act on each other through the fixing rod 24, the contact surfaces of the second petals 22 and the third petals 23 can abut on each other, thereby realizing stable fixation of the entire inner cylinder 2.

[0053] Specifically, the circumferential dimension of the second petals 22 is smaller than that of the third petals 23, and the central angle of the second petals 22 gradually decreases from inside to outside along the radial direction, vertical grooves are formed in the inner sides of the two second petals 22, and the fixing rod 24 is transversely arranged between the two second petals 22 and connected to the two vertical grooves in a one-to-one correspondence at both ends, so as to abut the contact surfaces of the two second petals 22 and the two third petals 23. The inner surfaces of the first petals 32, the second petals 22 and the third petals 23 are coated with an insulating and heat-conducting coating, which ensures the effective performance of electroosmosis and the safety of the equipment.

[0054] Referring to Figure 1 and Figure 2 In some embodiments of the present application, a cross plate 64, a threaded rod 65 and a butterfly screw 66 are further included, a first through hole is formed in the middle of the cross plate 64, a threaded hole is formed in the top center of the base 1, a second through hole is formed in the fixed rod 24, the lower end of the threaded rod 65 is sequentially inserted into the first through hole and the second through hole downward, and is threadedly connected with the threaded hole, the butterfly screw 66 is threadedly connected with the upper end of the threaded rod 65 and abuts against the top surface of the cross plate 64, and the bottom surface of the cross plate 64 is pressed against the cover plate 4.

[0055] In the present application, the lower end of the threaded rod 65 is fixedly connected with the base 1 through the threaded connection with the threaded hole, the cross plate 64 can be pressed against the cover plate 4 by screwing the butterfly screw 66 into the threaded rod 65 downward, so that the bottom of the cover plate 4 can be tightly attached to the upper end of the inner cylinder 2 and the outer cylinder 3, and the butterfly screw 66 has a hand screw structure, without the aid of other tools, the tightening effect can be achieved, and the operation is more convenient.

[0056] Referring to Figure 1 In some embodiments of the present application, an outer cover cylinder 7 is coaxially arranged outside the outer cylinder 3, a first annular groove is formed in the base 1, the lower end of the outer cover cylinder 7 is sealingly inserted into the first annular groove, and the bottom surface of the cross plate 64 is formed with a second annular groove, and the upper end of the outer cover cylinder 7 is inserted into the second annular groove.

[0057] In the present application, the first annular groove and the second annular groove are used to achieve the clamping positioning of the outer cover cylinder 7, and when the butterfly screw 66 is tightened, the pressing action of the cross plate 64 enables the outer cover cylinder 7 to be fixed in the first annular groove and the second annular groove.

[0058] Referring to Figure 1 In some embodiments of the present application, a temperature buffer cavity 67 is formed between the outer cover cylinder 7 and the outer cylinder 3 and inside the inner cylinder 2, clean water can be contained in the temperature buffer cavity 67, an electric heating wire 81 and a temperature sensor 82 are arranged in the temperature buffer cavity 67, the temperature sensor 82 is electrically connected with the electric heating wire 81, the electric heating wire 81 is electrically connected with an external power supply, a temperature controller 83 is arranged on the outer wall of the outer cover cylinder 7, and the temperature controller 83 is electrically connected with the electric heating wire 81 and the temperature sensor 82.

[0059] In the present application, the temperature controller 83 is arranged to control the start and stop of the electric heating wire 81 in the temperature buffer cavity 67, the contained clean water can be heated, and the temperature of the entire device can be controlled through the joint action of the temperature sensor 82 and the electric heating wire 81, so that the temperature can be preheated before grouting to reach the required temperature.

[0060] Specifically, the material of the outer cover cylinder 7 is organic glass, and when the temperature controller 83 controls the work of the heating wire 81, the outer cover cylinder 7 of the organic glass material has a certain temperature insulation effect, which ensures the stability of the preheating temperature.

[0061] Referring to Figure 1 In some embodiments of the present application, a buffer solution channel 14 is formed in the base 1, two ends of the buffer solution channel 14 pass through the top surface of the base 1 upward and are respectively connected with the temperature buffer cavity 67 between the outer cover cylinder 7 and the outer cylinder 3 and the inside of the inner cylinder 2.

[0062] In the present application, the buffer solution channel 14 realizes the communication between the area surrounded by the inner cylinder 2 and the area surrounded by the outer cylinder 3 and the outer cover cylinder 7, so that the two sides of the sample preparation cavity 62 can be uniformly preheated by the heated clean water before grouting.

[0063] Specifically, the temperature buffer cavity 67 further comprises a liquid storage container, and the liquid storage container comprises at least two chambers, wherein the two chambers are respectively used for placing cementing liquid and soybean urease solution, the influence of environmental pH value on grouting reinforcement is controlled by adjusting the pH value of the cementing liquid, and the concentration and ratio of the soybean urease solution and the cementing liquid are adjusted by controlling the addition amount of the soybean urease solution and the cementing liquid.

[0064] In some embodiments of the present application, an anti-seepage net is arranged in each of the grouting holes 61, and filter paper is arranged on the bottom and the side wall of the sample preparation cavity 62.

[0065] In the present application, the anti-seepage net arranged in the grouting hole 61 prevents soil particles from entering the grouting hole 61 and causing blockage, the filter paper arranged on the inner wall of the sample preparation cavity 62 prevents back filtration of the slurry, improves the uniformity of grouting, effectively prevents the chemical liquid and the cementing liquid from staying on one side of the sample preparation cavity 62 for too long during grouting, avoids too fast cementing on the grouting side of the sample, and further hinders the further penetration of the slurry, thereby improving the reinforcement effect of the sample. In addition, it can also prevent the soil sample from adhering to the mold, avoid the problem of difficult demolding, and improve the uniformity of the overall consolidation of the sample.

[0066] Specifically, after the filter paper is arranged on the bottom and the side wall of the sample preparation cavity 62, the soil body is slowly added into the sample preparation cavity 62, and is preliminarily stirred uniformly by the stirring rod, and the soil body is compacted by the compactor, the compaction thickness is controlled to be 2 cm, the top surface of the soil body is scraped to improve the adhesion, the above process is repeated, the height of the test piece is controlled to be 20 cm, and the annular filter paper is placed on the top surface of the soil body to ensure that the soil body is completely wrapped by the filter paper, thereby avoiding the adhesion of the soil sample.

[0067] The application is fixed first when assembling, the threaded rod 65 is screwed into the threaded hole of the base 1 to complete the fixation, the two second petals 22 and the two third petals 23 are spliced to form the inner cylinder 2, and the waterproof tape is pasted at the joint, and the inner cylinder 2 is sealed and connected on the base 1, the fixing rod 24 is sleeved on the threaded rod 65, and the two ends of the fixing rod 24 are connected with the vertical grooves on the two second petals 22 respectively, then a plurality of first petals 32 are spliced to form the outer cylinder 3, and the waterproof tape is pasted at the joint, the outer cylinder 3 is sealed and installed on the base 1 through the hoop butt joint, the clamping buckle 33, the filter paper is arranged on the bottom and the side wall of the sample preparation cavity 62, the soil body is added into the sample preparation cavity 62, and the soil body is stirred and compacted, and the annular filter paper is arranged on the top of the soil body; the first joint 12 on the liquid injection channel 11 is communicated with the third joint 21 on the inner cylinder 2 through the conduit 63, and the second joint 13 on the liquid injection channel 11 and the fourth joint 31 on the outer cylinder 3 are connected with the peristaltic pump, the peristaltic pump is connected with the liquid storage container in communication, the lower end of the outer cover cylinder 7 is sealed and connected with the first annular groove on the base 1, then the cover plate 4 is sealed and covered on the top of the inner cylinder 2 and the outer cylinder 3, the cross compression plate 64 is sleeved on the threaded rod 65, and the upper end of the outer cover cylinder 7 is sealed and inserted into the second annular groove, the cross compression plate 64 is tightly pressed on the cover plate 4 through the tightening butterfly screw 66, clean water is injected into the temperature buffer cavity 67 as the temperature buffer liquid, the temperature controller 83 is opened, and the temperature is controlled through the temperature sensor 82 and the electric heating wire 81; the direct current power supply 51 and the multimeter 52 are connected in series through the wire, and the positive and negative poles of the direct current power supply 51 are connected with the two conductive sheets 53 respectively, so that the soybean urease solution is injected at the cathode and the cementing liquid is injected at the anode.

[0068] When working, the peristaltic pump is opened, the peristaltic pump respectively absorbs the soybean urease solution and the cementing liquid in the liquid storage container, the soybean urease solution is injected into the sample preparation cavity 62 from the grouting hole 61 on the inner cylinder 2 through the second joint 13, the liquid injection channel 11, the first joint 12, the conduit 63 and the third joint 21, the cementing liquid is injected into the sample preparation cavity 62 from the grouting hole 61 on the outer cylinder 3 through the fourth joint 31, when the grouting holes 61 of the inner cylinder 2 and the outer cylinder 3 are filled with the slurry, the electroosmosis device 5 is opened, when the slurry is injected, the peristaltic pump is controlled to reverse the pumping, the waste liquid in the grouting hole 61 is pumped out, the grouting hole 61 is prevented from being blocked during the maintenance process, the above-mentioned pumping and pumping processes are repeated until the predetermined cementing times are reached. After the grouting and cementing process is completed, the peristaltic pump, the temperature controller 83 and the electroosmosis device 5 are closed, after the device is cooled, the butterfly screw 66 is loosened, the outer cover cylinder 7 is removed, then the butterfly screw 66 is tightened again, so that the test piece is maintained. After the maintenance is completed, the device is slowly poured, the butterfly screw 66 is unscrewed, the cross compression plate 64, the cover plate 4 and the base 1 are removed, the fixing rod 24 is pulled out of the inner cylinder 2, the second petals 22 and the third petals 23 are removed in turn, and then the test piece is placed on the water-permeable stone to remove the outer cylinder 3.

[0069] The above merely describes the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structural variations or direct / indirect applications in other related technical fields, which are made based on the content of the present application specification and drawings, are included in the patent protection scope of the present application.

Claims

1. A hollow cylindrical sample preparation device for biomineralized radially solidified sand, characterized in that, The device includes a base (1), an inner cylinder (2), and an outer cylinder (3). The bottoms of the inner cylinder (2) and the outer cylinder (3) are coaxially sealed on the base (1). The tops of the inner cylinder (2) and the outer cylinder (3) are sealed with a cover plate (4). A sample preparation chamber (62) is formed between the inner cylinder (2) and the outer cylinder (3). Multiple grouting holes (61) are evenly spaced and staggered on the side walls of the inner cylinder (2) and the outer cylinder (3) near the sample preparation chamber (62). The grouting holes (61) of the inner cylinder (2) and the outer cylinder (3) are used to inject urease or bacterial solution and cementing liquid, respectively. An electroosmosis device (5) is provided on the cover plate (4). The positive and negative electrodes of the electroosmosis device (5) are electrically connected to the inner cylinder (2) and the outer cylinder (3), respectively, so that the negatively charged urease or bacterial solution moves towards the positive electrode and the positively charged cementing liquid moves towards the negative electrode.

2. The device for preparing hollow cylindrical samples of biomineralized radially solidified sand according to claim 1, characterized in that, The electroosmosis device (5) includes a DC power supply (51), a multimeter (52) and two conductive plates (53). The DC power supply (51) is located on the outside of the cover plate (4). The multimeter (52) is connected in series with the DC power supply (51) through a wire. The two conductive plates (53) are inserted through the cover plate, with their outer ends connected to the positive and negative terminals of the DC power supply (51) respectively, and their inner ends connected to the inner cylinder (2) and the outer cylinder (3) near the side wall of the sample preparation chamber (62) respectively.

3. The device for preparing hollow cylindrical samples of biomineralized radially solidified sand according to claim 1, characterized in that, The base (1) is provided with an injection channel (11). The two ends of the injection channel (11) extend upward and are connected to a first connector (12) and a second connector (13). The lower part of the side wall of the inner cylinder (2) and the outer cylinder (3) are respectively provided with a third connector (21) and a fourth connector (31). The third connector (21) and the fourth connector (31) are connected to the corresponding grouting hole (61). The first connector (12) and the third connector (21) are connected through a conduit (63). The second connector (13) and the fourth connector (31) are used to connect a peristaltic pump and respectively draw up the urease or bacterial solution and the cementing liquid.

4. The device for preparing hollow cylindrical samples of biomineralized radially solidified sand according to claim 1, characterized in that, The outer cylinder (3) includes a plurality of first petals (32) that are evenly divided radially. Waterproof tape can be pasted at the joint of two adjacent first petals (32). The outer wall of the first petal (32) is provided with buckles (33) for binding the hoops.

5. The device for preparing hollow cylindrical samples of biomineralized radially solidified sand according to claim 1, characterized in that, The inner cylinder (2) includes two second lobes (22) and two third lobes (23) that are offset from the radial division. The second lobes (22) and the third lobes (23) are arranged alternately, and waterproof tape can be pasted at the joint. A fixing rod (24) is provided between the two second lobes (22) to support them. The fixing rod (24) abuts and fixes the end faces of the two second lobes (22) to the end faces of the two third lobes (23).

6. The device for preparing a hollow cylindrical sample of radially solidified biomineralized sand according to claim 5, characterized in that, It also includes a cross plate (64), a threaded rod (65) and a wing screw (66). The cross plate (64) has a first through hole in the middle. The base (1) has a threaded hole at the top center. The fixing rod (24) has a second through hole. The lower end of the threaded rod (65) passes through the first through hole and the second through hole in sequence and is threadedly connected to the threaded hole. The wing screw (66) is threaded to the upper end of the threaded rod (65) and abuts against the top surface of the cross plate (64). The bottom surface of the cross plate (64) is pressed against the cover plate (4).

7. The device for preparing hollow cylindrical samples of biomineralized radially solidified sand according to claim 6, characterized in that, It also includes an outer cover (7) coaxially disposed on the outside of the outer cylinder (3), a first annular groove is provided on the base (1), the lower end of the outer cover (7) is sealed and inserted into the first annular groove, the bottom surface of the cross pressure plate (64) is formed with a second annular groove, and the upper end of the outer cover (7) is inserted into the second annular groove.

8. The device for preparing hollow cylindrical samples of biomineralized radially solidified sand according to claim 7, characterized in that, A temperature buffer chamber (67) is formed between the outer casing (7) and the outer cylinder (3) and inside the inner cylinder (2). The temperature buffer chamber (67) can hold clean water. A heating wire (81) and a temperature sensor (82) are provided in the temperature buffer chamber (67). The temperature sensor (82) is electrically connected to the heating wire (81). The heating wire (81) is electrically connected to an external power source. A temperature controller (83) is provided on the outer wall of the outer casing (7). The temperature controller (83) is electrically connected to the heating wire (81) and the temperature sensor (82).

9. The device for preparing a hollow cylindrical sample of radially solidified biomineralized sand according to claim 8, characterized in that, The base (1) has a buffer channel (14) inside. The two ends of the buffer channel (14) extend upward through the top surface of the base (1) and are respectively connected to the temperature buffer chamber (67) between the outer cover (7) and the outer cylinder (3) and the inside of the inner cylinder (2).

10. A hollow cylindrical sample preparation device for biomineralized radially solidified sand according to any one of claims 1 to 9, characterized in that, Each of the grouting holes (61) is provided with an anti-seepage mesh, and the bottom and sidewalls of the sample preparation chamber (62) are provided with filter paper.

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