CN113155567A - Hollow cylinder sample MICP curing sample preparation instrument and sample preparation method - Google Patents

Abstract

Translated fromChinese

本发明公开了一种空心圆柱试样MICP固化制样仪及制样方法，所述制样仪包括菌液存放皿、一号注浆管、一号蠕动泵、胶凝液存放皿、二号注浆管、二号蠕动泵、防水通气阀、一号玻璃塞、浆液路径扩散筒、管箍、有机玻璃管、二号玻璃塞、止水塞、石墨电极棒、直流电源以及渗出液收集皿，所述制样方法是基于MICP固化技术通过压力注浆提供浆液结合电渗增加浆液流动路径来进行制样，本发明的制样仪和制样方法实现了胶凝液与菌液的分离式注浆，避免了传统混合式注入方式引起的因过早发生碳酸钙沉积而堵塞渗透路径的缺陷，能显著提高所制试样固化均匀性和固化效果。

The invention discloses a hollow cylindrical sample MICP solidification sample preparation device and a sample preparation method. The sample preparation device comprises a bacterial liquid storage dish, a No. 1 grouting pipe, a No. 1 peristaltic pump, a gelling liquid storage dish, a No. 2 Grouting tube, No. 2 peristaltic pump, waterproof vent valve, No. 1 glass plug, slurry path diffusion cylinder, pipe clamp, plexiglass tube, No. 2 glass plug, water stopper, graphite electrode rod, DC power supply and exudate collection The sample preparation method is based on the MICP solidification technology to provide the slurry through pressure grouting combined with electroosmosis to increase the flow path of the slurry to prepare the sample. It avoids the defect of blocking the infiltration path due to premature calcium carbonate deposition caused by the traditional mixed injection method, and can significantly improve the curing uniformity and curing effect of the prepared samples.

Description

Hollow cylinder sample MICP curing sample preparation instrument and sample preparation method

Technical Field

The invention belongs to the technical field of solidification of samples crossed by multiple subjects such as geotechnical engineering subjects, chemistry, microorganisms, electronics and electricians and the like, and relates to a hollow cylindrical sample MICP solidification sample preparation instrument and a sample preparation method.

Background

The sea bed in south China sea is rich in calcareous sand, and is easy to break, liquefy, reduce bearing capacity and the like under the action of dynamic load (wave load, ocean current, engineering construction and the like). The main substance component of the calcareous sand is calcium Carbonate, and microorganism Induced calcium Carbonate Precipitation (MICP) can utilize spontaneous reaction in the microbial metabolism process to induce mineral Precipitation cemented particles so as to solve the problems of seabed sandy soil liquefaction, slope reinforcement, wind prevention and sand fixation, rock and soil material repair and the like, and the mineralized component is consistent with the original calcareous sand component, is ecological and environment-friendly, so that the application prospect in the south China sea engineering construction field is wide.

For fully researching the dynamic characteristics of MICP reinforced sandy soil under the action of waves, the dynamic property test of solidified calcareous sand needs to be carried out, the influence of continuous rotation of the main stress axis of the solidified sandy soil unit body under the action of wave circulating shear on the mechanical properties of sandy soil cannot be considered by a traditional dynamic triaxial (unidirectional and bidirectional) instrument, the continuous rotation of the main stress of the solidified sandy soil unit body under the action of dynamic load can be realized only through the carried hollow cylinder torsional shear test, however, the existing instrument and device for sample preparation and in-situ solidification of a hollow cylinder sample is still deficient, and the corresponding research needs to be carried out urgently.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a hollow cylindrical sample MICP curing sample preparation instrument and a sample preparation method, the sample preparation instrument increases the seepage path of the slurry in the sample by utilizing a mode of combining pressure grouting and electroosmosis grouting based on the MICP technology, and obviously improves the uniformity of the cured sample; the sample preparation instrument achieves the purpose of starting solidification from the inside of a sample by injecting a gelling liquid and a bacterial liquid into the sample through a special design in a path way, and avoids the condition of uneven solidification caused by the blockage of a sample internal permeation path due to the deposition of calcium carbonate on the outer surface of the sample in the traditional grouting process; this system appearance adopts and combines to adopt different forms of electrode at sample upper and lower both ends two-way pressure slip casting to make the electroosmosis slip casting scope contain whole sample, has not only increased the homogeneity of MICP solidification, has ensured the wholeness after the sample solidification, still can improve slip casting efficiency, this system appearance and method easy operation is convenient, labour saving and time saving.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a hollow cylinder sample MICP solidifies the sample preparation method, this method adopts the separated slip casting to realize the sample preparation based on MICP technology, inject the gel liquid and bacterium liquid of MICP into the sample preparation appearance of the hollow cylinder sample respectively according to different routes along the sample height specifically, make one of gel liquid and bacterium liquid inject the sample body of the hollow cylinder sample directly, and another injects the hollow position of the hollow cylinder sample; and (2) performing bidirectional pressure grouting on the liquid directly injected into the hollow cylindrical sample body, and applying voltage between different paths to enable ions in the gelled fluid and the bacterial liquid to radially move simultaneously, so that an omnibearing three-dimensional gelled fluid and bacterial liquid seepage network is formed in the sample, and the sample is uniformly solidified. Typically, the gelling fluid is urea and Ca containing²⁺The MICP cementing liquid is a bacterium liquid containing anions.

Further, the gel liquid is directly injected into the sample body of the hollow cylindrical sample, and the bacterial liquid is injected into the hollow part of the hollow cylindrical sample.

A hollow cylindrical sample MICP curing sample preparation instrument comprises a bacteria liquid storage vessel, a first grouting pipe, a first peristaltic pump, a gelled liquid storage vessel, a second grouting pipe, a second peristaltic pump, a waterproof vent valve, a first glass plug, a slurry path diffusion tube, an organic glass tube, a second glass plug, a water stop plug, a graphite electrode rod and a direct-current power supply;

the organic glass tube is formed by fixedly connecting double-petal molds through a tube hoop, and a transparent conductive film is adhered to the inner wall of the organic glass tube and is connected with the positive electrode of a direct-current power supply; the slurry path diffusion cylinder is coaxially arranged in the organic glass tube, and grouting holes are uniformly arranged on the cylinder wall; the first glass plug and the second glass plug are respectively arranged at the upper end and the lower end of the organic glass tube, the slurry path diffusion cylinder is fixed between the two glass plugs, and a sample body is arranged in an annular space formed by the slurry path diffusion cylinder and the organic glass tube; the graphite electrode bar is connected with the negative electrode of the direct-current power supply and penetrates through the second glass plug to be inserted into the slurry path diffusion cylinder;

the first glass plug and the second glass plug are internally provided with path diversion channels for diverting gelled fluid and bacterial fluid in paths, wherein the gelled fluid is directly introduced into the sample from the upper end and the lower end of the sample, and the bacterial fluid is directly introduced into the slurry path diffusion cylinder; the aim of increasing the permeation path of the gelling liquid in the sample while improving the grouting efficiency is fulfilled by adopting a bidirectional grouting and gelling liquid injection mode, the permeation uniformity of the gelling liquid in the sample is improved, and the bacterial liquid injected into the diffusion cylinder of the path of the gelling liquid is annularly injected into the sample along the grouting hole under the action of electroosmosis grouting, so that the bacterial liquid and the gelling liquid injected from the upper end and the lower end of the sample generate MICP curing reaction in the sample to generate calcium carbonate, and the design overcomes the defect that the inside of the sample cannot be continuously grouted due to the blockage of the path of the gelling liquid caused by the generation of the calcium carbonate on the outer surface of the sample in the traditional mixed grouting instrument; the fungus liquid is injected into the sample inside and carries out vertical diffusion under the dead weight effect along above-mentioned slip casting hole, has realized the three-dimensional infiltration diffusion of fungus liquid to make the solidification effect more even, the wholeness is better. In addition, the inner wall of the slurry path diffusion cylinder can be stuck with gauze to prevent sand samples from leaking out of the grouting holes;

the first grouting pipe is connected with the bacteria liquid storage vessel and the first glass plug; the first peristaltic pump is arranged on the first grouting pipe and used for injecting the bacterial liquid into the first glass plug and directly into the slurry path diffusion cylinder through the path diversion channel; the second grouting pipe is connected with a gel storage vessel, a first glass plug and a second glass plug; the second peristaltic pump is arranged on the second grouting pipe and is used for injecting the gelling liquid into the first glass plug and the second glass plug and directly into the sample body through the diversion channel;

the first glass plug is provided with a waterproof vent valve for communicating the annular space with the outside atmosphere, so that the internal and external pressure intensities of the sample preparation instrument can be balanced, and liquid in the sample preparation instrument can smoothly flow; and a water stop plug is arranged on the second glass plug and is used for controlling the outflow of the redundant bacteria liquid.

Furthermore, the transparent conductive film covers the whole sample body, and the graphite electrode rod is inserted into the whole slurry path diffusion cylinder, so that an electric field generated by the graphite electrode rod and the transparent conductive film after the power supply is switched on covers the whole sample; that is, after the electric current is applied, the transparent conductive film attracts the bacterial liquid in the slurry path diffusion tube to flow from the inner surface of the sample to the outer surface of the sample over the entire height of the sample, and the graphite electrode rod attracts the Ca-rich liquid over the entire height of the sample²⁺The gelling liquid of (2) flows; the lateral diffusion path of the bacterial liquid and the gelled liquid is increased on the basis that the bidirectional pressure grouting and slurry path diffusion cylinder increases the slurry diffusion path, and the uniformity of sample solidification is further improved.

Furthermore, the first glass plug is composed of a first cylinder at the upper part, a second cylinder and a third cylinder at the lower part, the first cylinder is provided with a top surface and a bottom surface, the third cylinder is coaxially sleeved in the second cylinder, the top parts of the first cylinder and the third cylinder are connected into a whole with the bottom surface of the first cylinder, the annular space between the second cylinder and the third cylinder is only a closed bottom surface, its top and first drum inner space intercommunication, second drum outer wall and organic glass tube inner wall closely cooperate, and thick liquid route diffusion section of thick bamboo closely cooperates with third drum inner wall, and open at first drum center has drainage tube to supply first slip casting pipe to directly pour into the thick liquid route diffusion section of thick bamboo into with the fungus liquid, and first drum is located that annular space corresponds the position department and opens and has drainage hole to supply the second slip casting pipe to pour into the annular space with the gelled liquid in, the closed bottom surface evenly opens has the through-hole, the gelled liquid by in the through-hole pours into the sample body.

Furthermore, biochemical cellucotton is arranged between the closed bottom surface and the sample body.

Furthermore, the second glass plug is composed of a fourth cylinder and a fifth cylinder on the upper part and a sixth cylinder on the lower part, the sixth cylinder is provided with a top surface and a bottom surface, the fifth cylinder is coaxially sleeved in the fourth cylinder, the bottoms of the fifth cylinder and the sixth cylinder are connected into a whole, the annular space between the fourth cylinder and the fifth cylinder is only a closed top surface, the bottom of the annular space is communicated with the inner space of the sixth cylinder, the outer wall of the fourth cylinder is tightly matched with the inner wall of the organic glass tube, the slurry path diffusion tube is tightly matched with the inner wall of the fifth cylinder, the center of the sixth cylinder is provided with a tube hole for inserting the graphite electrode rod, the graphite electrode rod and the tube hole are sealed, a drainage hole is arranged at the position of the sixth cylinder corresponding to the annular space for injecting the second grouting tube into the annular space, the closed top surface is uniformly provided with a through hole, and the cementing liquid is injected into the sample body through the through, and a through hole is formed in the position, corresponding to the slurry path diffusion cylinder, of the sixth cylinder and used for installing a water stop plug.

Furthermore, biochemical cellucotton is arranged between the closed top surface and the sample body.

The sample preparation method for MICP curing by adopting the sample preparation instrument comprises the following steps:

placing a sand sample in a sample preparation instrument, placing a bacterium solution in a bacterium solution storage dish, placing a gelling liquid in a gelling liquid storage dish, and installing the sample preparation instrument; and simultaneously opening all peristaltic pumps for pressure grouting to enable the gelled fluid to be continuously injected into the sand sample from the upper end and the lower end, continuously injecting the bacterial liquid into the slurry path diffusion cylinder, opening the direct-current power supply for electroosmosis grouting, closing the direct-current power supply and all peristaltic pumps after at least 6 hours, and ending grouting.

After grouting is finished, the pipe wall of the organic glass pipe can be tapped around the periphery of the organic glass pipe by a rubber hammer, then the pipe hoop is unfastened, the organic glass pipe and other components are removed, and then the sample is placed into a pressure chamber to carry out torsional shear test on the hollow cylindrical sample.

The invention has the beneficial effects that:

the sample preparation instrument injects the bacterial liquid and the gelling liquid into the sample by paths to realize MICP solidification, and overcomes the defect that after the bacterial liquid and the gelling liquid are injected by the same grouting path, calcium carbonate deposition occurs on the outer surface of the sample at first to cause the blockage of a permeation path, so that grouting cannot be continued; this system appearance adopts pressure + electroosmosis to combine together the mode to carry out the slip casting, is showing the solidification effect and the solidification efficiency that have improved the MICP sample:

1. the upper end and the lower end of the sample are subjected to bidirectional grouting by the gel liquid through pressure grouting, so that the grouting efficiency is improved, and the permeation path of the gel liquid is increased;

2. because the bacterial liquid is injected into the sample through the grouting hole on the side wall of the slurry path diffusion cylinder by utilizing pressure grouting, the bacterial liquid is injected into the sample along the grouting hole and is vertically diffused under the action of self weight, the three-dimensional osmotic diffusion of the bacterial liquid is realized, and the osmotic path of the bacterial liquid is obviously increased;

3. after electro-osmosis grouting, enabling the current to flow transversely in the sample on the premise that the bacterial liquid and the gel liquid flow vertically due to self weight;

therefore, the sample preparation instrument is triple designed to form an all-dimensional seepage network in the sample, and the uniformity of MICP curing in the sample and the integrity of the cured sample are strictly ensured;

when the conventional pure pressure grouting mode is adopted to reinforce the MICP sample, the phenomenon that the permeability coefficient of the sample is reduced by firstly solidifying the calcareous sand usually occurs, so that the MICP reinforcement cannot be realized by the sand inside the sample, and the uniformity of sample solidification is poor. The sample preparation instrument participates in electroosmotic grouting in the whole process, and is suitable for the conditions of large permeability of a sample at the initial stage and permeability coefficient reduction caused by the fact that a permeation path is blocked by curing MICP on the surface of the sample in the follow-up stage, so that the sample prepared by the sample preparation instrument has a better curing effect compared with pure pressure grouting; the electroosmotic grouting adopted by the sample preparation instrument enables the electroosmotic grouting range to comprise the whole sample by adopting electrodes in different forms, and ensures the integrity of the sample after solidification; the whole process of the invention is controllable and visible, the operation is simple and convenient, and the time and the labor are saved.

Drawings

FIG. 1 is a schematic view of a specific structure of a sample preparation instrument according to the present invention;

FIG. 2 is a schematic view of a specific structure of a glass plug No. one (unit: mm);

FIG. 3 is a schematic view of a specific structure of a No. two glass stopper (unit: mm);

in fig. 1: the device comprises a bacteria liquid storage dish-1, a first grouting pipe-2, a first peristaltic pump-3, a gelling liquid storage dish-4, a second grouting pipe-5, a second peristaltic pump-6, a waterproof vent valve-7, a first glass plug-8, a slurry path diffusion tube-9, a pipe hoop-10, an organic glass pipe-11, a second glass plug-12, a water stop plug-13, a graphite electrode rod-14, a direct current power supply-15 and a redundant slurry collection dish-16.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1-3, a concrete example of the hollow cylindrical sample MICP solidification sample preparation instrument of the present invention includes a bacteria liquid storage vessel 1, afirst grouting pipe 2, a firstperistaltic pump 3, a gel storage vessel 4, asecond grouting pipe 5, a secondperistaltic pump 6, a waterproof vent valve 7, a first glass plug 8, a slurrypath diffusion tube 9, apipe hoop 10, anorganic glass pipe 11, asecond glass plug 12, a water stop plug 13, agraphite electrode rod 14, adc power supply 15, and an excessslurry collection vessel 16;

the bacteria liquid storage vessel 1 is used for storing bacteria liquid with anions, and thefirst grouting pipe 2 is connected with the bacteria liquid storage vessel 1 and the first glass plug 8; the firstperistaltic pump 3 is arranged on the first grouting pipe, and injects the bacterial liquid in the bacterial liquid storage vessel 1 into the first glass plug 8 through the first grouting pipe; the gel storage dish 4 is used for storing urea and Ca²⁺The gelling solution of (a); thesecond grouting pipe 5 is connected with the gel storage dish 4, the first glass plug and thesecond glass plug 12; the secondperistaltic pump 6 inputs the gelled fluid in the gelled fluid storage vessel into the first glass plug 8 and thesecond glass plug 12 through thesecond grouting pipe 5; the waterproof vent valve 7 is used for balancing the internal and external pressure intensities of the sample preparation instrument, so that liquid in the sample preparation instrument can smoothly flow; the first glass plug 8 is arranged at the upper end of theorganic glass tube 11, and a special structure is arranged in the first glass plug for draining the gel liquid and the bacterial liquid in a path-divided manner, wherein the gel liquid is directly introduced into the sample from the upper end of the sample, and the bacterial liquid is introduced into the slurrypath diffusion tube 9; the slurrypath diffusion cylinder 9 is filled with bacterial liquid introduced from the first glass plug 8, and the bacterial liquid permeates into the sample along round holes (grouting holes) uniformly arranged on the side wall of the bacterial liquid; thepipe hoop 10 is used for connecting theorganic glass pipe 11 into a whole by the double-petal mould; the inner wall of theorganic glass tube 11 is pasted with a transparent conductive film and connected with the positive pole of a directcurrent power supply 15 for absorbing bacteria liquid with anionsFlowing; thesecond glass plug 12 is arranged at the lower end of theorganic glass tube 11, and the inner special structure of the second glass plug is used for introducing the gelled fluid into the sample from the lower end of the sample and simultaneously leading the redundant slurry out to the redundantslurry collecting vessel 16; thewater stop plug 15 is arranged in thesecond glass plug 12 and is used for controlling the outflow of redundant bacteria liquid; thegraphite electrode rod 14 penetrates through a circular tube at the center of the bottom of thesecond glass plug 12 and extends into the slurrypath diffusion cylinder 9, and is finally connected to the negative electrode of a directcurrent power supply 15 and used for attracting Ca²⁺Flowing; the directcurrent power supply 15 provides direct current for electroosmotic grouting; the excessslurry collecting vessel 16 is used for collecting excess slurry so as not to pollute the environment.

In the above scheme, it is further, No. two slip casting union couplings gel storage vessel, a glass stopper and No. two glass stoppers to utilize the peristaltic pump to pour into the sample with the gel in from the sample upper and lower both ends, adopt two-way slip casting's mode to realize increasing the infiltration route of gel in the sample when improving slip casting efficiency, improve the homogeneity of gel infiltration in the sample.

Furthermore, the first glass plug is composed of a first cylinder at the upper part, a second cylinder at the lower part and a third cylinder at the lower part, the diameter of the first cylinder at the upper part is larger than that of the second cylinder at the lower part, the first cylinder is provided with a top surface and a bottom surface, the third cylinder is coaxially sleeved in the second cylinder, the top parts of the first cylinder and the second cylinder are connected into a whole with the bottom surface of the first cylinder, the annular space between the second cylinder and the third cylinder is only provided with a closed bottom surface, the top part of the annular space is communicated with the inner space of the first cylinder, the outer wall of the second cylinder is tightly attached to the inner wall of the organic glass tube, the slurry path diffusion cylinder is tightly attached to the inner wall of the third cylinder, the center of the first cylinder is provided with a drainage pipeline for the first grouting tube to directly inject a bacterial liquid into the slurry path diffusion cylinder, the first cylinder is provided with drainage holes at the corresponding positions of the annular space for the second grouting tube to inject a gelling liquid into the annular space, and the closed bottom surface is uniformly provided with four holes, the gel is injected into the sample body through the hole, and a layer of biochemical cellucotton is arranged below the closed bottom surface and used for preventing the sand sample from leaking;

furthermore, the slurry path diffusion cylinder can be a glass cylinder without a bottom at the upper part and the lower part, grouting holes with the same diameter are uniformly arranged on the cylinder wall, and gauze is pasted on the inner wall of the cylinder to prevent sand samples from leaking out of the round holes; the bacteria liquid in the slurry path diffusion cylinder is annularly injected into the sample through the cylinder wall grouting hole, so that the bacteria liquid and the gelling liquid injected from the upper end and the lower end of the sample generate MICP reaction in the sample to generate calcium carbonate, and the defect that the inside of the sample cannot be continuously grouted due to the fact that the slurry deposits on the outer surface of the sample to generate calcium carbonate in a conventional grouting instrument is overcome; the fungus liquid is injected into the sample through above-mentioned slip casting hole inside and carries out vertical diffusion under the dead weight effect, has realized the three-dimensional infiltration diffusion of fungus liquid to make the solidification effect more even, the wholeness is better.

Furthermore, the organic glass tube is of a double-petal structure and can be connected into a whole by a tube hoop, and a sand sample is arranged in an annular space formed by the organic glass tube and the slurry path diffusion cylinder so as to form a hollow cylindrical sample meeting the standard requirement; a transparent conductive film is pasted on the inner wall of the organic glass tube, and the two wires at the bottom of the double-petal mold of the organic glass tube are connected with the positive electrode of a direct-current power supply to attract bacteria liquid to flow; the transparent conductive film surrounds the whole outer surface of the hollow cylindrical sample so that the electroosmotic grouting range covers the whole sample; after the power is switched on, the transparent conductive film can absorb bacterial liquid in the slurry path diffusion cylinder to flow from the inner surface of the sample to the outer surface of the sample in the whole height range of the sample, so that the transverse bacterial liquid diffusion path is further increased on the basis that the slurry diffusion path is increased by the bidirectional pressure grouting and slurry path diffusion cylinder, and the solidification uniformity of the sample is further improved.

Furthermore, the second glass plug is composed of a fourth cylinder and a fifth cylinder on the upper part and a sixth cylinder on the lower part, the sixth cylinder is provided with a top surface and a bottom surface, the fifth cylinder is coaxially sleeved in the fourth cylinder, the bottoms of the fifth cylinder and the fifth cylinder are connected into a whole with the top surface of the sixth cylinder, the annular space between the fourth cylinder and the fifth cylinder is only provided with a closed top surface, the bottom of the annular space is communicated with the inner space of the sixth cylinder, the outer wall of the fourth cylinder is tightly attached to the inner wall of the organic glass tube, the slurry path diffusion tube is tightly attached to the inner wall of the fifth cylinder, the center of the sixth cylinder is provided with a tube hole for inserting the graphite electrode rod, the graphite electrode rod and the tube hole are sealed, the sixth cylinder is provided with a drainage tube at the position corresponding to the annular space for injecting the second grouting tube to inject the gel into the annular space, the closed top surface is uniformly provided with four holes, and the gel is injected into the sample body through the holes, and a hole is formed in the position, corresponding to the slurry path diffusion cylinder, of the sixth cylinder and used for installing a water stop plug, and a layer of biochemical fiber cotton is arranged on the closed top surface to prevent sand samples from leaking.

Furthermore, the graphite electrode rod is positioned in the slurry path diffusion cylinder and fixed by a circular tube at the center of the bottom surface of the second glass plug, is connected with a power supply cathode and attracts Ca-rich substances after being electrified²⁺The gelling liquid of (2) flows; ca attracted by graphite electrode rod²⁺The range comprises the full height of the sample, so that electroosmotic grouting is more uniform; the electric field generated after the graphite electrode bar and the transparent conductive film are electrified contains the whole sample, so that the electroosmosis grouting range is wide, and the MICP curing effect is obviously improved.

In one embodiment, the inner circular tubes of the first glass plug and the second glass plug are circular tubes with an inner diameter of 6mm and a wall thickness of 1mm, and the upper and lower ends of the circular tubes are not provided with bottoms, wherein the diameters of all circular holes on the top surface of the first glass plug are 6mm, the diameters of all circular holes on the bottom surface of the first glass plug are 3mm, the diameters of all circular holes on the top surface of the second glass plug are 3mm, and the diameters of all circular holes on the bottom surface of the second glass plug are 6 mm.

In one embodiment, the first grouting pipe and the second grouting pipe are circular pipes with an outer diameter of 5mm and a pipe wall thickness of 1mm, and a circle of sealing belt with a thickness of 1mm is arranged at the contact part of all the grouting pipes and the glass plug after installation, so that the grouting pipes and the glass plug are tightly fixed.

In a specific example, the graphite electrode rod is a cylinder with the diameter of 5mm and the height of 300mm, and a circle of sealing tape with the thickness of 1mm is arranged at the position 250mm from top to bottom of the graphite electrode rod (namely, the position contacted with the bottom surface of the second glass plug), so that the second glass plug and the graphite electrode rod are tightly fixed.

In one embodiment, the waterproof vent valve has an outer diameter of 6mm, and can be tightly connected with a round hole of a first glass plug so as to prevent water leakage.

In one embodiment, the first glass plug is as shown in fig. 2: the outer diameter of the upper large cylinder (first cylinder) is 150mm, the height of the upper large cylinder is 20mm, the outer diameter of the outer cylinder (second cylinder) in the lower cylinder is 98mm, the outer wall of the upper large cylinder is provided with a circle of sealing belt with the thickness of 2mm, the inner diameter of the inner cylinder (third cylinder) is 58mm, the height of the inner cylinder is 30mm, the upper end contact part of the inner cylinder and the slurry path diffusion cylinder is provided with a circle of sealing belt with the thickness of 2mm, and the wall thickness of the first glass plug is 1 mm.

In one embodiment, the second glass plug is shown in fig. 3: the outer diameter of a lower large cylinder (a sixth cylinder) is 150mm, the height of the lower large cylinder is 20mm, the outer diameter of an outer cylinder (a fourth cylinder) in an upper cylinder is 98mm, a circle of sealing strip with the thickness of 2mm is arranged on the outer wall of the upper cylinder, the inner diameter of glass of an inner cylinder (a fifth cylinder) is 58mm, the height of the inner cylinder is 30mm, a circle of sealing strip with the thickness of 2mm is arranged on the contact part of the inner cylinder and the lower end of a slurry path diffusion cylinder, and.

In a specific example, the slurry path diffusion cylinder is 2mm in wall thickness, 60mm in outer diameter and 260mm in height, round holes with the diameter of 1mm and the clear distance of 2mm are uniformly distributed on the side wall of the slurry path diffusion cylinder, and gauze is attached to the inner wall of the slurry path diffusion cylinder so as to prevent sand and sand samples from leaking out of the round holes.

In a specific example, the inner diameter of the organic glass tube is 100mm, the wall thickness is 2mm, the height is 260mm, the structure is a double-petal mold structure, the installation and the disassembly are convenient through the combination of the tube hoops, and the inner walls of the double-petal mold of the organic glass tube are both pasted with a transparent conducting film with the thickness of 0.1 mm.

In a specific example, the water stop plug is a rubber round table with an upper bottom diameter of 5mm, a lower bottom diameter of 10mm and a height of 30 mm.

In one embodiment, the organic glass tube and the slurry path diffusion cylinder form a space with the outer diameter of 100mm, the inner diameter of 60mm and the height of 200mm for sample preparation, and the outer wall of the slurry path diffusion cylinder is provided with a marking line, and when the sample reaches the marking line, the height of the sample is just 200mm, so that the sample size specified by the hollow cylinder torsional shear test is met.

The method for preparing the sample by adopting the hollow cylindrical sample MICP curing sample preparation instrument is realized by combining pressure grouting and electroosmosis grouting with a MICP technology, and the sample preparation instrument realizes uniform curing of the hollow cylindrical sample by utilizing the method of providing slurry by combining the pressure grouting with electroosmosis to increase a slurry flow path based on the MICP technology; the sample preparation instrument realizes MICP solidification from the inside to the outside of a sample by injecting bacterial liquid and gel liquid in different ways, thereby overcoming the defect that calcium carbonate deposition firstly occurs on the outer surface of the sample to block a slurry permeation path due to the fact that the bacterial liquid and the gel liquid are injected in the same path by the traditional sample preparation instrument, and enabling the integrity and uniformity of the solidified sample to be better.

A specific working process of this embodiment is as follows:

after vaseline is uniformly coated on the inner wall of theorganic glass tube 11, thetube hoop 10 is used for fixing the tube into a whole, asecond glass plug 12 is inserted into the lower end of theorganic glass tube 11, a large cylinder at the lower part of thesecond glass plug 12 is tightly attached to the lower end of theorganic glass tube 11, and awater stop plug 12, asecond grouting tube 5 and agraphite electrode rod 14 are installed at the bottom of thesecond glass plug 12. Vaseline is evenly coated on the outer wall of the slurrypath diffusion cylinder 9, and the lower end of the slurry path diffusion cylinder is inserted into a fifth cylinder on the upper part of asecond glass plug 12 until the slurry path diffusion cylinder and the second glass plug are tightly attached. Fill in the annular space that thickliquid route diffuser 9 andorganic glass pipe 11 formed and adorn sand sample, specifically do: the method comprises the steps of independently preparing dried sand samples according to the quality of each layer of particles with required particle size in a grading mode, pouring 5 layers of the sand samples into an annular space, compacting each layer of the sand samples by using a compacting hammer, performing shaving treatment among the layers of the sand samples to ensure the uniformity of the samples, achieving the height of a marking line on the outer wall of a slurrypath diffusion cylinder 9 after the last layer of calcareous sand is filled, inserting a first glass plug 8 from the top of anorganic glass pipe 11 to enable the bottom surface of a first cylinder on the upper portion of theorganic glass pipe 11 to be in tight contact with the upper end of theorganic glass pipe 11, inserting the upper end of the slurrypath diffusion cylinder 9 into a third cylinder on the lower portion of the first glass plug 8 to enable the first cylinder and the third cylinder to be in tight contact, and installing a waterproof vent valve 7, afirst grouting pipe 2 and asecond grouting pipe 5 on the first glass plug.

Then, placing sufficient bacteria liquid in the bacteria liquid storage dish 1, placing sufficient gelling liquid in the gelling liquid storage dish 4, simultaneously opening all peristaltic pumps for pressure grouting, opening the directcurrent power supply 15 for electroosmosis grouting when a certain gelling liquid exists in the sample and a certain bacteria liquid exists in the slurrypath diffusion cylinder 9, closing the directcurrent power supply 15 and all the peristaltic pumps after 6 hours, and ending grouting.

Further, after grouting is completed, the water stop plug 13 is taken down, redundant slurry flows into a redundantslurry collecting vessel 16, after standing for a set time, a rubber hammer is used for tapping the pipe wall of the organic glass pipe along the height of the organic glass pipe around the periphery of the organic glass pipe, then the pipe hoop is unfastened, the organic glass pipe and other components are removed, and then the sample is placed into a pressure chamber for hollow cylinder torsional shear test.

The embodiments described in this specification are merely illustrative of implementations of the inventive concepts, which are intended for purposes of illustration only. The scope of the present invention should not be construed as being limited to the particular forms set forth in the examples, but rather as being defined by the claims and the equivalents thereof which can occur to those skilled in the art upon consideration of the present inventive concept.

Claims (9)

Translated fromChinese

1.一种空心圆柱试样MICP固化制样方法，其特征在于，该方法基于MICP技术采用分离式注浆实现制样，具体是将胶凝液与菌液沿试样高度按照不同的路径分别注入至空心圆柱试样制样仪中，使得胶凝液和菌液中一种直接注入至空心圆柱试样的试样本体，而另一种则注入至空心圆柱试样的空心部位；对直接注入空心圆柱试样本体的液体采用双向压力注浆，同时在所述的不同路径之间通直流电，使得胶凝液、菌液中的离子同时发生径向移动，在试样内部形成全方位立体化的胶凝液与菌液渗流网络，从而使试样均匀固化。1. a hollow cylindrical sample MICP solidification sample preparation method, is characterized in that, the method adopts separate grouting based on MICP technology to realize sample preparation, specifically by gelling liquid and bacterial liquid along the sample height according to different paths respectively. Inject into the hollow cylinder sample preparation instrument, so that one of the gelling liquid and the bacterial liquid is directly injected into the sample body of the hollow cylinder sample, and the other is injected into the hollow part of the hollow cylinder sample; The liquid injected into the hollow cylinder sample body adopts bidirectional pressure grouting, and at the same time, direct current is passed between the different paths, so that the ions in the gelling liquid and the bacterial liquid move radially at the same time, forming an omnidirectional three-dimensional inside the sample. The gelatinized liquid and bacterial liquid seep through the network, so that the sample solidifies uniformly.2.根据权利要求1所述的空心圆柱试样MICP固化制样方法，其特征在于，将胶凝液直接注入空心圆柱试样的试样本体，而菌液则注入空心圆柱试样的空心部位。2. The MICP-cured sample preparation method of the hollow cylindrical sample according to claim 1, wherein the gelling liquid is directly injected into the sample body of the hollow cylindrical sample, and the bacterial liquid is injected into the hollow part of the hollow cylindrical sample .3.一种空心圆柱试样MICP固化制样仪，其特征在于，包括菌液存放皿、一号注浆管、一号蠕动泵、胶凝液存放皿、二号注浆管、二号蠕动泵、防水通气阀、一号玻璃塞、浆液路径扩散筒、有机玻璃管、二号玻璃塞、止水塞、石墨电极棒以及直流电源；3. A hollow cylindrical sample MICP solidifying sample preparation instrument is characterized in that, comprising bacterial liquid storage dish, No. 1 grouting pipe, No. 1 peristaltic pump, gelling liquid storage dish, No. 2 grouting pipe, No. 2 peristaltic pump Pump, waterproof vent valve, No. 1 glass plug, slurry path diffusion cylinder, plexiglass tube, No. 2 glass plug, water stopper, graphite electrode rod and DC power supply;所述的有机玻璃管由管箍将双瓣模固定连接形成，内壁贴有透明导电膜并连接直流电源正极；所述浆液路径扩散筒同轴置于有机玻璃管内，筒壁上均匀布置有注浆孔；一号玻璃塞、二号玻璃塞分别安置于有机玻璃管上下两端，并将所述浆液路径扩散筒固定，在浆液路径扩散筒与有机玻璃管所形成的环向空间内设置试样本体；所述的石墨电极棒一端连接直流电源负极，另一端穿过二号玻璃塞插入至浆液路径扩散筒内；The plexiglass tube is formed by the fixed connection of the double-lobed mold by the tube hoop, and the inner wall is pasted with a transparent conductive film and connected to the positive pole of the DC power supply; the slurry path diffusion cylinder is coaxially placed in the plexiglass tube, and the cylinder wall is evenly arranged with injection molding. Slurry hole; No. 1 glass plug and No. 2 glass plug are respectively placed on the upper and lower ends of the plexiglass tube, and the slurry path diffusion cylinder is fixed. Sample body; one end of the graphite electrode rod is connected to the negative electrode of the DC power supply, and the other end is inserted into the slurry path diffusion cylinder through the No. 2 glass plug;所述的一号玻璃塞、二号玻璃塞内部具有分路径引流通道；The No. 1 glass plug and No. 2 glass plug have sub-path drainage channels inside;所述的一号注浆管连接菌液存放皿以及一号玻璃塞；一号蠕动泵设于一号注浆管上用于将菌液注入至一号玻璃塞中经分路径引流通道直接注入浆液路径扩散筒内；所述的二号注浆管连接胶凝液存放皿及一号玻璃塞和二号玻璃塞；二号蠕动泵设于二号注浆管上用于将胶凝液注入至一号玻璃塞和二号玻璃塞中，经分路径引流通道直接注入至试样本体中；The No. 1 grouting pipe is connected to the bacterial liquid storage vessel and the No. 1 glass plug; the No. 1 peristaltic pump is installed on the No. 1 grouting pipe to inject the bacterial liquid into the No. 1 glass plug directly through the sub-path drainage channel. The slurry path is in the diffusion cylinder; the No. 2 grouting pipe is connected to the gelling liquid storage vessel and the No. 1 glass plug and the No. 2 glass plug; the No. 2 peristaltic pump is installed on the No. 2 grouting pipe for injecting the gelling liquid into the No. 1 glass stopper and No. 2 glass stopper, and directly injected into the sample body through the sub-path drainage channel;所述的一号玻璃塞上设置有防水通气阀，用于连通所述环向空间与外界大气，所述的二号玻璃塞上设置有止水塞用于控制多余菌液的流出。The No. 1 glass plug is provided with a waterproof ventilation valve for connecting the annular space with the outside atmosphere, and the No. 2 glass plug is provided with a water stopper to control the outflow of excess bacterial liquid.4.根据权利要求3所述的空心圆柱试样MICP固化制样仪，其特征在于，所述的透明导电膜覆盖整个试样本体，所述的石墨电极棒插入至整个浆液路径扩散筒内，使得接通电源后石墨电极棒与透明导电膜产生的电场覆盖整个试样。4. The hollow cylindrical sample MICP curing sample preparation instrument according to claim 3, wherein the transparent conductive film covers the entire sample body, and the graphite electrode rod is inserted into the entire slurry path diffusion cylinder, After the power is turned on, the electric field generated by the graphite electrode rod and the transparent conductive film covers the entire sample.5.根据权利要求3所述的空心圆柱试样MICP固化制样仪，其特征在于，所述的一号玻璃塞为由上部的第一圆筒及下部的第二、第三圆筒构成，第一圆筒具有顶面及底面，第三圆筒同轴套置于第二圆筒内，二者顶部与第一圆筒的底面连为一体，第二、第三圆筒之间的环形空间只有封闭底面，其顶部与第一圆筒内部空间连通，第二圆筒外壁与有机玻璃管内壁紧密配合，浆液路径扩散筒与第三圆筒内壁紧密配合，第一圆筒中心开有引流管道供第一注浆管将菌液直接注入浆液路径扩散筒内，第一圆筒位于环形空间对应位置处开有引流孔洞供第二注浆管将胶凝液注入环形空间内，所述封闭底面均匀开有通孔，胶凝液由所述通孔注入试样本体中。5. The hollow cylindrical sample MICP curing sample preparation instrument according to claim 3, wherein the No. 1 glass plug is composed of the first cylinder in the upper part and the second and third cylinders in the lower part, The first cylinder has a top surface and a bottom surface, the third cylinder is coaxially sleeved in the second cylinder, and the tops of the two cylinders are integrated with the bottom surface of the first cylinder. The space has only a closed bottom surface, the top of which is communicated with the inner space of the first cylinder, the outer wall of the second cylinder is closely matched with the inner wall of the plexiglass tube, the slurry path diffusion cylinder is closely matched with the inner wall of the third cylinder, and a drainage is opened in the center of the first cylinder. The pipeline is used for the first grouting pipe to directly inject the bacterial liquid into the slurry path diffusion cylinder, and the first cylinder is located at the corresponding position of the annular space with a drainage hole for the second grouting pipe to inject the gelling liquid into the annular space. Through holes are evenly opened on the bottom surface, and the gelling liquid is injected into the sample body through the through holes.6.根据权利要求5所述的空心圆柱试样MICP固化制样仪，其特征在于，所述的封闭底面与试样本体之间设有生化纤维棉。6 . The hollow cylindrical sample MICP curing sample preparation apparatus according to claim 5 , wherein a biochemical fiber cotton is arranged between the closed bottom surface and the sample body. 7 .7.根据权利要求3所述的空心圆柱试样MICP固化制样仪，其特征在于，所述的二号玻璃塞为由上部的第四、第五圆筒及下部的第六圆筒构成，第六圆筒具有顶面及底面，第五圆筒同轴套置于第四圆筒内，二者底部与第六圆筒的顶面连为一体，第四、第五圆筒之间的环形空间只有封闭顶面，其底部与第六圆筒内部空间连通，第四圆筒外壁与有机玻璃管内壁紧密配合，浆液路径扩散筒与第五圆筒内壁紧密配合，第六圆筒中心设有管孔，供石墨电极棒插入且石墨电极棒与所述管孔间采用密封处理，第六圆筒位于环形空间对应位置处开有引流孔洞供第二注浆管将胶凝液注入环形空间内，所述封闭顶面均匀开有通孔，胶凝液由所述通孔注入试样本体中，在第六圆筒位于浆液路径扩散筒对应位置处开有通孔用于安装止水塞。7. The hollow cylindrical sample MICP curing sample preparation instrument according to claim 3, wherein the No. 2 glass stopper is composed of the fourth and fifth cylinders in the upper part and the sixth cylinder in the lower part, The sixth cylinder has a top surface and a bottom surface, the fifth cylinder is coaxially sleeved in the fourth cylinder, the bottoms of the two are connected with the top surface of the sixth cylinder, and the space between the fourth and fifth cylinders is integrated. The annular space has only a closed top surface, the bottom of which is communicated with the inner space of the sixth cylinder, the outer wall of the fourth cylinder is closely matched with the inner wall of the plexiglass tube, the slurry path diffusion cylinder is closely matched with the inner wall of the fifth cylinder, and the center of the sixth cylinder is set. There is a tube hole for the graphite electrode rod to be inserted and the graphite electrode rod and the tube hole are sealed. The sixth cylinder is located at the corresponding position of the annular space with a drainage hole for the second grouting tube to inject the gelling liquid into the annular space. Inside, the closed top surface evenly has through holes through which the gelling liquid is injected into the sample body, and the sixth cylinder is located at the corresponding position of the slurry path diffusion cylinder with through holes for installing the water stopper .8.根据权利要求7所述的空心圆柱试样MICP固化制样仪，其特征在于，所述的封闭顶面与试样本体之间设有生化纤维棉。8 . The hollow cylindrical sample MICP curing sample preparation instrument according to claim 7 , wherein a biochemical fiber cotton is arranged between the closed top surface and the sample body. 9 .9.一种空心圆柱试样MICP固化制样方法，其特征在于，采用如权利要求3-8任一项所述的制样仪实现，方法如下：9. a hollow cylindrical sample MICP solidification sample preparation method is characterized in that, adopts the sample preparation instrument as described in any one of claim 3-8 to realize, and the method is as follows:在制样仪中装好砂样，在菌液存放皿内放置菌液，在胶凝液存放皿内放置胶凝液，安装好制样仪；同时打开所有蠕动泵进行压力注浆，使得胶凝液不断从上、下两端注入砂样中且菌液持续注入到浆液路径扩散筒中，并打开直流电源进行电渗注浆，至少6小时后关闭直流电源以及所有蠕动泵，注浆结束。Install the sand sample in the sample preparation instrument, place the bacterial liquid in the bacterial liquid storage vessel, place the gelling liquid in the gelling liquid storage vessel, and install the sample preparation instrument; The condensate was continuously injected into the sand sample from the upper and lower ends, and the bacterial liquid was continuously injected into the slurry path diffusion cylinder, and the DC power supply was turned on for electroosmotic grouting. After at least 6 hours, the DC power supply and all peristaltic pumps were turned off, and the grouting was completed.

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