CN113514347B - An in-situ shear test device and test method in a hole - Google Patents

Abstract

The invention discloses an in-situ shearing test device in a hole, which comprises a center shaft, a loading system, a first-stage shearing test device and a second-stage shearing test device, wherein the loading system is arranged on the center shaft and comprises a middle loading water bag, an upper loading water bag and a lower loading water bag which are positioned on the upper side and the lower side of the middle loading water bag, the middle loading water bag is used for solidifying and pressurizing a soil sample, and the upper loading water bag and the lower loading water bag are used for providing uniform shearing force; the cutting system is arranged on the center shaft and comprises an upper layer cutting assembly and a lower layer cutting assembly which are positioned above the loading system and used for cutting soil body to form an annular soil sample; the humidifying system is arranged on the central shaft and comprises an upper humidifying component and a lower humidifying component, wherein the upper humidifying component is arranged above the upper cutting component, and the lower humidifying component is arranged below the lower cutting component and is used for humidifying and saturating the soil sample. The invention overcomes the defect that the traditional in-hole shearing test can only test the shearing strength between the soil body and the shearing equipment, and accurately measures the shearing strength parameter of the soil body in practical sense.

Description

An in-situ shear test device and test method in a hole

technical field

The patent of the invention belongs to the technical field of geotechnical engineering, and specifically relates to an in-situ shear test device and test method in a hole.

Background technique

The shear test parameters of rock and soil are the key mechanical parameters in the design of industrial and civil construction projects and the management and prevention of geological disasters. In-situ testing and laboratory testing are two important basic means to obtain rock and soil mechanical parameters. Compared with the indoor test, the in-situ test has the advantages of strong representativeness, small disturbance, and can truly reflect the actual situation of the project, which can greatly meet the needs of engineering design and disaster management. At present, the in-situ shear test methods mainly include on-site large shear test and in-hole shear test, but there are still some shortcomings in the test process: the on-site large shear test can only be used to measure the shear of the shallow surface layer of in-situ soil. strength parameters, it is difficult to reflect the real situation of deep rock and soil; while the existing in-hole shear test uses a pressure plate to directly pressurize and shear the soil. The actual shear force reflected by this method is the loading plate and soil The shear strength of the body is not the shear strength between the soil in the true sense. Therefore, the current in-situ shear test methods in rock and soil holes still need to be perfected to reflect the real rock and soil shear process and obtain real shear mechanical parameters.

Contents of the invention

The object of the present invention is to provide an in-situ shear strength testing device in a hole to solve the problem that the existing in-hole in-situ test technology cannot truly obtain the shear strength parameters of the soil body.

The technical scheme adopted in the present invention is:

An in-situ shear test device in a hole, comprising

axis,

The loading system is arranged on the central axis, including the middle loading water bag, the upper layer loading water bag and the lower layer loading water bag located on the upper and lower sides of the middle loading water bag, and the middle loading water bag is used to consolidate and pressurize the soil sample , the upper loading water bag and the lower loading water bag are used to provide uniform shearing force;

The cutting system is arranged on the central axis, including an upper layer cutting assembly and a lower layer cutting assembly located above the loading system, which are used to cut the soil to form a ring-shaped soil sample;

The humidification system is arranged on the central axis, and includes an upper layer humidification assembly located above the upper layer cutting assembly, and a lower layer humidification assembly located below the lower layer cutting assembly, and is used for humidifying and saturating the soil sample.

Preferably, the central axis is a hollow cylindrical rod, on which a ball joint and a tension sensor are sequentially arranged, and the tension sensor is used to measure the tension during the shearing process.

Preferably, the upper cutting assembly and the lower cutting assembly are symmetrical to each other, and both include a cutterhead, the cutterhead is a ring structure, the inner wall of the inner ring of the cutterhead is engaged with the outer wall of the rotating shaft, and the rotating shaft is connected to the hollow shaft through a bearing. Cylindrical rods are movably connected, gears are also arranged on the rotating shaft, cutting blades and electric push rods distributed at equal intervals along the circumferential direction of the cutter head are arranged on one surface of the cutter head, and the electric push rods are located on the inner side wall of the cutting blades and It is fixedly connected with the inner side wall of the cutting blade; a motor is arranged on the other surface of the cutter head, and a transmission wheel is arranged on the output shaft of the motor, and the transmission wheel meshes with the gear.

Preferably, the cutter head is further provided with perforations distributed at equal intervals along its circumferential direction, and each perforation is respectively located between two adjacent electric push rods.

Preferably, the loading system further includes a middle water bag pressurized water injection pipe and two side pressurized water injection pipes, the middle water bag pressurized water injection pipe and both sides pressurized water injection pipes are arranged inside the hollow cylindrical rod, the The pressurized water injection pipe of the middle water bag includes two nozzles, one of which runs through the side wall of the hollow cylindrical rod and extends to the inside of the middle loading water bag, and the other nozzle passes through the side wall of the hollow cylindrical rod and extends to the outside of the hollow cylinder , the pressurized water injection pipe on both sides includes three nozzles, one of which penetrates the side wall of the hollow cylindrical rod and extends to the inside of the lower loading water bag, and the other nozzle penetrates the side wall of the hollow cylindrical rod and extends to the upper loading water bag. Inside the capsule, the third nozzle extends from above the side wall of the hollow cylinder rod to the outside of the hollow cylinder.

Preferably, the upper humidification assembly and the lower humidification assembly are symmetrical to each other, and both include an annular perforated water ring, a humidification water injection pipe and a water injection chamber, and the main water pipe is arranged inside the hollow cylindrical rod, which includes three nozzles , one of the nozzles penetrates the side wall of the hollow cylindrical rod and extends to the interior of the water injection chamber on the upper humidification component, the other nozzle penetrates the side wall of the hollow cylindrical rod and extends to the interior of the water injection chamber on the lower humidification component, and the third The nozzle extends from above the side wall of the hollow cylindrical rod to the outside of the hollow cylinder, and the annular perforated water ring is located below the water injection chamber and communicates with the water injection chamber, and is used for water to pass through the water injection chamber to humidify the soil sample.

Preferably, the lower end of the central axis is provided with a guide rail, and the guide rail includes a base, a bracket, a spring and a roller, one end of the bracket is hinged to the side wall of the base, and the other end is connected to a roller, and the side wall of the bracket is connected to the side wall of the bracket through a spring. Base side wall connection.

The present invention also provides a method for in-situ shear testing in a hole with the above testing device, comprising the following steps:

Step 1, connect the drilling robot through the central axis, and move the test device to the position of the specified depth;

Step 2, the motor starts to rotate, and the transmission wheel drives the gear to rotate. Under the action of the gear, the cutter head and the electric push rod are driven to rotate, and the electric push rod gradually extends to push the cutting blade outward to cut the soil and form a ring Soil sample;

Step 3, the upper loading water bag and the lower loading water bag are gradually pressurized and expanded to wrap the annular soil sample, and the middle loading water bag is gradually pressurized to apply normal stress to the soil;

Step 4: Under the action of the tension of the drilling robot in the hole, the soil starts to be sheared, the tension sensor records the measured tension, the drilling robot records the walking position, and then calculates the stress-strain curve of the soil sample institute.

Step 5: After the soil sample is destroyed, the middle loading water bladder, the upper loading water bladder and the lower loading water bladder are gradually decompressed and retracted, and the electric push rod is gradually retracted and restored to the original.

Preferably, before the above step 3 starts, the soil body is humidified and saturated with a humidification system, and then the consolidation and shearing operations are continued.

Beneficial effects of the present invention: the in-situ shear test device in the hole of the present invention can perform in-situ soil shear tests in boreholes, overcoming the traditional in-hole shear test that can only test the difference between soil and shear equipment. The shear strength defect between them can accurately measure the shear strength parameters of the soil in the actual sense.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is an overall structural diagram of an in-situ shear test device in a hole of the present invention;

Fig. 2 is a schematic diagram of the central axis;

Fig. 3 is the schematic diagram of cutting system;

Fig. 4 is the schematic diagram of humidification system;

Fig. 5 is a schematic diagram of the loading system;

Figure 6 is a schematic diagram of the guide rail;

Fig. 7 is the test principle of the present invention;

Fig. 8 is a schematic diagram of conventional work of the present invention;

Among them, 1-central shaft; 101-hollow cylindrical rod; 102-ball joint; 103-tension sensor; 2-cutting system; 201-cutter; 202-rotating shaft; 203-gear; 204-bearing; 205-motor; 206-drive wheel; 207-electric push rod; 208-cutting blade; 209-perforation; 3-humidification system; 301-humidification water injection pipe; ;401-upper water bag; 402-lower water bag; 403-middle water bag; 404-middle water bag pressurized water injection pipe; 405-both sides pressurized water injection pipe; - bracket; 503 - spring; 504 - roller.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

The present invention specifically provides an in-situ shear test device in a hole, as shown in Figure 1, comprising

Axis 1,

The loading system 4 is arranged on the central shaft 1, and includes a middle loading water bag 403 and an upper loading water bag 401 and a lower loading water bag 402 located on the upper and lower sides of the middle loading water bag 403, and the middle loading water bag 403 is used for The soil sample is consolidated and pressurized, and the upper loading water bladder 401 and the lower loading water bladder 402 are used to provide uniform shear force;

The cutting system 2 is arranged on the central axis 1, and includes an upper layer cutting assembly and a lower layer cutting assembly located above the loading system, and is used for cutting the soil to form a ring-shaped soil sample;

The humidification system 3 is arranged on the central shaft 1 and includes an upper humidification component located above the upper cutting component and a lower humidifying component located below the lower cutting component, for humidifying and saturating the soil sample.

As shown in Figure 2, the central axis 1 is a hollow cylindrical rod 101, on which a ball joint 102 and a tension sensor 103 are sequentially arranged, and the tension sensor 103 is used to measure the tension in the shearing process, and the ball joint 102 is used to ensure the self-adaptation of the test device in the hole.

As shown in Figure 3, the upper cutting assembly and the lower cutting assembly are symmetrical to each other, and both include a cutter head 201, the cutter head 201 is a ring structure, the inner wall of the inner ring of the cutter head 201 is engaged with the outer wall of the rotating shaft 202, and the The rotating shaft is movably connected with the hollow cylindrical rod through the bearing, the rotating shaft 202 is also provided with a gear 203, and one surface of the cutter head 201 is provided with cutting blades 208 and electric push rods 207 distributed at equal intervals along its circumferential direction. The electric push rod 207 is positioned at the inner sidewall of the cutting blade 208 and is fixedly connected with the inner sidewall of the cutting blade 208; the other side of the cutterhead 201 is provided with a motor 205, and the output shaft of the motor 205 is provided with a drive wheel 206, so The transmission wheel 206 meshes with the gear 203. The cutter head 201 is also provided with perforations 209 distributed at equal intervals along its circumferential direction, and each perforation 209 is respectively located between two adjacent electric push rods 207 .

The motor 205 provides power for the rotation of the cutterhead 201 and the cutting blade 208, the gear 203 is used to transmit the rotation of the motor 205 to the cutterhead 201 and the cutting blade 208, and the bearing 204 is used to ensure that the cylindrical main rod It remains stationary under the action of the gear rotation; the electric push rod 207 is used for elongation of the cutting blade 208 .

As shown in Figure 5, the loading system 4 includes a middle loading water bag 403 and an upper loading water bag 401 and a lower layer loading water bag 402 located on the upper and lower sides of the middle loading water bag 401, and the middle loading water bag 403 is used for soil When the sample is consolidated before body shearing, the upper loading water bladder 401 , the lower loading water bladder 402 and the cutting blade 208 jointly provide shearing force.

The loading system 4 also includes a middle water bag pressurized water injection pipe 404 and both sides pressurized water injection pipes 405, and the middle water bag pressurized water injection pipe 404 and both sides pressurized water injection pipes 405 are arranged inside the hollow cylindrical rod 101 , the middle water bag pressurization water injection pipe 404 includes two nozzles, one of which runs through the side wall of the hollow cylindrical rod 101 and extends to the inside of the middle loading water bag 403, and the other nozzle passes through the side wall of the hollow cylindrical rod 101 Extending to the outside of the hollow cylinder 101, the pressurized water injection pipe 405 on both sides includes three nozzles, one of which penetrates the side wall of the hollow cylindrical rod 101 and extends to the inside of the lower loading water bag 402, and the other nozzle penetrates The side wall of the hollow cylindrical rod 101 extends to the inside of the upper loading water bag 401 , and the third nozzle passes through the side wall of the hollow cylindrical rod 101 and extends to the outside of the hollow cylindrical rod 101 .

As shown in Figure 4, the upper humidification assembly and the lower humidification assembly are arranged symmetrically to each other, and both include an annular perforated water ring 303, a humidification water injection pipe 301 and a water injection chamber 302, and the humidification water injection pipe 301 is arranged on a hollow cylindrical rod Inside, it includes three nozzles, one of which runs through the side wall of the hollow cylindrical rod 101 and extends to the inside of the water injection chamber 302 on the upper humidification assembly, and the other nozzle runs through the side wall of the hollow cylindrical rod 101 and extends to the lower humidification unit. Inside the water injection chamber 302 on the wet assembly, the third nozzle extends from above the side wall of the hollow cylindrical rod 101 to the outside of the hollow cylinder 101, and the annular perforated water ring 303 is located below the water injection chamber 302 and communicates with the water injection chamber 302 , for water to pass through the water injection chamber 302 to humidify the soil sample.

As shown in Figure 6, the lower end of the central axis 1 is provided with a guide rail 5, the guide rail 5 includes a base 501, a bracket 502, a spring 503 and a roller 504, one end of the bracket 502 is hinged to the side wall of the base 501, and the other side of the bracket 502 is hinged. One end is connected with a roller 504 , and the side wall of the bracket 502 is connected with the side wall of the base 501 through a spring 503 . The base 501 is used to fix the central shaft 1, the spring 503 is used to provide pressure for the roller 504 to ensure that the roller 504 is in contact with the drilling soil, and the roller 504 is used for crawling on the hole wall.

The testing principle of the present invention is as follows:

The test principle of the in-situ shear test device in the hole is based on the indoor direct shear test. Different from the existing in-hole shear test, the shear failure surface generated by this method is located inside the soil, and the Shear strength, the stress of the soil sample during the shearing process is shown in Figure 7. The cutting system of the test device is in the hole to make a ring-shaped soil sample. The ring-shaped soil sample is subjected to the normal stress of the water bag loaded in the middle. The test soil sample and the original soil sample produce relative displacement S and shear under the tension of the parallel hole wall. The force Fs, the tension sensor and the displacement sensor record the shear force Fs and the shear displacement S during the shearing process respectively, and the stress-strain curve of the undisturbed loess in the hole can be drawn.

In view of the above test principle, the present invention also provides an in-situ shear test method in a hole, as shown in Figure 8, comprising the following steps:

Step 1, connect the drilling robot through the central axis 1, and move the test device to the position of the specified depth;

Step 2, the motor 205 starts to rotate, and the gear 203 is driven to rotate through the transmission wheel. Under the action of the gear 203, the cutter head 201 and the electric push rod 207 are driven to rotate, and the electric push rod 207 gradually extends to push the cutting blade 208 outwards, and the soil The body is cut to form a ring-shaped soil sample;

Step 3, the upper loading water bladder 401 and the lower loading water bladder 402 are gradually pressurized and expanded to wrap the annular soil sample, and the middle loading water bladder 403 is gradually pressurized to apply normal stress to the soil;

Step 4, under the action of the tension of the drilling robot in the hole, start to shear the soil, the tension sensor 103 records the measured tension, the drilling robot records the walking position, and then calculates the stress-strain curve of the soil sample institute.

Step 5: After the soil sample is destroyed, the middle loading water bladder 403, the upper loading water bladder 401 and the lower loading water bladder 402 are gradually decompressed and retracted, and the electric push rod 207 is gradually retracted and restored to its original packaging.

Before the above step 3 starts, the soil body is humidified and saturated with the humidification system 3, and then the consolidation and shearing operations are continued.

The borehole shearing instrument of the present invention can perform in-situ soil shear tests in boreholes, overcomes the traditional in-hole shear test that can only test the shear strength defect between the soil mass and the shearing equipment, and is accurate Determination of the actual shear strength parameters of the soil.

The above is only used to illustrate the technical solution of the present invention and not to limit it. Other modifications or equivalent replacements made by those skilled in the art to the technical solution of the present invention should be considered as long as they do not depart from the spirit and scope of the technical solution of the present invention. fall within the scope of the claims of the present invention.

Claims (6)

1. An in-situ shear test device in a hole, characterized in that, comprising axis, The loading system is arranged on the central axis, including the middle loading water bag, the upper layer loading water bag and the lower layer loading water bag located on the upper and lower sides of the middle loading water bag, and the middle loading water bag is used to consolidate and pressurize the soil sample , the upper loading water bag and the lower loading water bag are used to provide uniform shearing force; The cutting system is set on the central axis, including the upper cutting assembly and the lower cutting assembly above the loading system, which are used to cut the soil to form a ring-shaped soil sample; The humidification system is arranged on the central shaft, including an upper humidification component located above the upper cutting component, and a lower humidifying component located below the lower cutting component, for humidifying and saturating the soil sample; The central axis is a hollow cylindrical rod, on which a ball joint and a tension sensor are sequentially arranged, and the tension sensor is used to measure the tension in the shearing process; The upper-layer cutting assembly and the lower-layer cutting assembly are symmetrical to each other, and both include a cutter head. The cutter head is a ring structure. The inner wall of the inner ring of the cutter head is engaged with the outer wall of the rotating shaft, and the rotating shaft moves with the hollow cylindrical rod through a bearing. connected, the shaft is also provided with a gear, and one surface of the cutter head is provided with cutting blades and electric push rods distributed at equal intervals along its circumferential direction, and the electric push rods are located on the inner side wall of the cutting blades and are connected to the cutting blades The inner wall is fixedly connected; the other surface of the cutter head is provided with a motor, and the output shaft of the motor is provided with a transmission wheel, and the transmission wheel meshes with the gear; The upper layer humidification component and the lower layer humidification component are symmetrical to each other, and both include an annular perforated water ring, a humidification water injection pipe and a water injection chamber. The water injection pipe is arranged inside the hollow cylindrical rod and includes three nozzles, one of which is The nozzle runs through the side wall of the hollow cylindrical rod and extends to the interior of the water injection chamber on the upper humidification component; the other nozzle penetrates the side wall of the hollow cylindrical rod and extends to the interior of the water injection chamber on the lower humidification component; The side wall of the hollow cylindrical rod passes through and extends to the outside of the hollow cylinder. The annular perforated water-permeable ring is located below the water injection chamber and communicates with the water injection chamber, and is used for water to pass through the water injection chamber to humidify the soil sample. 2. The in-situ shear test device in a hole according to claim 1, wherein the cutter head is also provided with perforations distributed at equal intervals along its circumferential direction, and each perforation is respectively located in the adjacent Between two electric actuators. 3. The in-situ shear test device in a hole according to claim 1, wherein the loading system also includes a pressurized water injection pipe in the middle water bag and a pressurized water injection pipe on both sides, and the middle water bag The pressurized water injection pipe and the pressurized water injection pipes on both sides are arranged inside the hollow cylindrical rod, and the middle water bag pressurized water injection pipe includes two nozzles, one of which runs through the side wall of the hollow cylindrical rod and extends to the middle loading water Inside the bag, another nozzle passes through the side wall of the hollow cylindrical rod and extends to the outside of the hollow cylinder. The pressurized water injection pipe on both sides includes three nozzles, one of which runs through the side wall of the hollow cylindrical rod and extends to the lower layer Inside the loading water bag, another nozzle runs through the side wall of the hollow cylindrical rod and extends to the inside of the upper loading water bag, and the third nozzle passes through the side wall of the hollow cylindrical rod and extends to the outside of the hollow cylinder. 4. The in-situ shear test device in a hole according to claim 1, wherein the lower end of the central axis is provided with a guide rail, and the guide rail includes a base, a support, a spring and a roller, and the support's One end is hinged with the side wall of the base, and the other end is connected with a roller, and the side wall of the bracket is connected with the side wall of the base through a spring. 5. according to the test method that a kind of in-situ shear test device in the hole described in claim 1～4 carries out shear test to soil sample, it is characterized in that, comprises the following steps: Step 1, connect the drilling robot through the central axis, and move the test device to the position of the specified depth; Step 2, the motor starts to rotate, and the transmission wheel drives the gear to rotate. Under the action of the gear, the cutter head and the electric push rod are driven to rotate, and the electric push rod gradually extends to push the cutting blade outward to cut the soil and form a ring Soil sample; Step 3, the upper loading water bag and the lower loading water bag are gradually pressurized and expanded to wrap the annular soil sample, and the middle loading water bag is gradually pressurized to apply normal stress to the soil; Step 4, under the tension of the drilling robot in the hole, start to shear the soil, record the measured tension by the tension sensor, the drilling robot records the walking position, and then calculate the stress-strain curve of the soil sample; Step 5, After the soil sample is destroyed, the middle loading water bladder, the upper loading water bladder and the lower loading water bladder are gradually decompressed and retracted, and the electric push rod is gradually retracted and restored to its original state. 6. the test method that the in-situ shear test device in a kind of hole according to claim 5 carries out shear test to soil sample, it is characterized in that, before above-mentioned step 3 starts, the soil mass is increased by humidification system. Moisture saturation, and then continue to complete the operation of consolidation and shearing.

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