In-situ coring and while-drilling shearing casing device in drill hole and test method thereof

Abstract

The invention discloses an in-situ coring and while-drilling shearing casing device in a drill hole and a test method thereof. The in-situ coring and while-drilling shearing casing device comprises an outer pipe assembly, an inner pipe assembly, a shearing test module, a drilling machine and a fisher. The outer pipe assembly comprises an outer pipe, and an elastic clamp installation step is arranged on the inner wall of the middle of the outer pipe. The inner pipe assembly comprises an inner pipe arranged in the outer pipe, and the inner pipe comprises a spear head and an elastic clamp device matched with the elastic clamp mounting step; the shear test module comprises a sensor, a drilling shear instrument and a supporting rod. According to the in-situ coring and shear-while-drilling casing device in the drill hole and the test method thereof, organic combination of coring and shear-while-drilling tests can be achieved in the in-situ drilling process, only one-time drilling is needed, the drill rod and the drill hole shear instrument are placed to the specified depth, and the drilling operation is completed. The in-situ drilling shear test can be carried out on the hole wall at the coring position after coring, the shear strength parameter of the rock-soil body is obtained in real time, the tedious process of repeatedly increasing and detaching the drill rod is avoided, and the occurrence probability of in-hole accidents such as hole wall collapse is reduced.

Description

Technical Field

[0001] The invention relates to the field of soil engineering investigation technology and geotechnical engineering in-situ drilling shear test equipment research and development, and in particular to an in-situ coring and while-drilling casing shearing device in a borehole and a test method thereof. Background Art

[0002] In the field of engineering survey, drilling and coring are mainly used to obtain samples of underground soil and rock for laboratory analysis. Experimental data help evaluate the physical and mechanical properties of rock and soil (such as shear strength and elastic modulus, etc.), understand geological conditions, and provide basic data for design and construction. The significance of drilling test is that it can obtain information such as underground hydrology, soil distribution and pore pressure in real time, so that engineering personnel can understand the geological conditions in a timely manner, reduce the uncertainty of survey, and improve the safety and economy of the project.

[0003] At present, the mainstream coring technology in engineering survey is to use a drilling rig to drill a hole, connect the drill rod to the drill rig power head and press it into the formation, and then lift it up to the ground after the rock and soil (core) is filled with the drill rod. As the coring depth increases, this method often has problems such as complicated operation and long time cost for adding and removing the drill rod and coring. After coring, the core needs to be sealed and packaged in time and sent to the laboratory for separate geotechnical tests to obtain mechanical parameters. This not only consumes a lot of time, but may also affect the stability and integrity of the sample, and thus affect the reliability of the test results.

[0004] The in-situ drilling shear test requires that a drilling rig is first used to drill a hole to the predetermined depth of the test, then the drill is pulled out, the drill rod and drill bit are lifted out of the hole, and the drilling shear device is connected to the drill rod and placed in the hole. The drilling rig rotary mechanism is used to drive the drill rod and the drilling shear device to complete the in-hole shear test, and then the drill is pulled out to lift the drill rod and the drilling shear device out of the hole, and then the drill is lowered to carry out the next drilling. The repeated lifting and lowering of the drill bit and the drilling shear device during the process makes the test inefficient, labor-intensive, and construction costly. Repeated lifting and lowering of the drill rod can easily cause in-hole accidents such as hole wall collapse.

[0005] Therefore, an in-situ coring and shear-while-drilling casing device and a testing method thereof are proposed, which can realize the organic combination of coring and shear-while-drilling testing during the in-situ drilling process, which can not only improve the testing efficiency and reduce the cost, but also improve the accuracy and reliability of the test.

[0006] At present, for in-situ drilling and coring, a drilling rig is usually used to drive the drill rod into the soil to a specified depth and then lift it up to the ground. The core in the drill rod is taken out by knocking and other methods and sent to the laboratory to test its mechanical parameters. In the research and development of in-situ drilling shear devices, Feng Wenkai et al. proposed a hole wall spinning shear device and test method for in-situ drilling shear tests (CN117191601B) and a hole wall spinning shear probe for in-situ drilling shear tests (CN220961029U). They mainly designed a device that can be placed in a conventional domestic exploration hole while drilling to carry out in-situ drilling shear tests in real time. The device applies a vertical load to push the shear plate outward in the horizontal direction and insert it into the soil, ensuring that the soil it contacts is the original soil and reducing the error of the test data.

[0007] The existing coring technology requires the use of a drilling rig to drill a hole, and after completing the coring at the specified depth, all the drill rods must be lifted to the ground. This is a large amount of work and is time-consuming and labor-intensive. When using the existing drilling shearing device to conduct tests, the device must be placed in the borehole immediately after the coring is completed. After placement, a specific type of motor drive device must be replaced to rotate and complete the shearing test. After the test is completed, the entire device must be lifted from the hole to the ground, and the power head and drill rod must be replaced to conduct the next coring. The entire process is cumbersome. Whether it is the drill rod or the shearing device moving up and down in the hole, it will affect the hole wall, thereby affecting the accuracy of the test data. The entire test process consumes a lot of time, manpower and material resources. Summary of the invention

[0008] In view of the above-mentioned problems in the prior art, the present invention provides an in-situ coring and shearing casing device in a borehole and a testing method thereof, which solves the problem that the existing in-situ coring technology needs to repeatedly lift the drill bit during the coring and in-situ shearing test in the hole, resulting in cumbersome procedures, low testing efficiency and easy collapse of the hole wall.

[0009] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows: The present invention provides an in-situ coring and casing shearing device in a borehole, which comprises an outer tube assembly, an inner tube assembly, a shearing test module, a drilling rig and a salvage device; The outer tube assembly comprises an outer tube, a converter for connecting to the drilling rig is arranged on the top of the outer tube, a spring card installation step and an inner tube limiting step are arranged on the inner wall of the middle part of the outer tube, and a drill rod shoe is arranged on the bottom of the outer tube; The inner tube assembly comprises an inner tube arranged inside the outer tube, a spearhead for connecting with the salvage device is arranged on the top of the inner tube, a spring-cage device for cooperating with the spring-cage installation step is arranged on the spearhead, a limit joint for cooperating with the inner tube limit step is arranged in the middle of the inner tube, a drill bit is arranged at the bottom of the inner tube, and the drill bit extends out of the bottom of the outer tube; The shear test module includes a sensor, a drilling shear instrument and a support rod. The drilling shear instrument shears the hole wall soil. The sensor is arranged at the top of the drilling shear instrument to obtain the shear strength parameters of the hole wall soil. The support rod is arranged at the bottom of the drilling shear instrument.

[0010] In the above technical solution, the upper part of the adapter is connected to the power head of the drilling rig, and the lower part is connected to the outer tube. The spring-clip device on the spearhead is fixedly matched with the spring-clip installation step in the outer tube, and the limit joint is matched with the inner tube limit step to realize the installation of the inner tube in the outer tube. The bottom of the outer tube is a drill pipe boot. The outer tube mainly plays a supporting role in the entire coring and shearing test process to prevent the hole wall from collapsing; the cooperation of the spring-clip device and the spring-clip installation step aligns and fixes the outer tube and the inner tube, and the drilling rig drives the inner tube to rotate, thereby driving the inner tube to rotate downward for coring; the drill pipe boot protects the threads at the bottom of the inner tube.

[0011] A spring-cage device is set at the bottom of the spearhead, the bottom of the spring-cage device is connected to the inner tube, and the bottom of the inner tube is connected to the drill bit. The top of the spearhead is connected to the salvage device, which is lifted and lowered by a winch; during the test, the drill rig drives the outer tube and drives the inner tube to rotate at the same time to complete the coring; the drill bit at the bottom of the inner tube destroys the soil when drilling downward, which facilitates the smooth drilling of the drill rod.

[0012] As the drilling depth increases, the cores will be stored inside the inner tube; at this time, the inner tube filled with cores will be quickly lifted to the ground through the salvage device, and the shear test module will be lowered into the hole to carry out the spinning shear test at the specified depth.

[0013] Furthermore, the outer tube comprises a plurality of outer tube sections threadedly connected to each other. By designing the outer tube to be formed by threading the plurality of outer tube sections to each other, the length of the entire outer tube can be easily adjusted to adapt to different depths in different boreholes.

[0014] Furthermore, the spearhead comprises a round rod body, a conical connector with a tip facing upward is arranged on the top of the round rod body, and the spring-cage device is arranged in the middle of the round rod body. The arrangement of the conical connector enables the salvage device to be connected to the entire inner tube through the conical connector, so as to facilitate the subsequent lifting of the inner tube from the borehole.

[0015] Furthermore, as a specific setting method of the salvage device, the salvage device includes a boom, a lifting ring for connecting to a lifting device is arranged on the top of the boom, two salvage hooks are symmetrically arranged on the bottom of the boom, the middle parts of the two salvage hooks are rotatably connected to the boom through a pin shaft, a first spring in a compressed state is arranged between the tops of the two salvage hooks, and the bottoms of the two salvage hooks are connected to the conical connector.

[0016] Furthermore, as a specific setting method of the ejection card device, the ejection card device includes two ejection card blocks arranged inside the round rod body, the two ejection card blocks are matched with the sliding clearance of the round rod body, the two ejection card blocks are overlapped and symmetrically arranged, and a second spring is arranged between the two ejection card blocks. The second spring pushes the two ejection card blocks to move horizontally so that the outside of the two ejection card blocks cooperates with the ejection card installation step.

[0017] Furthermore, at least one matching hole is provided on each of the two spring-card blocks, and each matching hole is an elliptical structure with a small top and a large bottom, and the matching holes of the two spring-card blocks are in a one-to-one matching relationship; A driving shaft is vertically slidably arranged inside the round rod body, the top of the driving shaft is connected to the conical connector, the bottom of the driving shaft is penetrated by a clamping groove, two spring-clip blocks are arranged in the clamping groove, at least one connecting pin is arranged on the inner wall of the clamping groove, and the connecting pin passes through the matching holes on the two spring-clip blocks. Specifically, when the salvage device lifts the inner tube, when the driving shaft moves upward relative to the round rod body, the connecting pin cooperates with the top of the matching hole, so that the two elastic blocks move close to each other in the round rod body, and the outer parts of the two elastic blocks are separated from the elastic mounting steps, thereby unlocking the outer tube and the inner tube. After the coring of the inner tube is completed, it is convenient to lift the inner tube assembly from the middle of the outer tube assembly through the salvage device for subsequent shear test of the hole wall soil; when coring the inner tube, under the action of the deadweight of the inner tube, the driving shaft moves downward relative to the round rod body, and the connecting pin cooperates with the bottom of the matching hole, so that the two elastic blocks move back to back in the round rod body, and the outer parts of the two elastic blocks are in close contact with the elastic mounting steps, thereby locking the outer tube and the inner tube, ensuring that the drilling rig drives the outer tube while driving the inner tube to rotate, thereby completing the coring.

[0018] The present invention also provides a test method for in-situ coring in a borehole and a casing shearing while drilling device, which comprises: Step 1: Drill normally on the surface of the selected test site and drill to the specified depth; Step 2: Place the inner tube assembly into the outer tube assembly, align the spring-cage device and the spring-cage mounting step to fix the inner tube assembly and the outer tube assembly, so that the drill bit extends a certain distance beyond the outer tube, and after fixing, lower the entire assembly to a specified depth in the drill hole; Step 3: The drilling rig is fixedly connected to the top of the outer tube through the adapter, and the drilling rig is started to drive the outer tube assembly and the inner tube assembly to drill normally until the inner tube is full of cores; Step 4: After coring is completed, the outer tube assembly remains stationary, the salvage device lifts out the inner tube separately, and the shear test module is placed in the borehole. The drill rod of the drilling rig drives the drilling shear instrument to carry out the first in-situ drilling shear test on the borehole wall, and the shear strength parameters of the borehole wall soil are obtained through the sensor; Step 5: After completing a set of spinning shear tests, the drilling shear instrument in the borehole is lifted out through the drill rod of the drilling rig, and the inner tube assembly is hoisted and placed in the outer tube again. After the drilling rig is started to drive the outer tube and the inner tube to drill to the specified depth of the next set of tests, the salvage device lifts out the inner tube alone, and the shear test module is placed in the borehole to carry out the spinning shear test again; Step 6: Repeat steps 2 to 5 to complete multiple coring and in-situ drilling shear tests without repeatedly pulling out and drilling.

[0019] The beneficial effects of the present invention are as follows: an in-situ coring and drilling shearing casing device and a testing method thereof in a borehole can realize an organic combination of coring and drilling shearing test during the in-situ drilling process, and only requires drilling once, placing the drill rod and the borehole shear instrument to a specified depth, and then carrying out an in-situ borehole shear test on the borehole wall at the coring position after coring, and obtaining the shear strength parameters of the rock and soil body in real time, avoiding the tedious process of repeatedly adding and removing the drill rod, and reducing labor intensity, which can not only improve the test efficiency, reduce costs, and reduce the probability of in-hole accidents such as borehole wall collapse, but also improve the accuracy and reliability of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic diagram of the structure of a device for in-situ coring and casing shearing while drilling in a borehole.

[0021] Figure 2 It is a structural schematic diagram of the outer tube assembly.

[0022] Figure 3 It is a structural schematic diagram of the inner tube assembly.

[0023] Figure 4 Schematic diagram of the three-dimensional structure of the shear test module.

[0024] Figure 5 This is a schematic diagram of the structure of the salvage device.

[0025] Figure 6 It is a schematic diagram of the structure of the two salvage hooks in the salvage device cooperating with each other.

[0026] Figure 7 This is a schematic diagram of the structure in which the ejection device is arranged on the round rod body.

[0027] Figure 8 It is a schematic diagram of the structure of the driving shaft and the two elastic blocks.

[0028] Fig. 9 It is a schematic diagram of the structure in which two spring card blocks cooperate with each other.

[0029] Among them, 1. outer tube assembly; 11. outer tube; 12. adapter; 13. spring card installation step; 14. drill rod shoe; 2. Inner tube assembly; 21. Inner tube; 22. Spearhead; 221. Round rod body; 222. Conical connector; 23. Ejection device; 231. Ejection block; 232. Second spring; 233. Matching hole; 24. Drill bit; 25. Drive shaft; 26. Clamping groove; 27. Connecting pin; 3. Shear test module; 31. Sensor; 32. Drilling shear instrument; 33. Support rod; 4. Drilling rig; 5. Salvage device; 51. Lifting rod; 52. Salvage hook; 53. Pin shaft; 54. First spring. DETAILED DESCRIPTION

[0030] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0031] like Figure 1~Figure 5 As shown, the present invention provides an in-situ coring and casing shearing device in a borehole, which includes an outer tube assembly 1, an inner tube assembly 2, a shear test module 3, a drilling rig 4 and a salvage device 5; The outer tube assembly 1 includes an outer tube 11, a conversion joint 12 for connecting to the drilling rig 4 is arranged on the top of the outer tube 11, a spring card installation step 13 and an inner tube limit step are arranged on the inner wall of the middle part of the outer tube 11, and a drill rod shoe 14 is arranged at the bottom of the outer tube 11; the outer tube 11 includes multiple outer tube sections that are threadedly connected to each other. By designing the outer tube 11 to be formed by threading multiple outer tube sections to each other, it is convenient to adjust the length of the entire outer tube 11 to adapt to different depths in different boreholes.

[0032] The inner tube assembly 2 includes an inner tube 21 arranged inside the outer tube 11, a fishing head 22 for connecting to the salvage device 5 is arranged on the top of the inner tube 21, a spring card device 23 for cooperating with the spring card installation step 13 is arranged on the fishing head 22, a limiting joint cooperating with the inner tube limiting step is arranged in the middle of the inner tube 21, and a drill bit 24 is arranged at the bottom of the inner tube 21, and the drill bit 24 extends out of the bottom of the outer tube 11.

[0033] The shear test module 3 includes a sensor 31, a drilling shear instrument 32 and a support rod 33. The drilling shear instrument 32 shears the hole wall soil. The sensor 31 is arranged at the top of the drilling shear instrument 32 to obtain the shear strength parameters of the hole wall soil. The support rod 33 is arranged at the bottom of the drilling shear instrument 32.

[0034] In the above technical solution, the upper part of the adapter 12 is connected to the power head of the drilling rig 4, and the lower part is connected to the outer tube 11. The ejection device 23 on the spearhead 22 is fixedly matched with the ejection installation step 13 in the outer tube 11, and the limit joint cooperates with the inner tube limit step to realize the installation of the inner tube in the outer tube. The bottom of the outer tube 11 is a drill pipe boot 14. The outer tube 11 mainly plays a supporting role in the entire coring and shearing test process to prevent the hole wall from collapsing; the cooperation of the ejection device 23 and the ejection installation step 13 aligns and fixes the outer tube 11 and the inner tube 21, and the drilling rig 4 drives the inner tube 21 to rotate, thereby driving the inner tube 21 to rotate downward for coring; the drill pipe boot 14 protects the thread at the bottom of the inner tube 21.

[0035] A spring-cage device 23 is provided at the bottom of the spearhead 22, the bottom of the spring-cage device 23 is connected to the inner tube 21, and the bottom of the inner tube 21 is connected to the drill bit 24. The top of the spearhead 22 is connected to the salvage device 5, and is lifted and lowered by a winch; during the test, the drill rig 4 drives the outer tube 11 while driving the inner tube 21 to rotate to complete the coring; the drill bit 24 at the bottom of the inner tube 21 destroys the soil when drilling downward, which facilitates the smooth drilling of the drill rod.

[0036] As the drilling depth increases, the cores will be stored inside the inner tube 21; at this time, the inner tube 21 filled with cores is quickly lifted to the ground by the salvage device 5, and the shear test module 3 is lowered into the hole to carry out the spinning shear test at a specified depth.

[0037] like Figure 5 , Figure 6 and Figure 7 As shown, the spearhead 22 includes a round rod body 221, a conical connector 222 with a tip facing upward is provided at the top of the round rod body 221, and the ejection device 23 is provided in the middle of the round rod body 221. The provision of the conical connector 222 enables the salvage device 5 to be connected to the entire inner tube 21 through the conical connector 222, so as to facilitate the subsequent lifting of the inner tube 21 from the borehole.

[0038] like Figure 5 As shown, as a specific arrangement of the salvage device 5, the salvage device 5 includes a boom 51, a hoisting ring for connecting to a hoisting device is arranged at the top of the boom 51, two salvage hooks 52 are symmetrically arranged at the bottom of the boom 51, the middle parts of the two salvage hooks 52 are rotatably connected to the boom 51 through a pin 53, a first spring 54 in a compressed state is arranged between the tops of the two salvage hooks 52, and the bottoms of the two salvage hooks 52 are connected to the conical connector 222.

[0039] like Figure 7 , Figure 8 and Fig. 9As shown, as a specific setting method of the ejection card device 23, the ejection card device 23 includes two ejection card blocks 231 arranged inside the round rod body 221, the two ejection card blocks 231 are matched with the round rod body 221 in a sliding clearance, the two ejection card blocks 231 are overlapped and symmetrically arranged, and a second spring 232 is arranged between the two ejection card blocks 231, and the second spring 232 pushes the two ejection card blocks 231 to move horizontally so that the outside of the two ejection card blocks 231 cooperates with the ejection card installation step 13.

[0040] At least one matching hole 233 is provided on each of the two elastic card blocks 231. Each matching hole 233 is an elliptical structure with a small top and a large bottom. The matching holes 233 of the two elastic card blocks 231 are in a one-to-one matching relationship. A drive shaft 25 is vertically slidably disposed inside the round rod body 221, the top of the drive shaft 25 is connected to the conical connector 222, a clamping groove 26 is penetrated through the bottom of the drive shaft 25, two spring-cage blocks 231 are disposed in the clamping groove 26, at least one connecting pin 27 is disposed on the inner wall of the clamping groove 26, and the connecting pin 27 penetrates the matching holes 233 on the two spring-cage blocks 231. Specifically, when the salvage device 5 hoists the inner tube 21, when the drive shaft 25 moves upward relative to the round rod body 221, the connecting pin 27 cooperates with the top of the matching hole 233, so that the two spring-cage blocks 231 are close to each other in the round rod body 221, and the outside of the two spring-cage blocks 231 is disengaged from the spring-cage installation step 13, thereby unlocking the outer tube 11 and the inner tube 21. After the coring of the inner tube 21 is completed, it is convenient to subsequently lift the inner tube assembly 2 from the middle of the outer tube assembly 1 through the salvage device 5 for subsequent Shear test of the hole wall soil; when coring the inner tube 21, under the action of the deadweight of the inner tube 21, the drive shaft 25 moves downward relative to the round rod body 221, and the connecting pin 27 cooperates with the bottom of the matching hole 233, so that the two elastic blocks 231 move back to back in the round rod body 221, and the outer parts of the two elastic blocks 231 are in tight contact with the elastic mounting step 13, thereby locking the outer tube 11 and the inner tube 21, ensuring that the drilling rig 4 drives the outer tube 11 while driving the inner tube 21 to rotate, completing the coring.

[0041] The borehole shearing instrument 32 can adopt the shearing soil body assembly in the existing invention patent - CN117191601B - hole wall spinning shearing device and test method for in-situ borehole shearing test, and its structure and principle will not be described in detail.

[0042] After the shear test is completed, the drilling rig 4 drives the drilling shear instrument 32 to pull upward. At this time, the rotating pressure shaft moves upward relative to the shear cylinder, and the return spring pushes the rotating pressure shaft to move upward. The upward moving rotating pressure shaft shrinks the four shear plates back into the annular mounting groove, which plays the role of actively accommodating the shear plates. At the same time, due to the setting of the rebound component, the shear plate is at a certain distance from the soil at the bottom of the borehole, eliminating the influence of the hole wall collapse on the test accuracy.

[0043] The present invention also provides a test method for in-situ coring in a borehole and a casing shearing while drilling device, which comprises: Step 1: Drill normally on the surface of the selected test site and drill to the specified depth; Step 2, put the inner tube assembly 2 into the outer tube assembly 1, align the spring card device 23 and the spring card installation step 13 to fix the inner tube assembly 2 and the outer tube assembly 1, the drill bit 24 extends a certain distance beyond the outer tube 11, and after fixing, the whole is lowered into the specified depth in the drill hole; Step 3, the drilling rig 4 is fixedly connected to the top of the outer tube 11 through the adapter 12, and the drilling rig 4 is started to drive the outer tube assembly 1 and the inner tube assembly 2 to drill normally until the inner tube 21 is full of cores; Step 4: After coring is completed, the outer tube assembly 1 remains stationary, the salvage device 5 independently lifts out the inner tube 21, and the shear test module 3 is placed into the borehole. The drill rod of the drilling rig 4 drives the drilling shear instrument 32 to carry out the first in-situ drilling shear test on the borehole wall, and the shear strength parameters of the borehole wall soil are obtained through the sensor 31. Step 5: After completing a set of spinning shear tests, the drilling shear instrument 32 in the borehole is lifted out through the drill rod of the drilling rig 4, and the inner tube assembly 2 is hoisted and placed in the outer tube 11 again. After the drilling rig 4 is started to drive the outer tube 11 and the inner tube 21 to drill to the specified depth of the next set of tests, the salvage device 5 lifts out the inner tube 21 alone, and the shear test module 3 is placed in the borehole to carry out the spinning shear test again; Step 6: Repeat steps 2 to 5 to complete multiple coring and in-situ drilling shear tests without repeatedly pulling out and drilling.

[0044] To sum up, the in-situ coring and drilling shearing casing device and the testing method thereof in the present invention can realize the organic combination of coring and drilling shearing test in the in-situ drilling process. Only one drilling is required, and the drill rod and the drilling shear instrument 32 are placed to the specified depth. Then, after coring, the in-situ drilling shear test can be carried out on the hole wall at the coring position, and the shear strength parameters of the rock and soil body can be obtained in real time, avoiding the tedious process of repeatedly adding and removing the drill rod. It can not only improve the test efficiency, reduce the cost, reduce the probability of in-hole accidents such as hole wall collapse, but also improve the accuracy and reliability of the test.

Claims

1. A device for in-situ coring and casing shearing while drilling in a borehole, characterized in that: Includes outer tube assembly, inner tube assembly, shear test module, drilling rig and salvage device; The outer tube assembly comprises an outer tube, a converter for connecting to the drilling rig is arranged on the top of the outer tube, a spring card installation step and an inner tube limiting step are arranged on the inner wall of the middle part of the outer tube, and a drill rod shoe is arranged on the bottom of the outer tube; The inner tube assembly comprises an inner tube arranged inside the outer tube, a spearhead for connecting with the salvage device is arranged on the top of the inner tube, a spring-cage device for cooperating with the spring-cage installation step is arranged on the spearhead, a limit joint for cooperating with the inner tube limit step is arranged in the middle of the inner tube, a drill bit is arranged at the bottom of the inner tube, and the drill bit extends out of the bottom of the outer tube; The shear test module includes a sensor, a drilling shear instrument and a support rod. The drilling shear instrument shears the hole wall soil. The sensor is arranged at the top of the drilling shear instrument to obtain the shear strength parameters of the hole wall soil. The support rod is arranged at the bottom of the drilling shear instrument.

2. The in-situ coring and casing shearing while drilling device according to claim 1, characterized in that: The outer tube comprises a plurality of outer tube sections which are threadably connected to each other.

3. The in-situ coring and casing shearing while drilling device according to claim 2, characterized in that: The spearhead comprises a round rod main body, a conical connector with a tip facing upward is arranged on the top of the round rod main body, and the spring-cage device is arranged in the middle of the round rod main body.

4. The in-situ coring and casing shearing while drilling device according to claim 3, characterized in that: The salvage device includes a boom, a hoisting ring for connecting to a hoisting device is arranged on the top of the boom, two salvage hooks are symmetrically arranged on the bottom of the boom, the middle parts of the two salvage hooks are rotatably connected to the boom through a pin shaft, a first spring in a compressed state is arranged between the tops of the two salvage hooks, and the bottoms of the two salvage hooks are connected to the conical connector.

5. The in-situ coring and casing shearing while drilling device according to claim 3, characterized in that: The ejection card device includes two ejection card blocks arranged inside the round rod body, the two ejection card blocks are matched with the round rod body in a sliding gap, the two ejection card blocks are overlapped and symmetrically arranged, a second spring is arranged between the two ejection card blocks, and the second spring pushes the two ejection card blocks to move horizontally so that the outside of the two ejection card blocks cooperates with the ejection card installation step.

6. The in-situ coring and casing shearing while drilling device according to claim 5, characterized in that: At least one matching hole is provided on each of the two elastic card blocks, each matching hole is an elliptical structure with a small top and a large bottom, and the matching holes of the two elastic card blocks are in a one-to-one matching relationship; A driving shaft is vertically slidably arranged inside the round rod body, the top of the driving shaft is connected to the conical connector, the bottom of the driving shaft is penetrated by a clamping groove, two spring-clip blocks are arranged in the clamping groove, at least one connecting pin is arranged on the inner wall of the clamping groove, and the connecting pin passes through the matching holes on the two spring-clip blocks.

7. A test method for in-situ coring and casing shearing while drilling in a borehole according to any one of claims 1 to 6, characterized in that: include: Step 1: Drill normally on the surface of the selected test site and drill to the specified depth; Step 2: Place the inner tube assembly into the outer tube assembly, align the spring-cage device and the spring-cage mounting step to fix the inner tube assembly and the outer tube assembly, so that the drill bit extends a certain distance beyond the outer tube, and after fixing, lower the entire assembly to a specified depth in the drill hole; Step 3: The drilling rig is fixedly connected to the top of the outer tube through the adapter, and the drilling rig is started to drive the outer tube assembly and the inner tube assembly to drill normally until the inner tube is full of cores; Step 4: After coring is completed, the outer tube assembly remains stationary, the salvage device lifts out the inner tube separately, and the shear test module is placed in the borehole. The drill rod of the drilling rig drives the drilling shear instrument to carry out the first in-situ drilling shear test on the borehole wall, and the shear strength parameters of the borehole wall soil are obtained through the sensor; Step 5: After completing a set of spinning shear tests, the drilling shear instrument in the borehole is lifted out through the drill rod of the drilling rig, and the inner tube assembly is hoisted and placed in the outer tube again. After the drilling rig is started to drive the outer tube and the inner tube to drill to the specified depth of the next set of tests, the salvage device lifts out the inner tube alone, and the shear test module is placed in the borehole to carry out the spinning shear test again; Step 6: Repeat steps 2 to 5 to complete multiple coring and in-situ drilling shear tests without repeatedly pulling out and drilling.

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