A two-in-one borehole shear testing system and method

Abstract

This invention relates to a two-in-one borehole shear testing system and method. The system includes an operating platform; a drilling rig system comprising a drilling rig, a first lifting mechanism, and a control unit, wherein the drilling rig, driven by the first lifting mechanism, descends and connects to the casing drive, driving the casing to rotate; a casing, detachably connected at the top to the drilling rig and at the top to a transmission end pipe; an integrated drilling tool, comprising a flap drill bit, an outer casing, a shear probe, and a sensor; a transmission end pipe, detachably connected at the bottom to the top of the flap drill bit of the integrated drilling tool; a retrieval mechanism; a normal stress loading mechanism; a motor drive module; and a data acquisition and recording device. This invention features a simple structure, saves testing steps, reduces disturbance, prevents borehole collapse risks, and improves the accuracy of the shear strength parameters of in-situ soil samples, providing a strong basis for the support of foundation pits and slopes.

Description

Technical Field

[0001] This invention relates to the field of in-situ testing in geotechnical engineering, specifically to a two-in-one borehole shear test system and method. Background Technology

[0002] Cohesion and internal friction angle are important shear strength indicators of soil, and are crucial parameters for calculating earth pressure and foundation bearing capacity, analyzing the stability of embankments, slopes, foundation pits, and tunnels, and designing their support structures. Currently, cohesion and internal friction angle are mainly determined through indoor testing of soil samples obtained by drilling. The indoor testing methods include direct shear tests and triaxial compression tests. However, indoor testing methods cause significant disturbance to the soil. After stress release and reloading during the indoor test, the soil's shear strength indicators inevitably differ from the in-situ shear strength indicators, resulting in large dispersion in the test results. Furthermore, indoor testing methods are unable to determine the shear strength parameters of sandy soils because it is difficult to obtain undisturbed samples.

[0003] Conventional in-situ drilling shear tests require drilling a hole separately with a drilling rig, then removing the drilling rig, and then using an in-situ drilling shearing instrument to conduct the test. This is cumbersome, inefficient, and prone to hole collapse. If the shearing head gets stuck in the hole, the losses can be enormous.

[0004] Another method is to test the soil shear strength parameters in situ. This method mainly includes in-situ direct shear tests and vane shear tests. In-situ direct shear tests need to be conducted in test holes, pits, trenches, or large-diameter boreholes. The advantages are minimal disturbance to the soil sample and accurate and reliable test results. The disadvantages are that testing deep soil layers is difficult and requires significant manpower and resources. Vane shear tests are advantageous because the equipment is simple and easy to operate. The disadvantage is that they are only suitable for determining the undrained shear strength of saturated cohesive soils with an internal friction angle that is essentially zero.

[0005] Furthermore, when conducting in-situ tests on various types of in-situ borehole shearing equipment in deeper formations, drilling systems are required to open the boreholes. This necessitates frequent addition and removal of probes and drilling, which significantly affects the integrity and stability of the borehole wall. Consequently, this impacts the accuracy of subsequent borehole shearing test results and can easily lead to borehole wall collapse, burying the in-situ borehole shearing probe inside the borehole and making it impossible to retrieve. This poses a significant risk and safety hazard to deep in-situ borehole shearing tests.

[0006] Therefore, to address the shortcomings of the prior art, one objective of this invention is to provide an integrated borehole shear testing system that combines drilling, wall protection, and shear testing. By integrating drilling and testing, the risk of borehole collapse is reduced, operation is simplified, and testing efficiency is improved. Summary of the Invention

[0007] The purpose of this invention is to address the aforementioned problems in the prior art by providing a two-in-one drilling shear test system and method.

[0008] To achieve the above-mentioned objectives, the present invention employs the following technical solution: a two-in-one borehole shear testing system comprising:

[0009] The operating platform is used to fix the location to be detected and to provide a mounting and fixing space for the drilling rig system, data acquisition recorder, normal stress loading mechanism and motor drive module.

[0010] The drilling rig system includes a drilling rig, a first lifting mechanism for driving the drilling rig to move up and down, and a control unit for controlling the drilling rig. The drilling rig can be driven by the first lifting mechanism to descend and connect with the casing drive and drive the casing to rotate.

[0011] The casing is detachably connected to the drilling rig at the top and detachably connected to the transmission end pipe at the top.

[0012] The drilling tool includes a flap drill bit, an outer sleeve disposed outside the flap drill bit, a shear probe disposed inside the flap drill bit, and a sensor disposed on the shear probe.

[0013] The bottom of the transmission end tube is detachably connected to the top of the valve drill bit of the integrated drilling tool so as to drive the integrated drilling tool to rotate.

[0014] A retrieval mechanism, a retrieval device and a pull line for passing through the casing to connect the transmission end pipe or the drilling integrated drill bit, and the pull line is connected to the motor drive module;

[0015] The normal stress loading mechanism includes an oil supply mechanism and a hydraulic hose connecting the oil supply mechanism and the shear probe. The oil supply mechanism is equipped with a pressure gauge and a hydraulic sensor.

[0016] The motor drive module is used to drive the pull line to pull the salvage device upward from inside the casing, and a tension sensor is provided at the connection between the pull line and the motor drive module;

[0017] The data acquisition and recording device communicates with all sensors and includes a normal stress gauge, a tangential stress gauge, a tangential displacement gauge, a normal displacement gauge, and a pore water pressure gauge. It is used to record normal stress, shear force, normal deformation force, shear deformation force, pore water pressure, and time readings.

[0018] Furthermore, the sleeve has a segmented structure, with each segment being detachably connected, and the bottommost segment serving as the first segment. Except for the first segment, the bottoms of the remaining segments are all smooth.

[0019] Furthermore, a spline tooth is formed on the outer side of the middle part of the outer sleeve, which meshes with the spline sleeve of the transmission end tube.

[0020] Furthermore, the outer casing is equipped with a tensioning shaft, which is divided into inner and outer layers. The inner layer is hollow and forms an oil passage, and has a first sensor wire interface at the top. The inner layer also has a side lug that passes through the outer layer and is fixed to the outer casing. The outer layer has a hollow structure that cooperates with the side lug, and the top of the outer layer has a retrieval spearhead. Through the connection and cooperation of the retrieval spearhead with the retrieval device, the outer layer can move up and down along the outer casing under the drive of the motor drive module. The valve drill bit is connected to the outer layer of the tensioning shaft, and the bottom of the outer layer has a sleeve located outside the valve drill bit, so that the valve drill bit can converge inward and push outward as the outer layer moves up and down.

[0021] Furthermore, the shearing probe includes a hydraulic cylinder and a first shearing plate and a second shearing plate arranged vertically in parallel. A gap is provided between the first shearing plate and the second shearing plate for the installation of the hydraulic cylinder. The two pistons of the hydraulic cylinder are nested together with a pre-reserved gap, and the hydraulic cylinder is connected to the bottom of the inner layer.

[0022] Furthermore, both the first and second shear plates are equipped with pore water pressure testing probes and stress probes, and a normal displacement sensor is also provided between the first and second shear plates. The pore water pressure testing probes, stress probes, and normal displacement sensors are all connected to the data acquisition and recording instrument.

[0023] Furthermore, the salvage device includes an outer shell and an inner shaft located inside the outer shell. The top of the outer shell can be connected to a pull line, and the bottom can be connected to a salvage spearhead. The top of the inner shaft is connected to a hydraulic hose through a etched line, and a data cable interface is provided below the etched line. The bottom of the inner shaft is connected to the top of the inner layer.

[0024] Furthermore, the transmission end tube includes an outer tube, a clip disposed on the outer tube, a spring disposed between the outer tube and the clip, and a sliding spear rod disposed on the top of the outer tube, the top of which can be connected to the retrieval device.

[0025] Furthermore, the motor drive module includes a motor housing, a second lifting mechanism located on the side of the motor housing, a fixed pulley assembly located on the second lifting mechanism, a stepper motor located inside the motor housing, a transverse slide rail located at the bottom of the motor housing, and a winch connected to the stepper motor. The transverse slide rail is detachably mounted on the operating platform. The motor housing can move back and forth and be fixed along the length of the transverse slide rail. The fixed pulley assembly can move up and down and be fixed along the second lifting mechanism.

[0026] A testing method for a two-in-one borehole shear testing system includes the following steps:

[0027] S1. Install a fixed operating platform at the predetermined detection location, and install the drilling rig system, data acquisition recorder, normal stress loading mechanism and motor drive module on the operating platform, while moving the motor drive module to the outermost position.

[0028] S2. Connect the transmission end pipe to the bottom end of the first section of the casing and connect the casing to the drilling system drive, so that the transmission end pipe at the bottom end of the casing is connected and engaged with the drilling tool. At the same time, the outer layer of the tensioning shaft at the bottom end of the casing does not move up, so that the valve drill bit remains closed.

[0029] S3. The drilling rig system drives the casing and the transmission end pipe located at the bottom of the casing to drill into the soft soil layer. The transmission end pipe drives the drilling tool to carry out drilling.

[0030] S4. After drilling to a set depth or to the predetermined in-situ shear test depth in the soft soil layer, disconnect the connection between the drilling rig and the upper end of the casing.

[0031] S5. Raise the drilling rig to the highest point along the first lifting mechanism, move the motor drive module to the innermost side, connect the pull wire to the winch, and pass it around the fixed pulley block. After connecting the other end to the retrieval device, raise the fixed pulley block along the second lifting mechanism to a position higher than the top of the casing, and use the retrieval device to take out the transmission end pipe.

[0032] S6. Connect one end of the hydraulic hose to the upper end of the salvage device. Connect the data acquisition recorder to the interface at the upper end of the salvage device via the data cable. Fix the salvage device to the salvage spearhead on the outer layer of the tensioning shaft. Pull the salvage device with the pull line to engage the salvage device with the salvage spearhead. Lift the salvage device with the winch to open the flap drill bit of the drilling tool and expose the shearing probe.

[0033] S7. Activate the oil supply mechanism and apply an initial normal stress to make the shear plate of the shear probe contact the borehole wall. Then, remove this normal stress and initialize the initial normal stress, shear force, normal deformation, shear deformation, pore water pressure and time readings of the data acquisition recorder to 0.

[0034] S8. Apply the first-level normal stress through the normal stress control unit in the normal stress loading mechanism, and after the soil has been consolidated for a certain period of time, observe the soil consolidation through the pore water pressure curve.

[0035] S9. Drive the winch to lift the salvage device and drilling tool at a constant rate. The tension sensor reading increases slowly until the tension sensor reading suddenly decreases and then the lifting stops. At this time, the soil is sheared and damaged, and the stress, normal deformation, pore water pressure image and maximum tension value of the soil before shearing failure are recorded.

[0036] S10. Close the winch and release the normal stress in the double-acting pressure cylinder of the shear probe through the normal stress control unit in the normal stress loading mechanism, so that the shear probe is closed, remove the salvage device, and lower the transmission end tube from the top of the casing. Due to gravity, the transmission end tube is fixed again at the bottom of the casing.

[0037] S11. Connect the drilling rig, continue drilling and repeat S5 to S9 to carry out the next level of normal stress test. Conduct in-situ shear tests with different normal stresses at each test point.

[0038] S12. Remove the drilling tool from the borehole and repeat S1 to S11 to conduct the in-situ shear test at the next location.

[0039] Working principle and beneficial effects: 1. Compared with existing technologies, this application integrates drilling, wall protection, and shear testing. Once the valve drill bit reaches the designated depth, the shear head is immediately exposed for shear testing. After the shear test, the shear head retracts, and the valve drill bit can drill further into the deeper part, repeating this cycle repeatedly, greatly improving testing efficiency. It also reduces the risk of borehole collapse, improving the stability of test results. The probe is hidden within the valve drill bit, making it less prone to damage. The casing always acts as a wall protector, preventing borehole collapse and probe jamming, making it particularly suitable for soft soils and other soil types prone to borehole collapse.

[0040] 2. Compared with the prior art, this application can quickly measure the relationship curve between shear stress and shear displacement under various normal stress conditions, and then obtain the soil shear strength parameters corresponding to proportional strength, yield strength, peak strength and residual strength, which enriches the test results and facilitates the selection of appropriate shear strength parameters according to different working conditions in engineering applications.

[0041] 3. Compared with the prior art, this application avoids the risk of drilling into the borehole for deep in-situ shear testing, and is especially suitable for deep in-situ shear testing. It has good test results on borehole wall integrity and stability, and the test data is accurate and reliable. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the state during drilling operations using the present invention.

[0043] Figure 2 This is a schematic diagram illustrating the process of retrieving the transmission end pipe using this invention.

[0044] Figure 3 This is a schematic diagram of the state during preparation for in-situ borehole shear test using the present invention.

[0045] Figure 4 This is a schematic diagram of the state during in-situ hole shear testing using the present invention.

[0046] Figure 5 This is a cross-sectional view of the integrated drilling tool of the present invention.

[0047] Figure 6 This is a cross-sectional view of the salvage device of the present invention.

[0048] Figure 7 This is a cross-sectional view of the transmission end tube of the present invention.

[0049] Figure 8 This is a schematic diagram of the first sensor wire interface at the top of the inner layer of the tension axis of the present invention.

[0050] Figure 9 This is a schematic diagram of the spline teeth of the integrated drilling tool of the present invention.

[0051] Figure 10 This is a schematic diagram of the shearing probe of the present invention;

[0052] Figure 11 This is a flowchart of the method of the present invention.

[0053] In the diagram, 1. Drilling rig system; 1-1. Drilling rig; 1-2. First lifting mechanism; 1-3. Control unit; 2. Casing; 3. Integrated drilling tool; 3-1. Retrieval spearhead; 3-2. Outer casing; 3-3. Spline teeth; 3-4. Disc drill bit; 3-5. Tensioning shaft; 3-5-1. Outer layer; 3-5-2. Inner layer; 3-5-3. Sleeve; 3-5-4. First sensor wire interface; 3-5-5. Side lug; 3-6. Shear probe; 3-6-1. First shear plate; 3-6-2. Second shear plate; 3-6-3. Hydraulic cylinder; 3-6-4. Normal displacement sensor; 3-6-5. Pore water pressure probe; 3-6-6. Stress probe; 4. Operating platform; 5. Data acquisition and recording. 6. Salvage Mechanism; 6-1. Salvage Device; 6-1-1. Outer Shell; 6-1-2. Inner Shaft; 6-1-3. Data Cable Interface; 6-1-4. Second Sensor Wire Interface; 6-2. Pull Wire; 7. Normal Stress Loading Mechanism; 7-1. Oil Supply Mechanism; 7-1-1. Oil Tank; 7-1-2. Oil Pump; 7-2. Hydraulic Hose; 7-3. Hydraulic Sensor and Pressure Gauge; 8. Transmission End Pipe; 8-1. Outer Pipe; 8-2. Sliding Spear Rod; 8-3. Card; 8-4. Spring; 8-5. Spline Sleeve; 9. Motor Drive Module; 9-1. Motor Box; 9-2. Second Lifting Mechanism; 9-3. Fixed Pulley Block; 9-4. Stepper Motor; 9-5. Transverse Slide Rail; 9-6. Winch. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0055] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0056] Example 1

[0057] like Figure 1-11 As shown, this two-in-one borehole shear testing system includes:

[0058] Specifically, the operating platform 4 is used to fix the position to be detected and to install and fix the drilling system 1, data acquisition recorder 5, normal stress loading mechanism 7 and motor drive module 9.

[0059] In this embodiment, the operating platform 4 is anchored to the ground by rivets.

[0060] Specifically, the drilling system 1 includes a drilling rig 1-1, a first lifting mechanism 1-2 for driving the drilling rig 1-1 to move up and down, and a control unit 1-3 for controlling the drilling rig 1-1. The drilling rig 1-1 can descend under the drive of the first lifting mechanism 1-2 to drive the casing 2 to rotate.

[0061] In this embodiment, the control units 1-3 are conventional technologies used to control the rotation speed and direction of the drilling rig 1-1. The drilling rig system 1 is fixed to the operating platform 4 by clips, allowing for quick assembly and disassembly.

[0062] Specifically, the top of the casing 2 is detachably connected to the drilling rig 1-1, and the top of the casing 2 is detachably connected to the transmission end pipe 8;

[0063] In this embodiment, the sleeve 2 has a segmented structure, with each segment being detachably connected, and the bottommost segment serving as the first segment. Preferably, the sleeve 2 has threads on both the top and bottom. The bottom end of the first sleeve 2 can be fixed to the transmission end pipe 8, and the top end can be connected to the next sleeve 2. Except for the first sleeve 2, the bottom ends of the other sleeves 2 are smooth.

[0064] Specifically, the drilling tool 3 includes a flap drill bit 3-4, an outer sleeve 3-2 disposed outside the flap drill bit 3-4, a shear probe 3-6 disposed inside the flap drill bit 3-4, and a sensor disposed on the shear probe 3-6.

[0065] In this embodiment, a spline tooth 3-3 is formed on the outer side of the middle part of the outer sleeve 3-2, and the spline tooth 3-3 meshes with the spline sleeve 8-5 of the transmission end tube 8;

[0066] The outer jacket 3-2 contains a tensioning shaft 3-5, which is divided into inner and outer layers. The inner layer 3-5-2 is hollow and forms an oil passage. It has a concentric circle first sensor wire interface 3-5-4 at the top. The inner layer 3-5-2 has a side ear 3-5-5, which passes through the outer layer 3-5-1 and is fixed to the outer jacket 3-2. The outer layer 3-5-1 has a hollow structure that cooperates with the side ear 3-5-5. The top of the outer layer 3-5-1 has a retrieval spearhead 3-1. The retrieval spearhead 3-1 is connected to the retrieval device 6-1 through the retrieval spearhead 3-1, which enables the outer layer 3-5-1 to move up and down along the outer jacket 3-2 under the drive of the motor drive module 9.

[0067] Among them, the valve drill bit 3-4 is connected to the outer layer 3-5-1 of the tensioning shaft 3-5, and the bottom of the outer layer 3-5-1 is provided with a sleeve 3-5-3 located outside the valve drill bit 3-4, so that the valve drill bit 3-4 can move up and down with the outer layer 3-5-1 to achieve inward convergence and outward push.

[0068] The shearing probe 3-6 includes a hydraulic cylinder 3-6-3 and a first shearing plate 3-6-1 and a second shearing plate 3-6-2 arranged vertically in parallel. A gap is provided between the first shearing plate 3-6-1 and the second shearing plate 3-6-2 for the installation of the hydraulic cylinder 3-6-3. The two pistons of the hydraulic cylinder 3-6-3 are nested together with a gap reserved, and the hydraulic cylinder 3-6-3 is connected to the bottom of the inner layer 3-5-2.

[0069] The first shear plate 3-6-1 and the second shear plate 3-6-2 are each equipped with a pore water pressure test probe and a stress probe 3-6-6. Two normal displacement sensors 3-6-4 are also installed between the first shear plate 3-6-1 and the second shear plate 3-6-2, and each normal displacement sensor 3-6-4 is connected to the corresponding side of the shear plate. The pore water pressure test probe, the stress probe 3-6-6, and the normal displacement sensors 3-6-4 are all communicatively connected to the data acquisition and recording instrument 5.

[0070] Each shearing plate is a steel plate with serrated horizontal grooves on the outer side.

[0071] When the shear probe 3-6 is working, the outer surfaces of the first shear plate 3-6-1 and the second shear plate 3-6-2 are both in contact with the inner wall of the borehole. The normal displacement sensor 3-6-4, the hydraulic cylinder 3-6-3, and the piston are located between the inner surfaces of the first shear plate 3-6-1 and the second shear plate 3-6-2. The fixed end of the hydraulic cylinder 3-6-3 is connected to the lower end of the inner layer 3-5-2. The two pistons of the hydraulic cylinder 3-6-3 are nested together with a gap, and one end is connected to the inner surface of the first shear plate 3-6-1 and the inner surface of the second shear plate 3-6-2. A baffle is provided at the piston rod end. In this way, the extension and retraction of the hydraulic cylinder 3-6-3 drives the extension and retraction of the shear probe 3-6.

[0072] Specifically, the bottom of the transmission end tube 8 is detachably connected to the top of the flap drill bit 3-4 of the integrated drilling tool 3 so as to drive the integrated drilling tool 3 to rotate.

[0073] In this embodiment, the transmission end tube 8 includes an outer tube 8-1, a card 8-3 disposed on the outer tube 8-1, a spring 8-4 disposed between the outer tube 8-1 and the card 8-3, and a sliding spear 8-2 disposed on the top of the outer tube 8-1. The top end of the sliding spear 8-2 can be connected to the retrieval device 6-1.

[0074] Specifically, the retrieval mechanism 6 is used to connect the retrieval device 6-1 and the pull line 6-2 through the casing 2 to the transmission end pipe 8 or the drilling integrated drill bit 3, and the pull line 6-2 is connected to the motor drive module 9.

[0075] In this embodiment, the salvage device 6-1 includes a housing 6-1-1 and an inner shaft 6-1-2 disposed within the housing 6-1-1. The top of the housing 6-1-1 can be connected to a pull wire 6-2, and the bottom can be connected to a salvage spearhead 3-1. The top of the inner shaft 6-1-2 is connected to a hydraulic hose 7-2 via a etched line, and a data cable interface 6-1-3 is located below this etched line. The bottom of the inner shaft 6-1-2 is connected to the top of the inner layer 3-5-2. When the salvage device 6-1 is connected to the salvage spearhead 3-1, the second sensor wire interface 6-1-4 is connected to the concentrically shaped first sensor wire interface 3-5-4.

[0076] Specifically, the normal stress loading mechanism 7 includes an oil supply mechanism 7-1 and a hydraulic hose 7-2 connecting the oil supply mechanism 7-1 and the shear probe 3-6. The oil supply mechanism 7-1 is equipped with a pressure gauge 7-3 and a hydraulic sensor (a sensor that displays the oil supply pressure).

[0077] In this embodiment, the upper end of the hydraulic hose 7-2 is connected to the oil supply mechanism 7-1, and the lower end is connected to the oil cylinder 3-6-3 in the shear probe 3-6.

[0078] Specifically, the motor drive module 9 is used to drive the pull line 6-2 to pull the salvage device 6-1 upward from the sleeve 2, and a tension sensor is provided at the connection between the pull line 6-2 and the motor drive module 9. The tension sensor is preferably a tension gauge.

[0079] In this embodiment, the motor drive module 9 includes a motor housing 9-1, a second lifting mechanism 9-2 disposed on the side of the motor housing 9-1, a fixed pulley group 9-3 disposed on the second lifting mechanism 9-2, a stepper motor 9-4 disposed inside the motor housing 9-1, a transverse slide rail 9-5 disposed at the bottom of the motor housing 9-1, and a winch 9-6 connected to the stepper motor 9-4. The transverse slide rail 9-5 is detachably disposed on the operating platform 4. The motor housing 9-1 can move back and forth and be fixed along the length direction of the transverse slide rail 9-5. The fixed pulley group 9-3 can move up and down and be fixed along the second lifting mechanism 9-2.

[0080] Preferably, the transverse slide rail 9-5 is fixed to the operating platform 4 by a buckle, allowing for quick assembly and disassembly.

[0081] The motor drive module 9 is equipped with a forward rotation control button, a reverse rotation control button, a speed control knob, and a stop button. The outputs of the forward rotation control button, the reverse rotation control button, and the stop button are all connected to the input of the controller of the motor drive module 9.

[0082] Specifically, the data acquisition recorder 5 is connected in communication with all sensors. The data acquisition recorder 5 includes a normal stress gauge, a tangential stress gauge, a tangential displacement gauge, a normal displacement gauge, and a pore water pressure gauge. It is used to record normal stress, shear force, normal deformation force, shear deformation force, pore water pressure, and time readings. All of these are existing technologies and can be purchased from the market.

[0083] Example 2

[0084] like Figure 11 Based on Example 1, the testing method for this two-in-one borehole shear testing system includes the following steps:

[0085] S1. Install the fixed operating platform 4 at the predetermined detection position, and install the drilling system 1, data acquisition recorder 5, normal stress loading mechanism 7 and motor drive module 9 on the operating platform 4. At the same time, move the motor drive module to the outermost side along the transverse slide rail 9-5.

[0086] S2. Connect the transmission end pipe 8 to the bottom end of the first section of the casing 2, and drive the casing 2 to the drilling system 1, so that the transmission end pipe 8 at the bottom end of the casing 2 is connected and engaged with the drilling tool 3. At the same time, the outer layer 3-5-1 of the tensioning shaft 3-5 at the bottom end of the casing 2 does not move up, so that the valve drill bit 3-4 remains closed.

[0087] S3. The drilling system 1 drives the casing 2 and the transmission end pipe 8 located at the bottom of the casing 2 to drill into the soft soil layer. The transmission end pipe 8 drives the drilling tool 3 to drill.

[0088] S4. After drilling to a set depth (2m) in the soft soil layer or to the predetermined in-situ shear test depth, disconnect the connection between the drilling rig 1-1 and the upper end of the casing 2.

[0089] S5. Raise the drilling rig 1-1 to the highest point along the first lifting mechanism 1-2, move the motor drive module 9 to the innermost side, connect the pull wire 6-2 to the winch 9-6, and pass it around the fixed pulley block 9-3. After connecting the other end to the salvage device 6-1, raise the fixed pulley block 9-3 along the second lifting mechanism 9-2 to a position higher than the top of the casing 2, and use the salvage device 6-1 to take out the transmission end pipe 8.

[0090] S6. Connect one end of the hydraulic hose 7-2 to the upper end of the salvage device 6-1. Connect the data acquisition recorder 5 to the interface at the upper end of the salvage device 6-1 through the data cable. Fix the salvage device 6-1 to the salvage spearhead 3-1 on the outer layer 3-5-1 of the tension shaft 3-5. Pull the salvage device 6-1 through the pull line 6-2 to engage the salvage device 6-1 with the salvage spearhead 3-1. Lift the salvage device 6-1 through the winch 9-6 to open the flap drill bit 3-4 of the drilling tool 3 and expose the shearing probe 3-6.

[0091] S7. Open the oil supply mechanism 7-1 and apply an initial normal stress (a very small force) to make the shear plate of the shear probe 3-6 contact the borehole wall. Then, remove this normal stress and initialize the initial normal stress, shear force, normal deformation, shear deformation, pore water pressure and time readings of the data acquisition recorder 5 to 0.

[0092] S8. Apply the first-level normal stress through the normal stress control unit 1-3 in the normal stress loading mechanism 7, and after the soil has been consolidated for a certain period of time, observe the soil consolidation through the pore water pressure curve.

[0093] S9. Drive the winch 9-6 to lift the salvage device 6-1 and the drilling tool 3 at a constant rate (0.8 mm / min). The reading of the tension sensor increases slowly until the reading of the tension sensor suddenly decreases and then the upward pull stops. At this time, the soil is sheared and damaged, and the stress, normal deformation, pore water pressure image and maximum tension value before the soil shear failure are recorded.

[0094] S10. Close the winch 9-6 and release the normal stress in the double-acting pressure cylinder 3-6-3 of the shear probe 3-6 through the normal stress control unit 1-3 in the normal stress loading mechanism 7, so that the shear probe 3-6 is closed, remove the salvage device 6-1, and lower the transmission end pipe 8 from the upper end of the sleeve 2. Due to gravity, the transmission end pipe 8 is fixed again at the bottom end of the sleeve 2.

[0095] S11. Connect drilling rig 1-1, continue drilling and repeat S5 to S9 to carry out the next level of normal stress test. Conduct in-situ shear tests of different normal stresses at each test point at multiple levels (4 to 5 levels).

[0096] S12. Remove the drilling tool 3 from the borehole and repeat S1 to S11 to carry out the in-situ shear test at the next location.

[0097] The parts of this invention not described in detail are prior art, therefore they are not described in detail here.

[0098] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0099] Although this paper extensively uses the following components: drilling rig system 1, drilling rig 1-1, first lifting mechanism 1-2, control unit 1-3, casing 2, integrated drilling tool 3, retrieval spearhead 3-1, outer sleeve 3-2, spline teeth 3-3, valve drill bit 3-4, tensioning shaft 3-5, outer layer 3-5-1, inner layer 3-5-2, sleeve 3-5-3, first sensor wire interface 3-5-4, side lug 3-5-5, shear probe 3-6, first shear plate 3-6-1, second shear plate 3-6-2, hydraulic cylinder 3-6-3, normal displacement sensor 3-6-4, pore water pressure probe 3-6-5, stress probe 3-6-6, operating platform 4, data acquisition recorder 5. The terms used include 6 (retrieval mechanism), 6-1 (retrieval device), 6-1-1 (outer shell), 6-1-2 (inner shaft), 6-1-3 (data cable interface), 6-1-4 (second sensor wire interface), 6-2 (pull wire), 7 (normal stress loading mechanism), 7-1 (oil supply mechanism), 7-1-1 (oil tank), 7-1-2 (oil pump), 7-2 (hydraulic hose), 7-3 (pressure gauge), 8 (transmission end pipe), 8-1 (outer pipe), 8-2 (sliding spear rod), 8-3 (card), 8-4 (spring), 8-5 (spline sleeve), 9 (motor drive module), 9-1 (motor box), 9-2 (second lifting mechanism), 9-3 (fixed pulley block), 9-4 (stepper motor), 9-5 (transverse slide rail), and 9-6 (winch), etc., but the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would be contrary to the spirit of the invention.

[0100] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes made to their shape or structure, any technical solution that is the same as or similar to that of this application falls within the protection scope of this invention.

Claims

1. A two-in-one borehole shear testing system, characterized in that, include: The drilling rig system includes a drilling rig, a first lifting mechanism for driving the drilling rig to move up and down, and a control unit for controlling the drilling rig. The drilling rig can be driven by the first lifting mechanism to descend and connect with the casing drive and drive the casing to rotate. The casing is detachably connected to the drilling rig at the top and detachably connected to the transmission end pipe at the top. The drilling tool includes a flap drill bit, an outer sleeve disposed outside the flap drill bit, a shear probe disposed inside the flap drill bit, and a sensor disposed on the shear probe. The bottom of the transmission end tube is detachably connected to the top of the valve drill bit of the integrated drilling tool so as to drive the integrated drilling tool to rotate. A retrieval mechanism, a retrieval device and a pull line for passing through the casing to connect the transmission end pipe or the drilling integrated drill bit, and the pull line is connected to the motor drive module; The normal stress loading mechanism includes an oil supply mechanism and a hydraulic hose connecting the oil supply mechanism and the shear probe. The oil supply mechanism is equipped with a pressure gauge and a hydraulic sensor. The motor drive module is used to drive the pull line to pull the salvage device upward from inside the casing, and a tension sensor is provided at the connection between the pull line and the motor drive module; The data acquisition and recording device communicates with all sensors and includes a normal stress gauge, a tangential stress gauge, a tangential displacement gauge, a normal displacement gauge, and a pore water pressure gauge. It is used to record normal stress, shear force, normal deformation force, shear deformation force, pore water pressure, and time readings. The outer sleeve has splined teeth on its outer side, which mesh with the splined sleeve of the transmission end tube. The inner sleeve contains a tensioning shaft, which is divided into inner and outer layers. The inner layer is hollow, forming an oil passage and has a first sensor wire interface at its top. The inner layer also has a side lug that passes through the outer layer and is fixed to the outer sleeve. The outer layer has a hollow structure that mates with the side lug, and a retrieval spearhead at its top. This spearhead connects to the retrieval device, allowing the outer layer to move up and down along the outer sleeve under the drive of the motor drive module. The valve drill bit is connected to the outer layer of the tensioning shaft, and a sleeve located outside the valve drill bit at the bottom of the outer layer allows the valve drill bit to converge inwards and extend outwards as the outer layer moves up and down. The sleeve has a segmented structure, with each segment detachably connected. The bottom segment is the first segment, and the bottoms of all other segments are smooth.

2. The two-in-one drilling shear testing system according to claim 1, characterized in that, It also includes an operating platform, which is used to fix the location to be detected and to install and fix the drilling rig system, data acquisition recorder, normal stress loading mechanism and motor drive module.

3. The two-in-one drilling shear testing system according to claim 1, characterized in that, The shearing probe includes a hydraulic cylinder and a first shearing plate and a second shearing plate arranged vertically in parallel. A gap is provided between the first shearing plate and the second shearing plate for the installation of the hydraulic cylinder. The two pistons of the hydraulic cylinder are nested together with a pre-reserved gap, and the hydraulic cylinder is connected to the bottom of the inner layer.

4. The two-in-one drilling shear testing system according to claim 3, characterized in that, Both the first shear plate and the second shear plate are equipped with a pore water pressure test probe and a stress probe, and a normal displacement sensor is also provided between the first shear plate and the second shear plate. The pore water pressure test probe, the stress probe and the normal displacement sensor are all communicatively connected to the data acquisition recorder.

5. A two-in-one drilling shear testing system according to any one of claims 1-4, characterized in that, The salvage device includes an outer shell and an inner shaft disposed within the outer shell. The top end of the outer shell can be connected to the pull line, and the bottom end can be connected to the salvage spearhead. The top end of the inner shaft is connected to the hydraulic hose through a etched line, and a data cable interface is provided below the etched line. The bottom end of the inner shaft is connected to the top end of the inner layer.

6. The two-in-one drilling shear testing system according to claim 1, characterized in that, The transmission end tube includes an outer tube, a card disposed on the outer tube, a spring disposed between the outer tube and the card, and a sliding spear rod disposed at the top of the outer tube, the top end of the sliding spear rod being able to connect to the retrieval device.

7. The two-in-one drilling shear testing system according to claim 2, characterized in that, The motor drive module includes a motor housing, a second lifting mechanism located on the side of the motor housing, a fixed pulley assembly on the second lifting mechanism, a stepper motor located inside the motor housing, a transverse slide rail located at the bottom of the motor housing, and a winch connected to the stepper motor. The transverse slide rail is detachably mounted on the operating platform. The motor housing can move back and forth and be fixed along the length of the transverse slide rail. The fixed pulley assembly can move up and down and be fixed along the second lifting mechanism.

8. A test method using the two-in-one borehole shear test system according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Install a fixed operating platform at the predetermined detection location, and install the drilling rig system, data acquisition recorder, normal stress loading mechanism and motor drive module on the operating platform, while moving the motor drive module to the outermost position. S2. Connect the transmission end pipe to the bottom end of the first section of the casing and connect the casing to the drilling system drive, so that the transmission end pipe at the bottom end of the casing is connected and engaged with the drilling tool. At the same time, the outer layer of the tensioning shaft at the bottom end of the casing does not move up, so that the valve drill bit remains closed. S3. The drilling rig system drives the casing and the transmission end pipe located at the bottom of the casing to drill into the soft soil layer. The transmission end pipe drives the drilling tool to carry out drilling. S4. After drilling to a set depth or to the predetermined in-situ shear test depth in the soft soil layer, disconnect the connection between the drilling rig and the upper end of the casing. S5. Raise the drilling rig to the highest point along the first lifting mechanism, move the motor drive module to the innermost side, connect the pull wire to the winch, and pass it around the fixed pulley block. After connecting the other end to the retrieval device, raise the fixed pulley block along the second lifting mechanism to a position higher than the top of the casing, and use the retrieval device to take out the transmission end pipe. S6. Connect one end of the hydraulic hose to the upper end of the salvage device. Connect the data acquisition recorder to the interface at the upper end of the salvage device via the data cable. Fix the salvage device to the salvage spearhead on the outer layer of the tensioning shaft. Pull the salvage device with the pull line to engage the salvage device with the salvage spearhead. Lift the salvage device with the winch to open the flap drill bit of the drilling tool and expose the shearing probe. S7. Activate the oil supply mechanism and apply an initial normal stress to make the shear plate of the shear probe contact the borehole wall. Then, remove this normal stress and initialize the initial normal stress, shear force, normal deformation, shear deformation, pore water pressure and time readings of the data acquisition recorder to 0. S8. Apply the first-level normal stress through the normal stress control unit in the normal stress loading mechanism, and after the soil has been consolidated for a certain period of time, observe the soil consolidation through the pore water pressure curve. S9. Drive the winch to lift the salvage device and drilling tool at a constant rate. The tension sensor reading increases slowly until the tension sensor reading suddenly decreases and then the lifting stops. At this time, the soil is sheared and damaged, and the stress, normal deformation, pore water pressure image and maximum tension value of the soil before shearing failure are recorded. S10. Close the winch and release the normal stress in the double-acting pressure cylinder of the shear probe through the normal stress control unit in the normal stress loading mechanism, so that the shear probe is closed, remove the salvage device, and lower the transmission end tube from the top of the casing. Due to gravity, the transmission end tube is fixed again at the bottom of the casing. S11. Connect the drilling rig, continue drilling and repeat S5 to S9 to carry out the next level of normal stress test. Conduct in-situ shear tests with different normal stresses at each test point. S12. Remove the drilling tool from the borehole and repeat S1 to S11 to conduct the in-situ shear test at the next location.

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