Pipe-shale overall torsional stiffness test device and method considering slurry setting process

Abstract

This invention provides a test device and method for the overall torsional stiffness of tunnel segments and strata considering the grout solidification process. The test device includes a grout loading system, an overall torsional stiffness testing device for tunnel segments and strata, a torque loading system, and a grouting device. The overall torsional stiffness testing device is connected to both the torque loading system and the grouting device, and the grouting device is connected to the grout loading system. The test device includes a model box, tunnel segments, partitions, multiple displacement sensors, and a data acquisition instrument. The tunnel segments and partitions are installed inside the model box. The partitions are installed between the inner wall of the model box and the tunnel segments. The space between the outer surface of the partitions and the inner wall of the model box is a sand zone, and the space between the inner surface of the partitions and the outer surface of the tunnel segments is a grout zone. The beneficial effect of this invention is that the overall torsional stiffness testing device for tunnel segments simulates torsional deformation of the test segments through the torque loading system.

Description

Technical Field

[0001] This invention relates to the field of civil engineering, and more particularly to a test apparatus and method for the overall torsional stiffness of a segment-stratum considering the grout solidification process. Background Technology

[0002] Description of existing technology:

[0003] Chinese patent CN 108241780 A discloses a method for calculating the cutterhead torque of a composite shield tunneling machine in mixed soil and rock geology. The calculated torques include the torque generated by the cutterhead breaking the rock, the frictional torque generated by the excavation compression of the cutterhead panel and the soft soil layer, the frictional torque caused by the overburden depth, the ground resistance torque of the cutterhead cutting the soil, the frictional torque between the cutterhead side and the soft soil, the frictional torque between the cutterhead side and the rock, and the mixing resistance torque of the mixing arm in the soil chamber. The method can quickly and accurately calculate the cutterhead torque of a composite earth pressure balance shield tunneling machine in mixed soil and rock geology.

[0004] Chinese patent CN 108388689A discloses a method for calculating the torque of a tunnel boring machine cutterhead based on dimensional analysis. The method includes determining the parameters affecting the cutterhead torque, calculating the main control terms and dimensionless cutterhead torque based on these parameters, summarizing the calculated main control terms and dimensionless cutterhead torque, identifying the coefficients of the main control terms using linear regression, and obtaining a calculation model for the cutterhead torque based on the identification results of the main control term coefficients and comprehensively considering influencing factors such as cutterhead diameter, tunneling speed, and cutterhead rotation speed.

[0005] Chinese patent CN 106351667 A discloses a tool turret torque anomaly monitoring system for TBMs. The system includes a tool turret torque acquisition device for collecting tool turret torque data provided by the tool turret drive system, a tool turret torque data filtering device for calculating the average tool turret torque at the current moment based on the tool turret torque data, and an anomaly judgment device for determining whether there is an anomaly in the tool turret torque data based on the first average tool turret torque and a preset tool turret torque reference value. The system can realize torque anomaly monitoring of the TBM tool turret drive system and realize automatic processing of torque anomaly states based on the torque monitoring results.

[0006] Chinese patent CN 112196848 A discloses a hydraulic control system for a shield machine's main drive anti-torsion device, which includes four telescopic cylinders. The telescopic cylinders are fixed relative to the outer ring of the main drive. The telescopic cylinders are connected to a control circuit. The return oil of both the low-pressure circuit and the high-pressure circuit of the control circuit is connected to the oil tank. The control circuit can realize the displacement maintenance of the main drive anti-torsion cylinder, the clockwise anti-torsion torque, and the counterclockwise anti-torsion torque.

[0007] Chinese patent CN 210859409 U discloses an anti-torsion propulsion hydraulic cylinder suitable for tunnel boring machines. The cylinder includes a hydraulic cylinder with a hydraulic cylinder rod inside. A countersunk hole is formed at the rear of the hydraulic cylinder, and an anti-torsion device is installed within the countersunk hole. An anti-torsion hole is formed within the hydraulic cylinder rod, and the anti-torsion device passes through the anti-torsion hole and cooperates with a hydraulic lever. The anti-torsion limit of the hydraulic cylinder is achieved by the counter-torque generated by the anti-torsion rod inserting into the hydraulic lever. This solves the problems of hydraulic cylinder torsion causing scratches on the inner wall of the shield and the difficulty in arranging an anti-torsion structure at the rear of the hydraulic cylinder.

[0008] Problems and shortcomings of existing technology:

[0009] Existing shield tunneling torsion testing devices and methods mainly employ the shield machine cutterhead and jacks to simulate torsional load conditions, focusing primarily on the torsional stress characteristics of the cutterhead under different load conditions. Currently, no specific testing device or method has been proposed for studying the torsional deformation resistance of shield tunnel segments and for considering the overall torsional resistance of the segment-soil system during the slurry solidification process. Summary of the Invention

[0010] This invention provides a segment-stratum integrated torsional stiffness testing device considering the grout solidification process, comprising a grout loading system, a segment-stratum integrated torsional testing device, a torque loading system, and a grouting device. The segment-stratum integrated torsional testing device is connected to the torque loading system and the grouting device, respectively, and the grouting device is connected to the grout loading system. The segment-stratum integrated torsional testing device includes a model box, tunnel segments, a partition, multiple displacement sensors, and a data acquisition instrument. The tunnel segments and the partition are respectively installed inside the model box. The partition is installed between the inner wall of the model box and the tunnel segments. The space between the outer surface of the partition and the inner wall of the model box is a sand zone, and the space between the inner surface of the partition and the outer surface of the tunnel segments is a grout zone. Multiple displacement sensors are installed on the inner side of the tunnel segments, and the displacement sensors are connected to the data acquisition instrument. The grouting device is connected to the model box, and the model box is connected to the torque loading system.

[0011] As a further improvement of the present invention, the grouting device includes a mixer, a material cup, an electric drill, a grouting machine, and a grouting pipe. The material cup is installed on the grouting machine, and the mixer is installed inside the grouting machine. The electric drill is connected to the grouting machine, and the mixer is connected to the material cup and the mold box respectively.

[0012] As a further improvement of the present invention, the grout loading system includes an air compressor and a professional pressure regulating valve, wherein the professional pressure regulating valve is installed on the air compressor and the air compressor is connected to the mixer; the grouting device also includes a funnel grout inlet valve, which is installed on the material cup bucket; the grouting device also includes a grouting valve, which is installed on the grouting machine.

[0013] As a further improvement of the present invention, the segment-stratum integrated torsional stiffness testing device also includes a high-pressure pipe and a grouting pipe. One end of the high-pressure pipe is connected to the mixer, and the other end of the high-pressure pipe is connected to the grouting pipe. A grouting hole is provided at the bottom of the grout zone in the model box, and the grouting pipe is installed on the grouting hole.

[0014] As a further improvement of the present invention, the grouting pipe is a steel pipe, the front end of the grouting pipe is provided with an external thread, the inner wall of the grouting hole is provided with an internal thread, and the grouting pipe is installed on the grouting hole by screwing the external thread into the internal thread on the grouting hole; the end of the grouting pipe is provided with an end thread, and the high-pressure pipe is provided with a thread that matches the end thread, and the grouting pipe and the high-pressure pipe are installed together by screwing the end thread into the thread.

[0015] As a further improvement of the present invention, a plurality of displacement sensors are fixed inside the tunnel segment, and the plurality of displacement sensors are arranged in three rings along the height direction of the ring, with four sensors in each ring, spaced at 90-degree intervals; the tunnel segment is a steel closed cylinder; the partition is a cylindrical thin plate; the segment-stratum overall torsional stiffness testing device also includes an anti-friction device, which is used to reduce the friction between the tunnel segment and the model box wall during the torsion process.

[0016] As a further improvement of the present invention, the anti-friction device includes a low-friction coefficient plastic material and industrial petroleum jelly. The low-friction coefficient plastic material is affixed to the vicinity of the tunnel segment on the inner wall of the model box and the industrial petroleum jelly is applied.

[0017] As a further improvement of the present invention, the torque loading system includes a rotating disk, a rotating power arm, a bearing, a torque sensor, a coupling, and a drive motor. The tunnel segment is mounted on the rotating disk, and the rotating power arm is mounted below the rotating disk. The rotating power arm is connected to the bearing, the bearing is connected to the torque sensor, the torque sensor is connected to the coupling, and the coupling is connected to the drive motor.

[0018] As a further improvement of the present invention, the segment-formation integrated torsional stiffness testing device also includes a base support, on which the torque loading system is mounted; the segment-formation integrated torsional stiffness testing device also includes a test bench, on which the segment-formation integrated torsional stiffness testing device and the grouting device are respectively installed, and on which the torque loading system is installed; the rotating power arm is welded from three steel bars with a diameter of 10mm and a length of 30mm, nuts, and rings; the drive motor has an adjustable speed of 1~10 rpm and a working speed of 3~7 rpm; the torque sensor has a maximum torque range of 100 N·m and an accuracy of 0.5 N·m; the torque sensor includes a signal excitation circuit, a secondary coil of an energy ring transformer, a primary coil of a signal ring transformer, and a transmitter.

[0019] This invention also discloses a test method for the overall torsional stiffness of the segment-formation considering the slurry solidification process, comprising the following steps:

[0020] Step S1: Install tunnel segments inside the model box and install multiple displacement sensors inside the tunnel segments.

[0021] Step S2: Install the torque loading system, and install the swing arm, torque sensor, drive motor, bearing and coupling in sequence.

[0022] Step S3: Assemble the partition between the inner wall of the model box and the tunnel segment. In the grout zone, i.e., the space between the inner surface of the partition and the outer surface of the tunnel segment, reserve a grouting pipe. In the sand zone, i.e., the space between the outer surface of the partition and the inner wall of the model box, fill with test sand.

[0023] Step S4: Measure and calculate the permeability coefficient, natural density, unit weight, and porosity of the test sand.

[0024] Step S5: Connect the mixer to the air compressor, connect the material cup to the mixer, and connect the displacement sensor to the data acquisition instrument.

[0025] Step S6: Prepare the grouting slurry according to the parameters designed for the experiment and stir it. Open the slurry inlet valve of the funnel and pour the grouting slurry into the material cup bucket so that it flows into the mixer. Then tighten the slurry inlet valve.

[0026] Step S7: Check the above steps, turn on the air compressor to store gas and prepare for grouting.

[0027] Step S8: Start grouting; open the grouting valve, adjust the pressure supply valve according to the pressure gauge reading to the designed grouting pressure value and keep it unchanged, observe the filling of the grout zone, and when the grout zone is filled to the same horizontal position, the grouting is completed.

[0028] Step S9: Close the grouting valve, open the grout inlet valve of the funnel, depressurize, and empty the remaining grout in the mixer.

[0029] Step S10: Remove the partition between the test sand and the grout to allow the test soil sample to come into contact with the grout.

[0030] Step S11: Apply low-friction plastic material near the tunnel segments on the inner wall of the model box and apply industrial petroleum jelly, then cover with the top cover.

[0031] Step S12: Before performing torsional deformation of the tunnel segments, the magnitude of the torque applied to the tunnel segments is determined using a torsion sensor, and the displacement sensor data is saved to monitor the torsion of the tunnel segments in real time.

[0032] Step S13: Based on the grout setting time, a segment-soil torsion test is conducted at 2 hours, 4 hours, 8 hours and 1 day after the grout is injected. The torsion test of the tunnel segment is carried out by adjusting the torque applied to the tunnel segment through the torque loading system. After completing one torsion test, the torsion deformation of the tunnel segment is re-determined.

[0033] Step S14: Repeat step S13 three times. Conduct the torsional test of the stratum-tunnel segment without disturbing the grout. Continue until all conditions in step S13 are completed. Complete the calculation of the overall torsional stiffness of the stratum-tunnel segment considering the spatial and temporal effects of grout solidification. During the test, a torque is applied to the tunnel segment at different solidification processes of the grout. After the tunnel segment, grout with different proportions, and the stratum are subjected to overall torsional resistance, the rotation angle of the tunnel segment is measured. Based on this, the overall torsional stiffness of the tunnel segment-stratum considering the solidification process of the grout is calculated.

[0034] The beneficial effects of this invention are as follows: The segment-stratum integrated torsional stiffness testing device of this invention can simulate the torsional deformation of the test segment through a torque loading system, and the grouting slurry loading system can simulate the injection process of slurry around the tunnel segment. The torsional stiffness of the segment-stratum as a whole can be calculated by considering different degrees of slurry solidification. The segment-stratum integrated torsional stiffness testing device of this invention maintains the applied load through a torque sensor, and performs torsional deformation of the test segment under the condition of maintaining the torque load. The grouting slurry system of the segment-stratum integrated torsional stiffness testing device of this invention, combined with a cylindrical thin plate, can simulate the back-wall grouting loading of the tunnel segment. The friction problem between the segment and the box wall during the rotation process can be solved by attaching a low-friction coefficient plastic material nearby and applying industrial petroleum jelly. Attached Figure Description

[0035] Figure 1 This is an overall structural diagram of the segment-formation integrated torsional stiffness testing device of the present invention;

[0036] Figure 2 This is a structural diagram of the torque loading system of the present invention. Detailed Implementation

[0037] In recent years, shield tunneling has been widely used in the construction of urban subway tunnels, underwater tunnels, and highway tunnels due to its high cost-effectiveness and minimal disturbance to the surrounding soil. During the construction process, involving cutterhead excavation, jack advancement, and interaction with the surrounding soil, the torque generated by the cutterhead rotation, the effect of synchronous grouting, and uneven stress on the tunnel segments often lead to insufficient frictional resistance from the surrounding rock to limit the torsion of the tunnel boring machine, resulting in excessive tunnel structural deformation. Therefore, research on the torsional strength of shield tunnel segments is crucial, and it is necessary to propose an experimental device that considers the grout solidification process to assess the overall torsional stiffness of the segment-soil structure.

[0038] like Figure 1 As shown, this invention discloses a segment-formation integrated torsional stiffness testing device considering the grout solidification process, comprising a grout loading system, a segment-formation integrated torsional testing device, a torque loading system, and a grouting device. The segment-formation integrated torsional testing device is connected to the torque loading system and the grouting device, respectively, and the grouting device is connected to the grout loading system. The segment-formation integrated torsional testing device includes a model box 23, tunnel segments 6, partitions 5, multiple displacement sensors 1, and a data acquisition instrument. The tunnel segments 6 and partitions 5 are respectively installed in the model box 23. Inside the model box 23, the partition 5 is installed between the inner wall of the model box 23 and the tunnel segment 6. The space between the outer surface of the partition 5 and the inner wall of the model box 23 is a sand zone, which is used to place the test sand sample 3. The space between the inner surface of the partition 5 and the outer surface of the tunnel segment 6 is a grout zone, which is used to place the grouting grout 2. Multiple displacement sensors 1 are installed on the inner side of the tunnel segment 6, and the displacement sensors 1 are connected to the data acquisition instrument. The grouting device is connected to the model box 23, and the model box 23 is connected to the torque loading system.

[0039] The grouting device includes a mixer 9, a material cup 11, an electric drill 12, a grouting machine 13, and a grouting pipe 15. The material cup 11 is installed on the grouting machine 13, the mixer 9 is installed inside the grouting machine 13, the electric drill 12 is connected to the grouting machine 13, and the mixer 9 is connected to the model box 23.

[0040] The grouting slurry loading system includes an air compressor and a specialized pressure regulating valve. The air compressor is equipped with the specialized pressure regulating valve and is connected to the mixer 9. An air compressor capable of providing stable air pressure is used to simulate backfill grouting of tunnel segments 6. The grouting machine 13 is pressurized by an electric drill 12.

[0041] The grouting device also includes a funnel grout inlet valve, which is installed on the material cup 11; the grouting device also includes a grouting valve, which is installed on the grouting machine 13.

[0042] The segment-formation overall torsional stiffness testing device also includes a high-pressure pipe 10 and a grouting pipe 15. One end of the high-pressure pipe 10 is connected to the mixer 9, and the other end of the high-pressure pipe 10 is connected to the grouting pipe 15. A grouting hole 14 is provided at the bottom of the grout zone inside the model box 23, and the grouting pipe 15 is installed on the grouting hole 14.

[0043] The grouting pipe 15 is a small-diameter steel pipe. The front end of the grouting pipe 15 is provided with an external thread, and the inner wall of the grouting hole 14 is provided with an internal thread. The grouting pipe 15 is installed on the grouting hole 14 by screwing the external thread into the internal thread of the grouting hole 14 to achieve a sealing effect. The end of the grouting pipe 15 is provided with a terminal thread, and the high-pressure pipe 10 is provided with a thread that matches the terminal thread. The grouting pipe 15 and the high-pressure pipe 10 are installed together by screwing the terminal thread into the thread.

[0044] The segment-stratum integrated torsional testing device also includes aluminum alloy plates and plexiglass. The model box 23 uses an impermeable perimeter to simulate dry sand and soft clay with poor permeability. The long side and one short side are made of high-strength, corrosion-resistant military-grade 5A06 aluminum alloy plates to ensure the box wall does not deform significantly under torsion. The other short side uses thicker plexiglass for easy observation of the sand sample and grouting fluid 2. Low-friction plastic material is affixed to the inner wall of the model box 23 near the tunnel segments, and industrial petroleum jelly is applied to reduce friction between the tunnel segments 6 and the box wall during torsion. The tunnel segments 6 are enclosed steel cylinders, with their bottoms mounted on the torsional loading system. The model box 23 also includes fixing bolts 4.

[0045] Tunnel segment 6 is a closed steel cylinder. The torsional stiffness reduction effect caused by the inter-ring joints of the segments has a relatively small impact in this test; therefore, the influence of the inter-ring joints is ignored, simplifying it as a uniform segment. Baffle 5 is used to form a cylindrical shape around tunnel segment 6 when grout 2 is injected. After the grout is filled, it is removed, allowing the grout 2 to contact the surrounding test soil sample. Displacement sensors 1 are fixed inside tunnel segment 6, arranged in three rings along the height direction of the rings. Each ring has four sensors, spaced 90 degrees apart. A data acquisition instrument is connected to displacement sensors 1, and the rotation angle of tunnel segment 6 during the test is calculated using the values ​​measured by displacement sensors 1 inside tunnel segment 6.

[0046] The partition 5 is a cylindrical thin plate.

[0047] The torque loading system includes a rotating disk 16, a rotating power arm 17, a bearing 18, a torque sensor 19, a coupling 20, and a drive motor 21. The tunnel segment 6 is mounted on the rotating disk 16, and the rotating power arm 17 is mounted below the rotating disk 16. The rotating power arm 17 is connected to the bearing 18, the bearing 18 is connected to the torque sensor 19, the torque sensor 19 is connected to the coupling 20, and the coupling 20 is connected to the drive motor 21.

[0048] The rotating arm 17 is welded from three steel bars, each 10mm in diameter and 30mm long, along with nuts and rings. The drive motor 21 has an adjustable speed of 1-10 rpm, with a working speed of 3-7 rpm. The torque sensor 19 has a maximum torque range of 100 N·m and an accuracy of 0.5 N·m. The torque sensor 19 is installed between the rotating arm 17 and the drive motor 21. The torque sensor 19 bracket supports the displacement sensor 1 and is stably connected to the test bench 7. The torque sensor 19 mainly consists of a torque signal excitation circuit, a secondary coil of an energy ring transformer, a primary coil of a signal ring transformer, and a transmitter. A speed-regulating motor drives the rotating disk 16, and the torque sensor 19 achieves the torque loading function.

[0049] This invention also discloses a test method for the overall torsional stiffness of the segment-formation considering the slurry solidification process, comprising the following steps:

[0050] Step S1: Install the tunnel segment 6 inside the model box 23, and install multiple displacement sensors 1 inside the tunnel segment 6.

[0051] Step S2: Install the torque loading system, and install the rotating arm 17, torque sensor 19, drive motor 21, bearing 18 and coupling 20 in sequence.

[0052] Step S3: Assemble the partition 5 between the inner wall of the model box 23 and the tunnel segment 6. In the grout zone, that is, the space between the inner surface of the partition 5 and the outer surface of the tunnel segment 6, reserve the grouting pipe 15. In the sand zone, that is, the space between the outer surface of the partition 5 and the inner wall of the model box 23, fill the test sand 3.

[0053] Step S4: Measure and calculate the permeability coefficient, natural density, unit weight, porosity and other parameters of the test sand 3.

[0054] Step S5: Connect the mixer 9 to the air compressor, connect the material cup 11 to the mixer 9, and connect the displacement sensor 1 to the data acquisition instrument.

[0055] Step S6: Prepare the grouting slurry 2 according to the parameters designed for the experiment and stir it. The indoor temperature during the experiment is about 28℃. Open the slurry inlet valve of the funnel and pour the grouting slurry 2 into the material cup bucket 11 so that it flows into the mixer 9. Then tighten the slurry inlet valve.

[0056] Step S7: Check the above steps, turn on the air compressor to store gas and prepare for grouting.

[0057] Step S8: Start grouting; open the grouting valve, adjust the pressure supply valve according to the pressure gauge reading to the designed grouting pressure value and keep it unchanged, observe the filling of the grout zone, and when the grout zone is filled to the horizontal position, the grouting is completed.

[0058] Step S9: Close the grouting valve, open the grout inlet valve of the funnel, depressurize, and empty the remaining grout 2 in the mixer 9.

[0059] Step S10: Gently remove the partition 5 between the test sand 3 and the grout 2 so that the test soil sample 3 comes into contact with the grout 2.

[0060] Step S11: Apply low-friction plastic material and industrial petroleum jelly to the inner wall of the model box 23 near the tunnel segment 6 to reduce friction between the model segment and the box wall during the torsion process, and then cover it with the top cover.

[0061] Step S12: Before torsional deformation of tunnel segment 6, the torque applied to tunnel segment 6 is determined by using a torsion sensor measurement system, and the displacement sensor 1 data is saved to monitor the torsion of tunnel segment 6 in real time.

[0062] Step S13: Based on the setting time of the grout 2, a segment-stratum torsion test is conducted after 2 hours, 4 hours, 8 hours and 1 day of the grout 2. The torsion test of the tunnel segment 6 is carried out by adjusting the torque applied by the torque loading system. After completing one torsion test, the torsion deformation of the tunnel segment 6 is re-determined.

[0063] Step S14: Repeat step S13 three times. Conduct the torsional test of the stratum-segment without disturbing the grout 2 until all working conditions of step S13 are completed. Complete the calculation of the overall torsional stiffness of the stratum-segment considering the spatial and temporal effects of grout solidification. In the test, a torque is applied to the tunnel segment 6 during different solidification processes of the grout 2. After the tunnel segment 6, the grout 2 with different proportions, and the stratum are subjected to overall torsional resistance, the rotation angle of the tunnel segment 6 is measured. Based on this, the overall torsional stiffness of the segment-stratum considering the solidification process of the grout 2 is calculated.

[0064] The effective effects of this invention are as follows: The segment-stratum integrated torsional stiffness testing device of this invention can simulate the torsional deformation of the test segment through a torque loading system, and the grouting slurry loading system can simulate the injection process of grout around the tunnel segment 6. The torsional stiffness of the segment-stratum as a whole can be calculated by considering different degrees of grout solidification. The segment-stratum integrated torsional stiffness testing device of this invention maintains the applied load through a torque sensor 19, and performs torsional deformation of the test segment under the condition of maintaining the torque load. The grouting slurry system of the segment-stratum integrated torsional stiffness testing device of this invention, combined with a cylindrical thin plate, can simulate the backfilling grouting loading of the tunnel segment 6. The friction problem between the segment and the box wall during the rotation process can be solved by attaching low-friction coefficient plastic material nearby and applying industrial petroleum jelly.

[0065] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A test device for the overall torsional stiffness of a segment-formation system considering the slurry solidification process, characterized in that: The system includes a grout loading system, a segment-stratum integrated torsional testing device, a torque loading system, and a grouting device. The segment-stratum integrated torsional testing device is connected to the torque loading system and the grouting device, respectively. The grouting device is connected to the grout loading system. The segment-stratum integrated torsional testing device includes a model box (23), tunnel segments (6), partitions (5), multiple displacement sensors (1), and a data acquisition instrument. The tunnel segments (6) and the partitions (5) are respectively installed in the model box (23). A partition (5) is installed between the inner wall of the model box (23) and the tunnel segment (6). The space between the outer surface of the partition (5) and the inner wall of the model box (23) is a sandy area. The space between the inner surface of the partition (5) and the outer surface of the tunnel segment (6) is a grouting area. Multiple displacement sensors (1) are installed on the inner side of the tunnel segment (6). The displacement sensors (1) are connected to the data acquisition instrument. The grouting device is connected to the model box (23). The model box (23) is connected to the torque loading system.

2. The segment-formation overall torsional stiffness testing device according to claim 1, characterized in that: The grouting device includes a mixer (9), a material cup (11), an electric drill (12), a grouting machine (13), and a grouting pipe (15). The material cup (11) is installed on the grouting machine (13), and the mixer (9) is installed inside the grouting machine (13). The electric drill (12) is connected to the grouting machine (13), and the mixer (9) is connected to the material cup (11) and the model box (23) respectively.

3. The segment-formation overall torsional stiffness testing device according to claim 2, characterized in that: The grouting slurry loading system includes an air compressor and a professional pressure regulating valve. The air compressor is equipped with the professional pressure regulating valve and is connected to the mixer (9). The grouting device also includes a funnel slurry inlet valve, which is installed on the material cup (11). The grouting device also includes a grouting valve, which is installed on the grouting machine (13).

4. The segment-formation integrated torsional stiffness testing device according to claim 2, characterized in that: The segment-stratum overall torsional stiffness test device also includes a high-pressure pipe (10) and a grouting pipe (15). One end of the high-pressure pipe (10) is connected to the mixer (9), and the other end of the high-pressure pipe (10) is connected to the grouting pipe (15). A grouting hole (14) is provided at the bottom of the grout zone in the model box (23), and the grouting pipe (15) is installed on the grouting hole (14).

5. The segment-formation integral torsional stiffness testing device according to claim 4, characterized in that: The grouting pipe (15) is a steel pipe. The front end of the grouting pipe (15) is provided with an external thread, and the inner wall of the grouting hole (14) is provided with an internal thread. The grouting pipe (15) is installed on the grouting hole (14) by screwing the external thread into the internal thread on the grouting hole (14). The end of the grouting pipe (15) is provided with an end thread, and the high-pressure pipe (10) is provided with a thread that matches the end thread. The grouting pipe (15) and the high-pressure pipe (10) are installed together by screwing the end thread into the thread.

6. The segment-formation integrated torsional stiffness testing device according to claim 1, characterized in that: Multiple displacement sensors (1) are fixed inside the tunnel segment (6). The multiple displacement sensors (1) are arranged in three rings along the height direction of the ring, with four sensors in each ring, spaced 90 degrees apart. The tunnel segment (6) is made of steel closed cylinder. The partition plate (5) is a cylindrical thin plate. The tunnel segment-stratum overall torsional stiffness test device also includes an anti-friction device, which is used to reduce the friction between the tunnel segment (6) and the wall of the model box (23) during the torsion process.

7. The segment-formation integrated torsional stiffness testing device according to claim 6, characterized in that: The anti-friction device includes a low-friction coefficient plastic material and industrial petroleum jelly. The low-friction coefficient plastic material is affixed to the inner wall of the model box (23) near the tunnel segment (6) and the industrial petroleum jelly is applied.

8. The segment-formation integrated torsional stiffness testing device according to claim 1, characterized in that: The torque loading system includes a rotating disk (16), a rotating power arm (17), a bearing (18), a torque sensor (19), a coupling (20), and a drive motor (21). The tunnel segment (6) is mounted on the rotating disk (16). The rotating power arm (17) is mounted below the rotating disk (16). The rotating power arm (17) is connected to the bearing (18). The bearing (18) is connected to the torque sensor (19). The torque sensor (19) is connected to the coupling (20). The coupling (20) is connected to the drive motor (21).

9. The segment-formation integral torsional stiffness testing device according to claim 8, characterized in that: The segment-formation overall torsional stiffness test device also includes a base support (22), and the torque loading system is installed on the base support (22); the segment-formation overall torsional stiffness test device also includes a test bench (7), the segment-formation overall torsional stiffness test device and the grouting device are respectively installed on the test bench (7), and the torque loading system is installed below the test bench (7); the rotating power arm (17) is welded from three steel bars with a diameter of 10mm and a length of 30mm, nuts, and rings; the drive motor (21) has an adjustable speed of 1~10 rpm and a working speed of 3~7 rpm; the torque sensor (19) has a maximum torque range of 100 N·m and an accuracy of 0.5 N·m; the torque sensor (19) includes a signal excitation circuit, a secondary coil of an energy ring transformer, a primary coil of a signal ring transformer, and a transmitter.

10. A test method for the overall torsional stiffness of the segment-formation system considering the grout solidification process, characterized in that, This includes performing the following steps: Step S1: Install tunnel segments (6) inside the model box (23) and install multiple displacement sensors (1) inside the tunnel segments (6); Step S2: Install the torque loading system, and install the rotating power arm (17), torque sensor (19), drive motor (21), bearing (18) and coupling (20) in sequence. Step S3: Assemble the partition (5) between the inner wall of the model box (23) and the tunnel segment (6). In the grout zone, that is, the space between the inner surface of the partition (5) and the outer surface of the tunnel segment (6), reserve the grouting pipe (15). In the sand zone, that is, the space between the outer surface of the partition (5) and the inner wall of the model box (23), fill the test sand (3). Step S4: Measure and calculate the permeability coefficient, natural density, unit weight, and porosity of the test sand (3); Step S5: Connect the mixer (9) to the air compressor, connect the material cup (11) to the mixer (9), and connect the displacement sensor (1) to the data acquisition instrument; Step S6: Prepare the grouting slurry (2) according to the parameters designed for the experiment and stir it. Open the slurry inlet valve of the funnel and pour the grouting slurry (2) into the material cup bucket (11) so that it flows into the mixer (9). Then tighten the slurry inlet valve. Step S7: Check the above steps, turn on the air compressor to store gas and prepare for grouting; Step S8: Start grouting; open the grouting valve, adjust the pressure supply valve according to the pressure gauge reading to the designed grouting pressure value and keep it unchanged, observe the filling of the grout area, when the grout area is filled to the horizontal position, the grouting is completed; Step S9: Close the grouting valve, open the funnel grout inlet valve, depressurize, and empty the remaining grout (2) in the mixer (9). Step S10: Remove the partition (5) between the test sand (3) and the grout (2) to bring the test sand (3) into contact with the grout (2); Step S11: Apply low-friction plastic material and industrial petroleum jelly to the inner wall of the model box (23) near the tunnel segment (6), and cover it with the top cover; Step S12: Before the torsional deformation of the tunnel segment (6), the torque applied to the tunnel segment (6) is determined by the torsion sensor, and the displacement sensor (1) data is saved to monitor the torsion of the tunnel segment (6) in real time. Step S13: Based on the setting time of the grout (2), a segment-stratum torsion test is conducted after 2 hours, 4 hours, 8 hours and 1 day of the grout (2). The torsion test of the tunnel segment (6) is carried out by adjusting the torque applied by the torque loading system. After completing one torsion test, the torsion deformation of the tunnel segment (6) is re-determined. Step S14: Repeat the operation of step S13 three times. Under the condition that the grout (2) is not disturbed, the torsional test of the stratum-segment is carried out until all the working conditions of step S13 are completed. The calculation of the overall torsional stiffness of the stratum-segment considering the spatial and temporal effects of grout solidification is completed. During the test, a torque is applied to the tunnel segment (6) during different solidification processes of the grout (2). After the tunnel segment (6), the grout (2) with different proportions and the overall torsional resistance of the stratum are completed, the rotation angle of the tunnel segment (6) is measured. Based on this, the overall torsional stiffness of the segment-stratum considering the solidification process of the grout (2) is calculated.

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