A same direction tension-torsion loading device, and a crack anchoring rock mass test system and method

Abstract

This invention provides a unidirectional tension-torsion loading device and a test system and method for anchored rock mass in fractures, relating to the field of rock mechanics. The device includes a tensile loading mechanism, a linkage mechanism, and a torsional loading mechanism. A linkage mechanism is provided between the torsional loading mechanism and the tensile loading mechanism to ensure synchronous loading. The anchored rock mass assembly is loaded through the linkage mechanism. The tension-compression cylinder can achieve bidirectional loading; adjusting the piston position of the tension-compression cylinder allows for loading of anchor specimens of different lengths. This loading device allows for tensile and torsional motion constraint control, thereby applying combined tension and torsional stress to the anchor bolt-rock mass bonding interface at the fracture surface of the anchored rock mass. This test method can perform synchronous loading of large-sized fractured specimens anchored in rock mass with one side fixed and the other side subjected to tension and torsion, providing convenience for studying the interface failure and stress law of the anchor bolt at the anchoring fracture under combined tension and torsional stress.

Description

Technical Field

[0001] This invention relates to the field of rock mechanics, and in particular to a unidirectional tension-torsion loading device and a test system and method for fracture anchoring rock mass. Background Technology

[0002] Rock bolt support, as a crucial support technology for the surrounding rock mass, provides reliable technical assurance for the safe and efficient construction of underground space engineering projects. Currently, there are many types of rock bolts, the most commonly used being ordinary threaded steel rock bolts, Cone rock bolts, D-bolts, Garford anchor cables, Roofex rock bolts, Durabar rock bolts, and Yielding Secura rock bolts. Different types of rock bolts exhibit different interaction mechanisms and support principles with the surrounding rock. The quality of rock bolt anchoring performance is determined through both field experience and scientific research using laboratory tests.

[0003] At engineering sites, due to the influence of geological structure and original fissures, tunnels often undergo non-uniform deformation, resulting in a combined stress loading effect on anchor bolts at the anchoring fissure surface. Because of the concealed nature of anchor bolt anchoring, effective observation and research are difficult to conduct on-site, necessitating detailed experimental studies using indoor testing equipment. Previous experimental studies have focused on the pull-out shearing effect between the anchor bolt and the rock mass, and the shearing effect perpendicular to the anchor bolt caused by rock mass displacement, while neglecting the deflection and displacement between hard rock masses. In practical engineering, the angle of deflection and displacement between rock masses is not very large, typically between 0-10°. However, because the distance between the fissures in the two rock masses is generally small, or even in a compressed and closed state, even a small deflection of the rock mass at the anchoring fissure can cause damage and failure of the anchoring interface or yielding failure of the anchor bolt.

[0004] In the prior art, there are a test device and method for anchored rock mass torsion shear test (CN110243701A) and a test device and method for anchor bolt (cable) support structure test and anchoring system performance comprehensive test (CN110274831A). The rock mass tensile loading mechanism and the rock mass torsion loading mechanism are located at the front and rear of the test machine, respectively. Therefore, in order to more perfectly and scientifically reproduce engineering problems and test the tensile and torsional mechanical properties of anchor bolts between rock masses, a unidirectional tensile and torsional loading device suitable for fracture anchored rock mass test system is proposed. Summary of the Invention

[0005] To achieve constraint control of tensile and torsional motion, a combined tensile and torsional stress is applied to the bonding interface between the anchor rod and the rock mass at the anchored rock fracture surface. A synchronous loading test is conducted on a large-sized fracture specimen anchored in the rock mass with one side fixed and the other side subjected to tensile and torsional stress. This facilitates the study of the interface failure and stress law of the anchor rod at the anchored fracture under the action of combined tensile and torsional stress. The present invention provides a unidirectional tensile and torsional loading device and a fracture anchored rock mass test system and method. The specific technical solution is as follows.

[0006] A unidirectional tension-torsion loading device includes a tension loading mechanism, a linkage mechanism, and a torsion loading mechanism. The linkage mechanism is provided between the torsion loading mechanism and the tension loading mechanism, and the fracture anchored rock mass composite specimen is placed in the linkage mechanism. The tension loading mechanism uses a tension-compression cylinder for bidirectional loading, and the piston position of the tension-compression cylinder is adjusted to load anchored solid specimens of different lengths. The unidirectional tension-torsion loading device provides tension and torsion motion constraint control. The bonding interface between the anchor rod and the rock mass at the fracture surface of the anchored rock mass is subjected to combined tension and torsion stress. One side of the fracture anchored rock mass composite specimen is fixed, while the other side is subjected to synchronous tension and torsion loading.

[0007] Preferably, the tension / compression cylinder is a bidirectional loading cylinder, which is fixed to the support plate at the front of the main frame by a fixing rod; the support plate has a pre-drilled circular hole with a diameter larger than the piston diameter of the tension / compression cylinder; the piston tail end of the tension / compression cylinder is a variable diameter threaded screw, and the spoke sensor cooperates with the variable diameter threaded screw; the spoke sensor is fixedly connected to the first guide plate and the internal threaded connecting plate by a long stud; the first guide plate is provided with a drilled hole with a diameter larger than the piston diameter of the tension / compression cylinder.

[0008] Preferably, the spoke sensor senses the axial tension between the hydraulic cylinder and the fixed shaft, and the threaded connecting plate is fixed to the threaded screw at the front end of the fixed shaft; a one-way thrust bearing and a thrust cylindrical roller bearing are arranged in the inner cavity formed by the coupling between the fixed shaft and the variable cross-section cylindrical shaft on the rear side of the threaded connecting plate; a double row of cylindrical roller bearings are arranged in the inner cavity formed by the variable cross-section cylindrical shaft and the second guide plate, and the cylindrical shaft rotates around the fixed shaft.

[0009] Preferably, the first guide plate and the second guide plate are connected to the load-bearing plate in front of the main frame via directional guide rods.

[0010] Preferably, a first pulley is installed on the outer ring of the variable cross-section cylindrical shaft, and a torsion motor drives a second pulley to rotate. A belt connects the first pulley and the second pulley. The rotation of the first pulley simultaneously drives the variable cross-section cylindrical shaft and the tension-torsion loading frame to rotate.

[0011] Preferably, the torsion motor is mounted on the torsion motor mounting frame via a motor mounting bracket, and the torsion motor mounting frame is fixedly mounted on the slider of the fixed plate of the torsion loading mechanism. The slider is fitted on the guide rail of the torsion loading mechanism, and the fixed plate is connected to the side plate of the main frame via a torque reaction plate.

[0012] More preferably, the motor mounting base is a hollow cylindrical structure, the first torsion drive shaft passes through the motor mounting base and is connected to the rotating shaft of the torsion motor, the first torsion drive shaft and the second torsion drive shaft are both connected to the torque sensor, the second torsion drive shaft is connected to the ball bearing and the second pulley, and the ball bearing is mounted on the slider of the fixed plate through the bearing seat.

[0013] More preferably, the torsion motor fixing frame is fixedly connected to the first guide plate and the second guide plate through a linkage mechanism, and the upper part of the linkage mechanism is connected to the torsion loading device through a guide rail slider mechanism; the torsion loading mechanism moves simultaneously with the intermediate linkage mechanism and the tension loading mechanism through the linkage mechanism.

[0014] A fracture anchoring rock mass testing system includes the aforementioned unidirectional tension-torsion loading device, and further comprises a main frame and a fracture anchoring rock mass assembly. The main frame includes a steel pad, multiple sets of main frame side plates, a front bearing plate, and a rear bearing plate, with the multiple sets of main frame side plates positioned between the front and rear bearing plates. The fracture anchoring rock mass assembly is placed within the main frame, and an assembly clamps the assembly. The assembly includes a similar material sample and an outer frame. The tension-torsion clamping frame includes a variable cross-section disk, a connecting rod, and a rectangular groove disk, and the assembly cooperates with the tension-torsion clamping frame.

[0015] A test method for fractured anchored rock mass, utilizing the aforementioned fractured anchored rock mass test system, includes: during a tension-torsion combined test of the fractured anchored rock mass, a unidirectional tension-torsion loading device applies tensile and torsional loads to the fractured anchored rock mass assembly; during a tension-torsion combined test of the anchor rod, the tension-torsion loading frame is replaced with a tension-torsion hydraulic clamp, the tension-torsion hydraulic clamp including a front tension-torsion hydraulic clamp mounted on the tension-torsion loading device and a rear tension-torsion hydraulic clamp mounted within the main frame; the fixed position of the rear tension-torsion hydraulic clamp is adjusted to conduct tension-torsion combined tests on anchor rods of different lengths.

[0016] The beneficial effects of the unidirectional tension-torsion loading device, fracture anchoring rock mass test system, and method provided by this invention are:

[0017] (1) Through the cooperation between bearings and related structural components, an intermediate linkage mechanism is formed, which enables the torsional loading and measurement mechanism to be synchronously loaded with the tensile loading and measurement mechanism, thereby realizing the constraint control of tensile and torsional motion, and applying tensile and torsional composite stress to the bonding interface between the anchor rod and the rock mass at the rock fracture surface.

[0018] (2) Through the effective cooperation of the coaxial tension-torsion loading device with the main frame of the test system, the tension-torsion loading frame, the anchoring rock mass sample assembly, etc., one-side fixation and synchronous tension-torsion loading on the other side of the large-size fissure-anchored rock mass are achieved. The structure of the coaxial tension-torsion loading device adopts a co-side linkage layout, releasing the space above and behind the test system for use, making the test system have greater functional expandability and making it easier to install large-size anchored rock mass combined samples.

[0019] (3) Using this test system for the test of the fissure-anchored rock mass test method, the tension-torsion combined test of the fissure-anchored rock mass and the tension-torsion combined test of the bolt rod body can be carried out, facilitating the study of the interface failure at the bolt anchoring interface at the anchored fissure under the action of tension-torsion composite stress and the stress law of the bolt. Brief Description of the Drawings

[0020] Figure 1 is a schematic diagram of the fissure-anchored rock mass test system;

[0021] Figure 2 is a side view of the fissure-anchored rock mass test system;

[0022] Figure 3 is a top view of the fissure-anchored rock mass test system after removing the upper cover plate;

[0023] Figure 4 is a sectional view of the fissure-anchored rock mass test system;

[0024] Figure 5 is a three-dimensional view of the coaxial tension-torsion loading device;

[0025] Figure 6 is a schematic diagram of the shape of the rock mass sample;

[0026] Figure 7 is a schematic diagram of the outer frame structure matching the rock mass sample;

[0027] Figure 8 is a schematic diagram of the tension-torsion clamping frame structure;

[0028] Figure 9 is a schematic diagram of the structure of the fissure-anchored rock mass test system equipped with tension-torsion hydraulic clamps.

[0029] In the diagram: 1-Main frame side plate; 2-Front main frame bearing plate; 3-Rear main frame bearing plate; 4-Support; 5-Padded plate; 6-L-shaped stop; 7-Auxiliary stop; 8-Front and rear moving baffles; 9-Pull-torsion hydraulic clamp; 10-Same-direction pull-torsion loading device; 11-Pull-compression cylinder; 12-Cylinder fixing rod; 13-Pull-compression cylinder piston; 14-Directional guide rod; 15-First guide plate; 16-Wheel spoke sensor; 17-Threaded connecting disc; 18-Double row cylindrical roller bearing; 19-Second guide plate; 20-First pulley; 21-One-way thrust bearing; 22-Cylindrical shaft; 23-Thrust cylindrical roller bearing; 24 - Fixed axis; 25- Belt; 26- Second pulley; 27- Torsion motor; 28- Motor mounting base; 29- Torsion motor mounting frame; 30- First torsion drive shaft; 31- Torque sensor; 32- Second torsion drive shaft; 33- Ball bearing; 34- Bearing housing; 35- Linkage frame; 36- Slider; 37- Track; 38- Fixed plate; 39- Torque reaction plate; 100- Anchored rock mass sample assembly; 100-1, First anchored rock mass sample assembly; 100-2, Second anchored rock mass sample assembly; 100-3, Third anchored rock mass sample assembly; 200- Tension-torsion loading frame. Detailed Implementation

[0030] Combination Figures 1 to 9 As shown, the specific implementation of the same-direction tension-torsion loading device and fracture anchoring rock mass test system and method provided by the present invention will be described.

[0031] A unidirectional tension-torsion loading device applies tension and torsion loads to anchor bolts fixed in another rock mass by driving the rock mass. This loading mode better reflects the stress behavior of anchor bolts in engineering sites under conditions of opening and deflection of surrounding rock between rock strata or on both sides of fractures. Therefore, the mechanical properties of anchor bolts and their cooperative working performance with the surrounding rock tested using this device are more reliable. The unidirectional tension-torsion loading device includes a tension loading mechanism, a linkage mechanism, and a torsion loading mechanism. A linkage mechanism is set between the torsion loading mechanism and the tension loading mechanism, and the fractured anchored rock mass composite specimen is placed in the linkage mechanism. The tension loading mechanism uses a bidirectional tension-compression cylinder for loading, and the piston position of the tension-compression cylinder is adjusted to load anchored solid specimens of different lengths. The tension loading mechanism is installed on the front part of the main frame of the fractured anchored rock mass test system.

[0032] A unidirectional tension-torsion loading device provides tensile and torsional motion constraint control. The anchor bolt and rock mass bonding interface at the rock fracture surface bear the combined tensile and torsional stress. One side of the fracture-anchored rock mass composite specimen is fixed, while the other side undergoes synchronous tension-torsion loading. The tension loading mechanism is used for tension and measurement, and may specifically include a tension / compression cylinder 11, a cylinder fixing rod 12, a tension / compression cylinder piston 13, a tension-torsion mechanism directional guide rod 14, a first guide plate 15, a spoke sensor 16, and a connecting plate 17. A linkage mechanism forms an intermediate linkage between the tension loading mechanism and the unidirectional torsional loading mechanism, including a double-row cylindrical roller bearing 18, a second guide plate 19, a first pulley 20, a unidirectional thrust bearing 21, a cylindrical shaft 22, a thrust cylindrical roller bearing 23, a fixed shaft 24, a belt 25, a second pulley 26, and a linkage frame 35. The torsional loading mechanism realizes torsional loading and measurement, including a torsional motor 27, a torsional motor mounting base 28, a torsional motor mounting frame 29, a first torsional drive shaft 30, a torque sensor 31, a second torsional drive shaft 32, a ball bearing 33, a bearing housing 34, a slider 36, a track 37, a torsional device fixing plate 38, and a torque reaction plate 39, etc. The torsional loading mechanism, through a linkage mechanism, moves back and forth with the piston of the tension / compression cylinder in the tension loading mechanism, achieving synchronous tension and torsional loading and measurement.

[0033] The tension / compression cylinder 11 is a bidirectional loading cylinder, fixed to the front bearing plate 2 of the main frame by fixing rods, specifically as shown in the figure, it can be fixed to the front bearing plate 2 of the main frame by twelve cylinder fixing rods 12. A pre-drilled circular hole is provided on the front bearing plate 2 of the main frame, the diameter of which is slightly larger than the piston diameter of the tension / compression cylinder 11, allowing the piston 13 of the tension / compression cylinder to pass through the front bearing plate 2 of the main frame and connect with the subsequent components. When the rear chamber of the tension / compression cylinder 11 is filled with oil, the piston moves forward; when the front chamber is filled with oil, the piston moves backward. By adjusting the piston position, loading of anchored rock mass sample assembly 100 of different lengths can be achieved to a certain extent. The piston 13 of the tension / compression cylinder also acts as a variable cross-section connecting rod to a certain extent. The tail end of the piston is a variable diameter threaded screw, and the spoke sensor 16 cooperates with the variable diameter threaded screw. The force form of the spoke sensor 16 satisfies the shear force measurement principle on the spokes of the sensor. The spoke sensor 16 is fixedly connected to the first guide plate 15 and the internal threaded connecting plate 17 via a long stud. The first guide plate 15 has a drilled hole with a diameter slightly larger than that of the hydraulic cylinder piston 13, so that it does not contact the hydraulic cylinder piston 13 and does not affect the load sensing of the spoke sensor 16.

[0034] The threaded connecting plate 17 does not contact the threaded screw at the tail end of the tension / compression cylinder piston 13, but is fixed to the threaded screw at the front end of the variable cross-section fixed shaft 24 via its internal thread. The spoke sensor 16 senses the axial tension between the tension / compression cylinder and the fixed shaft 24. The threaded connecting plate 17 is fixed to the threaded screw at the front end of the fixed shaft. During tensile loading, the tension / compression cylinder piston 13, carrying the spoke sensor 16, tends to move forward, while the fixed shaft 24 and the threaded connecting plate 17 fixed thereon tend to move backward relative to it. The relative shear deformation between the inner and outer rings of the spoke sensor 16 causes spoke strain signals, thereby measuring the axial load.

[0035] A one-way thrust bearing and a thrust cylindrical roller bearing 23 are arranged in the inner cavity formed by the coupling of the fixed axis and the variable cross-section cylindrical shaft 22 on the rear side of the internal threaded connecting disc 17. A one-way thrust bearing 21 is arranged in the front cavity and a thrust cylindrical roller bearing 23 is arranged in the rear cavity. A double-row cylindrical roller bearing 18 is arranged in the inner cavity formed by the variable cross-section cylindrical shaft 22 and the second guide plate 19, so that the cylindrical shaft 22 can rotate around the fixed axis 24 to achieve torsional loading on the specimen behind it. When the cylindrical shaft 22 rotates around the fixed axis 24 and synchronous tension is performed, the thrust cylindrical roller bearing 23 is subjected to the pulling and compressing action of the fixed axis 24 and the cylindrical shaft 22, which drives the cylindrical shaft 22 to move forward to apply a tensile load to the rear component. Therefore, the maximum load that the thrust cylindrical roller bearing 23 and its directly acting component can withstand at the contact points with the cylindrical shaft 22 and the fixed axis 24 should be greater than the tensile load designed for the testing machine and have an appropriate safety factor.

[0036] The first guide plate 15 and the second guide plate 19 are connected to the bearing plate in front of the main frame via directional guide rods, guiding the forward and backward linkage of the torsion loading mechanism and the linkage mechanism. A first pulley 20 is mounted on the outer ring of the variable cross-section cylindrical shaft 22. The torsion motor 27 drives the second pulley 26 to rotate. A belt 25 connects the first pulley 20 and the second pulley 26, with the second pulley 26 located directly above the first pulley 20. The rotation of the first pulley 20 simultaneously drives the variable cross-section cylindrical shaft 22 and the tension-torsion loading frame to rotate.

[0037] The torsion motor 27 is mounted on the torsion motor mounting frame via the motor mounting base 28. The torsion motor mounting frame is fixedly mounted on the slider of the fixed plate 38 of the torsion loading mechanism. The slider 36 is fitted on the guide rail of the torsion loading mechanism. The fixed plate 38 is connected to the side plate of the main frame via the torque reaction plate 39.

[0038] The motor mounting base 28 is a hollow cylindrical structure. The first torsion drive shaft 30 passes through the motor mounting base and is connected to the rotating shaft of the torsion motor 27. Both the first torsion drive shaft 30 and the second torsion drive shaft 32 are connected to the torque sensor 31. The second torsion drive shaft 32 is connected to the ball bearing 33 and the second pulley 26. The ball bearing 33 is mounted on the slider of the fixed plate 38 through the bearing seat 34.

[0039] The torsion motor's fixed frame is fixedly connected to the first guide plate 15 and the second guide plate 19 via a linkage mechanism. The upper part of the linkage mechanism is connected to the torsion loading device via a guide rail slider mechanism. This allows the torsion loading and measuring mechanism, which can move back and forth on the fixed large plate 38 of the torsion loading device, to follow the intermediate linkage mechanism via the linkage frame 35, and subsequently the tensile loading and measuring mechanism. The linkage frame 35 also suspends the tensile loading and measuring mechanism and the intermediate linkage mechanism, preventing deformation of the hydraulic cylinder piston 13 due to its own weight. The torsion loading mechanism moves simultaneously with the intermediate linkage mechanism and the tensile loading mechanism via the linkage mechanism.

[0040] A fracture anchored rock mass testing system includes the aforementioned unidirectional tension-torsion loading device, and further comprises a main frame and a fracture anchored rock mass assembly. The main frame includes a steel pad, multiple sets of main frame side plates, a front bearing plate, and a rear bearing plate. The multiple sets of main frame side plates are positioned between the front and rear bearing plates. The main frame side plates, the front bearing plate, and the rear bearing plate are fixed to the steel pad by multiple sets of supports, and the steel pad is fixed to the ground. The main frame maintains a suitable overall testing height, providing ease of operation and stability. During the test, the main frame serves as the foundation reaction frame of the testing system, and the unidirectional tension-torsion loading device uses this reaction frame as a fixed foundation to achieve loading.

[0041] The fracture anchoring rock mass assembly is placed within the main frame. The assembly, which includes a similar material sample and an outer frame, clamps the assembly and facilitates tensile and torsional clamping. The tension and torsion clamping frame includes a variable cross-section disk, connecting rods, and a rectangular groove disk, which cooperate with the assembly. The rock mass in front of the fracture (e.g., the first anchoring rock mass sample assembly 100-1) provides tensile and torsional loads, while the rock mass behind the fracture (e.g., the second anchoring rock mass sample assembly 100-2) is constrained for tensile and torsional movement by L-shaped blocks 6 fixed to the side plate of the main frame, auxiliary blocks 7 fixed to the L-shaped blocks, and front and rear moving baffles 8 of the anchoring rock mass. This allows the anchor rod and rock mass bonding interface at the fracture surface of the anchoring rock mass to withstand combined tensile and torsional stresses. To achieve tensile and torsional clamping of the anchored rock mass specimen assembly 100, the tension-torsion clamping frame 200 comprises, from front to back: a variable cross-section disk 201 with a rectangular groove, a connecting rod 202, and a disk 203 with a rectangular groove. Before the test, the rectangular cross-section anchored rock mass specimen assembly 100-1 on the front side of the fracture is nested in the tension-torsion clamping frame 200, while the anchored rock mass specimen assembly 100-2 on the rear side of the fracture is blocked in the front-to-back direction and compressed and restrained on both sides.

[0042] This system, through the cooperation of bearings and related structural components, forms an intermediate linkage mechanism, enabling the torsional loading and measurement mechanism to synchronously follow the tensile loading and measurement mechanism. This achieves constraint control of tensile and torsional motion and applies combined tensile and torsional stress to the bonding interface between the anchor rod and the rock mass at the fracture surface of the anchored rock mass. Through the effective cooperation of the unidirectional tensile-torsional loading device with the main frame of the test system, the tensile-torsional loading frame, and the anchored rock mass sample assembly, it achieves simultaneous tensile-torsional loading on one side of a large-sized fractured anchored rock mass while the other side is fixed. The unidirectional tensile-torsional loading device structure adopts a unilateral linkage arrangement, freeing up space in the upper and rear parts of the test system, giving the test system greater functional expandability and making it easier to install large-sized anchored rock mass composite samples.

[0043] A test method for fracture-anchored rock mass, utilizing the aforementioned unidirectional tension-torsion loading device, includes:

[0044] During the combined tensile-torsional test of fractured anchored rock mass, a unidirectional tensile-torsional loading device applies tensile and torsional loads to the fractured anchored rock mass assembly. Three anchored rock mass specimen assemblies 100 can be placed sequentially within the main frame of the test system; that is, the three rock masses are anchored together by a single anchor rod. During the test, tensile and torsional loads are applied to the first anchored rock mass specimen assembly 100-1, while the second and third anchored rock mass specimen assemblies 100-2 and 100-3 are fixed in place.

[0045] During the tension-torsion combined test of the anchor bolt body, the tension-torsion loading frame was replaced with a tension-torsion hydraulic clamp, which includes a front tension-torsion hydraulic clamp mounted on the tension-torsion loading device and a rear tension-torsion hydraulic clamp mounted inside the main frame. The fixed position of the rear tension-torsion hydraulic clamp was adjusted to conduct tension-torsion combined tests on anchor bolts of different lengths.

[0046] This experimental method enables combined tensile-torsion tests on fractured anchored rock masses and combined tensile-torsion tests on anchor rods, facilitating the study of interface failure and stress law of anchor rods at anchor fractures under combined tensile-torsion stress.

[0047] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A unidirectional tension-torsion loading device, characterized in that, The system includes a tensile loading mechanism, a linkage mechanism, and a torsional loading mechanism. A linkage mechanism is provided between the torsional loading mechanism and the tensile loading mechanism, and the fracture anchored rock mass composite specimen is placed in the linkage mechanism. The tensile loading mechanism uses a bidirectional tension-compression cylinder to load anchored specimens of different lengths by adjusting the piston position of the tension-compression cylinder. A unidirectional tension-torsion loading device provides tensile and torsional motion constraint control. The bonding interface between the anchor rod and the rock mass at the fracture surface of the anchored rock mass is subjected to combined tension and torsional stress. One side of the fracture anchored rock mass composite specimen is fixed, while the other side is subjected to synchronous tension and torsional loading. The tension / compression cylinder is a bidirectional loading cylinder, which is fixed to the bearing plate at the front of the main frame by a fixing rod; the bearing plate has a pre-drilled circular hole with a diameter larger than the piston diameter of the tension / compression cylinder; the piston tail end of the tension / compression cylinder is a variable diameter threaded screw, which is matched with the spoke sensor; the spoke sensor is fixedly connected to the first guide plate and the internal threaded connecting plate by a long stud; the first guide plate has a drilled hole with a diameter larger than the piston diameter of the tension / compression cylinder; The spoke sensor senses the axial tension between the hydraulic cylinder and the fixed shaft. The threaded connecting plate is fixed to the threaded screw at the front end of the fixed shaft. A one-way thrust bearing and a thrust cylindrical roller bearing are arranged in the inner cavity formed by the coupling between the fixed shaft and the variable cross-section cylindrical shaft on the rear side of the threaded connecting plate. A double row of cylindrical roller bearings are arranged in the inner cavity formed by the variable cross-section cylindrical shaft and the second guide plate. The cylindrical shaft rotates around the fixed shaft. The first guide plate and the second guide plate are connected to the load-bearing plate in front of the main frame through directional guide rods; A first pulley is installed on the outer ring of the variable cross-section cylindrical shaft, and a torsion motor drives a second pulley to rotate. A belt connects the first pulley and the second pulley. The rotation of the first pulley simultaneously drives the variable cross-section cylindrical shaft and the tension-torsion loading frame to rotate. The torsion motor is mounted on the torsion motor mounting frame via a motor mounting bracket. The torsion motor mounting frame is fixedly mounted on the slider of the fixed plate of the torsion loading mechanism. The slider is fitted on the guide rail of the torsion loading mechanism. The fixed plate is connected to the side plate of the main frame via a torque reaction plate.

2. The unidirectional tension-torsion loading device according to claim 1, characterized in that, The motor mounting base is a hollow cylindrical structure. The first torsion drive shaft passes through the motor mounting base and is connected to the rotating shaft of the torsion motor. Both the first and second torsion drive shafts are connected to the torque sensor. The second torsion drive shaft is connected to the ball bearing and the second pulley. The ball bearing is mounted on the slider of the fixed plate through the bearing seat.

3. The unidirectional tension-torsion loading device according to claim 1, characterized in that, The torsion motor fixing frame is fixedly connected to the first guide plate and the second guide plate through a linkage mechanism. The upper part of the linkage mechanism is connected to the torsion loading device through a guide rail slider mechanism. The torsion loading mechanism moves simultaneously with the intermediate linkage mechanism and the tension loading mechanism through the linkage mechanism.

4. A fracture anchoring rock mass testing system, comprising a unidirectional tension-torsion loading device as described in any one of claims 1 to 3, characterized in that, It also includes a main frame and a fracture anchoring rock mass assembly. The main frame includes a steel pad, multiple sets of main frame side plates, a front bearing plate of the main frame, and a rear bearing plate of the main frame. The multiple sets of main frame side plates are arranged between the front bearing plate and the rear bearing plate of the main frame. The fracture anchoring rock mass assembly is placed inside the main frame. An assembly clamps the fracture anchoring rock mass assembly. The assembly includes a similar material sample and an outer frame. The tension-torsion clamping frame includes a variable cross-section disk, a connecting rod, and a rectangular groove disk. The assembly and the tension-torsion clamping frame cooperate with each other.

5. A method for testing fractured anchored rock mass, utilizing the fractured anchored rock mass testing system described in claim 4, characterized in that, include: During the combined tensile-torsional test of fractured anchored rock mass, the unidirectional tensile-torsional loading device applies tensile and torsional loads to the fractured anchored rock mass assembly. When conducting the tension-torsion combined test of the anchor bolt body, the tension-torsion loading frame is replaced with a tension-torsion hydraulic clamp, which includes a front tension-torsion hydraulic clamp installed on the tension-torsion loading device and a rear tension-torsion hydraulic clamp installed in the main frame; the fixed position of the rear tension-torsion hydraulic clamp is adjusted to conduct tension-torsion combined tests of anchor bolts of different lengths.

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