A combined anchor bearing capacity test device and test method

Abstract

The present invention provides a bearing capacity test device and test method for a combined anchor, which relates to bridge engineering and includes an anchor model; a first bearing capacity simulation unit, including a plurality of pressure applying devices, the pressure applying devices including a first jack, a reaction beam and an anchor cable, each first jack being respectively arranged at a different pressure applying position on the upper surface of the superstructure, the reaction beam being arranged at the top of the piston rod of the first jack, anchor cables being fixed at both ends of the reaction beam, the anchor cables being vertically inserted into the anchor model and extending to the outside of the anchor model; a second bearing capacity simulation unit, including a plurality of second jacks, the piston rods of the second jacks being arranged against the end face of the rear end of the substructure; and a collection unit, the collection unit including a plurality of strain gauges and a plurality of pressure sensors. The present invention can simultaneously simulate the bearing capacity corresponding to the anchor gravity part and the surrounding rock clamping effect, and thereby determine the bearing capacity of the combined anchor and the size and distribution of the rock-anchor surface contact force, providing a basis for the bearing capacity calculation model.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge engineering, and in particular to a bearing capacity testing device and a testing method for a combined anchorage. Background Art

[0002] Currently, the most widely used anchoring systems for suspension bridges include gravity anchors and tunnel anchors. The former relies primarily on the anchor's gravity and the friction between the anchor and the foundation to provide bearing capacity. Its load-bearing capacity is clear and calculations are simple, but the cost is relatively high. The latter, on the other hand, relies primarily on the resistance of the surrounding rock to the anchor plug to provide bearing capacity. It can fully utilize the surrounding rock to achieve higher bearing capacity and a relatively low cost, but the mechanism and calculations are complex.

[0003] The combined half-anchor and gravity anchor embeds part of the anchor into the rock, leveraging the advantages of the first two anchor types. Testing requires simulating both the effects of the anchor's gravity and the clamping effect of the surrounding rock. However, due to the complex form of the combined anchor and gravity anchor, simply creating a model based on the anchor's shape would be overly complex. Furthermore, the force exerted by gravity on the bottom surface is extremely unevenly distributed, so traditional anchor bearing capacity testing methods cannot effectively simulate the corresponding bearing capacities of the anchor's gravity and the surrounding rock's clamping effect. Summary of the Invention

[0004] The purpose of the present invention is to provide a combined anchor bearing capacity test device and test method to improve the above problems. To achieve the above objectives, the technical solutions adopted by the present invention are as follows:

[0005] On the one hand, the present application provides a combined anchor bearing capacity test device, comprising:

[0006] An anchor model, the anchor model comprising an upper structure and a lower structure, the upper structure being a reinforced concrete slab structure, the lower structure comprising a reinforced concrete anchor structure, the horizontal cross-section of the reinforced concrete anchor structure being in the shape of a trapezoid with a smaller front portion and a larger rear portion;

[0007] a first bearing capacity simulation unit, the first bearing capacity simulation unit comprising a plurality of pressure applying devices, the pressure applying devices comprising a first jack, a reaction beam, and an anchor cable, the first jacks being respectively arranged at different pressure applying locations on the upper surface of the superstructure, the reaction beam being arranged at the top of the piston rod of the first jack, and anchor cables being fixed at both ends of the reaction beam, the anchor cables being vertically inserted into the anchor model and extending to the outside of the anchor model;

[0008] a second bearing force simulation unit, the second bearing force simulation unit comprising a plurality of second jacks, the piston rods of the second jacks being disposed against an end surface of the rear end of the lower structure;

[0009] The acquisition unit includes a plurality of strain gauges and a plurality of pressure sensors, wherein the strain gauges are evenly distributed inside the anchor model along the longitudinal direction of the anchor model, and the pressure sensors are evenly distributed on the outer surface of the lower structure.

[0010] In a second aspect, the present application provides a test method for a bearing capacity test device for the combined anchor, comprising:

[0011] Select a test site that meets the test requirements, including the expected rock and soil type, rock and soil density, and rock and soil moisture content;

[0012] Mark the required installation location of the anchor on the selected test site, and dig the anchor foundation pit at the installation location;

[0013] Installing a combined anchor bearing capacity test device to the anchor foundation pit, placing the bottom of the second jack of the bearing capacity test device against the rear end of the anchor foundation pit, placing the front end of the anchor model in the bearing capacity test device against the front end of the anchor foundation pit, and extending the anchor cable of the bearing capacity test device into the rock mass below the anchor foundation pit;

[0014] Simulating the first bearing capacity corresponding to the combined anchorage's gravity, different vertical loads are applied to different pressure points on the anchorage model's superstructure using different first jacks in the bearing capacity test device until all vertical loads meet the test requirements. The magnitude of the different vertical loads applied at different pressure points is determined by the actual gravity distribution of the combined anchorage.

[0015] The second bearing capacity corresponding to the clamping effect of the surrounding rock is simulated, the initial value of each of the second jacks is measured, and different levels of pushback loads are applied to the rear end of the anchor model through the second jacks. Each level of pushback load is maintained for a preset loading duration, and the readings of the strain gauge and pressure sensor under each level of pushback load are read.

[0016] The beneficial effects of the present invention are:

[0017] The present invention uses a bearing capacity test device and test method for a combined anchor, which can simplify model making and well simulate the distribution form of the base pressure generated by the anchor weight, thereby realizing simultaneous simulation tests of the bearing capacity corresponding to the anchor weight part and the surrounding rock clamping effect, and thereby determining the bearing capacity of the combined anchor and the rock-anchor surface contact force and distribution form, providing a basis for the bearing capacity calculation model. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 Shown is a structural diagram of a combined anchoring test device according to an embodiment of the present invention;

[0020] Figure 2 The figure shows the state of use of the combined anchor test device in the embodiment of the present invention;

[0021] Figure 3 FIG2 is a schematic structural diagram of a first bearing capacity simulation unit in an embodiment of the present invention;

[0022] Figure 4 FIG2 is a schematic diagram of a half-section structure of an anchoring model according to an embodiment of the present invention;

[0023] Figure 5 The figure shows a schematic diagram of force analysis of an isolator in an embodiment of the present invention;

[0024] 1-anchor model; 2-reaction beam; 202-anchor cable; 203-top fixing plate; 204-anchor; 206-bottom fixing plate; 207-steel pad; 208-bottom plate; 209-roller; 2011, 2012-channel steel; 4-second jack; 12-anchor cable channel; 13-pressure sensor; 14-strain gauge; second reaction beam; 202-anchor cable; 203-top fixing plate; 204-anchor; 205-first jack; 206-bottom fixing plate; 207-steel pad; 31-data processing terminal. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are used only to distinguish the description and should not be understood as indicating or implying relative importance.

[0027] The main idea of ​​the present invention is that the combined semi-anchor and gravity anchor is a new type of anchor. Unlike the test of the existing anchor, it is necessary to simulate the influence of the anchor's gravity and the clamping effect of the surrounding rock at the same time during the test. Among them, the anchor is complex in form, so the distribution of the force generated by its gravity on the bottom surface is extremely uneven, and its distribution form has an important influence on the bearing capacity. Therefore, the problems to be solved include: it is not possible to make a model directly according to the shape of the anchor, which will make the model making process too complicated and unable to better simulate the pressure distribution form of the anchor on the bottom surface. In order to solve the above problems, the applicant thought of: simplifying the upper part of the anchor to a reinforced concrete slab of equal thickness to facilitate model making; using multiple jacks to apply different pressures at different positions on the top plate of the model to simulate the distribution form of the base pressure generated by the anchor's gravity.

[0028] Therefore, the applicant conceived of using a combined anchor bearing capacity test device and test method of the present invention to simultaneously simulate the bearing capacity corresponding to the anchor gravity part and the surrounding rock clamping effect.

[0029] This embodiment provides a combined anchor bearing capacity test device, comprising:

[0030] An anchor model 1, the anchor model 1 comprising an upper structure and a lower structure, the upper structure being a reinforced concrete slab structure, the lower structure comprising a reinforced concrete anchor structure, the horizontal cross-section of the reinforced concrete anchor structure being in the shape of a trapezoid with a smaller front portion and a larger rear portion;

[0031] a first bearing capacity simulation unit, the first bearing capacity simulation unit comprising a plurality of pressure applying devices, the pressure applying devices comprising a first jack 205, a reaction beam 2 and an anchor cable 202, the first jacks 205 being respectively arranged at different pressure applying points on the upper surface of the superstructure, the reaction beam 2 being arranged at the top of the piston rod of the first jack 205, and anchor cables 202 being fixed at both ends of the reaction beam 2, the anchor cables 202 being vertically inserted into the anchor model 1 and extending to the outside of the anchor model 1;

[0032] A second bearing force simulation unit, comprising a plurality of second jacks 4, wherein piston rods of the second jacks 4 are disposed against an end surface of the rear end of the lower structure;

[0033] The acquisition unit includes a plurality of strain gauges 14 and a plurality of pressure sensors 13. The strain gauges 14 are evenly distributed inside the anchor model 1 along the longitudinal direction of the anchor model 1, and the pressure sensors 13 are evenly distributed on the outer surface of the lower structure.

[0034] A plurality of anchor cable holes 12 are vertically opened on the anchoring model 1 , and an anchor cable 202 is passed through each of the anchor cable holes 12 , with a gap being left between the outer wall of the anchor cable 202 and the hole wall of the anchor cable hole 12 .

[0035] The anchor cable holes 12 are arranged at intervals along the longitudinal horizontal center axis of the anchor model 1 .

[0036] The pressure sensors 13 are evenly distributed on the side surface and bottom surface of the lower structure, and two adjacent pressure sensors 13 are spaced apart.

[0037] The reaction beam 2 includes two channel steels 2011 and 2012 and a fixing plate. The two channel steels 2011 and 2012 are arranged in parallel. The top ends of the two channel steels 2011 and 2012 are fixedly connected by the top fixing plate 203, and the bottom ends of the two channel steels 2011 and 2012 are fixedly connected by the bottom fixing plate 206. The anchor cable 202 passes through the corresponding top fixing plate 203 and bottom fixing plate 206 in sequence and is fixedly connected to the top fixing plate 203 and the bottom fixing plate 206 through the anchor 204.

[0038] A roller shaft 209 is provided between the first jack 205 and the upper structure.

[0039] The end surface of the rear end of the lower structure against which the second jack 4 is mounted is an inclined surface, and the installation angle of the second jack 4 on the inclined surface is consistent with the installation angle of the main cable in the actual combined anchoring.

[0040] The acquisition unit further includes a data processing terminal 31 , and the pressure sensor 13 and the strain gauge 14 are electrically connected to the data processing terminal 31 , respectively.

[0041] like Figure 1 and Figure 2 As shown, this embodiment provides a combined anchor bearing capacity test device, comprising:

[0042] Anchor model 1, comprising an upper structure and a lower structure, wherein the upper structure is a reinforced concrete slab structure, and the lower structure comprises a reinforced concrete anchor structure. The horizontal cross-section of the reinforced concrete anchor structure is a trapezoidal shape with a small front portion and a large rear portion. This allows the anchor model to generate a clamping effect with the surrounding rock mass, effectively improving the bearing capacity. This embodiment simulates a combined anchor with dual anchors, wherein the lower structure comprises two reinforced concrete anchor structures, one on each side of the bottom of the reinforced concrete slab structure.

[0043] a first bearing capacity simulation unit, the first bearing capacity simulation unit comprising a plurality of pressure applying devices, the pressure applying devices comprising a first jack 205, a reaction beam 2 and an anchor cable 202, each of the first jacks 205 being respectively arranged at a different pressure applying point on the upper surface of the superstructure, the reaction beam 2 being arranged at the top of the piston rod of the first jack 205, anchor cables 202 being fixed at both ends of the reaction beam 2, the anchor cables 202 being vertically inserted into the anchor model 1 and extending to the outside of the anchor model 1, wherein the top of the piston rod of the first jack 205 is in contact with the bottom of the reaction beam 2 via a steel pad 207;

[0044] A second bearing force simulation unit, comprising a plurality of second jacks 4, wherein piston rods of the second jacks 4 are disposed against an end surface of the rear end of the lower structure;

[0045] The acquisition unit includes a plurality of strain gauges 14 and a plurality of pressure sensors 13. The strain gauges 14 are evenly distributed inside the anchor model 1 along the longitudinal direction of the anchor model 1, and the pressure sensors 13 are evenly distributed on the outer surface of the lower structure.

[0046] like Figure 4 As shown, the strain gauge 14 is arranged inside the anchor model 1, and the strain gauge 14 is evenly distributed in the cross section of the anchor model 1 perpendicular to the horizontal central axis. Several strain gauges 14 are arranged along the horizontal central axis of the anchor model 1, and adjacent two strain gauges 14 are arranged at intervals.

[0047] A plurality of anchor cable holes 12 are vertically opened on the anchoring model 1 , and an anchor cable 202 is passed through each of the anchor cable holes 12 , with a gap being left between the outer wall of the anchor cable 202 and the hole wall of the anchor cable hole 12 .

[0048] The anchor cable holes 12 are arranged at intervals along the longitudinal horizontal center axis of the anchor model 1 .

[0049] The pressure sensors 13 are evenly distributed on the side surface and bottom surface of the lower structure, and two adjacent pressure sensors 13 are spaced apart.

[0050] In the existing reaction force system, the anchor cables are all set outside the loaded object, which can be used when the loaded object is small in size. However, for the combined anchorage in this application, due to its large planar size, even if the test is carried out according to the commonly used geometric similarity ratio of 1:10, the length of its reaction beam for the spanning model can reach 8-9m. The longer the beam is, the larger the required size of the beam cross section is under the same reaction force load (because the bending moment is also greater). The problems caused by this are, first, the waste of materials, and second, the difficulty of installation. To solve the above problems, the applicant has come up with the following solutions:

[0051] The anchor cable 202 is set within the plane of the anchor model 1 and has a length of about 1 meter. Compared with the traditional reaction beam, its length and cross-section are greatly reduced, so the amount of material used can be greatly reduced and it is very easy to install.

[0052] In order to ensure that the setting of the anchor cable 202 does not affect the free movement of the anchor model 1 during the loading process, an anchor hole is preset on the anchor model 1, and a gap is left between the outer wall of the anchor cable 202 and the hole wall of the anchor cable channel 12, so that the anchor cable 202 is separated from the anchor model 1 and there is enough space for the horizontal movement of the anchor model 1 during the loading process;

[0053] A roller shaft 209 is provided between the anchor model 1 and the bottom plate 208 of the first jack 205 to reduce the horizontal resistance of the loading structure to the anchor model 1 and reduce the influence of the horizontal movement of the anchor on the loading device.

[0054] like Figure 3 As shown, the reaction beam 2 includes two channel steels 2011 and 2012 and a top fixing plate 203 and a bottom fixing plate 206. The two channel steels 2011 and 2012 are arranged side by side. The two channel steels 2011 and 2012 are arranged in parallel with each other at a certain distance. The top ends of the two channel steels 2011 and 2012 are fixedly connected by the top fixing plate 203, and the bottom ends of the two channel steels 2011 and 2012 are fixedly connected by the bottom fixing plate 206. The top fixing plate 203 and the bottom fixing plate 206 are symmetrically arranged up and down. On both sides of the two channel steels 2011 and 2012, the anchor cable 202 passes through the corresponding top fixing plate 203 and bottom fixing plate 206 in sequence and is fixedly connected to the top fixing plate 203 and the bottom fixing plate 206 through the anchor 204, wherein the top ends of the two channel steels 2011 and 2012 are respectively connected to the top fixing plate 203 by ring welding, and the bottom ends of the two channel steels 2011 and 2012 are respectively welded to the bottom fixing plate 206, and a roller shaft 209 is provided between the first jack 205 and the upper structure.

[0055] The end surface of the rear end of the lower structure against which the second jack 4 is mounted is an inclined surface, and the installation angle of the second jack 4 on the inclined surface is consistent with the installation angle of the main cable in the actual combined anchoring.

[0056] The acquisition unit further includes a data processing terminal 31 , and the pressure sensor 13 and the strain gauge 14 are electrically connected to the data processing terminal 31 , respectively.

[0057] The method for testing the bearing capacity of the combined anchorage comprises:

[0058] Select a test site that meets the test requirements, including the expected rock and soil type, rock and soil density, and rock and soil moisture content;

[0059] Mark the required installation location of the anchor on the selected test site, and dig the anchor foundation pit at the installation location;

[0060] Install the combined anchor bearing capacity test device to the anchor foundation pit, place the bottom of the second jack 4 of the bearing capacity test device against the rear end of the anchor foundation pit, place the front end of the anchor model 1 in the bearing capacity test device against the front end of the anchor foundation pit, and extend the anchor cable 202 of the bearing capacity test device into the rock mass below the anchor foundation pit;

[0061] To simulate the first bearing capacity corresponding to the combined anchorage's gravity, different vertical loads of varying magnitude are applied to different pressure points on the upper structure of the anchorage model 1 using different first jacks 205 in the bearing capacity test apparatus until all vertical loads meet the test requirements. The magnitudes of the different vertical loads applied at different pressure points are determined by the actual weight distribution of the combined anchorage. The vertical loads are supplemented by the first jacks 205 to simulate the anchorage model's deadweight, meeting similarity theory requirements.

[0062] The second bearing capacity corresponding to the clamping effect of the surrounding rock is simulated, the initial value of each of the second jacks 4 is measured, and different levels of pushback loads are applied to the rear end of the anchor model 1 through the second jacks 4. Each level of pushback load maintains a preset loading time, and the readings of the strain gauge 14 and the pressure sensor 13 under each level of pushback load are read. In this embodiment, the design load is used as the first-level load through the pushback jack, and each level of load is maintained for 30 minutes.

[0063] The distribution of anchor-rock side friction resistance is determined based on the distribution curve of the normal stress of the anchor rock surface and the distribution curve of the axial stress: the push-back jack is used to provide load to the anchor model, and the normal stress on the side and the internal axial stress of the anchor model under different levels of load are monitored to obtain the distribution curves of load-anchor rock normal stress and load-anchor axial stress. The distribution of anchor-rock side friction resistance is determined based on the distribution curve of the normal stress of the anchor rock surface and the distribution curve of the axial stress.

[0064] The method for determining the ultimate bearing capacity of the bearing capacity testing device for the combined anchorage comprises the following steps:

[0065] The anchor model 1 is divided into several half-anchor sections, and each half-anchor section is used as an isolation body, such as Figure 5 As shown, the isolator includes a top surface, left and right side surfaces, a bottom surface, a front section, and a rear section;

[0066] The areas of the two side surfaces, the bottom surface, the front section, and the rear section are obtained respectively, wherein the angles between the two side surfaces and the bottom surface and the longitudinal horizontal center axis of the isolator are equal;

[0067] Read the stress data of the strain gauge 14 and the pressure data of the pressure sensor 13 under each level of pushback load of the second jack 4;

[0068] Acquire stress magnitudes of the two side surfaces and the bottom surface according to the stress data;

[0069] Calculating normal forces on the two side surfaces and the bottom surface respectively according to the stress magnitudes and areas of the two side surfaces and the bottom surface;

[0070] Obtaining axial stress magnitudes of the front section and the rear section according to the pressure data;

[0071] Calculating the axial force of the front section and the rear section respectively according to the axial stress and area of ​​the front section and the rear section;

[0072] The tangential force between the isolator and the surrounding rock is calculated based on the normal force magnitudes of the two side surfaces and the bottom surface, the axial force magnitudes of the front section and the rear section, the angle between the side surfaces and the longitudinal horizontal center axis of the isolator, and the angle between the bottom surface and the longitudinal horizontal center axis of the isolator. The tangential force calculation formula is:

[0073]

[0074] According to the size and distribution of the tangential force and the normal force on the side, combined with the bearing capacity obtained from the test, a basis is provided for the bearing capacity calculation model.

[0075] Where ΔQ i is the axial force difference between the front and rear sections of the isolator i, N ij is the normal force on the surface j of the isolator i, T i is the magnitude of the tangential force on the surface of the isolator i, and α is the angle between the side edge, bottom edge and the axis of the isolator.

[0076] This application addresses the large cross-sectional dimensions of combined anchors and proposes a method for measuring the interaction force between the anchor and the surrounding rock by installing sensor elements only in the rock-embedded (and adjacent) portion. The tangential force at the anchor-rock interface is crucial information for anchors of this type, but currently, no effective measurement method exists. This application proposes a method for determining this tangential force using anchor axial strain gauge measurements and pressure sensors at the anchor-rock interface, and also establishes a corresponding calculation method, addressing this technical challenge.

[0077] The beneficial effects of the present invention compared to the prior art are:

[0078] 1. After reasonable simplification, the device layout becomes simpler and easier. In addition, this anchor model can effectively demonstrate the load-bearing capacity of the semi-anchor and semi-gravity combined anchor, thus ensuring its stability and reliability in various application scenarios.

[0079] 2. This invention achieves the required anchorage weight for model test similarity ratios through the application of vertical supplementary loads. It has the advantages of simple structure, convenient operation, and significant effectiveness, and possesses important practical application value. In practical applications, this invention can be widely applied to various anchorage model tests. By supplementing vertical supplementary loads, it can effectively address the problem of insufficient anchorage model weight, improve the accuracy and reliability of model tests, and provide strong support for engineering design and construction.

[0080] 3. This invention innovatively places the anchor cable inside the anchor, rather than outside it. This not only simplifies the setup process but also significantly shortens the reaction beam length. Furthermore, pre-set perforations in the anchor model allow the anchor cable to pass smoothly through without affecting the normal movement of the anchor cable body. This design combines practicality and efficiency, providing new insights and directions for technological development in related fields.

[0081] 4. This invention utilizes automatically acquired axial and normal stress data of the anchor model and the resulting ultimate bearing capacity. Through a series of transformation calculations, it successfully deduces the magnitude and distribution of the rock-anchor surface tangential and normal forces, providing a basis for the bearing capacity calculation model. The entire testing process is concise and efficient, and the data monitoring process is equally simple and easy, ensuring the high feasibility and practicality of this invention.

[0082] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0083] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A combined anchor bearing capacity test device, characterized in that: include: An anchor model (1), the anchor model (1) comprising an upper structure and a lower structure, the upper structure being a reinforced concrete slab structure, the lower structure comprising a reinforced concrete anchor structure, the horizontal section of the reinforced concrete anchor structure being in the shape of a trapezoid with a smaller front portion and a larger rear portion; a first bearing capacity simulation unit, the first bearing capacity simulation unit comprising a plurality of pressure applying devices, the pressure applying devices comprising a first jack (205), a reaction beam (2) and an anchor cable (202), each of the first jacks (205) being respectively arranged at a different pressure applying position on the upper surface of the superstructure, the reaction beam (2) being arranged at the top of the piston rod of the first jack (205), anchor cables (202) being fixed at both ends of the reaction beam (2), and the anchor cables (202) being vertically inserted into the anchor model (1) and extending to the outside of the anchor model (1); A second bearing force simulation unit, the second bearing force simulation unit comprising a plurality of second jacks (4), the piston rods of the second jacks (4) being arranged against the end surface of the rear end of the lower structure; A collection unit, the collection unit comprising a plurality of strain gauges (14) and a plurality of pressure sensors (13), the strain gauges (14) being evenly distributed inside the anchor model (1) along the longitudinal direction of the anchor model (1), and the pressure sensors (13) being evenly distributed on the outer surface of the lower structure; A plurality of anchor cable holes (12) are vertically opened on the anchor model (1), and a gap is left between the outer wall of the anchor cable (202) and the hole wall of the anchor cable hole (12).

2. The combined anchor bearing capacity test device according to claim 1, characterized in that: One anchor cable (202) is correspondingly passed through each anchor cable hole (12).

3. The combined anchor bearing capacity test device according to claim 2, characterized in that: The anchor cable holes (12) are arranged at intervals along the longitudinal horizontal center axis of the anchor model (1).

4. The combined anchor bearing capacity testing device according to claim 1, characterized in that: The pressure sensors (13) are evenly distributed on the side surface and the bottom surface of the lower structure, and two adjacent pressure sensors (13) are spaced apart.

5. The combined anchor bearing capacity testing device according to claim 1, characterized in that: The reaction beam (2) comprises two channel steels, a top fixing plate (203) and a bottom fixing plate (206); the two channel steels are arranged in parallel; the top ends of the two channel steels are fixedly connected via the top fixing plate (203); the bottom ends of the two channel steels are fixedly connected via the bottom fixing plate (206); the anchor cable (202) passes through the corresponding top fixing plate (203) and bottom fixing plate (206) in sequence and is fixedly connected to the top fixing plate (203) and the bottom fixing plate (206) via an anchor (204).

6. The combined anchor bearing capacity testing device according to claim 1, characterized in that: A roller shaft (209) is provided between the first jack (205) and the upper structure.

7. The combined anchor bearing capacity testing device according to claim 1, characterized in that: The end surface of the rear end of the lower structure against which the second jack (4) is mounted is an inclined surface, and the installation angle of the second jack (4) on the inclined surface is consistent with the installation angle of the main cable in the actual combined anchoring.

8. The combined anchor bearing capacity testing device according to claim 1, characterized in that: The acquisition unit further includes a data processing terminal (31), and the pressure sensor (13) and the strain gauge (14) are electrically connected to the data processing terminal (31) respectively.

9. A test method for the bearing capacity test device of the combined anchorage according to any one of claims 1 to 8, characterized in that: include: Select a test site that meets the test requirements, including the expected rock and soil type, rock and soil density, and rock and soil moisture content; Mark the required installation location of the anchor on the selected test site, and dig the anchor foundation pit at the installation location; Installing a combined anchor bearing capacity test device to the anchor foundation pit, placing the bottom of the second jack of the bearing capacity test device against the rear end of the anchor foundation pit, placing the front end of the anchor model in the bearing capacity test device against the front end of the anchor foundation pit, and extending the anchor cable of the bearing capacity test device into the rock mass below the anchor foundation pit; Simulating the first bearing capacity corresponding to the combined anchorage's gravity, different vertical loads are applied to different pressure points on the anchorage model's superstructure using different first jacks in the bearing capacity test device until all vertical loads meet the test requirements. The magnitude of the different vertical loads applied at different pressure points is determined by the actual gravity distribution of the combined anchorage. The second bearing capacity corresponding to the clamping effect of the surrounding rock is simulated, the initial value of each of the second jacks is measured, and different levels of pushback loads are applied to the rear end of the anchor model through the second jacks. Each level of pushback load is maintained for a preset loading duration, and the readings of the strain gauge and pressure sensor under each level of pushback load are read.

10. The test method according to claim 9, characterized in that The following steps are involved: Divide the anchor model into several half-anchor sections, and use each half-anchor section as an isolator, wherein the isolator includes a top surface, left and right side surfaces, a bottom surface, a front section, and a rear section; The areas of the two side surfaces, the bottom surface, the front section, and the rear section are obtained respectively, wherein the angles between the two side surfaces and the bottom surface and the longitudinal horizontal center axis of the isolator are equal; Read the stress data of the strain gauge and the pressure data of the pressure sensor under each level of pushback load of the second jack; Acquire stress magnitudes of the two side surfaces and the bottom surface according to the stress data; Calculating normal forces on the two side surfaces and the bottom surface respectively according to the stress magnitudes and areas of the two side surfaces and the bottom surface; Obtaining axial stress magnitudes of the front section and the rear section according to the pressure data; Calculating the axial force of the front section and the rear section respectively according to the axial stress and area of ​​the front section and the rear section; The tangential force between the isolator and the surrounding rock is calculated based on the normal force magnitudes of the two side surfaces and the bottom surface, the axial force magnitudes of the front section and the rear section, the angle between the side surfaces and the longitudinal horizontal center axis of the isolator, and the angle between the bottom surface and the longitudinal horizontal center axis of the isolator. The tangential force calculation formula is: Where ΔQ i is the axial force difference between the front and rear sections of the isolator i, N ij is the normal force on the surface j of the isolator i, T i is the magnitude of the tangential force on the surface of the isolator i, and α is the angle between the side edge, bottom edge and the axis of the isolator.

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