Bearing capacity test device and test method for combined anchorage

Abstract

The invention provides a bearing capacity test device and test method of a combined anchorage, and relates to bridge engineering. The first bearing force simulation unit comprises a plurality of pressure applying devices, each pressure applying device comprises a first jack, a counter-force beam and anchor cables, the first jacks are arranged on different pressurizing sites on the upper surface of the upper structure respectively, the counter-force beams are arranged at the tops of piston rods of the first jacks, the anchor cables are fixed to the two ends of each counter-force beam, and the anchor cables are fixed to the upper surface of the upper structure; the anchor cable is vertically inserted into the anchorage model and extends to the outside of the anchorage model; the second bearing force simulation unit comprises a plurality of second jacks, and piston rods of the second jacks abut against the end face of the rear end of the lower structure; and the acquisition unit comprises a plurality of strain gauges and a plurality of pressure sensors. According to the invention, a simulation test can be simultaneously carried out on the gravity part of the anchorage and the bearing capacity corresponding to the clamping effect of the surrounding rock, so that the bearing capacity of the combined anchorage and the size and the distribution form of the rock-anchor surface contact force are determined, and a basis is provided for a calculation model of the bearing capacity.

Description

Technical Field

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

[0002] The anchoring systems currently widely used in suspension bridges include gravity anchors and tunnel anchors. The former mainly relies on the gravity of the anchor and the friction between the anchor and the foundation to provide bearing capacity. Its force is clear and the calculation is simple, but the cost is high. The latter mainly relies on the resistance of the surrounding rock to the anchor plug to provide bearing capacity. It can give full play to the role of the surrounding rock and obtain a higher bearing capacity. The cost is relatively low, but the mechanism and calculation are complex.

[0003] The semi-anchor and gravity combined anchor embeds part of the anchor into the rock, which can give full play to the advantages of the first two anchors. During the test, it is necessary to simulate the influence of the anchor gravity and the clamping effect of the surrounding rock at the same time. However, due to the complex form of the anchor and gravity combined anchor, if the model is made directly according to the shape of the anchor, the model making process will be too complicated. Since the distribution of the force generated by its gravity on the bottom surface is extremely uneven, according to the traditional anchor bearing capacity test method, it is impossible to simulate the anchor gravity and the corresponding bearing capacity of the surrounding rock clamping. 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. In order to achieve the above purpose, the technical solution adopted by the present invention is 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, and the horizontal section of the reinforced concrete anchor structure being in a trapezoidal shape with a small front portion and a large rear portion;

[0007] A first bearing capacity simulation unit, the first bearing capacity simulation unit includes a plurality of pressure applying devices, the pressure applying devices include a first jack, a reaction beam and an anchor cable, each of the first jacks is respectively arranged at a different pressure applying position on the upper surface of the superstructure, the reaction beam is arranged at the top of the piston rod of the first jack, and anchor cables are fixed at both ends of the reaction beam, and the anchor cables are vertically inserted into the anchor model and extend to the outside of the anchor model;

[0008] A second bearing force simulation unit, the second bearing force simulation unit comprises a plurality of second jacks, the piston rods of the second jacks being disposed against the 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 position of the anchor on the selected test site, and dig the anchor foundation pit at the installation position;

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

[0014] Simulate the first bearing capacity corresponding to the combined anchorage gravity, apply different vertical loads to different pressure points of the anchorage model superstructure through different first jacks in the bearing capacity test device until all the vertical loads meet the test requirements. The different vertical loads applied at different pressure points are 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 maintains a preset loading time, 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 combined anchor bearing capacity test device and test method to simplify model making and well simulate the distribution form of base pressure generated by the anchor gravity, thereby achieving simultaneous simulation tests of the bearing capacity corresponding to the anchor gravity 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.

[0018] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or be understood by implementing the embodiments of the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 Shown is a structural diagram of a combined anchor test device in an embodiment of the present invention;

[0021] Figure 2 The figure shows the use state of the combined anchor test device in the embodiment of the present invention;

[0022] Figure 3 It is a schematic structural diagram of the first bearing capacity simulation unit in an embodiment of the present invention;

[0023] Figure 4 Shown is a schematic diagram of a half-section structure of an anchoring model in an embodiment of the present invention;

[0024] Figure 5 The figure is a schematic diagram of force analysis of an isolator in an embodiment of the present invention;

[0025] 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

[0026] 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, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here 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 in 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.

[0027] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0028] The main idea of ​​the present invention is that the semi-anchor and gravity combined anchor is a new type of anchor. Unlike the test of the existing anchor, it is necessary to simulate the influence of the anchor 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: the model cannot be made 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 into 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 gravity.

[0029] 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.

[0030] This embodiment provides a combined anchor bearing capacity test device, comprising:

[0031] An anchor model 1, the anchor model 1 comprises an upper structure and a lower structure, the upper structure is a reinforced concrete slab structure, the lower structure comprises a reinforced concrete anchor structure, and the horizontal section of the reinforced concrete anchor structure is a trapezoidal shape with a small front and a large rear;

[0032] A first bearing capacity simulation unit, the first bearing capacity simulation unit includes a plurality of pressure applying devices, the pressure applying devices include a first jack 205, a reaction beam 2 and an anchor cable 202, each of the first jacks 205 is respectively arranged at a different pressure applying position on the upper surface of the superstructure, the reaction beam 2 is arranged on the top of the piston rod of the first jack 205, and anchor cables 202 are fixed at both ends of the reaction beam 2, and the anchor cables 202 are vertically inserted into the anchor model 1 and extend to the outside of the anchor model 1;

[0033] A second bearing force simulation unit, the second bearing force simulation unit comprises a plurality of second jacks 4, the piston rods of the second jacks 4 being disposed against the end surface of the rear end of the lower structure;

[0034] 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.

[0035] A plurality of anchor cable holes 12 are vertically opened on the anchor model 1 , and an anchor cable 202 is correspondingly passed through each of the anchor cable holes 12 , and a gap is left between the outer wall of the anchor cable 202 and the hole wall of the anchor cable hole 12 .

[0036] The anchor cable holes 12 are arranged at intervals along the longitudinal horizontal center axis of the anchor model 1.

[0037] 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.

[0038] The reaction beam 2 includes two channel steels 2011, 2012 and a fixing plate. The two channel steels 2011, 2012 are arranged in parallel. The top ends of the two channel steels 2011, 2012 are fixedly connected by the top fixing plate 203, and the bottom ends of the two channel steels 2011, 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.

[0039] A roller shaft 209 is provided between the first jack 205 and the upper structure.

[0040] 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.

[0041] 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.

[0042] like Figure 1 and Figure 2 As shown, this embodiment provides a combined anchor bearing capacity test device, comprising:

[0043] Anchor model 1, the anchor model 1 includes an upper structure and a lower structure, the upper structure is a reinforced concrete slab structure, the lower structure includes a reinforced concrete anchor structure, the horizontal section of the reinforced concrete anchor structure is a trapezoidal shape with a small front and a large rear, so that the anchor model can produce a clamping effect with the surrounding rock mass, which can effectively improve the bearing capacity. In this embodiment, a combined anchor with double anchor bodies is simulated, and the lower structure includes two reinforced concrete anchor structures respectively arranged on the left and right sides of the bottom of the reinforced concrete slab structure;

[0044] A first bearing capacity simulation unit, the first bearing capacity simulation unit includes a plurality of pressure applying devices, the pressure applying devices include a first jack 205, a reaction beam 2 and an anchor cable 202, each of the first jacks 205 is respectively arranged at a different pressure applying position on the upper surface of the superstructure, the reaction beam 2 is arranged at the top of the piston rod of the first jack 205, and anchor cables 202 are fixed at both ends of the reaction beam 2, the anchor cables 202 are vertically inserted into the anchor model 1 and extend to the outside of the anchor model 1, wherein the top of the piston rod of the first jack 205 contacts the bottom of the reaction beam 2 through a steel pad 207;

[0045] A second bearing force simulation unit, the second bearing force simulation unit comprises a plurality of second jacks 4, the piston rods of the second jacks 4 being disposed against the end surface of the rear end of the lower structure;

[0046] 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.

[0047] 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. A plurality of strain gauges 14 are arranged along the horizontal central axis of the anchor model 1, and two adjacent strain gauges 14 are arranged at intervals.

[0048] A plurality of anchor cable holes 12 are vertically opened on the anchor model 1 , and an anchor cable 202 is correspondingly passed through each of the anchor cable holes 12 , and a gap is left between the outer wall of the anchor cable 202 and the hole wall of the anchor cable hole 12 .

[0049] The anchor cable holes 12 are arranged at intervals along the longitudinal horizontal center axis of the anchor model 1.

[0050] 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.

[0051] 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 plane 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 can reach 8-9m for the spanning model. 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. In order to solve the above problems, the applicant has come up with the following solutions:

[0052] The anchor cable 202 is arranged within the plane of the anchor model 1, and its length is about 1m. Compared with the traditional reaction beam, its length and cross section are greatly reduced, so the amount of material can be greatly reduced, and it is very convenient to install;

[0053] 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;

[0054] A roller shaft 209 is arranged 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.

[0055] like Figure 3As 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 in parallel, and the two channel steels 2011 and 2012 are arranged in parallel with a certain distance. The top ends of the two channel steels 2011 and 2012 are respectively fixedly connected by the top fixing plate 203, and the bottom ends of the two channel steels 2011 and 2012 are respectively 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 a ring welding method, 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.

[0056] 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.

[0057] 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.

[0058] The method for the bearing capacity test device of the combined anchorage comprises:

[0059] 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;

[0060] Mark the required installation position of the anchor on the selected test site, and dig the anchor foundation pit at the installation position;

[0061] 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;

[0062] Simulate the first bearing capacity corresponding to the combined anchoring gravity, apply different vertical loads to different pressure points of the upper structure of the anchoring model 1 through different first jacks 205 in the bearing capacity test device, until all the vertical loads meet the test requirements, the different vertical loads applied at different pressure points are determined by the actual weight distribution of the combined anchoring, and the vertical load is supplemented by using the first jack 205 to simulate the deadweight of the anchoring model to meet the similarity theory requirements;

[0063] 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 push-back loads are applied to the rear end of the anchor model 1 through the second jacks 4. Each level of push-back load maintains a preset loading duration, and the readings of the strain gauge 14 and the pressure sensor 13 under each level of push-back load are read. In this embodiment, the push-back jack is used with the design load as the first-level load, and each level of load is maintained for 30 minutes.

[0064] The distribution of anchor-rock side friction resistance is determined based on the distribution curve of anchor rock surface normal stress and the distribution curve of axial stress: the push-back jack is used to provide load to the anchor model, and the normal stress on the side of the anchor model and the internal axial stress 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 anchor rock surface normal stress and the distribution curve of axial stress.

[0065] The method for determining the ultimate bearing capacity of the bearing capacity testing device for the combined anchor comprises the following steps:

[0066] The anchor model 1 is divided into several half-anchor sections, and each of the half-anchor sections is used as an isolation body, such as Figure 5 As shown, the isolator comprises a top surface, two left and right side surfaces, a bottom surface, a front section and a rear section;

[0067] The areas of the two side surfaces, the bottom surface, the front section and the rear section are obtained respectively, and the angles between the two side surfaces and the bottom surface and the longitudinal horizontal center axis of the isolator are equal;

[0068] 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;

[0069] Acquire stress magnitudes of the two side surfaces and the bottom surface according to the stress data;

[0070] Calculating normal forces on the two side surfaces and the bottom surface respectively according to stress magnitudes and areas of the two side surfaces and the bottom surface;

[0071] Acquire the magnitude of the axial stress of the front section and the rear section according to the pressure data;

[0072] Calculating the magnitude of the axial force of the front section and the rear section respectively according to the magnitude and area of ​​the axial stress of the front section and the rear section;

[0073] The tangential force between the isolator and the surrounding rock is calculated according to 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 surface 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:

[0074]

[0075] According to the magnitude 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.

[0076] Where, tangential force, 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 isolated body 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.

[0077] In view of the large cross-sectional dimensions of combined anchors, this application proposes a method for measuring the interaction force between the anchor and the surrounding rock by installing sensor elements only in the embedded rock (and adjacent) part. The tangential force on the anchor-surrounding rock interface is important information on the anchor force in the embedded anchor of this application, but there is currently no good measurement method. This application proposes a method for determining the tangential force from the anchor axial strain measurement results and the anchor-surrounding rock interface pressure sensor, and determines the corresponding calculation method, solving this technical problem.

[0078] Compared with the prior art, the present invention has the following beneficial effects:

[0079] 1. After reasonable simplification, the arrangement of the device becomes simpler and easier. In addition, this anchor model can effectively demonstrate the bearing capacity of the semi-anchor and semi-gravity combined anchor, thereby ensuring its stability and reliability in various application scenarios.

[0080] 2. The present invention achieves the anchor weight required by the model test similarity ratio by means of vertical supplementary load, has the advantages of simple structure, convenient operation, significant effect, etc., and has important practical application value. In practical applications, the present invention can be widely used in various anchor model tests. By means of vertical supplementary load, the problem of insufficient anchor model weight can be effectively solved, the accuracy and reliability of the model test can be improved, and strong support can be provided for engineering design and construction.

[0081] 3. The present invention innovatively places the anchor cable inside the anchor, rather than outside, which not only simplifies the setting process, but also significantly shortens the length of the reaction beam. At the same time, the anchor model is pre-set with perforations to allow the anchor cable to pass smoothly without affecting the normal displacement of the anchor cable body. This design is both practical and efficient, and provides new ideas and directions for the technical development of related fields.

[0082] 4. The present invention uses the automatically acquired axial and normal stress data of the anchor model and the ultimate bearing capacity to successfully derive the magnitude and distribution of the rock-anchor surface tangential force and normal force of the anchor model through a series of transformation calculations, providing a basis for the calculation model of the bearing capacity. The entire test process is simple and efficient, and the data monitoring link is also simple and easy, thus ensuring that the implementation of the present invention is highly feasible and practical.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0084] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope 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 small front portion and a large 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 arranged at a different pressure applying position on the upper surface of the upper structure, the reaction beam (2) being arranged at the top of the piston rod of the first jack (205), the two ends of the reaction beam (2) being fixed with an anchor cable (202), the anchor cable (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 disposed 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.

2. The combined anchor bearing capacity test device according to claim 1, characterized in that: A plurality of anchor cable holes (12) are vertically opened on the anchor model (1), and an anchor cable (202) is correspondingly passed through each of the anchor cable holes (12), and a gap is left between the outer wall of the anchor cable (202) and the hole wall of the 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 test 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 arranged at intervals.

5. The combined anchor bearing capacity test device according to claim 1, characterized in that: The reaction beam (2) comprises two channel steels (2011, 2012), a top fixing plate (203) and a bottom fixing plate (206); the two channel steels (2011, 2012) are arranged in parallel; the top ends of the two channel steels (2011, 2012) are respectively fixedly connected via the top fixing plate (203); the bottom ends of the two channel steels (2011, 2012) are respectively 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 test 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 test 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 test device according to claim 1, characterized in that: The acquisition unit also 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 position of the anchor on the selected test site, and dig the anchor foundation pit at the installation position; Install the combined anchor bearing capacity test device to the anchor foundation pit, place the bottom of the second jack of the bearing capacity test device against the rear end of the anchor foundation pit, place the front end of the anchor model in the bearing capacity test device against the front end of the anchor foundation pit, and extend the anchor cable of the bearing capacity test device into the rock mass below the anchor foundation pit; Simulate the first bearing capacity corresponding to the combined anchorage gravity, apply different vertical loads to different pressure points of the anchorage model superstructure through different first jacks in the bearing capacity test device until all the vertical loads meet the test requirements. The different vertical loads applied at different pressure points are 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 maintains a preset loading time, 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: The anchor model is divided into a plurality of half-anchor sections, and each of the half-anchor sections is used as an isolation body, wherein the isolation body 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, and 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 stress magnitudes and areas of the two side surfaces and the bottom surface; Acquire the magnitude of the axial stress of the front section and the rear section according to the pressure data; Calculating the magnitude of the axial force of the front section and the rear section respectively according to the magnitude of the axial stress and the area of ​​the front section and the rear section; The tangential force between the isolator and the surrounding rock is calculated according to 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 surface 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, tangential force, 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 isolated body 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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