Ultra-large bottom-openable three-dimensional loading device and test method

Abstract

The present invention relates to the technical field of three-dimensional physical model tests with similar materials for deep underground engineering. Disclosed are an ultra-large bottom-openable three-dimensional loading device and a test method. The present invention provides a new ultra-large bottom-openable three-dimensional loading frame structure, which is suitable for automated bottom access of physical model specimens with dimensions of 5 m or larger and provides an optimal access mode. A prestressed composite structure is used for a vertical reaction frame, and a high-strength prestressed steel wire wound assembled structure composed of multiple longitudinal single-beam units with circumferential T-shaped dovetailed joints is used for a horizontal reaction frame, thus meeting high-rigidity design requirements of a three-dimensional loading device. The vertical reaction frame cooperates with a movable lifting beam for specimen bearing and is assisted by a reaction support base beam during a test to directly bear an applied load, thus ensuring equipment stability and operational precision during a loading test, and preventing lifting risks caused by unsynchronized positions of lifting cylinders. In regard to the problem of test data acquisition being affected by the abrupt rupture of a specimen impacting a loading frame test, a back-pressure buffering damping technique is applied to the lifting cylinders, ensuring the continuity of data acquisition.

Description

An ultra-large bottom-opening and closing three-dimensional loading device and test method Technical Field

[0001] The present invention belongs to the technical field of three-dimensional similar material physical model testing for deep engineering, and in particular relates to an ultra-large bottom opening and closing three-dimensional loading device and a testing method. Background Art

[0002] Deep engineering mainly covers mining projects, tunnel projects, water conservancy and hydropower projects, underground laboratories, geothermal and oil and gas development projects, continental deep drilling projects, etc. The object or engineering carrier of deep engineering is rock mass. Under the action of gravity field and tectonic stress field, these rock masses are subjected to three-dimensional unequal ground stress (σ1>σ2>σ3>0, where σ1, σ2 and σ3 are major principal stress, medium principal stress and minor principal stress, respectively). Deep engineering is the process of excavating and transforming rock mass into a specific engineering form. Excavation breaks the original ground stress equilibrium state, causing the magnitude and direction of ground stress at different locations in the engineering rock mass to change dramatically. This is the main reason for the frequent occurrence of deep engineering disasters. At present, the disaster mechanism and engineering stability control principles of deep engineering under the three-dimensional unequal ground stress field are still in the preliminary stage of understanding.

[0003] Recreating disaster processes under three-dimensional geostress conditions using large-scale physical model experiments is one of the most effective methods for studying deep engineering disasters. To this end, considering the structural properties of the strata, it is necessary to design an ultra-large three-dimensional loading device with meter-scale dimensions. This device must be capable of outputting 10,000-ton triaxial loads, with the loaded object (a similar material body) placed in a three-dimensional, six-sided closed force structure. A comparable device is the 10,000-ton hydraulic press, but this is primarily designed for metal forging. Loading is one-dimensional, with metal specimens visible and open, and specimen entry and exit are horizontal. Furthermore, the forging process differs significantly from the geological simulation process. The high geostress properties of deep rock engineering necessitate three-dimensional stress loading, which requires stress gradient control and full specimen coverage. In particular, during disasters such as rockbursts, the three-dimensional loading device must rapidly decompress and activate damping protection. Therefore, the 10,000-ton hydraulic press offers limited reference compared to the process requirements of ultra-large three-dimensional loading devices for rock engineering disaster simulation. Therefore, it is very necessary to develop a loading device and test method that is convenient for the entry and exit of large-scale model specimens (5m and above), has a relatively simple structure, and is three-way and six-sided closed.

[0004] The main characteristics of existing three-dimensional physical simulation devices for rock engineering and geotechnical engineering are that the loading tonnage is generally not high, and only boundary stress can be simply applied. The specimen is vibrated and cast inside the loading device, and the reaction loading unit in a certain direction is mechanically closed or sealed (such as by removing bolts) to form a closed three-dimensional reaction loading structure.

[0005] Chinese patent application number 202210820592.6 published "A large-scale three-dimensional physical simulation test system for the entire process of deep engineering rockburst incubation", Chinese patent application number 202310058018.6 published "A super-large deep engineering disaster physical simulation facility", and Chinese patent application number 202310058789.5 published "A three-dimensional loading structure of a super-large deep engineering disaster physical simulation facility". These similar material physical model loading devices have increased the size of physical model specimens from 1m to 5m, realizing the simulation of various engineering activities under complex geological structures and occurrence environments.

[0006] Among them, the Chinese patent application with application number 202310058789.5 published "A three-dimensional loading structure for a super-large deep engineering disaster physical simulation facility" adopts an upper feeding method. After crossing the annular beam, the supporting platform needs to be first lifted up to the model sample, and then lowered to the bottom test station. Although it is feasible, it has many automated operation steps, high positioning accuracy requirements, and a complex hydraulic system support structure.

[0007] In addition, the Chinese patent application with application number 201710432131.0, entitled "A Large-Scale Quasi-Static Test Device and Method for Soil-Underground Structures", is a three-dimensional loading test device for large-size soil samples. The soil samples are rammed inside the test device, and then the reaction metal frame unit on the top of the test device is closed to form a closed force system.

[0008] The testing process for large-scale physical model specimens should be simplified as much as possible, and installation and removal should be automated as much as possible. Simplifying, automating, and accurately moving physical model specimens into and out of the three-dimensional loading device has always been a top priority for developers. Furthermore, the method by which large-scale physical model specimens are moved into and out of the test device significantly impacts the device's three-dimensional loading structure, a factor that must be balanced in the test device's structural design.

[0009] Summary of the Invention

[0010] In response to the problems existing in the prior art, the present invention proposes an ultra-large bottom opening and closing three-dimensional loading device and test method, which is suitable for the automatic entry and exit of the bottom of physical model specimens of 5m and larger sizes, and can achieve ultra-high rigidity and high reliability of the loading frame, and convenient entry and exit of the physical model specimens. The ultra-large bottom opening and closing three-dimensional loading device consists of a horizontal reaction frame, a vertical reaction frame, a specimen carrying lifting mechanism, and a reaction support cushion beam. During the test, it directly bears the test reaction force, which can ensure the stability and operation accuracy of the equipment under ultra-high load and ultra-long time loading. The physical model specimen is lifted, installed and disassembled by the carrying lifting beam under the action of the hydraulic servo-controlled lifting cylinder. The lifting beam serves as both an entry and exit platform for the ultra-large physical model specimen and a lifting platform for the maintenance and disassembly of the actuator. The hydraulic servo-controlled lifting cylinder has a redundant design and high synchronous lifting accuracy, which avoids the lifting safety risks caused by inconsistent lifting cylinder movements. In the physical simulation test of deep engineering disasters, in order to solve the problem that the instantaneous destruction of super-large physical model specimens affects the reliability of the loading frame, a buffering and damping technology of a super-large three-beam and four-column prestressed loading frame was proposed. By setting the back pressure of the lifting cylinder, it can play the role of a buffer cylinder at the moment of destruction of the super-large physical model specimen, quickly absorb the impact energy and slow down the impact in a short time, and ensure the reliability of the test process and the integrity and continuity of the test data.

[0011] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: an ultra-large bottom opening and closing three-dimensional loading device, comprising a horizontal reaction frame, a vertical reaction frame, a specimen carrying lifting beam, a lifting cylinder, a reaction support pad beam, an array actuator group and a linear dynamic actuator group; the horizontal reaction frame adopts an annular cantilever structure, and the horizontal reaction frame is installed on four high-strength reinforced concrete support piers, the height of the high-strength reinforced concrete support piers is higher than the height of the ultra-large physical model specimen, and the bottom of the high-strength reinforced concrete support piers is at the same elevation as the ground floor; the vertical central axis of the vertical reaction frame coincides with the vertical central axis of the horizontal reaction frame, the lower end of the vertical reaction frame is partially located in the foundation pit, and the lower end of the vertical reaction frame is fixed to the bottom of the foundation pit by anchor bolts; The specimen-carrying lifting beam is installed in the middle of the vertical reaction frame and is located below the lower surface of the horizontal reaction frame. The specimen-carrying lifting beam is connected to the four corners of the top of the vertical reaction frame through four lifting cylinders; a set of array-type actuator groups is provided on the lower surface of the top of the vertical reaction frame; four sets of array-type actuator groups are evenly distributed along the circumference on the inner side of the horizontal reaction frame, and a through-type actuator is provided in one set of the array-type actuator groups. A robot excavation entry and exit channel is provided on the horizontal reaction frame opposite to the through-hole of the through-type actuator; a set of linear dynamic actuator groups is provided on the upper part of the specimen-carrying lifting beam; the inlet and outlet of the super-large physical model specimen and the inlet and outlet of the reaction support beam are respectively provided at the opening of the high-strength reinforced concrete support pier below the horizontal reaction frame.

[0012] The horizontal reaction frame adopts a longitudinal multiple-group single-beam annular T-shaped joint assembly structure, and the horizontal reaction frame includes fan-shaped beams, fan-shaped perforated beams, arc-shaped bearing pads and a frame bearing base; the number of the fan-shaped perforated beams is four and they are evenly distributed along the circumference of the horizontal reaction frame, and the adjacent fan-shaped perforated beams are formed by chopping and combining the fan-shaped beams to form an annular assembly, and a double-layer steel wire winding layer is provided on the outside of the annular assembly; the joint contact surfaces of the fan-shaped beams and the fan-shaped perforated beams adopt a T-shaped bite self-limiting structure; on each fan-shaped perforated beam, A lifting cylinder passage hole is provided, and a frame bearing base is fixedly provided under each fan-shaped perforated beam, and the frame bearing base is connected to the high-strength reinforced concrete support pier through a high-load-bearing shock absorber; the number of the arc-shaped bearing pads is four and they are evenly distributed on the inside of the annular assembly, the outer arc of the arc-shaped bearing pads fits with the inner arc surface of the annular assembly, and the array actuator group is arranged on the inner plane of the arc-shaped bearing pads; the robot excavation entry and exit channel is located on one of the fan-shaped beams and the arc-shaped bearing pad directly opposite to it.

[0013] The vertical reaction frame includes a top beam, a bottom beam, a hollow column and a prestressed tie rod; the prestressed tie rod adopts an integral forging structure; the top beam adopts a rectangular structure, and lifting cylinder barrel adapter ears are provided at the four corners of the top beam, and the cylinder barrel end of the lifting cylinder is fixedly connected to the lifting cylinder barrel adapter ears; the bottom beam adopts a rectangular structure, and the bottom beam is located directly below the top beam, and four hollow columns are provided between the bottom beam and the four corners of the top beam, and a prestressed tie rod is installed in each hollow column, and the top end of the prestressed tie rod is fixed to the top beam by a nut, and the bottom end of the prestressed tie rod is fixed to the bottom beam by a nut; the array actuator group is arranged on the lower surface of the top beam.

[0014] The sample-carrying lifting beam adopts a rectangular structure, and lifting cylinder rod adapter ears are provided at the four corners of the sample-carrying lifting beam, and the cylinder rod end of the lifting cylinder is fixedly connected to the lifting cylinder rod adapter ears; a hollow column passing guide hole is provided on the inner side of the lifting cylinder rod adapter ear, and the hollow column passes through the hollow column passing guide hole; an actuator installation groove is provided in the middle of the sample-carrying lifting beam, and the linear dynamic actuator group is arranged inside the actuator installation groove, and the single actuator in the linear dynamic actuator group adopts dynamic disturbance Hydraulic actuator; a friction-reducing support roller group is provided on the upper surface of the specimen-carrying lifting beam; when the specimen-carrying lifting beam is located on the bottom beam of the vertical reaction frame, the ultra-large physical model specimen is transported to the specimen-carrying lifting beam by the heavy-duty RGV rail flat car using a horizontal push-pull rigid chain; after the specimen-carrying lifting beam carries the ultra-large physical model specimen, the specimen-carrying lifting beam is lifted by four lifting cylinders to the specimen loading station in the center of the horizontal reaction frame, completing the opening and closing action of the three-dimensional loading device of the ultra-large physical model specimen.

[0015] The lifting cylinder adopts proportional closed-loop displacement control technology. A high-precision displacement sensor is arranged between the cylinder rod and the cylinder sleeve of the lifting cylinder. The hydraulic chamber in the cylinder of the lifting cylinder is connected to the accumulator through a throttle valve and a relief valve in sequence; an anti-fall locker is installed between the hollow column and the sample-carrying lifting beam. The anti-fall locker includes an anti-fall high-strength rack and an anti-fall locking cylinder. The anti-fall high-strength rack is vertically fixed on the outer surface of the hollow column, and the anti-fall locking cylinder is horizontally fixed on the sample-carrying lifting beam. An anti-fall pad is installed at the end of the cylinder rod of the anti-fall locking cylinder, and the anti-fall pad is engaged and locked with the anti-fall high-strength rack.

[0016] A reaction support beam inlet and outlet tunnel is provided on the ground outside the inlet and outlet of the reaction support beam on the high-strength reinforced concrete support pier, and a heavy-load track is provided in the reaction support beam inlet and outlet tunnel. The upper surface of the heavy-load track is flush with the upper surface of the bottom beam of the vertical reaction frame; the reaction support beam adopts a servo motor as a driving actuator.

[0017] A heavy-loaded RGV rail flat car is arranged on the ground outside the inlet and outlet of the super-large physical model specimen on the high-strength reinforced concrete support pier. The super-large physical model specimen is transferred to a working position by the heavy-loaded RGV rail flat car. The heavy-loaded RGV rail flat car adopts a low-voltage rail power supply mode and a horizontal push-pull rigid chain method to move the super-large physical model specimen. When the specimen-carrying lifting beam is at the lower limit position, the upper surface of the heavy-loaded RGV rail flat car is flush with the upper surface of the specimen-carrying lifting beam. A friction-reducing support roller group is provided on the upper surface of the heavy-loaded RGV rail flat car.

[0018] A health monitoring sensor system is arranged on the vertical reaction frame, horizontal reaction frame and lifting cylinder, and the health monitoring sensor system includes a composite deformation sensor and a displacement-pressure-temperature sensor; a composite deformation sensor is arranged at the upper end, middle end and lower end of each prestressed tie rod, and a total of twelve composite deformation sensors are arranged on the four prestressed tie rods; a composite deformation sensor is arranged at the upper end, middle end and lower end of the outer side of each hollow column, and a total of twelve composite deformation sensors are arranged on the four hollow columns; a composite deformation sensor is arranged at the upper end and lower end of the fan-shaped beam, the inner side of the fan-shaped perforated beam and the upper end and lower end of the contact surface of the horizontal reaction frame, and the total number of composite deformation sensors on the horizontal reaction frame is thirty-two; the composite deformation sensor is used to monitor the stress, strain, vibration and position information of the super-large bottom opening and closing three-dimensional loading device under the test state; the displacement-pressure-temperature sensor is installed on the lifting cylinder to monitor the operating posture and stability of the lifting cylinder.

[0019] The test method using the ultra-large bottom opening and closing three-dimensional loading device includes the following steps:

[0020] Step 1: Synchronously start the four lifting cylinders so that their rods extend downward synchronously, driving the specimen-carrying lifting beam to descend at a uniform speed. At the same time, the composite deformation sensor and displacement-pressure-temperature sensor are used to monitor the operating posture and stability of the lifting cylinder pistons and the specimen-carrying lifting beam in real time until the specimen-carrying lifting beam falls to the upper surface of the bottom beam of the vertical reaction frame. At this time, the specimen-carrying lifting beam is at the lower limit position.

[0021] Step 2: Use a heavy-load RGV rail flat car to transport the prepared ultra-large physical model specimen to the ultra-large physical model specimen entrance and exit at the high-strength reinforced concrete support pier crotch. Then, use a rigid chain horizontal push-pull method to move the ultra-large physical model specimen to the upper surface of the specimen-bearing lifting beam.

[0022] Step 3: Synchronously start the four lifting cylinders again, so that the cylinder rods of the four lifting cylinders retract synchronously, driving the specimen-carrying lifting beam to rise at a uniform speed. The super-large physical model specimen rises synchronously with the specimen-carrying lifting beam. At the same time, the composite deformation sensor and displacement-pressure-temperature sensor are used to monitor the operating posture and stability of the lifting cylinder piston and the specimen-carrying lifting beam in real time. The anti-fall locker is used to ensure the safety of the installation of the super-large physical model specimen in real time until the super-large physical model specimen enters the center of the horizontal reaction frame. At this time, the specimen-carrying lifting beam is at the upper limit position.

[0023] Step 4: Move the reaction support beam in and out of the tunnel from the heavy-load track to the upper surface of the bottom beam of the vertical reaction frame, then lower the specimen-carrying lifting beam to eliminate the gap between the lower surface of the specimen-carrying lifting beam and the reaction support beam, so that the specimen-carrying lifting beam and the reaction support beam are in full contact. At this time, the super-large physical model specimen is completely enclosed inside the super-large bottom opening and closing three-dimensional loading device;

[0024] Step 5: Use the ultra-large bottom-opening and closing three-dimensional loading device to carry out loading tests on the ultra-large physical model specimen inside. At the same time, composite deformation sensors and displacement-pressure-temperature sensors are used to monitor the stress, strain, vibration, and position information of the vertical reaction frame, horizontal reaction frame, and lifting cylinder in real time to ensure the healthy operation of the ultra-large bottom-opening and closing three-dimensional loading device.

[0025] Step 6: When the loading test is completed, first raise the specimen-carrying lifting beam to restore the gap between the lower surface of the specimen-carrying lifting beam and the reaction support pad beam, then move the reaction support pad beam from the upper surface of the bottom beam of the vertical reaction frame back to the heavy-load track in the reaction support pad beam entry and exit tunnel, and then drive the specimen-carrying lifting beam down through four lifting cylinders to make the specimen-carrying lifting beam fall to the upper surface of the bottom beam of the vertical reaction frame. The super-large physical model specimen will be synchronously lowered with the specimen-carrying lifting beam, and then the super-large physical model specimen will be moved back to the heavy-load RGV rail flat car, and finally the heavy-load RGV rail flat car will transport the super-large physical model specimen to the finished product area.

[0026] Beneficial effects of the present invention:

[0027] The ultra-large bottom opening and closing three-dimensional loading device and test method of the present invention are suitable for the automatic entry and exit of the bottom of physical model specimens of 5m level and larger, and can achieve ultra-high rigidity and high reliability of the loading frame, and convenient entry and exit of the physical model specimens. The ultra-large bottom opening and closing three-dimensional loading device is composed of a horizontal reaction frame, a vertical reaction frame, a specimen carrying lifting mechanism, and a reaction support cushion beam. It directly bears the test reaction force during the test, and can ensure the stability and operation accuracy of the equipment under ultra-high load and ultra-long time loading. The physical model specimen is lifted, installed and disassembled by the carrying lifting beam under the action of the hydraulic servo-controlled lifting cylinder. The lifting beam serves as an entry and exit platform for the ultra-large physical model specimen and a lifting platform for the maintenance and disassembly of the actuator. The hydraulic servo-controlled lifting cylinder has a redundant design and high synchronous lifting accuracy, which avoids the lifting safety risks caused by inconsistent lifting cylinder actions. In the physical simulation test of deep engineering disasters, in order to solve the problem that the instantaneous destruction of ultra-large physical model specimens affects the reliability of the loading frame, a buffering and damping technology for an ultra-large three-beam and four-column prestressed loading frame was proposed. By setting the back pressure of the lifting cylinder, it can act as a buffer cylinder at the moment of destruction of the ultra-large physical model specimen, quickly absorb the impact energy and slow down the impact in a short time, and ensure the reliability of the test process and the integrity and continuity of the test data; a health monitoring sensor system based on the combination of big data and simulation fault assessment was proposed to collect equipment parameters such as stress, strain, vibration, position, and temperature in real time to realize health assessment, fault prediction and maintenance decision-making of the loading structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a partial cross-sectional structural diagram of an ultra-large bottom-opening and closing three-dimensional loading device according to the present invention;

[0029] FIG2 is a schematic structural diagram of the assembly of the horizontal reaction frame, the arrayed actuator assembly, and the ultra-large physical model specimen of the present invention;

[0030] FIG3 is a schematic diagram of a fan-shaped beam structure equipped with a composite deformation sensor according to the present invention;

[0031] FIG4 is a schematic diagram of the structure of a fan-shaped perforated beam equipped with a composite deformation sensor according to the present invention;

[0032] FIG5 is a partial cross-sectional structural diagram of the vertical reaction frame of the present invention;

[0033] FIG6 is a schematic structural diagram of the assembly of the vertical reaction frame, the lifting cylinder, the specimen-carrying lifting beam, and the reaction support beam according to the present invention;

[0034] FIG7 is a schematic diagram of the installation process of an ultra-large physical model specimen of an ultra-large bottom opening and closing three-dimensional loading device of the present invention;

[0035] In the figure, 1 is a horizontal reaction frame, 2 is a vertical reaction frame, 3 is a specimen-carrying lifting beam, 4 is a lifting cylinder, 5 is a reaction support pad beam, 6 is an array actuator group, 7 is a linear dynamic actuator group, 8 is a high-strength reinforced concrete support pier, 9 is an ultra-large physical model specimen, 10 is a fan-shaped beam, 11 is a fan-shaped perforated beam, 12 is an arc-shaped bearing pad, 13 is a frame-carrying base, 14 is a lifting cylinder through hole, 15 is a robot excavation entry and exit channel, 16 is a double-layer steel wire winding layer, 17 is a top beam, 18 is a bottom beam, 19 is a hollow column, 20 is a prestressed tie rod, 21 is a lifting cylinder barrel adapter ear, 22 is a lifting cylinder rod adapter ear, 23 is an actuator mounting groove, 24 is a reaction support pad beam entering and exiting the tunnel, 25 is a heavy-duty RGV rail flat car, and 26 is a composite deformation sensor. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] As shown in Figures 1 to 7, an ultra-large bottom opening and closing three-dimensional loading device includes a horizontal reaction frame 1, a vertical reaction frame 2, a specimen carrying lifting beam 3, a lifting cylinder 4, a reaction support cushion beam 5, an array actuator group 6 and a linear dynamic actuator group 7; the horizontal reaction frame 1 adopts a ring-shaped cantilever structure, and the horizontal reaction frame 1 is installed on four high-strength reinforced concrete support piers 8. The height of the high-strength reinforced concrete support piers 8 is higher than the height of the ultra-large physical model specimen 9, and the bottom of the high-strength reinforced concrete support piers 8 is the same as the ground floor elevation; the vertical central axis of the vertical reaction frame 2 coincides with the vertical central axis of the horizontal reaction frame 1, and the lower end of the vertical reaction frame 2 is partially located in the foundation pit, and the lower end of the vertical reaction frame 2 is fixed to the bottom of the foundation pit by anchor bolts; the specimen carrying lifting The movable beam 3 is installed in the middle of the vertical reaction frame 2 and is located below the lower surface of the horizontal reaction frame 1. The specimen-carrying lifting movable beam 3 is connected to the four corners of the top of the vertical reaction frame 2 through four lifting cylinders 4; a set of array-type actuator groups 6 is provided on the lower surface of the top of the vertical reaction frame 2; four sets of array-type actuator groups 6 are evenly distributed along the circumference on the inner side of the horizontal reaction frame 1, and a through-type actuator is provided in one set of the array-type actuator groups 6. A robot excavation entry and exit channel 15 is provided on the horizontal reaction frame 1 opposite to the through-hole of the through-type actuator; a set of linear dynamic actuator groups 7 is provided on the upper part of the specimen-carrying lifting movable beam 3; the inlet and outlet of the super-large physical model specimen 9 and the inlet and outlet of the reaction support cushion beam 5 are respectively provided at the opening of the high-strength reinforced concrete support pier 8 below the horizontal reaction frame 1.

[0038] In this embodiment, the super-large physical model specimen 9 is made using 3D printing technology, and printing materials with specific similarity ratios can be prepared according to working conditions. The super-large physical model specimen 9 is a cube with dimensions of 5m×5m×5m (side length is 5m); the geometric center of the super-large physical model specimen 9 is defined as the origin of the coordinate system, and the six surfaces of the super-large physical model specimen 9 are defined as XR, XL, YF, YB, ZU, and ZD respectively, and each surface is equally divided into 25 independent loading unit surfaces; the foundation pit depth below the inner side of the high-strength reinforced concrete support pier 8 is -9m, and the vertical reaction frame 2 is fixed to the bottom of the foundation pit with anchor bolts to ensure that the vertical reaction frame 2 has good anti-overturning performance; the number of single actuators in the array actuator group 6 is 25, and the 25 single actuators adopt a 5×5 array layout; the number of single actuators in the linear dynamic actuator group 7 is 5, and the 5 single actuators adopt a 1×5 linear layout.

[0039] The horizontal reaction frame 1 adopts a longitudinal multi-group single beam annular T-shaped joint assembly structure, including fan-shaped beams 10, fan-shaped perforated beams 11, arc-shaped bearing pads 12 and frame bearing bases 13; the number of the fan-shaped perforated beams 11 is four and they are evenly distributed along the circumference of the horizontal reaction frame 1. The adjacent fan-shaped perforated beams 11 are formed by chopping and combining the fan-shaped beams 10 to form an annular assembly, and a double-layer steel wire winding layer 16 is provided on the outside of the annular assembly; the joint contact surfaces of the fan-shaped beams 10 and the fan-shaped perforated beams 11 adopt a T-shaped bite self-limiting structure, which can ensure that the adjacent fan-shaped beams 10 are more tightly joined under the loading state, reducing the horizontal reaction frame. 1; a lifting cylinder through hole 14 is provided on each fan-shaped perforated beam 11, and a frame bearing base 13 is fixedly provided under each fan-shaped perforated beam 11. The frame bearing base 13 is connected to the high-strength reinforced concrete support pier 8 through a high-load-bearing shock absorber; there are four arc-shaped bearing pads 12 and they are evenly distributed on the inside of the annular assembly. The outer arc of the arc-shaped bearing pad 12 fits with the inner arc surface of the annular assembly, and the array actuator group 6 is arranged on the inner plane of the arc-shaped bearing pad 12; the robot excavation entry and exit channel 15 is located on one of the fan-shaped beams 10 and the arc-shaped bearing pad 12 opposite to it.

[0040] In this embodiment, the overall stiffness of the horizontal reaction frame 1 is greater than 50GN / m, and it has good multi-directional bearing capacity. A robot excavation entry and exit channel 15 is reserved on the fan-shaped beam 10 to simulate the excavation action of the deep engineering active robot. The overall outer dimensions of the horizontal reaction frame 1 are φ20m×5.5m (diameter×height), and the double-layer steel wire winding layer 16 is pre-tightened and installed by the winding robot. The cross-sectional shape of the steel wire in the double-layer steel wire winding layer 16 is rectangular, with a cross-sectional size of 1.5mm×5mm, and the material of the steel wire is 65Mn.

[0041] The vertical reaction frame 2 includes a top beam 17, a bottom beam 18, a hollow column 19 and a prestressed tie rod 20; the prestressed tie rod 20 adopts an integral forging structure; the top beam 17 adopts a rectangular structure, and a lifting cylinder barrel adapter ear 21 is provided at the four corners of the top beam 17, and the cylinder end of the lifting cylinder 4 is fixedly connected to the lifting cylinder barrel adapter ear 21; the bottom beam 18 adopts a rectangular structure, and the bottom beam 18 is located directly below the top beam 17, and four hollow columns 19 are provided between the bottom beam 18 and the four corners of the top beam 17, and a prestressed tie rod 20 is installed in each hollow column 19, and the top end of the prestressed tie rod 20 is fixed to the top beam 17 by a nut, and the bottom end of the prestressed tie rod 20 is fixed to the bottom beam 18 by a nut; the array actuator group 6 is arranged on the lower surface of the top beam 17.

[0042] In this embodiment, the overall stiffness of the vertical reaction frame 2 is greater than 25GN / m. The top beam 17 and the bottom beam 18 can adopt an assembled combined structure and be pre-tightened and fixed by a prestressed tie rod 20. The prestressed tie rod 20 is forged from 42CrMo high-strength steel and has a tensile strength of 1600MPa and a compressive strength of 930MPa.

[0043] The sample-carrying lifting beam 3 adopts a rectangular structure, and lifting cylinder rod adapter ears 22 are provided at the four corners of the sample-carrying lifting beam 3, and the cylinder rod end of the lifting cylinder 4 is fixedly connected to the lifting cylinder rod adapter ears 22; a hollow column passing guide hole is provided on the inner side of the lifting cylinder rod adapter ear 22, and the hollow column 19 passes through the hollow column passing guide hole; an actuator mounting groove 23 is opened in the middle of the sample-carrying lifting beam 3, and the linear dynamic actuator group 7 is arranged inside the actuator mounting groove 23, and the single actuator in the linear dynamic actuator group 7 adopts dynamic Disturbance hydraulic actuator; a friction-reducing support roller group is provided on the upper surface of the sample-carrying lifting beam 3; when the sample-carrying lifting beam 3 is located on the bottom beam 18 of the vertical reaction frame 2, the super-large physical model sample 9 is transported to the sample-carrying lifting beam 3 by the heavy-duty RGV rail flat car 25 using a horizontal push-pull rigid chain; after the sample-carrying lifting beam 3 carries the super-large physical model sample 9, the sample-carrying lifting beam 3 is lifted by four lifting cylinders 4 to the sample loading station in the center of the horizontal reaction frame 1, completing the opening and closing action of the three-dimensional loading device of the super-large physical model sample 9.

[0044] Specifically, with the help of closed-loop displacement control of high-precision displacement sensors, the height position of the specimen-carrying lifting beam 3 and the super-large physical model specimen 9 on it can be accurately located. When the array actuator group 6 on the vertical reaction frame 2 suddenly loses load, the pressure of the hydraulic oil in the lifting cylinder 4 will increase instantaneously, and generate damping through the throttle valve and the overflow valve, and finally be discharged into the accumulator. The back pressure of the lifting cylinder cooperates with the damping generated by the throttle valve and the overflow valve to reduce the vibration of the loading frame under the action of impact load, thereby ensuring the stability of the loading frame under instantaneous load loss and vibration impact test conditions.

[0045] Specifically, the array actuator group 6 is recorded as the first 5×5 array static hydraulic actuator group, the second 5×5 array static hydraulic actuator group and the third 5×5 array static hydraulic actuator group according to the different installation positions; the first 5×5 array static hydraulic actuator group is provided with three sets and is respectively installed on the three arc-shaped bearing pads 12 in the horizontal reaction frame 1; the second 5×5 array static hydraulic actuator group is provided with one set and is installed on the arc-shaped bearing pad 12 in the horizontal reaction frame 1 where the robot excavation entry and exit channel 15 is provided, and the through-type actuator is provided in the second 5×5 array static hydraulic actuator group; the third 5×5 array static hydraulic actuator group is installed on the lower surface of the top beam 17 of the vertical reaction frame 2, and the third 5×5 array static hydraulic actuator group also includes multiple through-type actuators for establishing a deep engineering test channel in the vertical direction.

[0046] The lifting cylinder 4 adopts proportional closed-loop displacement control technology. A high-precision displacement sensor is arranged between the cylinder rod and the cylinder sleeve of the lifting cylinder 4. The hydraulic chamber in the cylinder of the lifting cylinder 4 is connected to the accumulator through the throttle valve and the overflow valve in turn; an anti-fall lock is installed between the hollow column 19 and the sample-carrying lifting beam 3. The anti-fall lock includes an anti-fall high-strength rack and an anti-fall locking cylinder. The anti-fall high-strength rack is vertically fixed on the outer surface of the hollow column 19, and the anti-fall locking cylinder is horizontally fixed on the sample-carrying lifting beam 3. An anti-fall pad is installed at the end of the cylinder rod of the anti-fall locking cylinder, and the anti-fall pad is engaged and locked with the anti-fall high-strength rack.

[0047] Specifically, when the sample-carrying lifting beam 3 falls unexpectedly, the cylinder rod of the anti-fall locking cylinder extends quickly, so that the anti-fall pad at the end of the cylinder rod is quickly engaged with the anti-fall high-strength rack on the outer surface of the hollow column 19, and then the sample-carrying lifting beam 3 is locked through the engagement of the anti-fall pad and the anti-fall high-strength rack, preventing the sample-carrying lifting beam 3 from continuing to fall, thereby ensuring the safety of equipment and personnel.

[0048] A reaction support cushion beam inlet and outlet tunnel 24 is provided on the ground outside the inlet and outlet of the reaction support cushion beam 5 on the high-strength reinforced concrete support pier 8, and a heavy-load track is provided in the reaction support cushion beam inlet and outlet tunnel 24. The upper surface of the heavy-load track is flush with the upper surface of the bottom beam 18 of the vertical reaction frame 2; the reaction support cushion beam 5 adopts a servo motor as a driving actuator.

[0049] In this embodiment, the movement accuracy of the reaction force support beam 5 along the heavy-load track is ±2 mm.

[0050] A heavy-loaded RGV rail flat car 25 is arranged on the ground outside the inlet and outlet of the super-large physical model specimen 9 on the high-strength reinforced concrete support pier 8. The super-large physical model specimen 9 is converted to a working position by the heavy-loaded RGV rail flat car 25. The heavy-loaded RGV rail flat car 25 adopts a low-voltage rail power supply mode and a horizontal push-pull rigid chain method to move the super-large physical model specimen 9; when the specimen-carrying lifting beam 3 is in the lower limit position, the upper surface of the heavy-loaded RGV rail flat car 25 is flush with the upper surface of the specimen-carrying lifting beam 3; a friction-reducing support roller group is provided on the upper surface of the heavy-loaded RGV rail flat car 25.

[0051] In this embodiment, the heavy-duty RGV rail flat car 25 has a carrying capacity of 400t, which can meet the carrying and transportation requirements of a 5m-class super-large physical model specimen 9, and the position accuracy of travel, positioning, and parking is ±1mm.

[0052] A health monitoring sensor system is configured on the vertical reaction frame 2, the horizontal reaction frame 1 and the lifting cylinder 4. The health monitoring sensor system includes a composite deformation sensor 26 and a displacement-pressure-temperature sensor; a composite deformation sensor 26 is set at the upper end, middle end and lower end of each prestressed tie rod 20, and a total of twelve composite deformation sensors 26 are set on the four prestressed tie rods 20; a composite deformation sensor 26 is set at the upper end, middle end and lower end of the outer side of each hollow column 19, and a total of twelve composite deformation sensors 26 are set on the four hollow columns 19. Twelve composite deformation sensors 26 are provided; one composite deformation sensor 26 is provided on the inner side of the fan-shaped beam 10 and the fan-shaped perforated beam 11 of the horizontal reaction frame 1 and on the upper and lower ends of the T-shaped joint surface, and a total of thirty-two composite deformation sensors 26 on the horizontal reaction frame 1 are provided; the composite deformation sensors 26 are used to monitor the stress, strain, vibration and position information of the ultra-large bottom opening and closing three-dimensional loading device under the test state; the displacement-pressure-temperature sensor is installed on the lifting cylinder 4 to monitor the operating posture and stability of the lifting cylinder.

[0053] The test method using the ultra-large bottom opening and closing three-dimensional loading device includes the following steps:

[0054] Step 1: Synchronously start the four lifting cylinders 4 so that the cylinder rods of the four lifting cylinders 4 extend downward synchronously, driving the sample-carrying lifting beam 3 to descend at a uniform speed. At the same time, the operating posture and stability of the pistons of the lifting cylinders 4 and the sample-carrying lifting beam 3 are monitored in real time by the composite deformation sensor 26 and the displacement-pressure-temperature sensor until the sample-carrying lifting beam 3 falls to the upper surface of the bottom beam 18 of the vertical reaction frame 2. At this time, the sample-carrying lifting beam 3 is at the lower limit position.

[0055] Step 2: Use the heavy-duty RGV rail flat car 25 to transport the prepared super-large physical model specimen 9 to the super-large physical model specimen 9 entrance and exit of the high-strength reinforced concrete support pier 8, and then use a horizontal push-pull rigid chain to move the super-large physical model specimen 9 to the upper surface of the specimen-bearing lifting beam 3;

[0056] Step 3: Synchronously start the four lifting cylinders 4 again, so that the cylinder rods of the four lifting cylinders 4 are synchronously retracted, driving the specimen-carrying lifting beam 3 to rise at a uniform speed, and the super-large physical model specimen 9 rises synchronously with the specimen-carrying lifting beam 3. At the same time, the composite deformation sensor 26 and the displacement-pressure-temperature sensor are used to monitor the running posture and stability of the lifting cylinder 4 piston and the specimen-carrying lifting beam 3 in real time, and the anti-fall lock is used to ensure the safety of the installation of the super-large physical model specimen 9 in real time until the super-large physical model specimen 9 enters the center of the horizontal reaction frame 1. At this time, the specimen-carrying lifting beam 3 is at the upper limit position;

[0057] Step 4: Move the reaction support cushion beam 5 in the reaction support cushion beam access tunnel 24 from the heavy-load track to the upper surface of the bottom beam 18 of the vertical reaction frame 2, and then lower the specimen-carrying lifting beam 3 to eliminate the gap between the lower surface of the specimen-carrying lifting beam 3 and the reaction support cushion beam 5, so that the specimen-carrying lifting beam 3 and the reaction support cushion beam 5 are in full contact. At this time, the super-large physical model specimen 9 is completely enclosed inside the super-large bottom opening and closing three-dimensional loading device;

[0058] Step 5: Use the ultra-large bottom-opening and closing three-dimensional loading device to carry out a loading test on the ultra-large physical model specimen 9 inside. At the same time, the composite deformation sensor 26 and the displacement-pressure-temperature sensor are used to monitor the stress, strain, vibration, and position information of the vertical reaction frame 2, the horizontal reaction frame 1, and the lifting cylinder 4 in real time to ensure the healthy operation of the ultra-large bottom-opening and closing three-dimensional loading device.

[0059] Step 6: When the loading test is completed, first raise the sample-carrying lifting beam 3 to restore the gap between the lower surface of the sample-carrying lifting beam 3 and the reaction support pad beam 5, and then move the reaction support pad beam 5 from the upper surface of the bottom beam 18 of the vertical reaction frame 2 back to the heavy-load track in the reaction support pad beam entrance and exit tunnel 24, and then drive the sample-carrying lifting beam 3 down through the four lifting cylinders 4, so that the sample-carrying lifting beam 3 falls to the upper surface of the bottom beam 18 of the vertical reaction frame 2, and the super-large physical model sample 9 is synchronously lowered with the sample-carrying lifting beam 3, and then the super-large physical model sample 9 is moved back to the heavy-load RGV rail flat car 25, and finally the heavy-load RGV rail flat car 25 transports the super-large physical model sample 9 to the finished product area.

[0060] The solutions in the embodiments are not intended to limit the patent protection scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention is included in the patent scope of this case.

Claims

1. An ultra-large bottom-opening and closing three-dimensional loading device, characterized by: It includes a horizontal reaction frame, a vertical reaction frame, a specimen-carrying lifting beam, a lifting cylinder, a reaction support pad beam, an array actuator group and a linear dynamic actuator group; the horizontal reaction frame adopts a ring-shaped cantilever structure, and the horizontal reaction frame is installed on four high-strength reinforced concrete support piers. The height of the high-strength reinforced concrete support piers is higher than the height of the super-large physical model specimen, and the bottom of the high-strength reinforced concrete support piers is the same as the ground floor elevation; the vertical center axis of the vertical reaction frame coincides with the vertical center axis of the horizontal reaction frame, the lower end of the vertical reaction frame is partially located in the foundation pit, and the lower end of the vertical reaction frame is fixed to the bottom of the foundation pit by anchor bolts; the specimen-carrying lifting beam is installed on the vertical reaction frame In the middle and below the lower surface of the horizontal reaction frame, the specimen-carrying lifting beam is connected to the four corners of the top of the vertical reaction frame through four lifting cylinders; a set of array-type actuator groups is provided on the lower surface of the top of the vertical reaction frame; four sets of array-type actuator groups are evenly distributed along the circumference on the inner side of the horizontal reaction frame, and a through-type actuator is provided in one set of the array-type actuator groups, and a robot excavation entry and exit channel is provided on the horizontal reaction frame opposite to the through-hole of the through-type actuator; a set of linear dynamic actuator groups is provided on the upper part of the specimen-carrying lifting beam; the inlet and outlet of the super-large physical model specimen and the inlet and outlet of the reaction support beam are respectively provided at the opening of the high-strength reinforced concrete support pier below the horizontal reaction frame.

2. The ultra-large bottom opening and closing three-dimensional loading device according to claim 1, characterized in that: The horizontal reaction frame adopts a longitudinal multiple-group single-beam annular T-shaped joint assembly structure, and the horizontal reaction frame includes fan-shaped beams, fan-shaped perforated beams, arc-shaped bearing pads and a frame bearing base; the number of the fan-shaped perforated beams is four and they are evenly distributed along the circumference of the horizontal reaction frame, and the adjacent fan-shaped perforated beams are formed by chopping and combining the fan-shaped beams to form an annular assembly, and a double-layer steel wire winding layer is provided on the outside of the annular assembly; the joint contact surfaces of the fan-shaped beams and the fan-shaped perforated beams adopt a T-shaped bite self-limiting structure; on each fan-shaped perforated beam, A lifting cylinder passage hole is provided, and a frame bearing base is fixedly provided under each fan-shaped perforated beam, and the frame bearing base is connected to the high-strength reinforced concrete support pier through a high-load-bearing shock absorber; the number of the arc-shaped bearing pads is four and they are evenly distributed on the inside of the annular assembly, the outer arc of the arc-shaped bearing pads fits with the inner arc surface of the annular assembly, and the array actuator group is arranged on the inner plane of the arc-shaped bearing pads; the robot excavation entry and exit channel is located on one of the fan-shaped beams and the arc-shaped bearing pad directly opposite to it.

3. The ultra-large bottom-opening and closing three-dimensional loading device according to claim 2, characterized in that: The vertical reaction frame includes a top beam, a bottom beam, a hollow column and a prestressed tie rod; the prestressed tie rod adopts an integral forging structure; the top beam adopts a rectangular structure, and lifting cylinder barrel adapter ears are provided at the four corners of the top beam, and the cylinder barrel end of the lifting cylinder is fixedly connected to the lifting cylinder barrel adapter ears; the bottom beam adopts a rectangular structure, and the bottom beam is located directly below the top beam, and four hollow columns are provided between the bottom beam and the four corners of the top beam, and a prestressed tie rod is installed in each hollow column, and the top end of the prestressed tie rod is fixed to the top beam by a nut, and the bottom end of the prestressed tie rod is fixed to the bottom beam by a nut; the array actuator group is arranged on the lower surface of the top beam.

4. The ultra-large bottom-opening and closing three-dimensional loading device according to claim 3, characterized in that: The sample-carrying lifting beam adopts a rectangular structure, and lifting cylinder rod adapter ears are provided at the four corners of the sample-carrying lifting beam, and the cylinder rod end of the lifting cylinder is fixedly connected to the lifting cylinder rod adapter ears; a hollow column passing guide hole is provided on the inner side of the lifting cylinder rod adapter ear, and the hollow column passes through the hollow column passing guide hole; an actuator installation groove is provided in the middle of the sample-carrying lifting beam, and the linear dynamic actuator group is arranged inside the actuator installation groove, and the single actuator in the linear dynamic actuator group adopts dynamic disturbance Hydraulic actuator; a friction-reducing support roller group is provided on the upper surface of the specimen-carrying lifting beam; when the specimen-carrying lifting beam is located on the bottom beam of the vertical reaction frame, the ultra-large physical model specimen is transported to the specimen-carrying lifting beam by the heavy-duty RGV rail flat car using a horizontal push-pull rigid chain; after the specimen-carrying lifting beam carries the ultra-large physical model specimen, the specimen-carrying lifting beam is lifted by four lifting cylinders to the specimen loading station in the center of the horizontal reaction frame, completing the opening and closing action of the three-dimensional loading device of the ultra-large physical model specimen.

5. The ultra-large bottom-opening and closing three-dimensional loading device according to claim 4, characterized in that: The lifting cylinder adopts proportional closed-loop displacement control technology. A high-precision displacement sensor is arranged between the cylinder rod and the cylinder sleeve of the lifting cylinder. The hydraulic chamber in the cylinder of the lifting cylinder is connected to the accumulator through a throttle valve and a relief valve in sequence; an anti-fall locker is installed between the hollow column and the sample-carrying lifting beam. The anti-fall locker includes an anti-fall high-strength rack and an anti-fall locking cylinder. The anti-fall high-strength rack is vertically fixed on the outer surface of the hollow column, and the anti-fall locking cylinder is horizontally fixed on the sample-carrying lifting beam. An anti-fall pad is installed at the end of the cylinder rod of the anti-fall locking cylinder, and the anti-fall pad is engaged and locked with the anti-fall high-strength rack.

6. The ultra-large bottom-opening and closing three-dimensional loading device according to claim 5, characterized in that: A reaction support beam inlet and outlet tunnel is provided on the ground outside the inlet and outlet of the reaction support beam on the high-strength reinforced concrete support pier, and a heavy-load track is provided in the reaction support beam inlet and outlet tunnel. The upper surface of the heavy-load track is flush with the upper surface of the bottom beam of the vertical reaction frame; the reaction support beam adopts a servo motor as a driving actuator.

7. The ultra-large bottom-opening and closing three-dimensional loading device according to claim 6, characterized in that: A heavy-loaded RGV rail flat car is arranged on the ground outside the inlet and outlet of the super-large physical model specimen on the high-strength reinforced concrete support pier. The super-large physical model specimen is transferred to a working position by the heavy-loaded RGV rail flat car. The heavy-loaded RGV rail flat car adopts a low-voltage rail power supply mode and a horizontal push-pull rigid chain method to move the super-large physical model specimen. When the specimen-carrying lifting beam is at the lower limit position, the upper surface of the heavy-loaded RGV rail flat car is flush with the upper surface of the specimen-carrying lifting beam. A friction-reducing support roller group is provided on the upper surface of the heavy-loaded RGV rail flat car.

8. The ultra-large bottom-opening and closing three-dimensional loading device according to claim 7, characterized in that: A health monitoring sensor system is arranged on the vertical reaction frame, horizontal reaction frame and lifting cylinder, and the health monitoring sensor system includes a composite deformation sensor and a displacement-pressure-temperature sensor; a composite deformation sensor is arranged at the upper end, middle end and lower end of each prestressed tie rod, and a total of twelve composite deformation sensors are arranged on the four prestressed tie rods; a composite deformation sensor is arranged at the upper end, middle end and lower end of the outer side of each hollow column, and a total of twelve composite deformation sensors are arranged on the four hollow columns; a composite deformation sensor is arranged at the upper end and lower end of the fan-shaped beam, the inner side of the fan-shaped perforated beam and the upper end and lower end of the contact surface of the horizontal reaction frame, and the total number of composite deformation sensors on the horizontal reaction frame is thirty-two; the composite deformation sensor is used to monitor the stress, strain, vibration and position information of the super-large bottom opening and closing three-dimensional loading device under the test state; the displacement-pressure-temperature sensor is installed on the lifting cylinder to monitor the operating posture and stability of the lifting cylinder.

9. A test method using the ultra-large bottom-opening and closing three-dimensional loading device according to claim 8, characterized in that: The steps include: Step 1: Synchronously start the four lifting cylinders so that their rods extend downward synchronously, driving the specimen-carrying lifting beam to descend at a uniform speed. At the same time, the composite deformation sensor and displacement-pressure-temperature sensor are used to monitor the operating posture and stability of the lifting cylinder pistons and the specimen-carrying lifting beam in real time until the specimen-carrying lifting beam falls to the upper surface of the bottom beam of the vertical reaction frame. At this time, the specimen-carrying lifting beam is at the lower limit position. Step 2: Use a heavy-load RGV rail flat car to transport the prepared ultra-large physical model specimen to the ultra-large physical model specimen entrance and exit at the high-strength reinforced concrete support pier crotch. Then, use a rigid chain horizontal push-pull method to move the ultra-large physical model specimen to the upper surface of the specimen-bearing lifting beam. Step 3: Synchronously start the four lifting cylinders again, so that the cylinder rods of the four lifting cylinders retract synchronously, driving the specimen-carrying lifting beam to rise at a uniform speed. The super-large physical model specimen rises synchronously with the specimen-carrying lifting beam. At the same time, the composite deformation sensor and displacement-pressure-temperature sensor are used to monitor the operating posture and stability of the lifting cylinder piston and the specimen-carrying lifting beam in real time. The anti-fall locker is used to ensure the safety of the installation of the super-large physical model specimen in real time until the super-large physical model specimen enters the center of the horizontal reaction frame. At this time, the specimen-carrying lifting beam is at the upper limit position. Step 4: Move the reaction support beam in and out of the tunnel from the heavy-load track to the upper surface of the bottom beam of the vertical reaction frame, then lower the specimen-carrying lifting beam to eliminate the gap between the lower surface of the specimen-carrying lifting beam and the reaction support beam, so that the specimen-carrying lifting beam and the reaction support beam are in full contact. At this time, the super-large physical model specimen is completely enclosed inside the super-large bottom opening and closing three-dimensional loading device; Step 5: Use the ultra-large bottom-opening and closing three-dimensional loading device to carry out loading tests on the ultra-large physical model specimen inside. At the same time, composite deformation sensors and displacement-pressure-temperature sensors are used to monitor the stress, strain, vibration, and position information of the vertical reaction frame, horizontal reaction frame, and lifting cylinder in real time to ensure the healthy operation of the ultra-large bottom-opening and closing three-dimensional loading device. Step 6: When the loading test is completed, first raise the specimen-carrying lifting beam to restore the gap between the lower surface of the specimen-carrying lifting beam and the reaction support pad beam, then move the reaction support pad beam from the upper surface of the bottom beam of the vertical reaction frame back to the heavy-load track in the reaction support pad beam entry and exit tunnel, and then drive the specimen-carrying lifting beam down through four lifting cylinders to make the specimen-carrying lifting beam fall to the upper surface of the bottom beam of the vertical reaction frame. The super-large physical model specimen will be synchronously lowered with the specimen-carrying lifting beam, and then the super-large physical model specimen will be moved back to the heavy-load RGV rail flat car, and finally the heavy-load RGV rail flat car will transport the super-large physical model specimen to the finished product area.

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