Ultra-large bottom opening and closing type three-dimensional loading apparatus and test method

1 . An ultra-large bottom opening and closing type three-dimensional loading apparatus, comprising: a horizontal reaction frame, a vertical reaction frame, a sample bearing lifting walking beam, four lifting cylinders, a reaction support pad beam, array type actuator groups, and a linear array dynamic actuator group, wherein the horizontal reaction frame adopts a ring scarf structure, and is mounted on four high-strength reinforced concrete support piers; a height of each high-strength reinforced concrete support pier is higher than that of an ultra-large physical model sample, and a bottom of the high-strength reinforced concrete support pier is the same in elevation as a ground floor; a vertical central axis of the vertical reaction frame coincides with that of the horizontal reaction frame, a lower end of the vertical reaction frame is locally located in a foundation pit, and the lower end of the vertical reaction frame is fixed to a bottom of the foundation pit through anchor bolts; the sample bearing lifting walking beam is mounted at a middle of the vertical reaction frame and located below a lower surface of the horizontal reaction frame; the sample bearing lifting walking beam is connected to four corners at a top of the vertical reaction frame through the four lifting cylinders; one array type actuator group is arranged on a lower surface of the top of the vertical reaction frame; four array type actuator groups are uniformly distributed on an inner side of the horizontal reaction frame along a circumference direction; a through type actuator is arranged in one of the four array type actuator groups, and a robot excavation entering and exiting channel is disposed in the horizontal reaction frame directly opposite to a through hole of the through type actuator; one linear array dynamic actuator group is arranged at an upper part of the sample bearing lifting walking beam; and an entering and exiting opening for the ultra-large physical model sample and an entering and exiting opening for the reaction support pad beam are respectively formed in a crotch part between the high-strength reinforced concrete support piers below the horizontal reaction frame.

2 . The ultra-large bottom opening and closing type three-dimensional loading apparatus according to claim 1 , wherein the horizontal reaction frame adopts a longitudinal multi-group single-beam circumferential T-shaped scarf assembly structure, and comprises fan-shaped beams, four fan-shaped perforated beams, four arc-shaped support beams, and a frame bearing base; the four fan-shaped perforated beams are uniformly distributed along the circumference direction of the horizontal reaction frame, the fan-shaped beams are scarfed between two adjacent fan-shaped perforated beams to form a ring assembly body, and a double-layer steel wire winding layer is arranged on an outer side of the ring assembly body; scarf contact surfaces of the fan-shaped beams and the fan-shaped perforated beams all adopt a T-shaped engaging self-limiting structure; a lifting cylinder through hole is formed in each fan-shaped perforated beam, the frame bearing base is fixedly arranged below each fan-shaped perforated beam, and the frame bearing base is connected to the high-strength reinforced concrete support pier through a high-bearing shock absorber; the four arc-shaped support beams are uniformly distributed on an inner side of the ring assembly body, an outer side arc surface of each arc-shaped support beam is in contact with an inner side arc surface of the ring assembly body, and one of the array type actuator groups is arranged on an inner side plane of the arc-shaped support beam; and the robot excavation entering and exiting channel is located on one fan-shaped beam and the arc-shaped support beam directly opposite to the one fan-shaped beam.

3 . The ultra-large bottom opening and closing type three-dimensional loading apparatus according to claim 2 , wherein the vertical reaction frame comprises a top beam, bottom beam, and four pre-stressed tension rods; the pre-stressed tension rods adopt an integral forging structure; the top beam adopts a rectangular structure, and adapter ears of cylinder barrels of the lifting cylinders are arranged at four corners of the top beam; ends of the cylinder barrels of the lifting cylinders are fixedly connected to the adapter ears of the cylinder barrels of the lifting cylinders; the bottom beam adopts a rectangular structure, and is located directly below the top beam; four hollow stand columns are arranged between four corners of the bottom beam and the four corners of the top beam, and one pre-stressed tension rod is mounted in each hollow stand column; a top end of each pre-stressed tension rod is fixed to the top beam through first nuts, and a bottom end of each pre-stressed tension rod is fixed to the bottom beam through second nuts; and one of the array type actuator groups is arranged on a lower surface of the top beam.

4 . The ultra-large bottom opening and closing type three-dimensional loading apparatus according to claim 3 , wherein the sample bearing lifting walking beam adopts a rectangular structure, and adapter ears of cylinder rods of the lifting cylinders are arranged at four corners of the sample bearing lifting walking beam; ends of the cylinder rods of the lifting cylinders are fixedly connected to the adapter ears of the cylinder rods of the lifting cylinders; a hollow stand column through guide hole is formed in an inner side of each adapter ear of the cylinder rod of the lifting cylinder, and each hollow stand column penetrates through each hollow stand column through guide hole; an actuator mounting groove is formed in a middle of the sample bearing lifting walking beam, the linear array dynamic actuator group is arranged in the actuator mounting groove, and a single actuator in the linear array dynamic actuator group adopts a dynamic disturbance hydraulic actuator; a friction reducing support roller group is arranged on an upper surface of the sample bearing lifting walking beam; when the sample bearing lifting walking beam is located on the bottom beam of the vertical reaction frame, the ultra-large physical model sample is delivered to the sample bearing lifting walking beam in a manner of horizontal push-pull rigid chain through a heavy-load RGV track flatcar; and after the sample bearing lifting walking beam bears the ultra-large physical model sample, the sample bearing lifting walking beam is lifted to a sample loading station in a center of the horizontal reaction frame by the four lifting cylinders, to complete opening and closing type action of the three-dimensional loading apparatus for the ultra-large physical model sample.

5 . The ultra-large bottom opening and closing type three-dimensional loading apparatus according to claim 4 , wherein each lifting cylinder adopts a proportional closed-loop displacement control technology, and a high-precision displacement sensor is arranged between the cylinder rod and the cylinder barrel of each lifting cylinder; a hydraulic chamber inside each lifting cylinder is connected to an accumulator through a throttle valve and an overflow valve sequentially; and an anti-falling locking device is mounted between each hollow stand column, and the sample bearing lifting walking beam, and comprises an anti-falling high-strength rack and an anti-falling locking cylinder, the anti-falling high-strength rack is vertically and fixedly arranged on an outer surface of each hollow stand column, the anti-falling locking cylinder is horizontally and fixedly arranged on the sample bearing lifting walking beam, an anti-falling pad is mounted at an end of a cylinder rod of the anti-falling locking cylinder, and the anti-falling pad and the anti-falling high-strength rack are in engaged and locked cooperation.

6 . The ultra-large bottom opening and closing type three-dimensional loading apparatus according to claim 5 , wherein a reaction support pad beam entering and exiting tunnel is arranged on a ground of an outer side of the entering and exiting opening for the reaction support pad beam in the high-strength reinforced concrete support pier, a heavy-load track is arranged in the reaction support pad beam entering and exiting tunnel, and an upper surface of the heavy-load track is flush with an upper surface of the bottom beam of the vertical reaction frame; and the reaction support pad beam adopts a servo motor as a driving actuator.

7 . The ultra-large bottom opening and closing type three-dimensional loading apparatus according to claim 6 , wherein the heavy-load RGV track flatcar is arranged on a ground of an outer side of the entering and exiting opening for the ultra-large physical model sample in the high-strength reinforced concrete support pier, the ultra-large physical model sample proceeds with a station conversion through the heavy-load RGV track flatcar, the heavy-load RGV track flatcar adopts a low-voltage track power supply mode, and the heavy-load RGV track flatcar adopts the manner of horizontal push-pull rigid chain to move the ultra-large physical model sample; when the sample bearing lifting walking beam is located in a lower limit position, an upper surface of the heavy-load RGV track flatcar is flush with the upper surface of the sample bearing lifting walking beam; and a friction reducing support roller group is arranged on the upper surface of the heavy-load RGV track flatcar.

8 . The ultra-large bottom opening and closing type three-dimensional loading apparatus according to claim 7 , wherein a health monitoring sensor system is arranged on the vertical reaction frame, the horizontal reaction frame, and the lifting cylinders, and comprises composite deformation sensors and displacement-pressure-temperature sensors; the composite deformation sensors are respectively arranged at an upper end, a middle, and a lower end of each pre-stressed tension rod, and twelve composite deformation sensors in total are arranged on the four pre-stressed tension rods; the composite deformation sensors are respectively arranged at an upper end, a middle, and a lower end of an outer side of each hollow stand column, and twelve composite deformation sensors in total are arranged on the four hollow stand columns; the composite deformation sensors are respectively arranged on an inner side of the fan-shaped beams and the fan-shaped perforated beams of the horizontal reaction frame, as well as an upper end and a lower end of the scarf contact surfaces, and thirty-two composite deformation sensors in total are arranged on the horizontal reaction frame; stress-strain information, vibration information, and position information of the ultra-large bottom opening and closing type three-dimensional loading apparatus in testing operation are monitored by using the composite deformation sensors; and the displacement-pressure-temperature sensors are mounted on each lifting cylinder to monitor operating posture and stability of the lifting cylinders.

9 . A test method adopting the ultra-large bottom opening and closing type three-dimensional loading apparatus according to claim 8 , comprising the following steps:

Step I: starting the four lifting cylinders synchronously, to enable the cylinder rods of the four lifting cylinders to extend downwards synchronously to drive the sample bearing lifting walking beam to descend at a uniform speed, and monitoring the operating posture and stability of a piston of the lifting cylinders and the sample bearing lifting walking beam in real time by the composite deformation sensors and the displacement-pressure-temperature sensors, until the sample bearing lifting walking beam falls to the upper surface of the bottom beam of the vertical reaction frame, wherein at this time, the sample bearing lifting walking beam is in the lower limit position;

Step II: transporting a prepared ultra-large physical model sample to the entering and exiting opening for the ultra-large physical model sample in the crotch part between the high-strength reinforced concrete support piers by the heavy-load RGV track flatcar, and then moving the ultra-large physical model sample to the upper surface of the sample bearing lifting walking beam in the manner of horizontal push-pull rigid chain;

Step III: starting the four lifting cylinders once again, to enable the cylinder rods of the four lifting cylinders to retract synchronously to drive the sample bearing lifting walking beam to ascend at a uniform speed, wherein the ultra-large physical model sample ascends synchronously along with the sample bearing lifting walking beam, monitoring the operating posture and stability of the piston of each lifting cylinder and the sample bearing lifting walking beam in real time by the composite deformation sensors and the displacement-pressure-temperature sensors, and ensuring mounting safety of the ultra-large physical model sample in real time by the anti-falling locking device, until the ultra-large physical model sample enters the center of the horizontal reaction frame, wherein at this time, the sample bearing lifting walking beam is in an upper limit position;

Step IV: moving the reaction support pad beam in the reaction support pad beam entering and exiting tunnel to the upper surface of the bottom beam of the vertical reaction frame from the heavy-load track, then lowering the sample bearing lifting walking beam, and eliminating a gap between a lower surface of the sample bearing lifting walking beam and the reaction support pad beam to enable the sample bearing lifting walking beam to be in full contact with the reaction support pad beam, so that at this time, the ultra-large physical model sample is fully sealed in the ultra-large bottom opening and closing type three-dimensional loading apparatus;

Step V: performing a loading test on the ultra-large physical model sample therein by the ultra-large bottom opening and closing type three-dimensional loading apparatus, and monitoring the stress-strain information, the vibration information and the position information of the vertical reaction frame, the horizontal reaction frame and each lifting cylinder in real time by the composite deformation sensors and the displacement-pressure-temperature sensors, so that the ultra-large bottom opening and closing type three-dimensional loading apparatus operates healthily; and

Step VI: after the loading test is completed, firstly raising the sample bearing lifting walking beam, recovering the gap between the lower surface of the sample bearing lifting walking beam and the reaction support pad beam, then moving the reaction support pad beam to the heavy-load track in the reaction support pad beam entering and exiting tunnel from the upper surface of the bottom beam of the vertical reaction frame, then driving the sample bearing lifting walking beam to descend by the four lifting cylinders, so that the sample bearing lifting walking beam falls to the upper surface of the bottom beam of the vertical reaction frame, the ultra-large physical model sample descends synchronously along with the sample bearing lifting walking beam, then the ultra-large physical model sample is moved to the heavy-load RGV track flatcar, and finally, the ultra-large physical model sample is transported to a finished product region by the heavy-load RGV track flatcar.