Pile group loading test device and method for simulating high-speed rail bridge operation load
阅读说明：本技术 模拟高铁桥梁运营荷载的群桩加载试验装置及方法 (Pile group loading test device and method for simulating high-speed rail bridge operation load ) 是由 陈耀春 王新国 吴文兵 姚赵田 余兴胜 李波 柏华军 秦寰宇 于 2019-10-25 设计创作，主要内容包括：本发明提供了一种模拟高铁桥梁运营荷载的群桩加载试验装置及方法,该装置包括模型组件、加载系统、控制系统以及数据采集系统；模型组件包括模型箱、承台以及多个模型桩,承台设置于模型箱中,模型桩固定在承台下方且下部通过试验土样埋置于模型箱中；加载系统包括水平反力架和伺服电动缸,伺服电动缸固定在水平反力架上；控制系统包括PLC控制器、伺服驱动器以及上位机PC,上位机PC用于对PLC控制器进行编程,伺服驱动器用于根据PLC控制器的相关指令控制伺服电动缸对所述承台施加相应的荷载；数据采集系统包括位移传感器、应变片以及应变仪,位移传感器安装在承台上,应变片布置在各模型桩内部。本发明制作较为简单、加载方便、准确性高,可控范围较广。(The invention provides a grouped pile loading test device and a method for simulating high-speed rail bridge operation load, wherein the device comprises a model assembly, a loading system, a control system and a data acquisition system; the model assembly comprises a model box, a bearing platform and a plurality of model piles, wherein the bearing platform is arranged in the model box, the model piles are fixed below the bearing platform, and the lower parts of the model piles are embedded in the model box through test soil samples; the loading system comprises a horizontal reaction frame and a servo electric cylinder, and the servo electric cylinder is fixed on the horizontal reaction frame; the control system comprises a PLC (programmable logic controller), a servo driver and an upper computer PC (personal computer), wherein the upper computer PC is used for programming the PLC, and the servo driver is used for controlling the servo electric cylinder to apply corresponding load to the bearing platform according to related instructions of the PLC; the data acquisition system comprises a displacement sensor, strain gauges and strain gauges, wherein the displacement sensor is installed on the bearing platform, and the strain gauges are arranged inside each model pile. The invention has the advantages of simple manufacture, convenient loading, high accuracy and wider controllable range.)
1. The utility model provides a pile group loading test device of simulation high-speed railway bridge operation load which characterized in that: the system comprises a model component, a loading system, a control system and a data acquisition system;
the model assembly comprises a model box, a bearing platform and a plurality of model piles, wherein the bearing platform is arranged in the model box, the model piles are fixed below the bearing platform, and the lower parts of the model piles are embedded in the model box through test soil samples;
the loading system comprises a horizontal reaction frame and a servo electric cylinder, the horizontal reaction frame is installed at the top end of the model box, the servo electric cylinder is fixed on the horizontal reaction frame, and the front end of a piston rod of the servo electric cylinder is abutted against the upper surface of the bearing platform;
the control system comprises a PLC (programmable logic controller), a servo driver and an upper computer PC (personal computer), wherein the upper computer PC is electrically connected with the PLC, the PLC is electrically connected with the servo driver, the servo driver is electrically connected with the servo electric cylinder, the upper computer PC is used for programming the PLC to input different superposed waveforms and frequencies of static waves and sine waves for simulating the operation load of the high-speed railway bridge, and the servo driver is used for controlling the servo electric cylinder to apply corresponding load to the bearing platform according to related instructions of the PLC;
the data acquisition system comprises a displacement sensor, strain gauges and strain gauges, wherein the displacement sensor is installed on the bearing platform, the strain gauges are multiple and are arranged inside each model pile, the displacement sensor and each strain gauge are connected with the strain gauges, and the strain gauges are connected with a data processing computer.
2. The pile group loading test device for simulating the operation load of the high-speed railway bridge according to claim 1, characterized in that: still including set up in servo electronic jar the piston rod and pressure sensor between the cushion cap, pressure sensor with servo driver electricity is connected, pressure sensor is used for measuring the actual load signal that receives of cushion cap and feeds back to servo driver, servo driver is used for the basis the signal regulation servo electronic jar that pressure sensor feedbacks applies the load for the cushion cap.
3. The pile group loading test device for simulating the operation load of the high-speed railway bridge according to claim 1, characterized in that: the horizontal reaction frame is detachably connected with the model box.
4. The pile group loading test device for simulating the operation load of the high-speed railway bridge according to claim 1, characterized in that: the pressure sensor is fixed at the front end of a piston rod of the servo electric cylinder or fixed on the upper surface of the bearing platform and vertically contacted with the piston rod of the servo electric cylinder.
5. The pile group loading test device for simulating the operation load of the high-speed railway bridge according to claim 1, characterized in that: the model pile is a hollow metal pipe, the strain gauge is adhered to the inner wall of the model pile, and a round hole for the lead of the strain gauge to penetrate out is formed in the upper portion of the model pile.
6. The pile group loading test device for simulating the operation load of the high-speed railway bridge according to claim 5, wherein: the model pile comprises two semicircular piles, opposite fixing holes are formed in the tops and the bottoms of the two semicircular piles, and the two semicircular piles are connected and closed through bolts penetrating through the two opposite fixing holes.
7. The pile group loading test device for simulating the operation load of the high-speed railway bridge according to claim 1, characterized in that: and silica gel is coated on the surface of the strain gauge.
8. A loading test method of the pile group loading test device for simulating the operation load of the high-speed railway bridge according to any one of claims 1 to 7, characterized by comprising the following steps:
(1) programming the PLC through an upper computer PC according to the vibration characteristics of the actual high-speed rail bridge operation load so as to input the superposed waveform and frequency of the static wave and the sine wave for simulating the high-speed rail bridge operation load;
(2) the servo driver receives a related instruction of the PLC and drives the servo electric cylinder to apply load to the bearing platform;
(3) the pressure sensor feeds back a measured load signal actually received by the bearing platform to the servo driver, and the servo driver adjusts the load applied to the bearing platform by the servo electric cylinder according to the fed back signal;
(4) in the loading test process, the displacement sensor, the strain gauge and the strain gauge acquire corresponding data in real time and transmit the data to the data processing computer.
9. The loading test method of the pile group loading test device for simulating the operation load of the high-speed railway bridge, according to claim 8, is characterized in that: in the step (1), the vibration characteristics of the actual high-speed railway bridge operation load are simulated by adopting an exciting force function formed by superposing static waves and three groups of dynamic sine waves, and the function form is as follows:
wherein F (t) is the actual operation load of the high-speed rail bridge, POIs the dead weight of the bridge superstructure, P1、P2、P3Vibration amplitudes, omega, of three groups of sine waves, respectively1、ω2、ω3The vibration frequencies of three groups of sine waves are respectively.
10. The loading test method of the pile group loading test device for simulating the operation load of the high-speed railway bridge, according to claim 8, is characterized in that: and the loading amount, the holding time and the switch of the loading device are artificially controlled in the PC.
Technical Field
The invention relates to the technical field of model tests of pile foundation engineering, in particular to a pile group loading test device and method for simulating high-speed railway bridge operation load.
Background
With the rapid development of the high-speed railway technology in China in recent years, in order to provide guarantee for the stable and high-speed operation of high-speed trains, the proportion of high-speed railway bridges is 50-60%. Most of newly-built high-speed railway bridges adopt pile group foundations, and because the high-speed railway has high requirements on the bearing characteristics of the foundations, the problem that how to ensure the stability of the pile group foundations when high-speed trains pass is a great concern in the engineering field. The high-speed railway bridge group pile foundation not only bears the self-weight of an upper structure, but also bears the dynamic load of a vehicle, and the dynamic load of a train is obviously different from the dynamic load and the earthquake load of a common power machine foundation, so that the research on the dynamic characteristic of the bridge group pile foundation under the action of the operation load of a high-speed railway becomes necessary. At the present stage, an indoor model test is one of important means for researching dynamic characteristics of a bridge pile group foundation, however, the existing related model test loading device can only apply simple dynamic variation load, and cannot truly and effectively simulate the actual vibration characteristics of the high-speed railway operation load. Therefore, the research of the pile group loading device capable of truly and effectively simulating the operation load of the high-speed railway bridge has very important significance.
Disclosure of Invention
The invention aims to provide a pile group loading test device and method capable of truly simulating the operation load of a high-speed railway bridge.
The invention is realized by the following steps:
on one hand, the invention provides a pile group loading test device for simulating the operation load of a high-speed railway bridge, which comprises a model assembly, a loading system, a control system and a data acquisition system;
the model assembly comprises a model box, a bearing platform and a plurality of model piles, wherein the bearing platform is arranged in the model box, the model piles are fixed below the bearing platform, and the lower parts of the model piles are embedded in the model box through test soil samples;
the loading system comprises a horizontal reaction frame and a servo electric cylinder, the horizontal reaction frame is installed at the top end of the model box, the servo electric cylinder is fixed on the horizontal reaction frame, and the front end of a piston rod of the servo electric cylinder is abutted against the upper surface of the bearing platform;
the control system comprises a PLC (programmable logic controller), a servo driver and an upper computer PC (personal computer), wherein the upper computer PC is electrically connected with the PLC, the PLC is electrically connected with the servo driver, the servo driver is electrically connected with the servo electric cylinder, the upper computer PC is used for programming the PLC to input different superposed waveforms and frequencies of static waves and sine waves for simulating the operation load of the high-speed railway bridge, and the servo driver is used for controlling the servo electric cylinder to apply corresponding load to the bearing platform according to related instructions of the PLC;
the data acquisition system comprises a displacement sensor, strain gauges and strain gauges, wherein the displacement sensor is installed on the bearing platform, the strain gauges are multiple and are arranged inside each model pile, the displacement sensor and each strain gauge are connected with the strain gauges, and the strain gauges are connected with a data processing computer.
The servo electric cylinder is arranged on the bearing platform, the servo driver is used for feeding back a load signal actually received by the bearing platform, and the servo driver is used for adjusting the load applied to the bearing platform by the servo electric cylinder according to the signal fed back by the pressure sensor.
Further, the horizontal reaction frame is detachably connected with the model box.
Further, the pressure sensor is fixed at the front end of a piston rod of the servo electric cylinder or fixed on the upper surface of the bearing platform and vertically contacted with the piston rod of the servo electric cylinder.
Furthermore, the model pile is a hollow metal pipe, the strain gauge is pasted on the inner wall of the model pile, and a round hole for the lead of the strain gauge to penetrate out is formed in the upper portion of the model pile.
Furthermore, the model pile comprises two semicircular piles, opposite fixing holes are formed in the tops and the bottoms of the two semicircular piles, and the two semicircular piles are connected and closed through bolts penetrating through the two opposite fixing holes.
Further, the surface of the strain gauge is coated with silica gel.
On the other hand, the invention also provides a loading test method of the pile group loading test device for simulating the operation load of the high-speed railway bridge, which comprises the following steps:
(1) programming the PLC through an upper computer PC according to the vibration characteristics of the actual high-speed rail bridge operation load so as to input the superposed waveform and frequency of the static wave and the sine wave for simulating the high-speed rail bridge operation load;
(2) the servo driver receives a related instruction of the PLC and drives the servo electric cylinder to apply load to the bearing platform;
(3) the pressure sensor feeds back a measured load signal actually received by the bearing platform to the servo driver, and the servo driver adjusts the load applied to the bearing platform by the servo electric cylinder according to the fed back signal;
(4) in the loading test process, the displacement sensor, the strain gauge and the strain gauge acquire corresponding data in real time and transmit the data to the data processing computer.
Further, in the step (1), an excitation force function obtained by superposing a static wave and three groups of dynamic sine waves is adopted to simulate the vibration characteristics of the actual high-speed rail bridge operation load, and the function form is as follows:
wherein F (t) is the actual operation load of the high-speed rail bridge, POIs the dead weight of the bridge superstructure, P1、P2、P3Vibration amplitudes, omega, of three groups of sine waves, respectively1、ω2、ω3The vibration frequencies of three groups of sine waves are respectively.
Further, the loading amount, the holding time and the on-off of the loading device are artificially controlled in the PC.
Compared with the prior art, the invention has the following beneficial effects:
the pile group loading test device and the method for simulating the operation load of the high-speed railway bridge have the advantages that the device is simple to manufacture, convenient to load and high in accuracy, meanwhile, different programming processing can be carried out on a PLC through an upper computer PC according to different actual test requirements, various dynamic loads with different vibration amplitudes and vibration frequencies are input, and the controllable range is wide; according to the device, the strain gauge is pasted in the pile body, so that the strain gauge can be better protected, the pasting success rate can be improved, and the measured axial force data is more accurate; the vibration characteristic of the actual operation load of the high-speed railway is simulated by adopting the excitation force function of superposition of the static waves and the three groups of dynamic sine waves, so that the stress characteristic of the high-speed railway bridge pile foundation under the actual operation load can be simulated more truly.
Drawings
Fig. 1 is a front view of a pile group loading test device for simulating operation load of a high-speed railway bridge according to an embodiment of the present invention;
fig. 2 is a top view of a pile group loading test device for simulating operation load of a high-speed railway bridge according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an arrangement of strain gauges according to an embodiment of the present invention.
Description of reference numerals: 1. a servo electric cylinder; 2. a horizontal reaction frame; 3. a vertical reaction frame; 4. a displacement sensor; 5. a bearing platform; 6. a model pile; 7. a model box; 8. a pressure sensor; 9. a servo driver; 10. a PLC controller; 11. a strain gauge; 12. an upper computer PC; 13. a strain gauge; 14. a fixing hole; 15. a circular hole.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1 to 3, an embodiment of the present invention provides a pile group loading test apparatus for simulating an operation load of a high-speed railway bridge, including a model component, a loading system, a control system, and a data acquisition system.
The model assembly comprises a model box 7, a bearing platform 5 and a plurality of model piles 6, wherein the model box 7 is of a cuboid box type structure formed by welding steel plates and section steel, the bearing platform 5 is arranged in the middle position of the upper portion of the model box 7, the model piles 6 are fixed below the bearing platform 5 through bolts, the lower portions of the model piles are embedded in the model box 7 through test soil samples, and the number of the model piles 6 is determined according to a simulated pile group design scheme.
The loading system comprises a horizontal reaction frame 2 and a servo electric cylinder 1, wherein the horizontal reaction frame 2 is installed at the top end of a model box 7, preferably, the horizontal reaction frame 2 is detachably connected with the model box 7 and specifically comprises a vertical reaction frame 3 arranged on the periphery of the model box 7, the horizontal reaction frame 2 is fastened on the upper portion of the vertical reaction frame 3 through bolts, the horizontal reaction frame 2 is of a rectangular steel frame structure, and the horizontal reaction frame 2 can be detached through detaching the bolts on the horizontal reaction frame 2, so that a model pile 6 is conveniently buried and filled with soil. The servo electric cylinder 1 is fixed on the horizontal reaction frame 2 through a bolt, the front end of a piston rod of the servo electric cylinder 1 is abutted to the upper surface of the bearing platform 5, and vertical load can be applied to a pile group foundation formed by the bearing platform 5 and the model pile 6 through a front section piston rod of the telescopic servo electric cylinder 1.
The control system comprises a PLC (programmable logic controller) 10, a servo driver 9 and an upper PC 12, wherein the upper PC 12 is electrically connected with the PLC 10, the PLC 10 is electrically connected with the servo driver 9, the servo driver 9 is electrically connected with the servo electric cylinder 1, the upper PC 12 is used for programming the PLC 10 to input different static waves and sine waves superposed waveforms and frequencies for simulating the operation load of a high-speed railway bridge, the servo driver 9 is used for controlling the servo electric cylinder 1 according to related instructions of the PLC 10 to apply corresponding load to the bearing platform 5, and meanwhile, the output thrust value and the advancing distance of a front end piston rod of the servo electric cylinder 1 can be detected and fed back to the upper PC 12. Meanwhile, the PLC controller 10 uses the upper PC 12 as an upper control unit, and the upper PC 12 can manually control options such as loading amount, holding time, and a switch of a loading device.
The data acquisition system comprises a displacement sensor 4, strain gauges 13 and strain gauges 11, the displacement sensor 4 is installed on the bearing platform 5 and used for measuring the displacement of the pile top of the model pile 6 under the dynamic load, the strain gauges 13 are provided with a plurality of strain gauges and arranged inside the model pile 6 and used for measuring the axial force distribution of the pile body of the model pile 6 under the vertical dynamic load, the displacement sensor 4 and the strain gauges 13 are connected with the strain gauges 11, the strain gauges 11 are connected with a data processing computer and used for transmitting acquired data to the data processing computer for storage and checking, and particularly, the data processing computer can directly adopt the upper computer PC 12.
The pile group loading test device and the method for simulating the operation load of the high-speed railway bridge, provided by the embodiment of the invention, have the advantages of simple manufacture, convenience in loading and high accuracy, and meanwhile, different programming processing can be carried out on the PLC through the PC according to different actual test requirements, various dynamic loads with different vibration amplitudes and vibration frequencies can be input, and the controllable range is wider.
As a preferable mode of the above embodiment, the servo device further includes a pressure sensor 8 disposed between the piston rod of the servo electric cylinder 1 and the platform 5, specifically, the pressure sensor 8 is fixed to a front end of the piston rod of the servo electric cylinder 1 or fixed to an upper surface of the platform 5 and vertically contacts with the piston rod of the servo electric cylinder 1, the pressure sensor 8 is electrically connected to the servo driver 9, the pressure sensor 8 is configured to measure a load signal actually received by the platform 5 and feed back the load signal to the servo driver 9, and the servo driver 9 is configured to servo a load applied to the platform by the electric cylinder 1 according to a signal fed back by the pressure sensor 8 so as to ensure loading accuracy.
In order to better protect the strain gauge 13 and improve the success rate of the mounting, the device selects to paste the strain gauge 13 inside the model pile 6. Specifically, model pile 6 is hollow tubular metal resonator, specifically can be aluminium alloy pipe or steel pipe, foil gage 13 paste in on the inner wall of model pile 6, the upper portion of model pile 6 is provided with and is used for the confession two relative round holes 15 that the wire of foil gage 13 wore out make things convenient for drawing forth of wire. Further preferably, the model pile 6 comprises two semicircular piles, opposite fixing holes 14 are formed at certain positions of the top and the bottom of the two semicircular piles, and the two semicircular piles are connected and closed through bolts penetrating through the opposite fixing holes 14. Specifically, firstly, the model pile 6 is cut into two semicircular piles along the central line by laser, then the strain gauges 13 are symmetrically adhered to the inner walls of the two semicircular piles by AB glue, silica gel is coated on the surfaces of the strain gauges 13 for strain moisture protection and protection treatment, a lead is punched from a round hole 15 at the upper end of the model pile 6 after the strain gauges 13 are adhered, and finally the two semicircular piles are closed by bolts and nuts penetrating through fixing holes 14.
The embodiment of the invention also provides a loading test method of the pile group loading test device for simulating the operation load of the high-speed railway bridge, which comprises the following steps:
(1) programming the PLC 10 through an upper computer PC 12 according to the vibration characteristics of the actual high-speed rail bridge operation load so as to input the superposed waveform and frequency of static waves and sine waves for simulating the high-speed rail bridge operation load;
(2) the servo driver 9 receives the relevant instructions of the PLC 10 and drives the servo electric cylinder 1 to apply load to the bearing platform 5;
(3) the pressure sensor 8 feeds back the measured load signal actually received by the bearing platform 5 to the servo driver 9, and the servo driver 9 adjusts the load applied to the bearing platform 5 by the servo electric cylinder 1 according to the fed-back signal;
(4) in the loading test process, the displacement sensor 4, the strain gauge 13 and the strain gauge 11 acquire corresponding data in real time and transmit the data to the data processing computer.
Preferably, in the step (1), an excitation force function obtained by superimposing a static wave and three groups of dynamic sine waves is adopted to simulate the vibration characteristics of the actual high-speed railway bridge operating load, and the function form is as follows:
wherein F (t) is the actual operation load of the high-speed rail bridge, POIs the dead weight of the bridge superstructure, P1、P2、P3Vibration amplitudes, omega, of three groups of sine waves, respectively1、ω2、ω3The vibration frequencies of three groups of sine waves are respectively.
The vibration characteristic of the actual operation load of the high-speed railway is simulated by adopting the excitation force function of superposing the static waves and the three groups of dynamic sine waves, so that the stress characteristic of the high-speed railway bridge pile foundation under the actual operation load can be simulated more truly.
Furthermore, options such as load capacity, holding time, and a switch of a loading device are artificially controlled in the upper computer PC 12, so that the control precision is improved.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.