Monitoring device for simulating vertical vibration of single pile under earthquake P wave

Abstract

The invention discloses a monitoring device for simulating vertical vibration of a single pile under earthquake P waves. The device belongs to the field of pile foundation engineering research in the civil engineering field, and comprises a model box, a pulley base, a vertical impact device, a spring, a laser displacement meter, an acceleration sensor, a stress strain gauge, a data transmission line, a data acquisition instrument, a computer host and a computer display which are connected with one another, according to the method, images of displacement, acceleration and stress-strain relation change after the pile is subjected to vertical impact force are more clearly presented through numerical control; the device is simple and easy to operate, vertical vibration simulation of the pile is simpler and more convenient, and vertical vibration of the pile in various environments can be simulated; in addition, by measuring the displacement change and acceleration change of the pile, the process that the pile is subjected to vertical impact load under the P wave is simulated more accurately.

Description

Technical Field

[0001] The invention belongs to the technical field of pile foundation engineering in the field of civil engineering, and relates to a monitoring device for simulating the vertical vibration of a single pile under earthquake P waves. Background Art

[0002] With the rapid development of engineering construction, the demand for pile foundation projects with large bearing capacity and high stability is increasing. As an important foundation form, pile foundation is widely used in bridges, high-rise buildings, ports, roads and other projects. Ensuring the stability and safety of pile foundation is the key to engineering design and construction. Under the action of earthquakes, pile foundations will be affected by vertical vibrations, which puts higher requirements on the design and construction of pile foundations. Simulating the vertical vibration characteristics of piles under earthquake P waves will help improve the seismic performance of the project.

[0003] Model tests are often used to study the bearing characteristics of piles, which can better reflect the bearing characteristics of piles. Due to the limitations of vertical loading equipment conditions and the complexity of the vertical vibration response analysis of piles, there are few monitoring tests on the vertical vibration of single piles under earthquake P waves. At present, most of the research on piles remains at the level of short-term static loads, and many engineering problems need to be solved urgently. There are few loading devices under vertical vibration loads, and the loading devices are relatively complex, difficult to operate, and easily affected by external factors;

[0004] Generally speaking, the disadvantages of the existing technology are high cost, low efficiency and long time consumption. The specific reasons are: (1) the monitoring device for simulating the vertical vibration of a single pile under earthquake P waves has fewer loading devices; (2) the loading device for simulating the vertical vibration of a single pile under earthquake P waves is relatively complex and difficult to operate; (3) the monitoring device for simulating the vertical vibration of a single pile under earthquake P waves is easily affected by external factors. Summary of the invention

[0005] In view of the above problems, the object of the present invention is to provide a monitoring device for simulating the vertical vibration of a single pile under earthquake P waves, thereby improving the efficiency and accuracy of monitoring the vertical vibration of a single pile under earthquake P waves.

[0006] The technical solution of the present invention is: a monitoring device for simulating the vertical vibration of a single pile under earthquake P waves described in the present invention comprises a pulley base, four springs are respectively arranged at the four corners of the upper end of the pulley base, and a model box is arranged at the top of the four springs.

[0007] Furthermore, a model pile is arranged inside the model box, at least two acceleration sensors and stress strain gauges are arranged on both sides of the model pile, and a laser displacement meter is arranged on the inner wall of the top of the model box facing the model pile.

[0008] Furthermore, a data transmission line is connected to the other end of the laser displacement meter, acceleration sensor and stress strain gauge, and the laser displacement meter, acceleration sensor and stress strain gauge are connected to a data acquisition instrument after being aggregated through the connected data transmission line.

[0009] Furthermore, a computer host is connected to the other end of the data acquisition instrument via a data transmission line, and the data transmission line connected to the computer host is connected to a computer display.

[0010] Furthermore, a vertical impact device is installed at the center position of the upper end of the pulley base.

[0011] Furthermore, the vertical impact device includes a spring, a control switch, a bottom device and a top device which are interconnected.

[0012] Furthermore, the data acquisition instrument adopts CR1000 or CR3000 model.

[0013] Furthermore, the data transmission line is a sensor connection line.

[0014] Furthermore, pulleys are arranged at the four corners of the bottom of the pulley base.

[0015] Furthermore, the operation method of the monitoring device for simulating the vertical vibration of a single pile under earthquake P waves is as follows:

[0016] Step (1): Determine the size of the model pile, the size of the model box, and the size of the spring according to the designed model test, and connect the pulley base and the model box through the spring; fix the vertical impact device (3), and connect the laser displacement meter, acceleration sensor, stress strain gauge and data transmission line, data acquisition instrument, computer host and computer display;

[0017] Step (2): Determine the soil in the model box according to the test plan;

[0018] Step (3): Control the properties of the soil according to the test plan, and fill the model box with soil to reach the position of the lower end of the set model pile;

[0019] Step (4): Fix the acceleration sensor and stress strain gauge on the model pile, then place the model pile on the buried soil, and then continue to fill the model box with soil;

[0020] Step (5): Fixing the laser displacement meter;

[0021] Step (6): using a vertical impact device to subject the model box to a vertical impact force, thereby causing the pile to vibrate vertically;

[0022] Step (7): Turn on the data acquisition instrument and the computer host to collect and save data.

[0023] The beneficial effects of the present invention are:

[0024] The purpose of the monitoring device of the present invention is to better understand and monitor the changes of a single pile under the action of earthquake P waves, thereby improving the safety and reliability of the pile foundation structure;

[0025] The purpose of the present invention is to provide a monitoring device for simulating the vertical vibration of a single pile under an earthquake P wave, so as to solve the problems existing in the prior art and improve the efficiency and accuracy of monitoring the vertical vibration of a single pile under an earthquake P wave;

[0026] The present invention provides a monitoring device for simulating the vertical vibration of a single pile under an earthquake P wave, comprising: a simulation box, a pulley base, a vertical impact device, a spring, a laser displacement meter, an acceleration sensor, a stress strain gauge, a data transmission line, a data acquisition instrument, a computer host, and a computer display.

[0027] The present invention adopts a laser displacement meter to more accurately and in real time measure the displacement of a single pile after being subjected to a vertical impact.

[0028] The present invention uses numerical control to more clearly present images of changes in displacement, acceleration and stress-strain relationship of a pile after it is subjected to a vertical impact force.

[0029] The device of the present invention is simple and easy to operate, which makes the simulation of the vertical vibration of the pile easier and can simulate the vertical vibration of the pile in various environments.

[0030] The present invention more accurately simulates the pile movement process when the pile is subjected to vertical impact load under P wave by measuring the displacement change and acceleration change of the pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] In the figure, 1. model box; 2. pulley base; 3. vertical impact device; 4. spring; 5. laser displacement meter; 6. acceleration sensor; 7. stress strain gauge; 8. data transmission line; 9. data acquisition instrument; 10. computer host; 11. computer display. DETAILED DESCRIPTION

[0033] The specific technical scheme of the present invention is further described in detail below with reference to specific examples.

[0034] As shown in the figure, a monitoring device for simulating the vertical vibration of a single pile under earthquake P wave according to the present invention comprises a simulation box 1, a pulley base 2, a vertical impact device 3, a spring 4, a laser displacement meter 5, an acceleration sensor 6, a stress strain gauge 7, a data transmission line 8, a data acquisition instrument 9, a computer host 10, and a computer display 11;

[0035] Four springs 4 are respectively arranged at the four corners of the upper end of the pulley base 2, and a model box 1 is arranged at the top of the four springs 4;

[0036] The model box 1: The diameter of the model box 1 is more than 5 times the diameter of the simulated pile; the main function is to provide a controllable and simulated experimental environment for filling and fixing simulated piles to study and monitor the influence of the vertical vibration of a single pile under earthquake P waves on the soil layer and structure;

[0037] The pulley base 2: The main function is to support the test and fix the experimental device to ensure the stability and safety of the experimental device during the experiment; it should be filled with sand, and pulleys should be installed at the four corners of the bottom to facilitate the movement of the experimental monitoring device;

[0038] The spring 4 has the main function of connecting the pulley base 2 and the model box 1, playing a connecting role, ensuring that the pulley base 2 and the model box 1 are tightly connected to ensure that the experiment proceeds smoothly.

[0039] Furthermore, a model pile is arranged inside the model box 1, at least two acceleration sensors 6 and a stress strain gauge 7 are arranged on both sides of the model pile, and a laser displacement meter 5 is arranged on the inner wall of the top of the model box 1, facing the model pile;

[0040] The laser displacement meter 5 has the main function of measuring the displacement of the pile after it is subjected to vertical impact force with high precision. The laser displacement meter 5 monitors the displacement change of the pile in real time.

[0041] The acceleration sensor 6: its main function is to accurately measure the acceleration of the pile after the pile is subjected to vertical impact force. The working principle of the piezoelectric acceleration sensor is based on the piezoelectric effect, which uses the stress generated by the piezoelectric material when it is subjected to vibration or acceleration, resulting in positive and negative charges on two opposite surfaces of the material, which are collected and converted into voltage signals through electrodes, and then amplified and processed;

[0042] The stress strain gauge 7 has the main function of providing accurate mechanical measurement, measuring the strain generated by the pile after the pile is subjected to vertical impact force, improving the safety of the pile foundation, and optimizing the structural design and construction.

[0043] Furthermore, a data transmission line 8 is connected to the other end of the laser displacement meter 5 , the acceleration sensor 6 and the stress strain gauge 7 , and the laser displacement meter 5 , the acceleration sensor 6 and the stress strain gauge 7 are connected to a data acquisition device 9 after being aggregated through the connected data transmission line 8 .

[0044] Furthermore, a computer host 10 is connected to the other end of the data acquisition instrument 9 through a data transmission line 8, and the data transmission line 8 connected to the computer host 10 is connected to a computer display 11;

[0045] The computer host 10 is a computer host (computer display 11), and its main function is to connect to the data acquisition instrument 9;

[0046] The computer display 11 is a common computer display, and its main function is to display test data and curves.

[0047] Furthermore, a vertical impact device 3 is installed at the center of the upper end of the pulley base 2;

[0048] The vertical impact device 3: The main function is to simulate the vertical impact force on the pile under the earthquake P wave, so that the pile produces vertical vibration, thereby generating vertical displacement. Its working principle is: before applying the vertical impact force, the spring 4 of the impact device is in a compressed state. When applying the vertical impact force, just press the lower switch, the spring 4 is released to generate the vertical impact force;

[0049] It includes springs, a control switch, a bottom device and a top device which are connected to each other.

[0050] Furthermore, the data collector 9 adopts the CR1000 or CR3000 model, and its main function is to collect and save sensor data in real time.

[0051] Furthermore, the data transmission line 8 is a sensor connection line, and its main function is to transmit sensor data to the data acquisition device 9.

[0052] Furthermore, the operation method of the monitoring device for simulating the vertical vibration of a single pile under earthquake P waves is as follows:

[0053] Step (1): Determine the size of the model pile, the size of the model box 1, and the size of the spring 4 according to the designed model test, connect the pulley base 2 to the model box 1 through the spring 4; fix the vertical impact device 3, and connect the laser displacement meter 5, the acceleration sensor 6, the stress strain gauge 7 and the data transmission line 8, the data acquisition instrument 9, the computer host 10 and the computer display 11;

[0054] Step (2): determining the soil in the model box 1 according to the test plan;

[0055] Step (3): Control the properties of the soil according to the test plan, and fill the model box 1 with soil to reach the position of the lower end of the set model pile;

[0056] Step (4): Fix the acceleration sensor 6 and the stress strain gauge 7 on the model pile, then place the model pile on the buried soil, and then continue to fill the model box 1 with soil;

[0057] Step (5): Fixing the laser displacement meter 5;

[0058] Step (6): using the vertical impact device 3 to subject the upper model box to a vertical impact force (the vertical impact force is greater than the total gravity of the backfill and the simulated pile in the simulation box), so that the pile generates vertical vibration;

[0059] Step (7): Turn on the data acquisition instrument 9 and the computer host 10 to collect and save data.

Claims

1. A monitoring device for simulating the vertical vibration of a single pile under earthquake P waves, characterized in that: It comprises a pulley base (2), four springs (4) are respectively arranged at the four corners of the upper end of the pulley base (2), and a model box (1) is arranged at the top ends of the four springs (4).

2. A monitoring device for simulating the vertical vibration of a single pile under earthquake P waves according to claim 1, characterized in that: A model pile is arranged inside the model box (1), at least two acceleration sensors (6) and stress strain gauges (7) are arranged on both sides of the model pile, and a laser displacement meter (5) is arranged on the inner wall of the top of the model box (1) facing the model pile.

3. A monitoring device for simulating the vertical vibration of a single pile under earthquake P waves according to claim 2, characterized in that: A data transmission line (8) is connected to the other end of the laser displacement meter (5), the acceleration sensor (6) and the stress strain gauge (7); and the laser displacement meter (5), the acceleration sensor (6) and the stress strain gauge (7) are connected to a data acquisition instrument (9) after being collected through the connected data transmission line (8).

4. A monitoring device for simulating the vertical vibration of a single pile under earthquake P waves according to claim 3, characterized in that: The other end of the data acquisition instrument (9) is connected to a computer host (10) via a connected data transmission line (8), and the data transmission line (8) connected to the computer host (10) is connected to a computer display (11).

5. The monitoring device for simulating the vertical vibration of a single pile under earthquake P waves according to claim 1, characterized in that: A vertical impact device (3) is also installed at the center position of the upper end of the pulley base (2).

6. A monitoring device for simulating the vertical vibration of a single pile under earthquake P waves according to claim 5, characterized in that: The vertical impact device (3) comprises a spring, a control switch, a bottom device and a top device which are connected to each other.

7. A monitoring device for simulating the vertical vibration of a single pile under earthquake P waves according to claim 3, characterized in that: The data acquisition instrument (9) adopts the CR1000 or CR3000 model.

8. The monitoring device for simulating the vertical vibration of a single pile under earthquake P waves according to claim 3, characterized in that: The data transmission line (8) is a sensor connection line.

9. A monitoring device for simulating the vertical vibration of a single pile under earthquake P waves according to claim 1, characterized in that: Pulleys are arranged at the four corners of the bottom of the pulley base (2).

10. The operating method of the monitoring device for simulating the vertical vibration of a single pile under earthquake P waves according to any one of claims 1 to 9, characterized in that: The operation method is as follows: Step (1): Determine the size of the model pile, the size of the model box (1), and the size of the spring (4) according to the designed model test, connect the pulley base (2) and the model box (1) through the spring (4); fix the vertical impact device (3), connect the laser displacement meter (5), the acceleration sensor (6), the stress strain gauge (7) and the data transmission line (8), the data acquisition instrument (9), the computer host (10) and the computer display (11); Step (2): determining the soil in the model box (1) according to the test plan; Step (3): controlling the properties of the soil according to the test plan, filling the model box (1) with soil to reach the position of the lower end of the set model pile; Step (4): fix the acceleration sensor (6) and the stress strain gauge (7) on the model pile, then place the model pile on the buried soil, and then continue to fill the model box (1); Step (5): fixing the laser displacement meter (5); Step (6): using the vertical impact device (3) to load the vertical impact force required for the experiment. When the vertical impact force is loaded, the control switch of the vertical impact device (3) is pressed to generate the vertical impact force, causing the pile to vibrate vertically; Step (7): Turn on the data acquisition instrument (9) and the computer host (10) to collect and save data.

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