Active monitoring device for evaluating locking effect of geogrid based on bending element

Abstract

The invention discloses an active monitoring device for evaluating the locking effect of a geogrid based on a bending element, and belongs to the technical field of geotechnical engineering detection. Comprising a plurality of monitoring devices arranged above and below a civil grid, each monitoring device comprises a frame, an excitation end and a receiving end, the excitation ends and the receiving ends are connected with a detection circuit, the detection circuit comprises a display circuit, and the display circuit comprises a multifunctional oscilloscope and a computer which are connected in sequence. By adopting the device, the overall structure of the bending element sensor monitoring device is placed into the roadbed soil body in advance, mechanical property data of the monitored soil body are obtained, quantifiable soil body performance indexes are obtained through accurate data, soil body performance change caused by digging of the soil body is avoided, and the accuracy and reliability of a test result are guaranteed. And meanwhile, the workload is reduced, and research development aiming at the mechanical property of the soil body and the locking effect of the geogrid is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering detection, and in particular to an active monitoring device for evaluating the locking effect of a geogrid based on bending elements. Background Art

[0002] In recent years, China has vigorously developed infrastructure construction and achieved fruitful results, but at the same time, various construction problems have followed, and uneven settlement and instability have occurred frequently. Geogrids can be used to reinforce weak foundations, which can quickly improve the bearing capacity of the foundation and control the development of settlement. The side limit effect on the road base can effectively distribute the load to a wider subbase, thereby reducing the thickness of the base, reducing the project cost, shortening the construction period, and extending the service life. The traditional evaluation of soil mechanical properties is mainly based on in-situ experiments, which occupy a large area of ​​site during testing, greatly affecting the normal production and life in the monitoring area, and also restricting the normal conduct of the experiment. At present, there is a lack of evaluation equipment for the locking effect of geogrids. After the locking of geogrids fails and settlement occurs, emergency repair measures can only be taken. Excavation to test the mechanical properties of the soil will destroy the existing state of the soil and affect the future mechanical properties of the soil.

[0003] Currently, there is no suitable means to evaluate the locking effect of geogrids, including the locking capacity, locking range, and the changing function of the locking effect on soil at different depths. Summary of the invention

[0004] The purpose of the present invention is to provide an active monitoring device for evaluating the locking effect of geogrids based on bending elements. By setting an active monitoring device on the geogrid, the soil layer around the geogrid is detected, and the locking effect of the geogrid is digitized. The locking effect of the geogrid can be measured in real time, and the mechanical properties of the soil can be detected, thereby solving the problems in the background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides an active monitoring device for evaluating the locking effect of geogrid based on bending elements, including a plurality of monitoring devices arranged above and below the geogrid, the monitoring device including a frame, an excitation end and a receiving end, the excitation end and the receiving end are both connected to a detection circuit, the detection circuit includes a display circuit, and the display circuit includes a multifunctional oscilloscope and a computer connected in sequence.

[0006] Preferably, the frame is configured as a flat rectangular metal frame, reinforcing rods are provided at the inner corners of the frame, the excitation end and the receiving end are respectively provided on the midlines of the two ends of the frame, and the distance between the excitation end and the receiving end is set to 0-3m.

[0007] Preferably, the structures of the excitation end and the receiving end are arranged to be the same, including a shell, a metal mesh cover is provided at the front end of the shell by a snap-fit, a bending element sensor is arranged inside the shell, the bending element sensor includes a brass electrode plate, piezoelectric ceramic electrodes are provided on the top and bottom surfaces of the brass electrode plate, and the bending element sensor is connected to the detection circuit; a layer of elastic epoxy resin is provided on the outer surface of the bending element sensor.

[0008] Preferably, the bending element sensor at the excitation end and the bending element sensor at the receiving end are arranged in a positional relationship pointing to each other through their respective metal mesh covers.

[0009] Preferably, the excitation end is connected to the function generator and the multifunctional oscilloscope via a signal amplifier, and the receiving end is connected to the multifunctional oscilloscope via a filter and a signal amplifier.

[0010] Therefore, the present invention adopts the above-mentioned active monitoring device for evaluating the locking effect of geogrid based on bending element, which has the following advantages: 1) The present invention uses the shear wave velocity generated by the bending element to reflect the change of the shear modulus of the soil, converts the mechanical properties of the soil into quantifiable actual parameters, and obtains quantifiable soil performance change indicators through precise data, which is conducive to the research on the mechanical properties of the soil and the locking effect of the geogrid.

[0011] 2) The present invention places the overall structure of the bending element monitoring device into the roadbed soil in advance, so as to obtain the mechanical property data of the monitored soil for a long time, avoid excavating the soil to cause changes in soil properties, and ensure the accuracy and reliability of the test results. At the same time, it reduces the workload and avoids affecting the normal production and life above the monitored soil.

[0012] 3) The present invention can obtain the relationship between the geogrid locking effect and the relative depth by burying multiple active monitoring devices at different depths, and then obtain the geogrid locking range function. This is conducive to quantitatively mastering the locking performance of the geogrid and contributing to more effective use of the geogrid in the future.

[0013] 4) The present invention obtains the mechanical property parameters of the soil through the shear wave actively generated by the bending element, can continuously monitor the changes in the mechanical properties of the soil over a long period of time, and obtain the law of changes in the mechanical properties of the soil over time, which is helpful to predict the time of soil instability. It can also obtain the soil changes before the geogrid lock fails, which is helpful to take preventive measures in time.

[0014] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1It is a schematic diagram of the installation of an active monitoring device for evaluating the locking effect of geogrid based on bending elements of the present invention; Figure 2 It is a schematic diagram of a frame in an active monitoring device for evaluating the locking effect of geogrid based on bending elements of the present invention; Figure 3 The internal structure of the exciting end and the receiving end of the active monitoring device for evaluating the locking effect of geogrid based on bending element of the present invention; Figure 4 It is a schematic diagram of a detection circuit in an active monitoring device for evaluating the locking effect of geogrid based on bending elements of the present invention; Figure numerals: 1, geogrid; 10, monitoring device; 101, frame; 102, exciting end; 103, receiving end; 201, piezoelectric ceramic plate; 202, brass plate; 203, housing; 204, metal mesh cover. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations. The specific model specifications need to be selected and determined according to the actual specifications of the device, etc. The specific selection calculation device adopts the existing technology in the field, so it will not be described in detail.

[0017] Example like Figure 1-Figure 3 As shown, the present invention provides an active monitoring device for evaluating the locking effect of geogrid based on bending elements, including a plurality of monitoring devices 10 arranged above and below the geogrid, so as to monitor the earthwork mechanics data above and below the geogrid 1, and then judge the locking effect of the geogrid 1.

[0018] The monitoring device 10 includes a frame 101, an excitation end 102 and a receiving end 103, and the excitation end 102 and the receiving end 103 are both connected to a detection circuit, such as Figure 4 As shown, the detection circuit includes a display circuit, and the display circuit includes a multifunctional oscilloscope and a computer connected in sequence. The excitation end 102 is connected to the multifunctional oscilloscope through a signal amplifier and a function generator, and the receiving end 103 is connected to the multifunctional oscilloscope through a filter and a signal amplifier. The oscilloscope is combined with the computer to realize the visualization of the detection data.

[0019] The frame 101 is configured as a flat rectangular metal frame, and reinforcing rods are provided at the inner corners of the frame 101, which can strengthen the structural strength of the frame 101. The excitation end 102 and the receiving end 103 are respectively arranged on the midlines of the two ends of the frame 101. The positions of the excitation end 102 and the receiving end 103 are fixed by the frame 101, which facilitates the detection of the earthwork in the frame 101. Because the detection range of the bending element sensor is 3m, the distance between the excitation end 102 and the receiving end 103 is set to 0-3m, and the bending element sensor of the receiving end 103 and the bending element sensor of the excitation end 102 are set to point to each other through the metal mesh cover, so that the signal propagation is more accurate.

[0020] The structures of the excitation end 102 and the receiving end 103 are set to be the same, including a shell 203, a metal mesh cover 204 is provided at the front end of the shell 203 by snap-fitting, a bending element sensor is provided inside the shell 203, and the remaining gaps in the shell 203 are filled with in-situ soil for detection. The bending element sensor of the excitation end 102 sends a signal through the metal mesh cover 204, and the signal is transmitted to the bending element sensor of the receiving end 103 through the sand medium in the frame 101 as a transmission medium, and the soil in the frame 101 is detected by the change of the signal.

[0021] The bending element sensor includes a brass plate 202, and piezoelectric ceramic plates 201 are arranged on the top and bottom surfaces of the brass plate 202. The bending element sensor is connected to the detection circuit to form a signal exchange. A layer of elastic epoxy resin is arranged on the outer surface of the bending element sensor. Acetone is used to dilute the epoxy resin at a ratio of 2:1. The epoxy resin can play a role of waterproof and acid proof, and has a protective effect on the bending element sensor. At the same time, the elastic property can not affect the detection effect of the device.

[0022] The specific usage process is as follows: In this embodiment, a number of monitoring devices are set at intervals of 150 mm, specifically, three monitoring devices are set above and below the geogrid respectively, with a total of six monitoring devices. The monitoring devices are connected to the detection circuit, and the function generator is started to generate two identical input signals, one of which is input to the multifunctional oscilloscope, and the other is transmitted to the excitation end through the signal amplifier. The bending element sensor in the excitation end receives the signal excitation, and then vibrates to transmit information. The vibration will be excited by the bending element sensor at the excitation end, and propagate through the soil layer through the metal mesh cover. The propagation process is affected by the soil layer and changes. The bending element sensor at the receiving end receives the vibration, and the corresponding vibration forms an output signal. The output signal is transmitted to the multifunctional oscilloscope after filtering and signal amplifier. The multifunctional oscilloscope summarizes the input signal and the output signal into the computer, calculates the shear wave, and then forms the parameterization of soil mechanics.

[0023] Therefore, the present invention adopts an active monitoring device based on bending element to evaluate the locking effect of geogrid. The overall structure of the bending element monitoring device is placed in advance into the roadbed soil to obtain the mechanical performance data of the monitored soil. Through the accurate data, quantifiable soil performance change indicators are obtained to avoid digging up the soil to cause changes in soil performance, thereby ensuring the accuracy and reliability of the test results. At the same time, the workload is reduced, which is conducive to the research on the mechanical properties of soil and the locking effect of geogrid.

[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An active monitoring device for evaluating the locking effect of geogrids based on bending elements, characterized in that: It includes several monitoring devices arranged above and below the civil grid, the monitoring devices include a frame, an excitation end and a receiving end, the excitation end and the receiving end are both connected to a detection circuit, the detection circuit includes a display circuit, and the display circuit includes a multifunctional oscilloscope and a computer connected in sequence.

2. The active monitoring device for evaluating the locking effect of geogrid based on bending element according to claim 1, characterized in that: The frame is configured as a flat rectangular metal frame, reinforcement rods are provided at the inner corners of the frame, the excitation end and the receiving end are respectively provided on the midlines of the two ends of the frame, and the distance between the excitation end and the receiving end is set to 0-3m.

3. The active monitoring device for evaluating the locking effect of geogrid based on bending element according to claim 2, characterized in that: The structures of the excitation end and the receiving end are arranged to be the same, including a shell, a metal mesh cover is arranged at the front end of the shell by a snap, a bending element sensor is arranged inside the shell, the bending element sensor includes a brass electrode plate, and piezoelectric ceramic electrodes are arranged on the top and bottom surfaces of the brass electrode plate. The bending element sensor is connected to the detection circuit; a layer of elastic epoxy resin is arranged on the outer surface of the bending element sensor.

4. The active monitoring device for evaluating the locking effect of geogrid based on bending element according to claim 3 is characterized by: The bending element sensor at the excitation end and the bending element sensor at the receiving end are arranged to point to each other through their respective metal mesh covers.

5. The active monitoring device for evaluating the locking effect of geogrid based on bending element according to claim 4, characterized in that: The excitation end is connected to the multifunctional oscilloscope through a signal amplifier, the function generator and the multifunctional oscilloscope, and the receiving end is connected to the multifunctional oscilloscope through a filter and a signal amplifier.

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