Soil layer testing structure and testing method

Abstract

The application discloses a soil layer testing structure and a testing method. The soil layer testing structure comprises a plurality of rod bodies which are arranged in the soil layer at intervals, the rod bodies are arranged along a height direction, and a measuring module is arranged in the rod bodies. The measuring module comprises a signal generating device and a signal receiving device, the signal generating device and the signal receiving device are located at different heights, the signal generating device comprises a vibrating part and a driving assembly, the driving assembly can excite the vibrating part to generate a vibration wave, the signal receiving device comprises a time recorder and a signal receiver which can receive the vibration wave, and the time difference between the time when the vibrating part generates the vibration wave and the time when the signal receiving device receives the vibration wave is obtained according to the time recorder, so that the propagation speed of the vibration wave is obtained, the shear modulus of the measured soil layer is calculated, and the testing method using the soil layer testing structure can accurately obtain the shear modulus of the measured soil layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soil layer parameter testing, and particularly relates to a soil layer testing structure and a testing method. BACKGROUND

[0002] In the fields of geological engineering and geotechnical engineering, accurate measurement of soil layer parameters is of great significance to engineering design and construction. The shear modulus of soil is an important parameter reflecting the stiffness characteristics of soil, and accurate measurement of the shear modulus plays a key role in ensuring engineering safety. Traditional soil layer shear modulus testing methods usually need to be performed in a laboratory, and are complicated to operate and have a long testing period, which cannot meet the requirements of rapid and accurate measurement on site. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the prior art, and provides a soil layer testing structure and a testing method, which can accurately obtain the shear modulus of the soil layer.

[0004] The technical solution adopted by the present application to solve the technical problems is as follows:

[0005] A soil layer testing structure comprises a plurality of rod bodies arranged at intervals in a soil layer, the rod bodies are arranged in a height direction, a measuring module is arranged in the rod bodies, the measuring module comprises a signal generating device and a signal receiving device, the signal generating device and the signal receiving device are located at different heights, the signal generating device comprises a vibrating component and a driving assembly, the driving assembly can excite the vibrating component to generate a vibration wave, the signal receiving device comprises a time recorder and a signal receiver capable of receiving the vibration wave, a time difference between the time when the vibrating component generates the vibration wave and the time when the signal receiving device receives the signal receiver is obtained according to the time recorder, so as to obtain the propagation speed of the vibration wave and calculate the shear modulus of the measured soil layer.

[0006] In some embodiments of the present application, the driving assembly comprises a solenoid valve and a connecting rod, the solenoid valve is connected with the connecting rod and can drive the connecting rod to move to knock the vibrating component to generate a vibration wave, and the vibrating component comprises a metal block.

[0007] In some embodiments of the present application, a first sealing ring is arranged in the rod body, the vibrating component is embedded in the first sealing ring, and the outer periphery of the first sealing ring is embedded in the rod wall of the rod body.

[0008] In some embodiments of the present application, a piezoelectric bending unit is arranged on the signal receiving device, the piezoelectric bending unit is connected with the time recorder, the signal generating device comprises a control unit, and the solenoid valve and the piezoelectric bending unit are both connected with the control unit.

[0009] In some embodiments of this application, the piezoelectric bending unit includes a metal sheet, the end of which is inserted into the signal receiving device.

[0010] In some embodiments of this application, the rod body includes multiple detachably connected hollow rod units, the measuring module is located in the hollow position of the rod body, the measuring module is connected to the rod body by bolts, and the rod body is made of high-strength lightweight material.

[0011] In some embodiments of this application, adjacent hollow rod units are connected by threads, and a second sealing ring is provided between adjacent hollow rod units. Within a single hollow rod unit, the second sealing ring is located below the measuring module.

[0012] In some embodiments of this application, the bottom of the rod is provided with a probe that can be easily inserted into the soil, and the probe is threadedly connected to the hollow rod unit.

[0013] In some embodiments of this application, a third sealing ring is provided between the hollow rod unit and the probe, and the third sealing ring includes a waterproof rubber ring.

[0014] This application also provides a testing method using the soil test structure in any of the above embodiments, including the following steps:

[0015] For the propagation path of the i-th vibration wave, if the time taken for the vibration wave to propagate is t... i Let n be the total number of vibration wave propagation paths, and R be the total number of paths. i Let S be the propagation path of the i-th vibration wave, and S be the reciprocal of the vibration wave velocity. Then we get formula (1):

[0016]

[0017] The soil layer to be tested is discretized into several regular grid cells to obtain a gridded model. Since the grid cells are small, the velocity v of the vibration wave in each grid cell is... i Treating it as a constant, we define d ij For the first i Let n be the length of the propagation path passing through the j-th grid, n be the number of propagation paths, and m be the number of grids. Then, it can be discretized into formula (2) using formula (1):

[0018]

[0019] Let s = 1 / V pm Substituting into formula (2), where V pm It is the wave velocity of the vibration wave, forming a system of linear equations (3):

[0020]

[0021] The equation set (3) is solved by a joint iteration method to calculate the elastic wave velocity in each grid unit, and the shear modulus of the tested soil layer is estimated according to the correspondence between the wave velocity obtained by the experiment and the shear modulus of the soil layer.

[0022] The soil layer testing structure has at least one of the following advantages or beneficial effects: The soil layer testing structure sets the signal generating device and the signal receiving device at different heights of the rod body, sets multiple signal generating devices and signal receiving devices, and can realize multi-point and multi-level soil layer parameter measurement. During operation, the driving assembly can excite the vibration component to generate vibration waves, the signal receiver records the time after receiving the vibration waves, and the propagation speed of the waves in the measured soil layer is calculated according to the time difference between the generation of the vibration waves and the reception of the vibration waves and the distance between the two rod bodies. The shear modulus of the measured soil layer is obtained by calculation. It can be understood that multiple rod bodies can be used to test the soil layer at a certain distance at the same time. The soil layer testing device is easy to operate and can be widely used in geological engineering, geotechnical engineering and other fields to provide accurate and fast soil layer parameter measurement data for engineering design and construction. The measurement method using the soil layer testing structure not only improves the testing accuracy and reliability, but also improves the testing efficiency and shortens the testing period by simultaneously testing multiple points.

[0023] Additional aspects and advantages of the application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0024] The above and / or additional aspects and advantages of the application will become apparent and be readily appreciated from the following description, including the appended drawings, wherein:

[0025] Figure 1 is one of the structure schematic diagrams of an embodiment of the soil layer testing structure in the application;

[0026] Figure 2 is the second structure schematic diagram of an embodiment of the soil layer testing structure in the application;

[0027] Figure 3 is the working principle diagram of an embodiment of the soil layer testing structure in the application;

[0028] Figure 4 is the calculation method schematic diagram of the test method in the application. DETAILED DESCRIPTION

[0029] The detailed description will be made to the specific embodiments of the present application, and the preferred embodiments of the present application are shown in the drawings, and the drawings are used to supplement the description of the text part of the specification, so that people can intuitively and visually understand each technical feature and the overall technical scheme of the present application, but it cannot be understood as the limitation of the protection scope of the present application.

[0030] In the present application, if the direction (up, down, left, right, front and back) is described, it is only for the convenience of describing the technical scheme of the present application, and it is not indicated or implied that the indicated technical feature must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as the limitation of the present application.

[0031] In the present application, the meaning of "several" is one or more, the meaning of "multiple" is two or more, and "greater than", "less than", "more than" and the like are understood as not including the number; "above", "below", "within" and the like are understood as including the number. In the description of the present application, if "first" and "second" are described, they are only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0032] In the present application, unless otherwise explicitly limited, the words "set", "install", "connect" and the like should be broadly understood, for example, they can be directly connected, or indirectly connected through intermediate media; can be fixedly connected, or detachably connected, or integrally formed; can be mechanically connected, or electrically connected or capable of communicating with each other; can be the internal connection of two elements or the interaction relationship of two elements. The skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical scheme.

[0033] Wherein, Figure 1 The reference direction coordinate system of the embodiment of the present application is given, and the embodiments of the present application are described below in combination with the directions shown in the drawings. Figure 1

[0034] The embodiment of the present application provides a soil layer test structure, which is described with reference to Figure 1 and Figure 2 ​The soil layer testing structure comprises a plurality of rod bodies 100 arranged in the soil layer at intervals, the rod bodies 100 are arranged in the height direction, a measuring module 200 is arranged in the rod body 100, the measuring module 200 comprises a signal generating device 210 and a signal receiving device 220, the signal generating device 210 and the signal receiving device 220 are located at different heights, the signal generating device 210 comprises a vibrating component 211 and a driving assembly, the driving assembly can excite the vibrating component 211 to generate a vibration wave, the signal receiving device 220 comprises a time recorder and a signal receiver capable of receiving the vibration wave, the time difference between the time when the vibrating component generates the vibration wave and the time when the signal receiving device receives the vibration wave is obtained according to the time recorder, so as to obtain the propagation speed of the vibration wave, and the shear modulus of the measured soil layer is calculated, the signal receiver can be an acceleration sensor or a vibration sensor or other devices for capturing the response of the soil layer to the vibration signal.

[0035] The soil layer testing structure can realize multi-point and multi-level soil layer parameter measurement by arranging the signal generating device 210 and the signal receiving device 220 at different heights of the rod body and by arranging a plurality of signal generating devices 210 and signal receiving devices 220. During operation, the driving assembly can excite the vibrating component 211 to generate a vibration wave, the time recorder records the time after the signal receiver receives the vibration wave, the propagation speed of the wave in the measured soil layer is calculated according to the time difference between the time when the vibration wave is generated and the time when the vibration wave is received and the distance between the two rod bodies, and the shear modulus of the measured soil layer is obtained by calculation. It can be understood that a plurality of rod bodies can be used to simultaneously test the soil layer at a certain distance. The soil layer testing device is easy to operate and can be widely used in the fields of geological engineering and geotechnical engineering to provide accurate and rapid soil layer parameter measurement data for engineering design and construction. The measurement method using the soil layer testing structure not only improves the testing accuracy and reliability, but also improves the testing efficiency and shortens the testing period by simultaneously performing multi-point testing. The time recorder uses a high-precision timer, such as a high-precision timer or a quartz crystal oscillator, to record the time difference between the signal generating device and the signal receiver.

[0036] The adjacent measuring modules 200 are connected through the power supply transmission line 300, and the measuring module 200 can communicate with the external control unit in a wireless transmission or wired connection mode.

[0037] Referring to Figure 2The driving assembly is driven by piezoelectric ceramics or electromagnetic drive. Specifically, the driving assembly comprises an electromagnetic valve 212 and a connecting rod 213. The electromagnetic valve 212 is connected with the connecting rod 213 and can drive the connecting rod 213 to move, so as to knock the vibrating part 211 to generate vibration wave. The vibrating part 211 comprises a metal block. When the electromagnetic valve is driven by alternating current, the connecting rod 213 connected with the electromagnetic valve can move linearly back and forth to generate hammering force. The connecting rod 213 moves linearly back and forth to continuously hammer the metal block, so as to generate vibration wave. In some embodiments, the electromagnetic valve 212 and the connecting rod 213 are connected by welding or screwing, so as to ensure that the connecting rod can move linearly back and forth with the electromagnetic valve. The metal block is a button-shaped large cylinder with a diameter of about 12-16 mm.

[0038] Referring to Figure 2 The rod body 100 is provided with a first sealing ring 120. The vibrating part 211 is embedded in the first sealing ring 120. The outer periphery of the first sealing ring 120 is embedded in the rod wall of the rod body 100, so as to prevent underground water from penetrating into the rod body through the hole around the metal block. That is, the metal block is first embedded into the inner ring of the first sealing ring 120 (rubber ring), and then the outer ring of the rubber ring is wrapped around the rod wall of the rod body, so that the rubber ring fully fills the gap between the metal block and the rod wall, thereby achieving the waterproof effect.

[0039] In some embodiments, the signal receiving device 220 is provided with a piezoelectric bending unit 221 connected with the time recorder. The signal generating device 210 comprises a control unit, which comprises a small microprocessor or single-chip microcomputer, etc., for processing data and controlling the entire testing process. The electromagnetic valve 212 and the piezoelectric bending unit 221 are both connected with the control unit. The control unit triggers the electromagnetic valve 212 to generate corresponding vibration source. The control unit is responsible for processing the data of the time recorder and calculating the propagation speed of the wave in the measured soil layer according to the known distance between the two rod bodies. Through the array cross measurement of the measuring modules 200 at different heights, the high-precision speed distribution of the test area can be obtained (see Figure 3 ), and the test results can be output in the form of numbers or charts and displayed to the user.

[0040] The piezoelectric bending unit 221 comprises a metal sheet. The metal sheet is long, and the end of the metal sheet is inserted into the signal receiving device 220 and connected with the signal receiving device 220 by screwing. When the surrounding soil layer vibrates, a certain deflection is generated on the piezoelectric bending unit 221, so that the wave is detected. Finally, the vibration signal is recorded through the change of voltage. The piezoelectric bending unit 221 is a flat metal, which is connected with the external soil through a hole in the rod body, so as to better receive the signal. In order to prevent underground water from penetrating, a waterproof rubber ring is arranged around the hole, which is fully attached to the hole wall, so as to achieve the waterproof purpose.

[0041] In some embodiments, the rod body 100 comprises a plurality of detachably connected hollow rod units 110, the measuring module 200 is located at the hollow position of the rod body 100, and the measuring module 200 is connected with the inner side wall of the rod body 100 by bolts. Specifically, the measuring module is provided with bolts, and the inner side wall of the rod body 100 is provided with nuts matched with the bolts. The rod body 100 is made of high-strength lightweight materials such as carbon fiber composite materials or aluminum alloys. These materials have high strength and rigidity and can withstand pressure and vibration during testing. At the same time, these materials are light in weight, convenient to operate and transport, and their length can be selected according to needs, generally 1-5 meters and 1-5 centimeters in diameter.

[0042] The adjacent hollow rod units 110 are connected by threads, and the second sealing ring 130 is arranged between the adjacent hollow rod units 110. In a single hollow rod unit 110, the second sealing ring 130 is located below the measuring module 200, which effectively prevents groundwater from seeping in. The total length of the rod body is generally determined according to the depth of the soil layer and the testing requirements.

[0043] Referring to Figure 1 , the bottom of the rod body 100 is provided with a probe 300 for deepening into the soil layer, and the probe 300 is threadedly connected with the hollow rod unit 110.

[0044] A third sealing ring is arranged between the hollow rod unit 110 and the probe 300, and the third sealing ring comprises a waterproof rubber ring to achieve a firm and waterproof effect.

[0045] The application also provides a testing method using the above soil testing structure, comprising the following steps:

[0046] Two rod bodies 100 are pressed into the measured soil layer at a certain distance apart, and one of the rod bodies 100 generates a vibration wave, and the other rod body 100 receives the vibration wave, forming a one-to-many receiving sound system, that is, a single point is emitted on one side, and the other side is arranged in a fan shape to receive, and then the source is moved along the profile line to scan and observe point by point (see Figure 3 When the vibration wave propagates in the soil body, the time of vibration wave propagation is a function of the speed v and the geometric path. For the i-th vibration wave propagation path, if the time of vibration wave propagation is t i , set n as the total number of vibration wave propagation paths, R i is the i-th vibration wave propagation path, and S is the inverse of the vibration wave speed, then formula (1) is obtained:

[0047]

[0048] The tested soil layer region is discretized into a plurality of regular grid cells to obtain a gridded model. Since the divided grid cells are small, the speed vi d is defined as a constant ij is the length of the i-th propagation path through the j-th grid, n is the number of propagation paths, and m is the number of grids, then formula (1) is discretized into formula (2) by formula (1):

[0049]

[0050] s = 1 / V pm is substituted into formula (2), where V pm is the wave velocity of the vibration wave, and a linear equation group (3) is formed:

[0051]

[0052] The equation group (3) is solved by using the method of joint iteration, the elastic wave velocity in each grid unit is calculated, and the shear modulus of the tested soil layer is estimated according to the corresponding relationship between the wave velocity obtained by the experiment and the shear modulus of the soil layer.

[0053] In the description of the present specification, the description of the terms "example", "embodiment" or "some embodiments" and the like means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0054] Of course, the present application is not limited to the above-mentioned embodiments, and those skilled in the art can make equivalent modifications or replacements without departing from the spirit of the present application, and these equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A soil layer testing structure, characterized in that: The device includes multiple rods spaced apart within the soil layer, arranged along the height direction. Each rod contains a measurement module, which includes a signal generator and a signal receiver located at different heights. The signal generator includes a vibration component and a drive assembly. The drive assembly includes a solenoid valve and a connecting rod. The solenoid valve is connected to the connecting rod and can drive the connecting rod to move, striking the vibration component to generate vibration waves. The signal receiver includes a time recorder and a signal receiver capable of receiving the vibration waves. The signal receiver is equipped with a piezoelectric bending unit connected to the time recorder. By obtaining the time difference between the vibration wave generated by the vibration component and the signal received by the time recorder, the shear modulus of the soil layer being measured can be calculated by obtaining the propagation speed of the vibration wave. The rod body includes multiple detachably connected hollow rod units. The measuring module is located in the hollow part of the rod body and is connected to the rod body by bolts. A first sealing ring is provided inside the rod body, and the vibration component is embedded in the first sealing ring. The outer periphery of the first sealing ring is embedded in the rod wall of the rod body. Adjacent hollow rod units are connected by threads, and a second sealing ring is provided between adjacent hollow rod units. In a single hollow rod unit, the second sealing ring is located below the measuring module.

2. The soil layer testing structure according to claim 1, characterized in that: The vibrating component includes a metal block.

3. The soil layer testing structure according to claim 2, characterized in that: The signal generating device includes a control unit, and the solenoid valve and the piezoelectric bending unit are both connected to the control unit.

4. The soil layer testing structure according to claim 3, characterized in that: The piezoelectric bending unit includes a metal sheet, the end of which is inserted into the signal receiving device.

5. The soil layer testing structure according to claim 1, characterized in that: The rod is made of high-strength, lightweight material.

6. The soil layer testing structure according to claim 5, characterized in that: The bottom of the rod is equipped with a probe that can easily penetrate into the soil layer, and the probe is threadedly connected to the hollow rod unit.

7. The soil layer testing structure according to claim 6, characterized in that: A third sealing ring is provided between the hollow rod unit and the probe, and the third sealing ring includes a waterproof rubber ring.

8. A testing method using any one of the soil test structures according to claims 1 to 7, characterized in that... Includes the following steps: Two rods are pressed into soil layers spaced a certain distance apart. One rod generates a vibration wave, and the other rod receives the vibration wave. For the propagation path of the i-th vibration wave, if the time taken for the vibration wave to propagate is... Let n be the total number of vibration wave propagation paths. For the first i Given the propagation path of a vibration wave, where S is the reciprocal of the wave velocity, we obtain formula (1): ； The soil layer to be tested is discretized into several regular grid cells to obtain a gridded model. Due to the small size of the grid cells, the velocity of the vibration wave in each grid cell is... Treat it as a constant, define For the i-th propagation path to pass through the i-th j The length of each grid, n For the number of propagation paths, m If the grid number is given, then it can be discretized into formula (2) using formula (1): ； Will Substituting into formula (2), where, It is the wave velocity of the vibration wave, forming a system of linear equations (3): ； The system of equations (3) is solved by a joint iteration method. The elastic wave velocity in each grid cell is calculated. The shear modulus of the tested soil layer is estimated based on the correspondence between the wave velocity obtained from the experiment and the shear modulus of the soil layer.

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