Diaphragm wall leakage detection device and method based on active vibration source

Abstract

The invention discloses an underground diaphragm wall leakage detection device and method based on an active vibration source. The method comprises the following steps that 1, a leakage detection working area is selected for a foundation pit underground diaphragm wall structure; 2, arranging an underground diaphragm wall leakage detection device based on an active vibration source; and 3, underground diaphragm wall leakage detection work is carried out. The underground diaphragm wall leakage detection device and method based on the active vibration source are suitable for leakage detection of a foundation pit underground diaphragm wall, the vibration source is excited by starting the vibration motor, vibration signals are communicated and propagated through a water body in a leakage area, leakage is recognized and positioned, leakage points of the underground diaphragm wall can be judged, and the detection accuracy is improved. The problem that sound signals generated by leakage are weak and cannot be accurately sensed can be effectively solved, the accuracy of underground diaphragm wall leakage detection is improved, the detection method is simple, the detection cost is low, and the method is suitable for industrial popularization and application.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation pit structure health monitoring, and in particular to a ground-connected wall leakage detection device and method based on an active vibration source. Background Art

[0002] As an important part of the underground structure, the stability of the ground-connected wall is directly related to the safety of the entire underground structure. Leakage in the ground-connected wall will cause groundwater to enter the foundation pit or basement, causing problems such as water accumulation and soaking, which will not only affect the construction progress, but may also cause water disasters. Through leakage monitoring, leakage points can be discovered in time and effective measures can be taken to seal them, preventing water disasters from occurring, thereby ensuring the safety and stability of the underground structure.

[0003] At present, leakage detection technologies mainly include pressure testing, infrared detection, transient electromagnetic and DC electric field combined leakage detection, resistivity detection, etc. Although there are many detection technologies to choose from, each technology has its limitations, such as detection cost, technical requirements, construction impact, etc. At present, the existing leakage detection technology is mainly suitable for leakage detection of hydropower stations, dams and other facilities. The detection cost is high and the technical requirements are high. There is no equipment and professional technology that can detect underground continuous wall leakage with high precision.

[0004] Fiber optic sensing technology has many advantages in terms of size, cost, life, resolution, anti-electromagnetic interference and resistance to harsh working conditions, and is widely used in various structural monitoring fields. Fiber optic sensing technology can identify and locate leaks by sensing the sound signals generated by water flowing through the leakage channel, but this method is prone to leaks due to the sound signals generated by the leakage being too small, and cannot be accurately sensed. Summary of the invention

[0005] In view of this, in order to overcome the defects of the prior art, the purpose of the present invention is to provide a ground-connected wall leakage detection device and method based on an active vibration source, which is suitable for leakage detection of ground-connected walls in foundation pits.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A ground-connected wall leakage detection device based on an active vibration source comprises a vibration sensing optical cable and a vibration source manufacturing device, wherein the vibration sensing optical cable and the vibration source manufacturing device are symmetrically arranged about the construction joint of the ground-connected wall, the vibration source manufacturing device is arranged on the facing soil surface of the ground-connected wall, and the vibration sensing optical cable is arranged on the back soil surface of the ground-connected wall.

[0008] Furthermore, the vibration sensing optical cable is a metal-based cable-shaped distributed strain optical cable, which is fixed to the steel cage by tying with a cable tie.

[0009] Furthermore, the vibration source manufacturing equipment includes a vibration steel pipe and a vibration motor, and the vibration motor is arranged in the vibration steel pipe to excite the vibration source.

[0010] Furthermore, the bottom of the vibration steel pipe is sealed and spot-welded to the inner side of the H-shaped steel at the joint of the previously constructed ground wall, and the interior of the vibration steel pipe is filled with water.

[0011] The present invention also discloses a ground-connected wall leakage detection method based on an active vibration source, which uses the ground-connected wall leakage detection device based on an active vibration source as described above to perform leakage detection, comprising the following steps:

[0012] Step 1: Selecting a leakage detection work area for the foundation pit ground-connected wall structure;

[0013] Step 2: Arrange a ground-connected wall leakage detection device based on an active vibration source;

[0014] Step three: Conduct ground-connected wall leakage detection.

[0015] Furthermore, in step one, the principle for selecting the leakage detection work area is: selecting the construction joints of adjacent ground-connected walls as the leakage detection work area.

[0016] Furthermore, in step 2, the step of arranging a ground-connected wall leakage detection device based on an active vibration source includes:

[0017] 1) The vibration sensing optical cable uses a metal-based distributed strain optical cable and is fixed to the steel cage with a cable tie;

[0018] 2) After the bottom of the vibration steel pipe is sealed with a plug, the vibration steel pipe is spot welded to the inner side of the H-shaped steel at the joint of the first construction ground wall, the inside of the vibration steel pipe is filled with water, and the vibration motor is lowered into the vibration steel pipe, thereby completing the assembly of the vibration source manufacturing equipment;

[0019] 3) The vibration sensing optical cable and the vibration source manufacturing equipment are symmetrically arranged at the construction joint of the ground-connected wall, the vibration source manufacturing equipment is arranged on the soil surface facing the ground-connected wall, and the vibration sensing optical cable is arranged on the soil surface behind the ground-connected wall;

[0020] There is no order of precedence for step 1) and step 2).

[0021] Furthermore, in step three, the steps of conducting ground-connected wall leakage detection work include:

[0022] Turn on the vibration motor to excite the vibration source, transmit the vibration signal through the water in the leakage area, and identify and locate the leakage.

[0023] Furthermore, a narrow coherent laser pulse is injected into the optical fiber in the vibration sensing optical cable arranged at the joint of the back soil surface of the ground-connected wall through an optical fiber demodulator. When leakage occurs in the ground-connected wall structure, the vibration sensing optical cable is disturbed, and the refractive index and length of the optical fiber at the corresponding position change, causing the light phase intensity at the corresponding position to change. The vibration intensity information is obtained by demodulating the amplitude of the light phase along the optical fiber through the optical fiber demodulator connected to the optical fiber, so as to identify whether leakage occurs in the ground-connected wall structure.

[0024] Furthermore, the location of the ground-connected wall leakage point can be identified by performing time domain analysis on the received optical phase difference signal based on formula (1) using an optical fiber demodulator:

[0025]

[0026] Where L is the distance from the leakage point to the end of the optical fiber, c is the propagation speed of light, n is the effective refractive index of the optical fiber, τ d The time required for light to travel back and forth through the leak.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention discloses a ground-connected wall leakage detection device and method based on an active vibration source, which is suitable for leakage detection of ground-connected walls in foundation pits. The device and method can identify and locate leakage by turning on a vibration motor to excite the vibration source and propagate vibration signals through the water body in the leakage area. The leakage point of the ground-connected wall can be judged, and the problem of inaccurate perception due to weak sound signals generated by leakage can be effectively improved, thereby improving the accuracy of ground-connected wall leakage detection. The detection method is simple and the detection cost is low, which is suitable for industrial promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention;

[0030] Among them, 1-vibration sensing optical cable; 2-vibration steel pipe; 3-vibration motor. DETAILED DESCRIPTION

[0031] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0032] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0033] like Figure 1 As shown, the present invention discloses a ground-connected wall leakage detection device based on an active vibration source, comprising a vibration sensing optical cable 1 and a vibration source manufacturing device, wherein the vibration sensing optical cable 1 and the vibration source manufacturing device are symmetrically arranged about the construction joint of the ground-connected wall, the vibration source manufacturing device is arranged on the front soil surface of the ground-connected wall, and the vibration sensing optical cable 1 is arranged on the back soil surface of the ground-connected wall, the vibration source manufacturing device comprises a vibration steel pipe 2 and a vibration motor 3, the bottom of the vibration steel pipe 2 is sealed with a plug and spot-welded to the inner side of the H-shaped steel at the joint of the first constructed ground-connected wall, the interior of the vibration steel pipe 2 is filled with water, and the vibration motor 3 is lowered into the vibration steel pipe 2 to excite the vibration source.

[0034] The vibration sensing optical cable 1 uses a metal-based cable-shaped distributed strain optical cable and is fixed to the steel cage with a cable tie.

[0035] The present invention also discloses a ground-connected wall leakage detection method based on an active vibration source, comprising the following steps:

[0036] Step 1: Selecting a leakage detection work area for the foundation pit ground-connected wall structure;

[0037] Step 2: Arrange a ground-connected wall leakage detection device based on an active vibration source;

[0038] Step 3: Detect ground-connected wall leakage:

[0039] The vibration source is stimulated to transmit the vibration signal through the water body in the leakage area to identify and locate the leakage.

[0040] In step one, the principle for selecting the leakage detection work area is: select the construction joints of adjacent ground-connected walls as the leakage detection work area.

[0041] In step 2, the steps of arranging the ground-connected wall leakage detection device based on active vibration source include:

[0042] 1) The vibration sensing optical cable 1 uses a metal-based cable-shaped distributed strain optical cable and is tied and fixed on the steel cage with a cable tie;

[0043] 2) After the bottom of the vibration steel pipe 2 is sealed with a plug, the vibration steel pipe 2 is spot welded to the inner side of the H-shaped steel at the joint of the first construction ground wall, the inside of the vibration steel pipe 2 is filled with water, and the vibration motor 3 is lowered into the vibration steel pipe 2, thereby completing the assembly of the vibration source manufacturing equipment;

[0044] 3) The vibration sensing optical cable 1 and the vibration source manufacturing equipment are symmetrically arranged at the construction joint of the ground-connected wall, the vibration source manufacturing equipment is arranged on the front soil surface of the ground-connected wall, and the vibration sensing optical cable 1 is arranged on the back soil surface of the ground-connected wall;

[0045] There is no order of precedence for step 1) and step 2).

[0046] In step three, the vibration motor 3 is turned on to excite the vibration source, and the vibration signal is transmitted through the water body in the leakage area to identify and locate the leakage.

[0047] In step three, the fiber optic demodulator injects narrow coherent laser pulses into the optical fiber in the vibration sensing optical cable set at the joint of the back soil surface of the ground-connected wall. When leakage occurs in the ground-connected wall structure, it will disturb the sensing optical cable, and the refractive index and length of the optical fiber at the corresponding position will change, causing the optical phase intensity at the corresponding position to change. By demodulating the amplitude of the optical phase along the optical fiber with the fiber optic demodulator connected to the optical fiber to obtain vibration intensity information, it can be identified whether the ground-connected wall structure has leakage. At the same time, the detector in the fiber optic demodulator can identify the location of the ground-connected wall leakage point by performing time domain analysis on the received optical phase difference signal based on formula (1):

[0048]

[0049] Where L is the distance from the leakage point to the end of the optical fiber, c is the propagation speed of light, n is the effective refractive index of the optical fiber, τ d The time required for light to travel back and forth through the leak.

[0050] Parts or structures not specifically described in the present invention may adopt existing technologies or existing products and will not be described in detail here.

[0051] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A ground-connected wall leakage detection device based on active vibration source, characterized in that: It includes a vibration sensing optical cable and a vibration source manufacturing device, which are symmetrically arranged about the construction joint of the ground-connected wall. The vibration source manufacturing device is arranged on the facing soil surface of the ground-connected wall, and the vibration sensing optical cable is arranged on the back soil surface of the ground-connected wall.

2. The ground-connected wall leakage detection device based on active vibration source according to claim 1 is characterized in that: The vibration sensing optical cable is a metal-based cable-shaped distributed strain optical cable, which is fixed on the steel cage by using a cable tie.

3. The ground-connected wall leakage detection device based on active vibration source according to claim 1 is characterized in that: The vibration source manufacturing equipment comprises a vibration steel pipe and a vibration motor, wherein the vibration motor is arranged in the vibration steel pipe and is used for exciting the vibration source.

4. The ground-connected wall leakage detection device based on active vibration source according to claim 3 is characterized in that: The bottom of the vibrating steel pipe is sealed and spot-welded to the inner side of the H-shaped steel at the joint of the previously constructed ground wall, and the interior of the vibrating steel pipe is filled with water.

5. A ground-connected wall leakage detection method based on active vibration source, characterized in that: The leakage detection is performed using the ground-connected wall leakage detection device based on an active vibration source as described in any one of claims 1 to 4, comprising the following steps: Step 1: Selecting a leakage detection work area for the foundation pit ground-connected wall structure; Step 2: Arrange a ground-connected wall leakage detection device based on an active vibration source; Step three: Conduct ground-connected wall leakage detection.

6. The method for detecting leakage of ground-connected wall based on active vibration source according to claim 5, characterized in that: In step one, the principle for selecting the leakage detection work area is: select the construction joints of adjacent ground-connected walls as the leakage detection work area.

7. The method for detecting leakage of ground-connected wall based on active vibration source according to claim 5, characterized in that: In step 2, the steps of arranging the ground-connected wall leakage detection device based on active vibration source include: 1) The vibration sensing optical cable uses a metal-based distributed strain optical cable and is fixed to the steel cage with a cable tie; 2) After the bottom of the vibration steel pipe is sealed with a plug, the vibration steel pipe is spot welded to the inner side of the H-shaped steel at the joint of the first construction ground wall, the inside of the vibration steel pipe is filled with water, and the vibration motor is lowered into the vibration steel pipe, thereby completing the assembly of the vibration source manufacturing equipment; 3) The vibration sensing optical cable and the vibration source manufacturing equipment are symmetrically arranged at the construction joint of the ground-connected wall, the vibration source manufacturing equipment is arranged on the soil surface facing the ground-connected wall, and the vibration sensing optical cable is arranged on the soil surface behind the ground-connected wall; There is no order of precedence for step 1) and step 2).

8. The method for detecting leakage of ground-connected wall based on active vibration source according to claim 5, characterized in that: In step 3, the steps of conducting ground-connected wall leakage detection work include: Turn on the vibration motor to excite the vibration source, transmit the vibration signal through the water in the leakage area, and identify and locate the leakage.

9. The method for detecting leakage of ground-connected wall based on active vibration source according to claim 8, characterized in that: Narrow coherent laser pulses are injected into the optical fiber in the vibration sensing optical cable installed at the joint of the back soil surface of the ground-connected wall through an optical fiber demodulator. When leakage occurs in the ground-connected wall structure, the vibration sensing optical cable will be disturbed, and the refractive index and length of the optical fiber at the corresponding position will change, causing the light phase intensity at the corresponding position to change. The optical fiber demodulator connected to the optical fiber demodulates the amplitude of the light phase along the optical fiber to obtain the vibration intensity information, so as to identify whether the ground-connected wall structure has leakage.

10. The method for detecting leakage of ground-connected wall based on active vibration source according to claim 8, characterized in that: The location of the ground-connected wall leakage point can be identified by performing time domain analysis on the received optical phase difference signal based on formula (1) using an optical fiber demodulator: Where L is the distance from the leakage point to the end of the optical fiber, c is the propagation speed of light, n is the effective refractive index of the optical fiber, τ d The time required for light to travel back and forth through the leak.

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