A nondestructive detection device and method for foundation pit enclosure leakage based on conductivity increase and decrease

Abstract

The present invention provides a non-destructive detection device and method for foundation pit enclosure leakage based on conductivity increase and decrease, which addresses the problems of limited quantitative analysis capability, reduced resolution and certain destructiveness of existing foundation pit enclosure leakage detection technology. It includes an outer tube with a closed bottom and a through hole on the side wall, an inner tube sleeved inside the outer tube, a conductive rod arranged in the inner cavity of the inner tube along the axis, a filling sand layer arranged in the inner cavity of the inner tube, and a control terminal connected to the conductive rod signal. Steps: pre-embed the detection device at the joint of the underground foundation pit enclosure, remove the inner tube within 24 hours after the initial setting of the concrete at the joint, regularly perform electric pulse monitoring on the conductive rod, the control terminal collects the initial value of each conductive segment of the conductive rod, regularly perform electric pulse monitoring on the conductive rod, the resistance of the corresponding position of the conductive rod is reduced and a reflection signal is generated, a database of the time and amplitude of the reflection signal is established and the monitoring results of each time are compared to obtain the initial position of the foundation pit enclosure leakage.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction monitoring, and in particular to a non-destructive detection device and method for foundation pit enclosure leakage based on conductivity increase and decrease. Background Art

[0002] As urban underground space development continues, foundation pit projects are growing in scale and complexity, increasing the risk of leakage. Leakage not only weakens the stability of the pit retaining structure but can also lead to surrounding soil collapse, groundwater loss, and environmental damage, potentially jeopardizing the safety of construction workers and project quality.

[0003] Existing technologies for detecting leakage in foundation pit retaining systems mainly include ultrasonic testing, geological radar detection, and osmotic pressure water testing. Ultrasonic testing determines the location of leakage by analyzing the propagation characteristics of sound waves in a medium, but its quantitative analysis of defects is limited. Although geological radar detection can quickly detect underground structures, it suffers from significant signal interference and reduced resolution under complex geological conditions. Although the osmotic pressure water test is intuitive, it is cumbersome to operate and has a certain degree of destructiveness to underground structures. These detection technologies have limitations in their application on actual construction sites and are difficult to meet the increasingly stringent engineering safety and quality requirements. Therefore, there is an urgent need to develop more efficient, accurate, and non-destructive leakage detection technologies to ensure the safe construction and long-term stability of foundation pit projects. Summary of the Invention

[0004] In view of the problems of limited quantitative analysis capability, reduced resolution and certain destructiveness of existing foundation pit enclosure leakage detection technology, the present invention aims to provide a non-destructive detection device and method for foundation pit enclosure leakage based on conductivity increase and decrease.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a non-destructive detection device for foundation pit enclosure leakage based on conductivity increase and decrease, which includes: an outer tube, an inner tube, a conductive rod, a filling sand layer and a control terminal. The top of the outer tube is open, and its bottom end is provided with a closed bottom plate. The side wall of the outer tube is provided with multiple through holes. The inner tube is in a through cylindrical shape, and the inner tube is sleeved in the outer tube. The side wall of the inner tube has no through holes. The conductive rod is arranged in the inner cavity of the inner tube along the axis of the inner tube. Sand is filled between the inner tube and the conductive rod to form a filling sand layer. The conductive rod is connected to the control terminal signal.

[0006] The present invention provides a nondestructive detection device for foundation pit enclosure leakage based on conductivity increase and decrease. The device comprises an outer tube with a closed bottom and a through hole in the side wall, an inner tube sleeved inside the outer tube, a conductive rod arranged in the inner cavity of the inner tube along the axis, a filling sand layer arranged in the inner cavity of the inner tube, and a control terminal connected to the conductive rod signal. During the concrete pouring process at the foundation pit enclosure joint, the inner tube is used to isolate and protect the conductive rod to prevent water in the concrete from seeping into the inner tube. The inner tube is removed within 24 hours after the concrete has initially set. When water leakage occurs at the joint, the leaked water penetrates through the through hole of the outer tube and the filling sand layer to the conductive rod. Construction personnel regularly perform electric pulse monitoring on the conductive rod. The conductive rod has a high resistance in a dry state, but after it comes into contact with water, water molecules will fill the conductive rod. The gaps between the polymer chains are filled, the ion transmission path is enhanced, the resistance of the corresponding position of the conductive rod is reduced and a reflected signal is generated. A database of the time and amplitude of the reflected signal is established and compared with the monitoring results of each time. The position of the resistance change can be accurately located, and the initial position of the foundation pit retaining wall leakage can be obtained. If a leakage of a longer length or more points occurs, it is determined whether the original leakage point is serious and spreading, or a new leakage point has appeared; the control terminal is used to receive the electric pulse reflection characteristics of the conductive rod to detect the leakage point. There is no signal interference at the construction site, which improves the accuracy of the detection result. Moreover, the detection device has a simple structure and is easy to operate. It will not cause damage to the foundation pit retaining structure, and realizes non-destructive detection of underground foundation pit retaining wall leakage points.

[0007] Furthermore, the conductive rod includes a plurality of conductive segments arranged along the axis, and an insulating layer arranged between two adjacent conductive segments, and each conductive segment is connected to the control terminal signal.

[0008] Furthermore, a corresponding locking structure is provided between the outer wall of the inner tube and the inner wall of the outer tube, so that the inner tube is embedded in the outer tube and locked therewith.

[0009] Furthermore, the conductive rod is made of conductive polymer.

[0010] Furthermore, the top of the conductive rod is at least 10 cm higher than the top of the foundation pit enclosure.

[0011] In addition, the present invention also provides a non-destructive detection method for foundation pit enclosure leakage based on conductivity increase and decrease, using the non-destructive detection device for foundation pit enclosure leakage based on conductivity increase and decrease, the steps are as follows:

[0012] S1: Pre-buried foundation pit retaining wall leakage non-destructive detection device at the joint of underground foundation pit retaining wall, with the top of the outer tube and inner tube flush with the top of the foundation pit retaining wall. The inner tube shall be removed within 24 hours after the concrete at the joint of the foundation pit retaining wall has initially set.

[0013] S2: After the conductive rod is stable, an electric pulse is sent to the conductive rod, and the control terminal collects the initial values ​​of each conductive segment of the conductive rod, and the conductive rod is regularly monitored by electric pulses; when there is water leakage at the joint, the conductive rod is regularly monitored by electric pulses, and the resistance of the corresponding position of the conductive rod is reduced and a reflected signal is generated. A database of the time and amplitude of the reflected signal is established and compared with each monitoring result, so as to locate the position of the resistance change and obtain the initial position of the foundation pit retaining wall leakage.

[0014] The present invention provides a non-destructive detection method for foundation pit retaining wall leakage based on conductivity increase and decrease. The non-destructive detection device for foundation pit retaining wall leakage is pre-buried at the joints of underground foundation pit retaining wall. The inner tube is removed within 24 hours after the initial setting of the concrete at the joints of the foundation pit retaining wall. The conductive rod is regularly monitored with electric pulses. The control terminal collects the initial values ​​of each conductive segment of the conductive rod. When there is water leakage at the joint, the leaked water penetrates through the through-hole of the outer tube and the filling sand layer to the conductive rod. The construction personnel regularly monitor the conductive rod with electric pulses. The resistance of the corresponding position of the conductive rod is reduced and a reflected signal is generated. A database of the time and amplitude of the reflected signal is established and compared each time. The monitoring results can accurately locate the position of resistance change and obtain the initial position of foundation pit retaining wall leakage. If leakage occurs over a longer length or at more locations, it can be determined whether the original leakage point is serious and has spread, or a new leakage point has appeared. By burying detection devices in the joints of foundation pit retaining wall in advance and utilizing the performance attenuation of the conductive rod after water seepage in the later stage, the position of the foundation pit leakage point and the range of leakage spread can be dynamically and accurately determined, thereby solving the problem that the position of underground foundation pit retaining wall leakage detection is difficult to accurately determine and the development of leakage points cannot be evaluated, and the function of in-situ non-destructive leakage detection of retaining walls at the construction site can be realized.

[0015] Furthermore, step S2 also includes: the conductive rod includes a plurality of conductive segments arranged along the axis, and an insulating layer arranged between two adjacent conductive segments, the plurality of conductive segments are numbered in advance, and each conductive segment is connected to the control terminal signal; when water seeps at the joint, the resistance of the corresponding conductive segment decreases and a reflected signal is generated, the control terminal receives the time and amplitude of the reflected signal, and locates the longitudinal position of the corresponding numbered conductive segment where the resistance changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of the non-destructive detection device for foundation pit enclosure leakage based on conductivity increase and decrease of the present invention;

[0017] Figure 2 Schematic diagram of a conductive rod and a filling sand layer in a nondestructive detection device for foundation pit enclosure leakage according to an embodiment of the present invention;

[0018] Figure 3 A top view of a nondestructive detection device for foundation pit enclosure leakage according to an embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of the connection between multiple conductive segments and a control terminal in a nondestructive detection device for foundation pit enclosure leakage according to an embodiment of the present invention;

[0020] Figure 5 This is a schematic diagram of an embodiment of the present invention's nondestructive detection method for foundation pit enclosure leakage based on conductivity increase and decrease. The numbers in the figure are as follows:

[0021] Nondestructive detection device for foundation pit enclosure leakage 10; outer tube 1; through hole 1a; inner tube 2; locking structure 3; conductive rod 5; conductive segment 51; insulating layer 52; filling sand layer 6; foundation pit enclosure 20; electric pulse transmitting device 30. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention. For ease of description, the terms "upper" and "lower" will be used in the following text in the same direction as in the accompanying drawings, but this does not constitute a limitation of the present invention.

[0023] Combine Figures 1 to 5 The present invention is described as follows: a nondestructive detection device 10 for foundation pit retaining wall leakage based on conductivity increase and decrease, comprising: an outer tube 1, an inner tube 2, a conductive rod 5, a filling sand layer 6, and a control terminal (not shown). The cylindrical outer tube 1 is open at the top and provided with a closed bottom plate at the bottom. The side wall of the outer tube 1 is evenly and densely distributed with a plurality of circular through holes 1a. The inner tube 2 is in a through cylindrical shape and is tightly sleeved within the outer tube 1. The side wall of the inner tube 2 has no through holes. The conductive rod 5 is arranged in the inner cavity of the inner tube 2 along its axis. Sand is filled between the inner tube 2 and the conductive rod 5 to form a filling sand layer 6. The conductive rod 5 is connected to the control terminal signal.

[0024] The present invention provides a nondestructive detection device 10 for foundation pit enclosure leakage based on conductivity increase and decrease, which includes an outer tube 1 with a closed bottom end and a through hole 1a provided on the side wall, an inner tube 2 sleeved inside the outer tube 1, a conductive rod 5 arranged along the axis in the inner cavity of the inner tube 2, a filling sand layer 6 arranged in the inner cavity of the inner tube 2, and a control terminal connected to the conductive rod 5 for signal connection. During the concrete pouring process at the joints of the foundation pit enclosure 20, the inner tube 2 is used to isolate and protect the conductive rod 5 to prevent water in the concrete from seeping into the inner tube 2. The inner tube 2 is removed within 24 hours after the initial setting of the concrete. When there is water leakage at the joints, the leaking water penetrates through the through hole 1a of the outer tube 1 and the filling sand layer 6 to the conductive rod 5. Construction personnel regularly perform electric pulse monitoring on the conductive rod 5. The conductive rod 5 has a high resistance in a dry state, but after it comes into contact with water, the water The molecules will fill the gaps between the polymer chains of the conductive rod 5, enhance the ion transmission path, cause the resistance of the corresponding position of the conductive rod 5 to decrease and generate a reflected signal. By establishing a database of the time and amplitude of the reflected signal and comparing the monitoring results each time, the position of the resistance change can be accurately located, and the initial position of the leakage of the foundation pit enclosure 20 can be obtained. If a leakage of a larger length or at more points occurs, it is determined whether the original leakage point is serious and spreads, or a new leakage point has appeared; the control terminal is used to receive the electric pulse reflection characteristics of the conductive rod 5 to detect the leakage point, and there is no signal interference at the construction site, which improves the accuracy of the detection result; moreover, the detection device has a simple structure and is easy to operate. It will not cause damage to the foundation pit enclosure 20 structure, and realizes non-destructive detection of leakage points of underground foundation pit enclosure 20.

[0025] like Figure 4 As shown, the conductive rod 5 comprises multiple conductive segments 51 arranged along its axis, and an insulating layer 52 disposed between adjacent segments 51. Each conductive segment 51 is signal-connected to a control terminal. The multiple conductive segments 51 are pre-numbered. Since each conductive segment 51 is signal-connected to a control terminal, the multiple conductive segments 51 are connected in parallel. When one or more conductive segments 51 come into contact with leaking water and cause a change in resistance, the control terminal receives the electrical pulse reflection signal from the corresponding conductive segment 51 and can accurately determine the longitudinal location of the leak. In this embodiment, a conductive segment 51 is positioned every 50 cm from the bottom of the inner tube 2, and the multiple conductive segments 51 are connected in parallel.

[0026] like Figure 3 As shown, a corresponding locking structure 3 is provided between the outer wall of the inner tube 2 and the inner wall of the outer tube 1, so that the inner tube 2 is embedded in the outer tube 1 and locked with it, thereby improving the stability of the connection between the two. The specific structure and connection relationship of the locking structure 3 are prior art and will not be repeated here.

[0027] The conductive rod 5 is made of a conductive polymer, such as polypyrrole, polyaniline, etc., but not limited thereto.

[0028] The top of the conductive rod 5 is at least 10 cm higher than the top of the foundation pit enclosure 20 to avoid being covered by the concrete poured outside the outer tube 1.

[0029] The following combination Figures 1 to 5 The nondestructive detection method for foundation pit enclosure leakage based on conductivity increase and decrease of the present invention is described as follows:

[0030] S1: If Figure 5 As shown, a non-destructive detection device 10 for foundation pit enclosure leakage is pre-buried at the joint of the underground foundation pit enclosure 20. The tops of the outer tube 1 and the inner tube 2 are flush with the top of the foundation pit enclosure 20. The inner tube 2 is removed within 24 hours after the concrete at the joint of the foundation pit enclosure 20 initially sets. Based on the actual situation, some sand is added between the outer tube 1 and the inner tube 2 to ensure that the filling sand layer 6 is dense.

[0031] S2: After the conductive rod 5 is stable, the electric pulse transmitting device 30 sends electric pulses to the conductive rod 5, and the control terminal collects the initial values ​​of each conductive segment 51 of the conductive rod 5, and regularly performs electric pulse monitoring on the conductive rod 5; when there is water leakage at the joint, the leaking water penetrates through the through hole 1a of the outer tube 1 and the filling sand layer 6 to the conductive rod 5, and the construction personnel regularly perform electric pulse monitoring on the conductive rod 5. The resistance of the corresponding position of the conductive rod 5 decreases and generates a reflected signal. A database of the time and amplitude of the reflected signal is established and compared with each monitoring result, so as to accurately locate the position of the resistance change and obtain the initial position of the leakage of the foundation pit enclosure 20. If there is leakage of a larger length or more points, it is determined whether the original leakage point is serious and spreads, or a new leakage point has appeared.

[0032] The present invention provides a nondestructive detection method for foundation pit enclosure leakage based on conductivity increase and decrease. The nondestructive detection device 10 for foundation pit enclosure leakage is pre-buried at the joints of the underground foundation pit enclosure 20. The inner tube 2 is removed within 24 hours after the concrete at the joints of the foundation pit enclosure 20 initially sets. The conductive rod 5 is regularly monitored for electric pulses. The control terminal collects the initial values ​​of each conductive segment 51 of the conductive rod 5. When there is water leakage at the joint, the leaking water penetrates through the through hole 1a of the outer tube 1 and the filling sand layer 6 to the conductive rod 5. The construction personnel regularly monitor the conductive rod 5 for electric pulses. The resistance at the corresponding position of the conductive rod 5 decreases and generates a reflection signal. The data of the time and amplitude of the reflection signal is established. By comparing the monitoring results of each time, the position of the resistance change can be accurately located, and the initial position of the leakage of the foundation pit retaining wall 20 can be obtained. If leakage occurs in a longer length or at more locations, it can be determined whether the original leakage point is serious and has spread, or a new leakage point has appeared. By burying the detection device in the joints of the foundation pit retaining wall 20 in advance, the performance attenuation of the conductive rod 5 after the later water seepage is used to dynamically and accurately determine the position of the foundation pit leakage point and the range of leakage spread, thereby solving the problem that the position of the underground foundation pit retaining wall 20 leakage detection is difficult to accurately determine and the development of the leakage point cannot be evaluated, and the function of in-situ non-destructive leakage detection of the retaining wall at the construction site can be realized.

[0033] The step S2 further includes: the conductive rod 5 includes a plurality of conductive segments 51 arranged along the axis, and an insulating layer 52 arranged between two adjacent conductive segments 51, the plurality of conductive segments 51 are numbered in advance, and each conductive segment 51 is connected to the control terminal signal; when water seeps at the joint, the leaked water penetrates through the through hole 1a of the outer tube 1 and the filling sand layer 6 into the conductive segment 51, causing the resistance of the corresponding conductive segment 51 to decrease and generate a reflected signal, the control terminal receives the time and amplitude of the reflected signal, and locates the longitudinal position of the corresponding numbered conductive segment 51 where the resistance changes, thereby accurately determining the depth of the leakage point and the leakage diffusion range.

[0034] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of the claims.

Claims

1. A non-destructive detection device for foundation pit enclosure leakage based on conductivity increase and decrease, characterized in that: It includes: An outer tube, an inner tube, a conductive rod, a filling sand layer, and a control terminal. The outer tube has an open top and a closed bottom plate at its bottom. The outer tube sidewall has multiple through holes. The inner tube is cylindrical and sleeved within the outer tube. The inner tube sidewall has no through holes. The conductive rod is arranged in the inner cavity of the inner tube along its axis. Sand is filled between the inner tube and the conductive rod to form a filling sand layer. The conductive rod is connected to the control terminal signal. The conductive rod includes multiple conductive segments arranged along the axis and an insulating layer provided between two adjacent conductive segments. Each conductive segment is connected to the control terminal signal. Pre-buried foundation pit retaining wall leakage non-destructive detection device at the underground foundation pit retaining wall joints, with the tops of the outer and inner pipes flush with the top of the foundation pit retaining wall. The inner pipe shall be removed within 24 hours after the concrete at the foundation pit retaining wall joints has initially set. After the conductive rod stabilizes, an electric pulse is sent to the conductive rod. The control terminal collects the initial values ​​of each conductive segment of the conductive rod and regularly monitors the conductive rod with electric pulses. When there is water leakage at the joint, the conductive rod is regularly monitored with electric pulses. The resistance at the corresponding position of the conductive rod decreases and generates a reflected signal. A database of the time and amplitude of the reflected signal is established and compared with each monitoring result. The position of the resistance change can be located and the initial position of the foundation pit retaining wall leakage can be obtained. The conductive rod includes multiple conductive segments arranged along the axis and an insulating layer arranged between two adjacent conductive segments. The multiple conductive segments are numbered in advance, and each conductive segment is connected to the control terminal signal. When water seeps at the joint, the resistance of the corresponding conductive segment decreases and generates a reflected signal. The control terminal receives the time and amplitude of the reflected signal and locates the longitudinal position of the corresponding numbered conductive segment where the resistance changes.

2. The nondestructive detection device for foundation pit enclosure leakage based on conductivity increase and decrease according to claim 1 is characterized in that: A corresponding locking structure is provided between the outer wall of the inner tube and the inner wall of the outer tube, so that the inner tube is embedded in the outer tube and locked therewith.

3. The nondestructive detection device for foundation pit enclosure leakage based on conductivity increase and decrease according to claim 1 is characterized in that: The conductive rod is made of conductive polymer.

4. The nondestructive detection device for foundation pit enclosure leakage based on conductivity increase and decrease according to claim 1 is characterized in that: The top of the conductive rod is at least 10 cm higher than the top of the foundation pit enclosure.

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