A method for detecting leakage position of a super-deep foundation pit enclosure structure

Abstract

The application relates to a foundation pit leakage detection method, in particular to a kind of leakage position detection method of ultra-deep foundation pit enclosure structure, comprising S1: preparation, before the construction of enclosure structure, insert several metal pipes at the position needing to be detected, set positive electrode outside the enclosure structure;S2: pouring foundation pit enclosure structure, the length of the metal pipe is greater than the thickness of foundation pit enclosure structure;S3: metal pipe top end sets negative electrode;S4: respectively measure the potential difference between positive and negative electrode and then increase the leakage energy flowing into underground continuous wall and its bottom by enhancing ECR tracer, by embedding steel pipe in enclosure structure in advance, it can be convenient to detect the leakage in foundation pit.

Description

Technical Field

[0001] This application relates to leakage detection of foundation pits, and more particularly to a method for detecting the leakage location of ultra-deep foundation pit retaining structures. Background Technology

[0002] After the foundation pit is excavated, when it is necessary to carry out foundation construction, a retaining structure needs to be set up inside the foundation pit. The retaining structure must not be permeable to water, otherwise water seepage will cause the foundation pit to be unable to continue construction or cause quality problems after construction.

[0003] An existing ECR leakage detection method is used to detect the leakage location of the foundation pit retaining structure. This method involves setting a positive electrode and then placing a negative electrode at the location to be detected. The potential difference between the positive and negative electrodes is used to determine whether leakage has occurred. In the case of leakage, even slight leakage will cause changes in the electric field of the entire stratum due to the movement of ions. By placing negative electrodes in different locations, detailed leakage information can be obtained.

[0004] Existing technologies involve the installation of electrodes, but the retaining structure in ultra-deep foundation pits is relatively thick, making it difficult to install and fix the electrodes. In order to allow the detection electrodes to contact the soil at the bottom of the retaining structure, existing technologies measure by drilling holes in the retaining structure and then inserting steel pipes. This method of drilling holes is labor-intensive and damages the retaining structure. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this application is to provide a method for detecting leakage locations in ultra-deep foundation pit retaining structures, which facilitates the installation and fixation of electrodes.

[0006] The above-mentioned objective of this application is achieved through the following technical solution: a method for detecting the leakage location of an ultra-deep foundation pit retaining structure, comprising: S1: preparation work, inserting several metal pipes at the location to be detected before the retaining structure is erected, and setting a positive electrode on the outside of the retaining structure; S2: pouring the foundation pit retaining structure, wherein the length of the metal pipes is greater than the thickness of the foundation pit retaining structure; S3: setting a negative electrode at the top of the metal pipes; S4: measuring the potential difference between the positive and negative electrodes respectively, and then increasing the leakage energy flowing into the underground continuous wall and its bottom by enhancing the ECR tracer.

[0007] By adopting the above technical solution, the potential difference between the positive and negative electrodes can be used to detect whether leakage occurs. Because it is an ultra-deep foundation pit, the bottom of the retaining structure can be detected by inserting a metal pipe first, which is more convenient than drilling holes later. Compared with building the retaining structure first and then conducting the test, it is more troublesome to drill holes in the retaining structure and insert the metal pipe into the soil. Drilling holes in the retaining structure will also damage the strength of the retaining structure.

[0008] Furthermore, the top end of the metal tube is provided with a fixing groove for inserting electrodes.

[0009] By adopting the above technical solution, the electrodes are fixed in the fixing groove, making them less prone to shaking and improving accuracy.

[0010] Furthermore, a vertical detection rod is provided inside the metal tube, and the vertical detection rod is slidably connected to the metal tube in the longitudinal direction.

[0011] By adopting the above technical solution, the tilt of the metal pipe can be detected by the vertical detection rod. Simply pull the vertical detection rod upward and slide it to make the metal pipe and the vertical detection rod collinear. In this way, as long as the vertical detection rod is vertical, the metal pipe is vertical, and the tilt of the vertical detection rod is the tilt of the metal pipe.

[0012] Furthermore, the top of the vertical probe is provided with a placeholder block of the same size as the negative electrode.

[0013] By adopting the above technical solution, the placeholder block is placed in the fixed groove to block the metal pipe. The placeholder block can block the metal pipe during the concrete pouring process, thereby making the inside of the metal pipe cleaner, facilitating the extension and retraction of the vertical probe, and making it less prone to jamming.

[0014] Furthermore, the bottom end of the vertical probe is connected to a limiting post that is slidably connected to the metal tube.

[0015] By adopting the above technical solution, the setting of the limiting post prevents the vertical probe from detaching directly when pulled upwards. When measuring whether the vertical probe is vertical, it is only necessary to pull the vertical probe upwards until the limiting post is at the opening of the metal tube. The limiting post prevents the vertical probe from detaching from the metal tube, so there is no need to worry about the vertical probe detaching from the metal tube. This setting facilitates the detection of the verticality of the vertical probe.

[0016] Furthermore, before measuring the potential between the positive and negative electrodes, the vertical probe is pulled upwards, and a plumb bob is used to measure whether the vertical probe is vertical. If it is vertical, the measurement continues. If there is a deviation, the actual position of the bottom of the metal tube is calculated before the measurement is performed to obtain an accurate measurement point.

[0017] By adopting the above technical solution, if the metal tube is tilted, the area directly below the electrode will not be the actual detection position. By measuring the vertical probe with a plumb bob, if it is not vertical, we know that the metal tube is tilted. The operation is convenient and easy.

[0018] Furthermore, the specific method for calculating the actual position of the bottom end of the metal tube is as follows: the length of the metal tube is *a*, the length of the vertical probe rod is *b*, the horizontal distance between the top of the vertical probe rod and the metal tube is measured as *c*, the vertical height of the metal tube is *d*, and the horizontal distance between the bottom of the metal tube and the top of the vertical probe rod is *e*. Obtaining *e* gives the actual position measured by the electrode at that location. A right triangle is drawn using the given coordinates A, B, and C, and the following formula... Calculate e.

[0019] By adopting the above technical solution, the metal pipe is already buried at the bottom of the concrete during construction. At this time, the steel pipe is tilted, and the actual position of the bottom end of the metal pipe extending into the soil is unknown. Through trigonometric function calculations, the actual position of the bottom end of the metal pipe extending into the soil can be obtained. Therefore, there is no need to limit the steel pipe during concrete pouring, allowing the metal pipe to tilt freely. This is because there should not be any unnecessary supports within the retaining structure that would affect its stability. Moreover, it is not easy to fix the metal pipe during concrete pouring because the ground is just soil, which has poor stability. If the retaining structure is completed first and then holes are drilled in it to insert the metal pipe, it will cause greater damage to the retaining structure and is more likely to cause leakage. However, in the above solution, the metal pipe is arranged in advance before pouring the concrete. The metal pipe not only does not damage the stability of the retaining structure, but also combines with the concrete to form a more robust structure.

[0020] Furthermore, the vertical detection rod is cylindrical and is threadedly connected to the limiting post.

[0021] By adopting the above technical solution, because of the threaded connection between the limiting post and the vertical detection rod, the vertical detection rod can be separated from the limiting post and reused, saving materials. The cylindrical vertical detection rod can also be easily rotated to separate the vertical detection rod from the limiting post. In this way, the limiting post is buried underground, and the vertical detection rod can be reused.

[0022] Furthermore, after the verticality measurement is completed, rotate the vertical probe rod to disengage it from the limiting post, remove the vertical probe rod for the next use, place the negative electrode in the fixing slot, and measure the potential difference between the negative electrode and the positive electrode to determine whether there is leakage. Insert the vertical probe rod into the next metal tube and connect it to the limiting post to check the verticality. If there is a deviation, calculate the actual measurement position, place the negative electrode and measure the potential difference between it and the positive electrode. If there is no deviation, directly place the electrode for testing.

[0023] By adopting the above technical solution, the reuse of the vertical probe rod saves a lot of costs. In this test, a lot of test points need to be set on the enclosure structure. If there is a vertical probe rod at each test point and it cannot be removed, a lot of costs will be wasted. The potential difference between the positive and negative poles is used.

[0024] In summary, this application includes at least one of the following beneficial technical effects: The potential difference between the positive and negative electrodes is used to detect whether there is leakage. Because it is an ultra-deep foundation pit, the bottom of the retaining structure can be detected by inserting a metal pipe first, which is more convenient than drilling later.

[0025] This method offers more precise measurements. Since the metal pipe is already buried at the bottom of the concrete, and the pipe is tilted, the actual point where the bottom of the pipe penetrates the soil is unknown. However, by calculating using trigonometric functions, the exact point can be determined. Therefore, there's no need to restrict the pipe's position during concrete pouring; the pipe can be allowed to tilt freely. This is because there shouldn't be any unnecessary supports within the retaining structure that could compromise its stability. Furthermore, it's difficult to secure the metal pipe during concrete pouring because the ground is soil, which has poor stability. If the retaining structure is constructed first, and then holes are drilled to insert the metal pipe, it would cause significant damage and increase the risk of leakage. In the above method, the metal pipe is pre-placed before pouring concrete. The metal pipe not only doesn't compromise the retaining structure's stability but also integrates with the concrete to form a more robust structure. Attached Figure Description

[0026] Figure 1 A schematic diagram of the internal structure of the metal tube and the vertical probe rod in the embodiment; Figure 2 yes Figure 1 Enlarged diagram of part A in the diagram; Figure 3 A diagram illustrating the trigonometric functions of the actual measurement points.

[0027] Reference numerals: 1. Metal tube; 2. Vertical probe; 3. Placeholder block; 4. Limiting post; 40. Flange. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the accompanying drawings.

[0029] An embodiment of a method for detecting leakage locations in an ultra-deep foundation pit retaining structure includes the following steps: S1: Preparation, referring to... Figure 1 , Figure 2Before the enclosure structure is erected, several metal pipes 1 are inserted at the detection location. In this embodiment, to make the detection more accurate, the spacing between each metal pipe is ±1m. In this embodiment, the metal pipes 1 are steel pipes, and the enclosure structure is a diaphragm wall. A vertical detection pipe is inserted into the steel pipe. The bottom of the vertical detection pipe is threadedly connected to a limit post 4. The limit post 4 has flanges 40 extending outward on both sides to prevent the limit post 4 from rotating relative to the steel pipe. A groove is provided inside the steel pipe for the flanges 40 to be embedded. A placeholder block 3 is provided at the top of the vertical detection pipe, and a fixing groove is provided at the top of the steel pipe. The placeholder block 3 is embedded in the fixing groove. S2: The foundation pit enclosure structure is poured, and the length of the steel pipe is greater than the thickness of the foundation pit enclosure structure. S3: A negative electrode is provided in the fixing groove. The size of the negative electrode is the same as that of the placeholder block 3. S4: The potential difference between the positive and negative electrodes is measured to determine whether there is water leakage.

[0030] Because the steel pipes are buried underground in advance, there is no need to drill holes after the enclosure structure is completed. This method saves a lot of time and work.

[0031] The fixed groove facilitates the installation of the negative electrode. The placeholder block 3 is used to prevent other impurities, concrete, etc. from entering the steel pipe before the negative electrode is installed. After the test is completed, the placeholder block 3 is placed in the fixed groove to protect the steel pipe from blockage, so that it can be retested after leakage repair.

[0032] When pouring concrete for the retaining structure, the pouring of concrete can easily cause the steel pipe to tilt. If the steel pipe is tilted after the retaining structure is completed, the position measured by the negative electrode will not be directly below the negative electrode, resulting in a deviation. In order to measure the leak point more accurately and to accurately measure the location of the leak, it is necessary to obtain the true measurement position of the negative electrode at this time.

[0033] After the retaining structure is completed, pull the occupant block 3 upwards, which will cause the vertical probe 2 to be pulled out upwards. Due to the setting of the limiting column 4, the vertical probe 2 is collinear with the steel pipe. At this time, a plumb bob is placed on the occupant block 3 to measure whether the vertical probe 2 is vertical. If the vertical probe 2 is vertical, the actual detection position is directly below the negative electrode. If the vertical probe 2 is not vertical, there is a deviation. At this time, it is necessary to calculate the actual position of the metal pipe 1 and the actual contact position of the soil below the retaining structure.

[0034] The specific method for calculating the actual position of the bottom end of the actual metal tube 1 is as follows: Let the length of the metal tube 1 be *a*, the length of the vertical probe 2 be *b*, the vertical distance between the top of the vertical probe 2 and the metal tube 1 be *c*, the vertical height of the metal tube 1 be *d*, and the horizontal distance between the bottom of the metal tube 1 and the top of the vertical probe 2 be *e*. Obtaining *e* gives the actual position measured by the electrode at that location. (Refer to...) Figure 3Draw a right triangle and calculate e using the given a, b, c and the following formula.

[0035] The calculated location of the probe point and the initially pre-buried steel pipe are likely to be misaligned. This is because the steel pipe may shift during the concrete pouring process. Furthermore, the steel pipe is inserted downwards a certain distance when it is pre-buried in the soil. Therefore, when the steel pipe tilts, the bottom of the steel pipe will be different from the pre-buried location, affecting the accuracy of the measurement.

[0036] After obtaining accurate detection points, each electrode position is tested to identify the leakage point. Then, each location with leakage will be excavated. If there is a deviation, the excavated area will be larger or inaccurate. On the one hand, this wastes manpower and resources, and on the other hand, errors may occur during the repair process, resulting in the actual leakage point not being resolved.

[0037] In this embodiment, the steel pipes and vertical probe rods 2 are standardized so that each steel pipe has the same length and material, and each vertical probe rod 2 has the same length and material, with the length of the vertical probe rod 2 being greater than that of the steel pipe.

[0038] To save materials, the vertical probe 2 can be reused because it is threadedly connected to the limiting post 4. After the measurement is completed, the vertical probe 2 can be rotated out and reused.

[0039] The spacer block 3 and the vertical probe rod 2 are separated. After the limiting post 4 is placed inside the steel pipe, the spacer block 3 is blocked in the fixed groove. When measurement is required, the spacer block 3 is removed, and the vertical probe rod 2 is threaded into the steel pipe. Then, the vertical probe rod 2 is rotated so that its thread is connected to the limiting post 4 before proceeding to the next measurement step.

[0040] In another embodiment, the placeholder block 3 is threadedly connected to the vertical probe rod 2, which facilitates the placement and removal of the vertical probe rod 2.

[0041] Because the detection of leaks requires not only information from the construction unit, but also from the inspection and supervision units, if there is no vertical probe to check the inclination, the only way to detect leaks is by using the location of the pre-embedded steel pipe as the detection point. However, this detection location is not consistent with the location of the electrodes exposed on the surface of the enclosure structure. Therefore, the inspection or supervision units can use the vertical probe to detect leaks without referring to the location of the pre-embedded steel pipe provided by the construction unit. This makes the measurement more accurate and makes it easier to pass the inspection by the inspection and supervision units.

[0042] The specific implementation process involves first selecting a standard-sized steel pipe, then placing a limiting post 4 inside the pipe, and then placing a occupant block 3 in the fixed groove at the top of the pipe. Concrete is then poured to form a diaphragm wall. When detecting leak points, the occupant block 3 is removed first, and then the vertical detection rod 2 is inserted into the steel pipe and threadedly connected to the limiting post 4. The vertical detection rod 2 is then pulled upwards. Because the limiting post 4 ensures that the vertical detection rod 2 is collinear with the steel pipe, a plumb bob or other instruments are used to measure the verticality of the vertical detection rod 2. If any deviation occurs, the actual measurement point is calculated. Then, the negative electrode is placed in the fixed groove, and the potential difference between the positive and negative electrodes is measured. Finally, an enhanced ECR tracer is used to increase the leakage energy flowing into the diaphragm wall and its bottom.

[0043] The embodiments described in this specific implementation are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for detecting leakage locations in the retaining structure of an ultra-deep foundation pit, characterized in that: The process includes: S1: Preparatory work, inserting several metal tubes (1) into the locations to be tested before the enclosure structure is erected, and setting positive electrodes on the outside of the enclosure structure; S2: Pouring the foundation pit enclosure structure, wherein the length of the metal tubes (1) is greater than the thickness of the foundation pit enclosure structure; S3: Setting negative electrodes at the top of the metal tubes (1); S4: Measuring the potential difference between the positive and negative electrodes respectively, and then increasing the leakage energy flowing into the enclosure structure and its bottom by enhancing the ECR tracer. The metal tubes (1) are steel pipes, and the top of the metal tubes (1) is provided with a fixing groove for electrode embedding. A vertical probe rod (2) is provided inside the metal tubes (1), and the vertical probe rod (2) is longitudinally slidably connected to the metal tubes (1). Before measuring the potential difference between the positive and negative electrodes, pull the vertical probe rod (2) upward and use a plumb bob to measure whether the vertical probe rod (2) is vertical. If it is vertical, continue measuring. If there is a deviation, calculate the actual position of the bottom of the actual metal tube (1) and then measure it to obtain an accurate measurement point. The specific method for calculating the actual position of the bottom end of the actual metal tube (1) is as follows: the length of the metal tube (1) is a, the length of the vertical probe (2) is b, the horizontal distance between the top of the vertical probe (2) and the metal tube (1) is measured as c, and the horizontal distance between the bottom of the metal tube (1) and the top of the vertical probe (2) is measured as e. Obtaining e gives the actual position of the negative electrode. Draw a right triangle using the known a, b, c, and the following formula... Calculate e.

2. The method for detecting leakage location in an ultra-deep foundation pit retaining structure according to claim 1, characterized in that, The top of the vertical probe (2) is provided with a placeholder block (3) of the same size as the negative electrode.

3. The method for detecting leakage location in an ultra-deep foundation pit retaining structure according to claim 2, characterized in that, The bottom end of the vertical probe (2) is connected to a limiting post (4) that is slidably connected to the metal tube (1).

4. The method for detecting leakage location in an ultra-deep foundation pit retaining structure according to claim 1, characterized in that, The vertical probe (2) is cylindrical and is threadedly connected to the limiting post (4).

5. The method for detecting leakage location in an ultra-deep foundation pit retaining structure according to claim 4, characterized in that, After the verticality measurement is completed, rotate the vertical probe rod (2) to separate it from the limiting post (4), remove the vertical probe rod (2) for the next use, put the negative electrode in the fixed groove, measure the potential difference between the negative electrode and the positive electrode to determine whether there is leakage here, insert the vertical probe rod (2) into the next metal tube (1) and connect it with the limiting post (4) to detect the verticality. If there is a deviation, calculate the actual measurement position and put in the negative electrode to measure the potential difference between it and the positive electrode. If there is no deviation, put in the electrode directly for detection.

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