Foundation pit groundwater leakage path detection and repair effect detection method

Abstract

The invention provides a foundation pit groundwater leakage path detection and repair effect detection method which is characterized by comprising the following steps: S1, detecting a leakage path outside a pit; s2, installing a leakage path detection system; s3, confirming a leakage path in the pit; and S4, leakage repairing is conducted, then S1 is repeated for repairing effect detection, if the repairing effect is not qualified, S2 to S4 are repeated till the leakage detection result is qualified. According to the method, the pre-buried inclinometer pipe is used as a detection tool, on the basis that the original strength of the diaphragm wall is not affected, through detection of the leakage paths inside and outside the pit, the leakage joints are rapidly judged, the leakage paths and the leakage point positions are accurately positioned, and rapid detection of the leakage stopping effect is achieved.

Description

Technical Field

[0001] This invention belongs to the field of building construction engineering testing technology, and in particular relates to a rapid detection method for groundwater leakage paths and a rapid inspection method for repair quality during the foundation pit excavation stage. Background Technology

[0002] With the increasing number of foundation pit projects, many foundation pits pose certain risks of geological disasters due to geological and foundation conditions, such as ground subsidence, soil erosion, and rock collapse. Therefore, during foundation pit excavation, monitoring is necessary to ensure construction safety and the smooth progress of other related projects. Inclinometer tubes are generally used, placed on the slopes of the foundation pit, at joints within the retaining (pile) walls, and at representative locations, buried at a certain depth in the soil (generally 1.5-2 times the depth of the foundation pit). The number and spacing are determined according to the design drawings, with symmetrical placement on both sides of the foundation pit, but at least one inclinometer tube should be installed on each side. Inclinometer tubes are used for geological surveys to measure the relative dip and movement of geological structures.

[0003] Meanwhile, to avoid geological disasters, diaphragm walls (or underground continuous walls) or retaining walls are installed as support structures before excavation. Because the diaphragm walls are constructed in sections, joints exist, and these joints are the most prone to construction quality problems. Inadequate concrete pouring can lead to voids in the diaphragm wall joints, causing groundwater to leak from the outside of the pit into the pit after excavation. This leakage weakens the load-bearing capacity and rigidity of the underground continuous wall, increasing deformation of the pit support system and potentially causing wall tilting, joint cracking, or partial collapse, seriously threatening construction safety. If the leakage point expands, it may lead to piping or quicksand, further exacerbating soil loss from the pit sidewalls and causing the entire support structure to fail.

[0004] Currently, although a multi-well dewatering test is conducted before the foundation pit is excavated to predict leakage, the following problems exist: 1) Since this is an unexcavated state, it cannot completely and realistically simulate groundwater leakage during excavation. It often happens that no leakage occurs during the dewatering test, but leakage occurs during the excavation process. 2) Even if leakage is discovered, it only means that leakage has occurred. Because groundwater can seep over long distances, the specific leakage joints and leakage paths are not clear. When a leak is detected, existing technology involves grouting to seal it. However, the effectiveness of the sealant needs to be confirmed by a pumping test, which typically takes 2-3 days to obtain the results, not just on the same day. Summary of the Invention

[0005] This invention designs a method for detecting the path of groundwater leakage in foundation pits and the detection of repair effects. By utilizing the technology of pre-embedded inclinometers, it can accurately locate the leakage points at the joints of diaphragm walls through bidirectional positioning of external and internal leakage in the foundation pit, and visually judge the leakage sealing effect.

[0006] The technical solution of the present invention is as follows: A method for detecting groundwater leakage paths in foundation pits and assessing the effectiveness of remediation efforts. S1, conduct external leakage path detection; S2, Install the leakage path detection system; S3, confirm the leakage path inside the pit; S4 is used to repair the leak. Then S1 is repeated to test the repair effect. If it fails, S2-S4 are repeated until the leak test result is satisfactory.

[0007] Furthermore, in the aforementioned method for detecting and repairing groundwater leakage paths in foundation pits, S1 further includes: during the foundation pit excavation stage, injecting water of different colors into several pre-set inclinometer tubes, and observing the color of groundwater in the dewatering well outside the pit after a certain period of time to determine whether there is leakage. The inclinometer tubes are located in the joint of the diaphragm wall in the foundation pit, and the inclinometer tubes are provided with holes. When the water color in the dewatering well near the inclinometer tube does not change, it indicates that there is no leakage path outside the pit at the joint of the inclinometer tube, and S2-S4 is not required. When the water in the dewatering well near the inclinometer changes to a specific color, it is determined that there is a leak at the joint where the inclinometer is injected with the specific color water, and then S2-S4 are performed.

[0008] Furthermore, in the aforementioned method for detecting and repairing groundwater leakage paths in foundation pits, S2, the leakage path detection system includes: iron nails, electrode sensors, a moving device, a wear-resistant hydraulic line, an electrical signal receiver, a power supply, a clinometer, and a current detection device. The iron nails are driven into the inner side of the retaining walls on both sides of the joint and into the soil around the joint in the pit. The iron nails are connected to the electrode sensors. The electrical signal receiver is placed on the moving device. The electrode sensors are connected to the electrical signal receiver through the wear-resistant hydraulic line. The power supply is installed near the joint to be detected and has two wires connected to it. One wire is connected to the clinometer at the joint, and the other is connected to the current detection device. The current detection device is connected to the power supply on one side and to the electrical signal receiver on the other. The clinometer has holes in its body.

[0009] Preferably, in the method for detecting groundwater leakage paths and repair effects in foundation pits, if the excavation depth of the foundation pit is greater than or equal to 3 meters, the nails are driven into the retaining wall to a depth of 2-3 cm and into the foundation pit soil to a depth of greater than or equal to 5 cm.

[0010] Preferably, in the method for detecting and repairing groundwater leakage paths in foundation pits, if the excavation depth of the foundation pit is less than 3 meters, the iron nails only need to be driven into the soil around the joint, and the driving depth of the iron nails is 3-8 cm.

[0011] Furthermore, in the aforementioned method for detecting and repairing groundwater leakage paths in foundation pits, the iron nails are placed in the soil on both sides of the joint, with two rows on each side of the retaining wall, spaced 2m apart in height and width, and the top row 0.8-1.2m away from the top of the retaining wall; and three rows are placed every 1.5m along the retaining direction and perpendicular to the retaining direction in the soil inside the foundation pit, with three rows on each side of the joint.

[0012] Preferably, in the method for detecting and repairing groundwater leakage paths in foundation pits, the nails are placed in the soil on both sides of the joint, preferably at the damp points.

[0013] Preferably, in the method for detecting and repairing groundwater leakage paths in foundation pits, the current detection device is an electrometer-type current meter.

[0014] Preferably, in the method for detecting and repairing groundwater leakage paths in foundation pits, in step S3, electrolyte saline is added to the inclinometer tube, or the colored water in step S1 contains electrolyte saline.

[0015] Furthermore, in the method for detecting groundwater leakage paths and assessing the effectiveness of repairs in foundation pits, S3 further includes: S3-1: Connect all electrode sensors on the retaining wall and the soil inside the pit to the electrical signal receiver. If there is current, there is leakage, proceed to S3-2; if there is no current, there is no leakage, and the operation ends. S3-2, disconnect all connections between the electrical signal receiver and the soil electrode sensor in the pit. If there is current, the retaining wall is leaking, proceed to S3-3; if there is no current, the retaining wall is not leaking, proceed to S3-4. S3-3, disconnect all electrode sensors on the enclosure wall, select one electrode sensor on the enclosure wall and connect it to the electrical signal receiver, record the current value and then disconnect it, then connect the next electrode sensor on the enclosure wall and the electrical signal receiver, until all electrode sensors on the enclosure wall are connected to the electrical signal receiver in sequence. If the current detection device in the leakage path detection system has current passing through it, then the point corresponding to the electrode sensor is the point through which the leakage path passes. The point of the electrode sensor corresponding to the maximum current value is the central leakage location. S3-4. Disconnect the electrode sensors on the retaining wall, select one soil electrode sensor in the pit and connect it to the electrical signal receiver. Record the current value and then disconnect it. Then connect the next soil electrode sensor in the pit and the electrical signal receiver, until all soil electrode sensors in the pit are connected to the electrical signal receiver in sequence. When the current detection device in the leakage path detection system has current passing through it, the point corresponding to the electrode sensor is the point through which the leakage path passes. The point of the electrode sensor corresponding to the maximum current value is the central leakage location.

[0016] Furthermore, the method for detecting the path of groundwater leakage in a foundation pit and the detection of the repair effect, S3, further includes: connecting the electrode sensors to the electrical signal receiver one by one to confirm whether there is current passing through and recording the current value; finding the electrode sensor point corresponding to the maximum current value, which is the leakage location.

[0017] Furthermore, the aforementioned method for detecting and repairing groundwater seepage paths in foundation pits uses the electrode sensor point corresponding to the maximum current value as the center and covers all points through which the seepage path passes to perform regional leak repair.

[0018] Furthermore, in the aforementioned method for detecting and repairing groundwater leakage paths in foundation pits, during the diaphragm wall construction stage, inclinometer tubes are pre-fixed at the interface positions at both ends of the reinforcing cage to ensure that the inclinometer tubes are at the joints at both ends of the diaphragm wall after the diaphragm wall is poured.

[0019] Preferably, in a method for detecting the path of groundwater leakage in a foundation pit and the detection of the repair effect, the diameter of the borehole in the inclinometer tube is 1.5-2mm, and 6 boreholes are evenly arranged around the radial direction of the tube, with a spacing of 0.8-1.2m between each layer.

[0020] The beneficial effects of this invention are as follows: This invention utilizes pre-embedded inclinometer tubes as detection tools. Without affecting the original strength of the diaphragm wall, it can quickly identify leakage joints by detecting leakage paths inside and outside the pit, accurately locate leakage paths and leakage points, and achieve rapid detection of leak sealing effects. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the electrode sensor connection for leakage path detection according to the present invention; Figure 2 This is a schematic diagram of the electrode sensor layout points according to the present invention; Figure 3 This is a schematic diagram of a leakage path detection principle circuit according to the present invention; Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0023] Example: Inclinometer tubes are part of inclinometers, which are instruments used to measure the apex and azimuth angles of engineering structures such as boreholes, foundation pits, foundations, walls, and dam slopes. The main function of inclinometer tubes is tilt observation. Inclinometer monitoring generally requires segmental measurement of the structure under test, necessitating the installation of inclinometer tubes within the structure. This invention innovatively utilizes inclinometer tubes pre-embedded in the soil on both sides of diaphragm wall joints or within the pit surrounding the joints for leakage path detection and leakage repair quality inspection, thus expanding the functionality of inclinometer tubes.

[0024] Dewatering wells are constructed by drilling wells around the foundation pit and installing water pumps to continuously extract groundwater, thereby lowering the groundwater level. This helps keep the bottom of the pit dry, preventing slope collapse and a decrease in the bearing capacity of the foundation due to groundwater seepage, and providing a stable working environment for construction.

[0025] After the foundation pit is excavated and the required floor height is reached, leakage testing must be conducted on each floor. Once the test is passed, the excavation of the next floor can begin.

[0026] After the foundation pit was excavated The steps for detecting leakage paths are as follows: S1, detection of leakage path outside the pit; S2, Sensors are buried in the pit; S3, the leakage path inside the pit has been confirmed; S4 is used to repair the leak. Then S1 is repeated to test the repair effect. If it fails, S2-S4 are repeated until the leak test result is satisfactory.

[0027] The detailed steps are as follows: 1) Detection of leakage paths outside the pit Different colored waters are filled into the inclinometer tube. The water seeps into the soil through the tube's holes. If there is leakage at the joint, the colored water mixes with the leaking groundwater, causing the water in the dewatering well to change color. Approximately two hours later, groundwater is taken from the dewatering well outside the foundation pit. The color of the groundwater is observed to confirm the presence of any unusual color, thus determining whether there is leakage at the external joint where the inclinometer tube connects.

[0028] A) If the water color in the dewatering well near the inclinometer tube does not change, it indicates that there is no leakage path outside the pit at the joint of the inclinometer tube, and no further testing is required here.

[0029] B) When the water color in the dewatering well near the inclinometer tube shows a trend similar to that of the water body in the inclinometer tube, it indicates that there is an external leakage path at the joint of the inclinometer tube. This area needs to be further investigated using S2-S4.

[0030] C) When the water color in the dewatering well near the inclinometer changes, but is inconsistent with the color change of the water in the inclinometer, it indicates that there is an external leakage path at the joint of another inclinometer and the water flows into the dewatering well. The two water colors are mixed. It is necessary to combine the color change to determine which inclinometer joint has leakage and carry out S2-S4 tests on the inclinometer at that joint.

[0031] 2) Installation of the leakage path detection system After confirming leakage outside the pit, install a leakage path detection system, such as... Figure 1 As shown, for joints with existing leakage paths, electrode sensors are embedded in the pit. The leakage path detection system includes an iron nail 3, an electrode sensor 4, a moving device 5, an anti-wear hydraulic line 6, and an electrical signal receiver 7. The iron nail 3 is connected to the electrode sensor 4; the moving device 5 holds the electrical signal receiver 7 and can move quickly; the electrode sensor 4 is connected to the electrical signal receiver 7 through the anti-wear hydraulic line 6.

[0032] A) If the foundation pit has already been excavated and the depth is greater than or equal to 3 meters, the iron nails 3 can be driven into the soil 2 in the pit around the joint and on the inner side of the retaining walls 1 on both sides of the joint to fix the electrode sensor 4. Figure 1 The retaining wall is driven to a depth of 2-3cm, and the soil is driven to a depth of 5cm or more. The electrode sensor 4 and the iron nail 3 are connected by magnetic attraction for easy and quick removal later.

[0033] B) If the foundation pit has just been excavated and the depth is less than 3 meters, it is only necessary to drive the iron nails 3 into the soil 2 around the joint 8 to connect the electrode sensor 4. The iron nails 3 are driven into the pit to a depth of 3-8 cm.

[0034] like Figure 2 The electrode sensor layout diagram is shown. Inclinometer tubes (not shown in the diagram) are installed in the joints. Sensors are installed on the ground wall at 2m intervals along both the height and width, with two rows on each side. The top row is 0.8-1.2m away from the top of the retaining wall. When there is local dampness on the ground wall, the sensors are preferentially installed at the dampest points. Electrode sensors are installed at 1.5m intervals along the retaining wall direction and perpendicular to the retaining wall direction, with three rows on each side.

[0035] Connect the anti-wear hydraulic line 6 on the upper part of all electrode sensors 4 to the interface of the electrical signal receiver 7 to complete the electrode sensor installation.

[0036] 3) Confirmation of leakage path within the pit Figure 3The principle of pit leakage detection is illustrated, demonstrating the principle of detecting leakage paths within the pit, such as... Figure 3 As shown, a power supply 8 is installed near the seam to be inspected, with two wires connected to it. One wire is connected to the inclinometer tube 9 at the seam, and the other is connected to the current detection device 10. The current detection device 10 is connected to the power supply 8 on one side and to an electrical signal receiver 7 on the other. The electrical signal receiver 7 is connected to the electrode sensor 4 via a wear-resistant hydraulic line 6. When leakage occurs, the presence of conductive ions in the leakage path 13 causes the electrode sensor 4 to form a closed circuit with the inclinometer tube 9, the power supply 8, the current detection device 10, and the electrical signal receiver 7 through the leakage path. Therefore, the presence of leakage can be determined by detecting the current; the presence of current indicates leakage, while the absence of current indicates no leakage.

[0037] As a preferred implementation, in order to more intuitively observe the detection results, the current detection device 10 in this embodiment is an electrometer-type current measuring instrument, which is equipped with an electrometer 11 and an alarm light 12. When current passes through, the electrometer 11 displays the reading and the alarm light 12 lights up.

[0038] 4) Testing process A) Add electrolyte salt water to the inclinometer tube 9 to increase the conductivity of the water. This step is not necessary if the colored water used in S1 contains electrolyte salt.

[0039] B) Connect all electrode sensors 4 on the retaining wall and the foundation pit soil to the electrical signal receiver 7. After 2 hours, check if the bulb is lit. After confirming that the circuit is connected, read the electrometer reading.

[0040] In practice, if a leakage path exists, the water in the inclinometer tube will generally disappear within 2-3 hours, leaving only a small amount at the bottom. If there is no leakage path, because the inclinometer tube is surrounded by cement, although the cement has a hygroscopic effect, even after two days, only a small amount of water in the inclinometer tube will disappear. Therefore, when the wire is connected to the inclinometer tube 9 at the joint, the wire comes into contact with the electrolyte saline solution inside the inclinometer tube, thus forming a pathway with the leakage path and enabling the detection of the leakage path.

[0041] 5) Determining the Leakage Path A) If the light does not turn on after 2 hours, it indicates that there is no electrical connection between the joints at the 9th joint of the inclinometer tube and the inside of the foundation pit and the inside of the retaining wall. In other words, there is no groundwater leakage at the joints, and the diaphragm wall or retaining wall does not need to be repaired.

[0042] B) If the light comes on after 2 hours, it indicates that the joint at the inclinometer tube is connected to the inside of the pit or the inside of the retaining wall. At this time, it is necessary to further determine whether the leakage location is inside the pit or inside the retaining wall.

[0043] C) Disconnect all electrode sensors 4 in the soil inside the pit from the electrical signal receiver 7. At this time, all electrode sensors 4 on the retaining wall are still connected to the electrical signal receiver 7. Using the leakage path detection system, connect all electrode sensors 4 on the retaining wall to the leakage detection circuit. Confirm whether there is current through the current detection device. If there is current, it means that there is leakage on the surface of the retaining wall structure, and perform operation D. If there is no current, it means that there is no leakage on the surface of the retaining wall structure, and it can be confirmed that there is a leakage path in the soil inside the pit, and perform operation E.

[0044] D) Disconnect the electrode sensors on the enclosure wall, select one electrode sensor on the enclosure wall and connect it to the electrical signal receiver, record the current value, then disconnect it, and then connect the next electrode sensor on the enclosure wall and the electrical signal receiver, until all electrode sensors on the enclosure wall are connected to the electrical signal receiver in sequence. If the current detection device in the leakage path detection system has current passing through it, then the point corresponding to that electrode sensor is the point through which the leakage path passes. The point of the electrode sensor corresponding to the maximum current value is the central leakage location.

[0045] E) Disconnect all electrode sensors 4 on the retaining wall, select one soil electrode sensor 4 in the pit and connect it to the electrical signal receiver 7, record the current value and then disconnect it. Then connect the next soil electrode sensor in the pit and the electrical signal receiver, until all soil electrode sensors in the pit are connected to the electrical signal receiver in sequence. When the current detection device 10 in the leakage path detection system has current passing through it, the point corresponding to the electrode sensor 4 is the point through which the leakage path passes. The point of the electrode sensor corresponding to the maximum current value is the central leakage location.

[0046] When there are insufficient testing personnel, such as only one person, since the electrode sensors are buried inside the foundation pit while the power supply and current detection devices may be installed outside the foundation pit, we use the above method to carry out the testing, saving the testing personnel the trouble of traveling around.

[0047] When there are multiple inspectors, the following inspection method is adopted: After 1)-3) are completed, 4) during the inspection process, B becomes B', that is, one person connects the electrode sensor 4 to the electrical signal receiver 7 one by one in the pit, and another person outside the pit confirms whether there is current passing through and records the current value; after all points have been measured (including all points on the retaining wall and the foundation pit), find the point corresponding to the maximum current value, which is the leakage location.

[0048] 6) Leak sealing and leak sealing effect testing When leakage occurs, leakage plugging should be carried out, centering on the location of the central leakage and covering all points along the leakage path. The corresponding retaining wall should be repaired, with a typical repair area of ​​1-3 square meters. If leakage occurs in the foundation pit soil, and the foundation pit at the time of measurement is not the last layer, repair can be temporarily omitted. If it is the last layer, repair is required. The repair location is also a 1-3 square meter area centered on the point corresponding to the maximum current, covering all points along the leakage path. The repair method should be handled according to the engineering construction plan, which is already known to those skilled in the art and will not be elaborated here.

[0049] After the external leak sealing of the foundation pit is completed, in order to test the sealing effect, fill the inclinometer tube with water of different colors and wait for 2 hours to check whether the color of the water in the nearby dewatering well has changed. If the color has not changed, the leak sealing is successful; if the color of the leaking water is the same as that in the inclinometer tube, the leak sealing is unsuccessful and steps 1)-6) need to be continued until the test is qualified and the operation is completed.

[0050] After the leak sealing inside the foundation pit is completed, in order to test the sealing effect, the leakage path detection system is used to connect the electrical signal receiver 7 to the leakage point electrode sensor 4 and check whether the reading of the current detection device 10 changes or whether the light is on. If the reading changes, the leak sealing is unsuccessful.

[0051] To improve the water seepage effect of inclinometer tubes, the following improvements are made to the conventional inclinometer tube materials and installation methods.

[0052] 1) Pipeline fabrication: Use a steel needle or other sharp object to drill holes in the inclinometer tube, creating multiple holes along the tube. As a preferred implementation, to ensure more uniform water seepage through the inclinometer tube, this embodiment uses holes with a diameter of approximately 1.5-2 mm, evenly spaced 6 holes around the circumference of the tube, with a spacing of approximately 1 meter between each layer. When drilling, avoid the grooves inside the inclinometer tube to ensure the overall integrity of the grooves.

[0053] 2) Pipeline pre-embedding method: During the construction of the diaphragm wall, pre-fixed inclinometer tubes are added at the interface positions of both ends of the steel cage to ensure that the inclinometer tubes are at the joints of both ends of the diaphragm wall after the diaphragm wall is poured.

[0054] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for detecting groundwater leakage paths and assessing the effectiveness of repairs in foundation pits, characterized in that, S1, conduct external leakage path detection; S2, Install the leakage path detection system; S3, confirm the leakage path inside the pit; S4 is used to repair the leak. Then S1 is repeated to test the repair effect. If it fails, S2-S4 are repeated until the leak test result is satisfactory.

2. The method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 1, characterized in that, S1 also includes: during the foundation pit excavation stage, injecting water of different colors into several pre-set inclinometer tubes, and observing the color of groundwater in the dewatering well outside the pit after a certain period of time to determine whether there is leakage. The inclinometer tubes are located in the joint of the foundation pit diaphragm wall, and the inclinometer tubes are provided with holes. When the water color in the dewatering well near the inclinometer tube does not change, it indicates that there is no leakage path outside the pit at the joint where the inclinometer tube is located, and S2-S4 is not required. When the water in the dewatering well near the inclinometer changes to a specific color, it is determined that there is a leak at the joint where the inclinometer is injected with the specific color water, and then S2-S4 are performed.

3. The method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 1, characterized in that... The leakage path detection system described in S2 includes iron nails, electrode sensors, a moving device, an anti-wear hydraulic line, an electrical signal receiver, a power supply, a clinometer tube, and a current detection device. The iron nails are driven into the soil inside the retaining walls on both sides of the joint and in the pits around the joint. The iron nails are connected to the electrode sensors. The electrical signal receiver is placed on the moving device. The electrode sensors are connected to the electrical signal receiver through the anti-wear hydraulic line. The power supply is installed near the joint to be detected and has two wires connected to it. One wire is connected to the clinometer tube at the joint, and the other is connected to the current detection device. The current detection device is connected to the power supply on one side and to the electrical signal receiver on the other side. The clinometer tube has holes in its body.

4. The method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 3, characterized in that, If the excavation depth of the foundation pit is greater than or equal to 3 meters, the iron nails shall be driven into the retaining wall to a depth of 2-3 cm and into the foundation pit soil to a depth of greater than or equal to 5 cm.

5. The method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 3, characterized in that... If the excavation depth of the foundation pit is less than 3 meters, the iron nails only need to be driven into the soil around the joint, and the driving depth of the iron nails is 3-8 cm.

6. In the method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 3, the characteristic is that... The nails are laid in the soil on both sides of the joint, with two rows on each side of the retaining wall, spaced 2m apart in height and width, and the top row 0.8-1.2m away from the top of the retaining wall; they are also laid every 1.5m along the retaining direction and perpendicular to the retaining direction in the soil of the pit, with three rows on each side of the joint.

7. In the method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 6, the method is characterized in that... The nails are placed in the soil on both sides of the joint, with priority given to placing them at damp locations.

8. In the method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 3, the characteristic is that... The current detection device is an electrometer-type current measuring instrument.

9. In the method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 3, the method is characterized in that... In S3, electrolyte saline solution is added to the inclinometer tube, or the colored water in S1 contains electrolyte saline solution.

10. The method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 3, characterized in that, S3 also includes: S3-1: Connect all electrode sensors on the retaining wall and the soil inside the pit to the electrical signal receiver. If there is current, there is leakage. Proceed to S3-2. If there is no current, there is no leakage. End the operation. S3-2, disconnect all connections between the electrical signal receiver and the soil electrode sensor in the pit. If there is current, the retaining wall is leaking, proceed to S3-3; if there is no current, the retaining wall is not leaking, proceed to S3-4. S3-3, disconnect the electrode sensors on the enclosure wall, select one electrode sensor on the enclosure wall to connect to the electrical signal receiver, record the current value, then disconnect it, and then connect the next electrode sensor on the enclosure wall to the electrical signal receiver, until all electrode sensors on the enclosure wall are connected to the electrical signal receiver in sequence. If the current detection device in the leakage path detection system has current passing through it, then the point corresponding to the electrode sensor is the point through which the leakage path passes. The point of the electrode sensor corresponding to the maximum current value is the central leakage location. S3-4. Disconnect all electrode sensors on the retaining wall. Select one soil electrode sensor in the pit and connect it to the electrical signal receiver. Record the current value and then disconnect it. Then connect the next soil electrode sensor in the pit to the electrical signal receiver, until all soil electrode sensors in the pit are connected to the electrical signal receiver in sequence. When the current detection device in the leakage path detection system has current passing through it, the point corresponding to that electrode sensor is the point through which the leakage path passes. The point of the electrode sensor corresponding to the maximum current value is the central leakage location.

11. The method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 3, characterized in that, S3 also includes: connecting the electrode sensors to the electrical signal receiver one by one to confirm whether current is flowing and recording the current value; finding the electrode sensor point corresponding to the maximum current value, which is the leakage location.

12. The method for detecting groundwater leakage paths and assessing the repair effect in foundation pits as described in any of claims 10-11, characterized in that, Using the electrode sensor point corresponding to the maximum current as the center and covering all points through which the leakage path passes, area repair is carried out.

13. The method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 2, characterized in that, During the construction of the diaphragm wall, pre-fixed inclinometer tubes are added at the joints at both ends of the reinforcing cage to ensure that the inclinometer tubes are at the joints at both ends of the diaphragm wall after the diaphragm wall is poured.

14. The method for detecting groundwater leakage paths and assessing repair effectiveness in foundation pits as described in claim 2, characterized in that, The diameter of the holes in the inclinometer tube is 1.5-2mm, and 6 holes are evenly distributed around the radial direction of the tube, with a spacing of 0.8-1.2m between each layer.

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