Active precipitation monitoring construction method for strong and weak permeable interbed stratum

Abstract

The invention discloses an active precipitation monitoring construction method for strong and weak permeable interbedding stratums. The method comprises the following steps that 1, a designed precipitation implementation scheme is input to a precipitation control platform to form a precipitation target; secondly, a plurality of water content measuring holes are formed in the trend of the foundation pit at intervals, an automatic water content measuring system is installed, and water content measuring data of the automatic water content measuring system are wirelessly transmitted to a precipitation control platform; thirdly, a dewatering well is dug in the inner side of the foundation pit, and an active dewatering system is installed; fourthly, observation wells are dug in the outer side of the foundation pit in the trend of the foundation pit according to the set intervals, automatic water level gauges are arranged in the observation wells, and water level data of the observation wells are wirelessly transmitted to the precipitation control platform; and 5, the rainfall control platform monitors and obtains moisture content data and underground water level data in real time, and controls the active rainfall system to actively rainfall into the rainfall target. According to the invention, real-time automatic monitoring and active precipitation control are carried out by monitoring a plurality of parameters, and the precipitation effect and the precipitation accuracy are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of underground engineering construction, and more specifically, to an active precipitation monitoring construction method for strong and weak water-permeable interlayer strata. Background Art

[0002] At present, in the construction of underground projects such as foundation pits, tunnels, and caissons, precipitation is usually used to lower the groundwater level within the construction range. For strata with alternating strong and weak permeability of clay, silt, and silt sand, the stratum permeability has the characteristic of large differences in the permeability of strong and weak interlayers. It is difficult to effectively drain the stratum by conventional pipe well precipitation, especially the clay layer has poor permeability and the stratum moisture content is not easy to reduce. The bearing capacity of clay strata is closely related to the moisture content. At present, there are insufficient means to monitor the moisture content of the soil layer. When excavating foundation pits in strata with alternating strong and weak permeability, the higher the moisture content, the smaller the bearing capacity. When the precipitation effect is not ideal, the stratum moisture content is high, the stratum bearing capacity is insufficient, and the soil strength does not meet the requirements for foundation pit excavation, it affects the mechanical excavation operation, which not only delays the construction progress, but also poses a safety hazard to water-carrying operations. Summary of the invention

[0003] One object of the present invention is to provide a construction method for active precipitation monitoring in strong and weak permeable interlayer strata, which improves precipitation effect and precipitation accuracy by monitoring multiple parameters to automatically monitor and control active precipitation in real time.

[0004] In order to solve the above technical problems, the present invention provides a construction method for active precipitation monitoring in strong and weak permeable interlayer strata, comprising the following steps: Step 1: Input the designed precipitation implementation plan into the precipitation control platform to form a precipitation target; Step 2: multiple moisture content measuring holes are set at intervals along the direction of the foundation pit, and an automatic moisture content measuring system is installed, and its moisture content measurement data is wirelessly transmitted to the precipitation control platform; Step 3: Drill a dewatering well inside the foundation pit and install an active dewatering system; Step 4: Observation wells are set up along the direction of the foundation pit at the set intervals outside the foundation pit, and automatic water level gauges are set inside the observation wells, and the water level data is wirelessly transmitted to the precipitation control platform; Step 5: The precipitation control platform monitors the moisture content data and groundwater level data in real time, and controls the active precipitation system to carry out active precipitation within the precipitation target.

[0005] Preferably, in the step three, a plurality of precipitation wells are provided inside the foundation pit, each of which is provided with an active precipitation system, the active precipitation system comprising a steel pipe buried in the foundation pit and a drainage mechanism arranged in the steel pipe, the middle and lower parts of the steel pipe are opened to form a filter tube, the upper part of the steel pipe close to the ground is not opened to form a solid tube, the outer periphery of the filter tube is filled with a matrix material to form a filter layer, the outer periphery of the solid tube is filled with a blocking material to form a sealing layer, the top of the steel pipe is sealed, the drainage mechanism comprises a submersible pump located at the bottom of the steel pipe, a drainage pipe connected to the submersible pump and a vacuum tube arranged in the steel pipe, the submersible pump is connected to a distribution box outside the foundation pit through a cable to power it and control its opening and closing, the drainage pipe extends to a sedimentation tank arranged outside the foundation pit, and groundwater is discharged through sedimentation in the sedimentation tank, the vacuum tube is connected to the vacuum pump outside the foundation pit, which is also powered by the distribution box and controlled to open and close, the distribution box is an intelligent distribution box and is intelligently controlled by a precipitation control platform.

[0006] Preferably, in step four, the well pipe of the observation well is set as a steel pipe, a hole is opened in the lower part and an automatic water level gauge is placed therein, the automatic water level gauge includes a water level sensor and a wireless transmission terminal, the water level data acquired by the water level sensor is transmitted to the wireless transmission terminal via a cable, and the wireless transmission terminal then transmits the water level data to the precipitation control platform via wireless signals.

[0007] Preferably, in step 2, the automatic moisture content measurement system includes at least one cable line arranged in the moisture content measuring hole, wherein the upper part is armored to form an armored lead, and a plurality of distributed temperature sensing optical cables are arranged at intervals on the upper side of the cable line in the height direction of the moisture content measuring hole, both ends of the cable line extend outside the moisture content measuring hole and are respectively connected to a heating module and a demodulator, the cable line is connected to a guide hammer connected by a steel strand, and the data acquired by the demodulator is transmitted to the precipitation control platform by wireless signals.

[0008] Preferably, the specific method for setting up the automatic moisture content measurement system includes: First, multiple water content measurement holes are drilled to the designed depth according to the locations measured and designed in advance, and the soil taken out from the holes is collected and stored in layers; Secondly, the cable is fixed to the guide hammer, and the distributed temperature sensing optical cables are fixedly arranged on the cable in sequence according to the set intervals; Next, in the water content measuring hole and with the help of a guide hammer, lower the cable to the bottom of the hole; Then, after the lowering is completed, the moisture content measuring hole is backfilled and compacted with the original soil collected and stored as above; Finally, one end of the cable is connected to the heating module, and the other end is connected to the demodulator. The monitoring data obtained by the demodulator is uploaded to the precipitation control platform.

[0009] Preferably, the automatic moisture content measurement system carries out a soil moisture content classification calibration test before field measurement, samples different types of soil on site, performs test calibration, and verifies the measurement accuracy under different types, different moisture contents, and different saturation conditions. The specific steps are as follows: Step 1: On-site sampling: Field sampling of different types of soil within the precipitation range; Step 2: Soil sample preparation: prepare soil samples with mass moisture contents of 5%, 10%, 15%, and 20% respectively; Step 3: Sample preparation: Prepare a sample box according to the designed size, and open a hole in the middle of the sample box for inserting the fiber grating sensor, and evenly fill the prepared soil sample into the sample box; Step 4: Equipment connection: Connect the fiber grating sensor cable to the demodulator, connect the cable to the DC regulated power supply, and keep the heating parameters consistent with the on-site heating parameters; Step 5. Data measurement: First, the actual moisture content is determined by the drying method; secondly, through classification calibration, the fiber grating sensor is used to measure the temperature response curve of samples with different moisture contents, and the calibration is performed by comparing with the standard value; finally, an accuracy test is performed, and soil samples with any moisture content are measured and compared with the standard value of the moisture content of the soil sample to verify the measurement accuracy.

[0010] Preferably, the step five is specifically: the precipitation control platform automatically generates control instructions to manage the active precipitation operation by real-time monitoring of the moisture content data and the groundwater level data and performing data analysis, which specifically includes the following steps: Step 1: The groundwater level data and water content data are wirelessly transmitted to the precipitation control platform, and the water level-time, water level-space, water content-time, and water content-space relationship curves are drawn and displayed respectively to monitor the water level change and water content change in real time; Step 2: Set the precipitation target, i.e., the groundwater level target value and the moisture content critical value, in the precipitation control platform. When the monitored moisture content is higher than the set moisture content critical value, send a command through the precipitation control platform to control the distribution box to turn on the power of the precipitation well and start precipitation; when the groundwater level is close to the set groundwater level target value, send a command to control the intelligent distribution box to turn off the power of some precipitation wells and implement precipitation on demand; when the monitored moisture content is lower than the set moisture content critical value, send a command to control the intelligent distribution box to turn off the power of all precipitation wells and stop precipitation, and pop up a prompt box on the precipitation control platform interface, prompting "The conditions for entering the site for excavation are met."

[0011] Preferably, the precipitation control platform identifies the operating status of the corresponding precipitation well by acquiring the current signal of the intelligent distribution box corresponding to each precipitation well, and intuitively displays the start and stop status of the precipitation well on the precipitation control platform.

[0012] Preferably, the groundwater level data and water content data acquired in the precipitation control platform are automatically stored, and viewing and downloading functions are provided.

[0013] Preferably, in step three, after the active precipitation system is installed and the inlet is sealed, a test pump is performed to test the pumping effect and only after it is qualified, the next step is performed.

[0014] The present invention has at least the following beneficial effects: 1. The present invention obtains moisture content data by setting up multiple moisture content measuring holes and correspondingly installing multiple moisture content automatic measuring systems; at the same time, by setting up an automatic water level meter, the corresponding groundwater level data is obtained; the active precipitation system is assisted by the moisture content data and the groundwater level data to perform intelligent active precipitation control, thereby improving the precipitation effect and precipitation accuracy.

[0015] 2. The present invention sets up a precipitation control platform, connects various data measurement devices and active precipitation systems set in the precipitation well, realizes real-time monitoring of the precipitation process, and performs intelligent control.

[0016] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the active precipitation system of the present invention; Figure 2 This is a schematic diagram of the structure of the automatic water level observation well of the present invention; Figure 3 It is a structural schematic diagram of the automatic moisture content measurement system of the present invention; Figure 4 This is a logic diagram of active precipitation control based on moisture content measurement of the present invention.

[0018] Description of reference numerals: 1. Filter tube, 2. Filter layer, 3. Solid tube, 4. Sealing layer, 5. Submersible pump, 6. Vacuum pump, 7. Vacuum tube, 8. Distribution box, 9. Cable, 10. Drain pipe, 11. Sedimentation tank, 12. Observation well, 13. Water level gauge, 14. Wireless transmission terminal, 15. Signal transmission, 16. Steel strand, 17. Armored lead wire, 18. Distributed temperature sensing optical cable, 19. Guide hammer, 20. Heating module, 21. Demodulator, 22. Precipitation control platform. DETAILED DESCRIPTION

[0019] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement it according to the description.

[0020] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] The construction method of the present invention is completed based on a monitoring construction system, which includes an active precipitation system, a moisture content automatic measurement system and a precipitation control platform 22, which together constitute an active precipitation monitoring construction system for strong and weak permeable interlayer strata.

[0022] like Figure 1 As shown, a number of precipitation wells are arranged inside the foundation pit, and active precipitation systems are arranged in each of them. The active precipitation system includes a steel pipe buried in the foundation pit and a drainage mechanism arranged in the steel pipe. The middle and lower parts of the steel pipe are opened to form a filter tube 1, and the upper part of the steel pipe close to the ground is not opened to form a solid tube 3. The periphery of the filter tube 1 is filled with matrix material to form a filter layer 2, and the periphery of the solid tube 3 is filled with blocking material to form a sealing layer 4. The top of the steel pipe is sealed. The drainage mechanism includes a submersible pump 5 located at the bottom of the steel pipe, a drainage pipe 10 connected to the submersible pump 5, and a vacuum tube 7 arranged in the steel pipe. The submersible pump 5 is connected to the distribution box 8 outside the foundation pit through a cable 9 for power supply and control of opening and closing. The drainage pipe 10 extends to a sedimentation tank 11 arranged outside the foundation pit, and the groundwater discharged through the sedimentation tank 11 is precipitated. The vacuum tube 7 is connected to the vacuum pump 6 outside the foundation pit, which is also powered and controlled by the distribution box 8. The distribution box 8 is an intelligent distribution box 8 and is intelligently controlled by the precipitation control platform 22.

[0023] The precipitation well is set up inside the foundation pit. The steel pipe with holes is used as the filter pipe 1, and the steel pipe without holes is used as the solid pipe 3. The precipitation pipe well consists of the filter pipe 1 and the solid pipe 3, and the solid pipe 3 is used near the ground. The filter pipe 1 is filled with medium-coarse sand around it, and the solid pipe 3 is sealed with clay balls around the 3-5m near the ground. A submersible pump 5, a vacuum pipe 7, a drainage pipe 10 and a cable 9 are placed in the well, and the wellhead is sealed with flanges and gaskets. A sedimentation tank 11 is set up at a suitable location outside the pit, and the pumped groundwater is first precipitated in the sedimentation tank 11 and then discharged to a suitable location. The submersible pump 5 and the vacuum pump 6 are connected to the intelligent distribution box 8, which can remotely control the opening or closing of the power supply channel.

[0024] like Figure 2As shown, the well pipe of the observation well 12 is set as a steel pipe, a hole is opened at the bottom and an automatic water level gauge 13 is placed. The automatic water level gauge 13 includes a water level sensor and a wireless transmission terminal 14. The water level data obtained by the water level sensor is transmitted to the wireless transmission terminal 14 through a cable 9, and the wireless transmission terminal 14 then transmits the wireless signal 15 to the precipitation control platform 22.

[0025] The water level observation well 12 is set outside the foundation pit and arranged at intervals of 50m along the direction of the foundation pit. The well pipe is made of steel pipe, and the bottom layer of steel pipe is opened. An automatic water level gauge 13 is placed in the observation well 12. The automatic water level gauge 13 includes a water level sensor and a wireless transmission terminal 14. The wireless transmission terminal 14 has an RTU wireless data transmission module. The water level sensor is hydraulic, consisting of a sensor body and a communication data line. The data line is connected to the RTU wireless data transmission module, and a 5G communication method is used to realize wireless transmission of water level data.

[0026] The water level meter 13 is put into the observation well 12, and the wireless transmission module is hung on the outer wall of the observation well 12. The water level signal is wirelessly transmitted to the precipitation control platform 22 and displayed in real time.

[0027] like Figure 3 As shown, in the step 2, the automatic moisture content measurement system includes at least one cable 9 arranged in the moisture content measuring hole, wherein the upper part is armored to form an armored lead 17, and a plurality of distributed temperature sensing optical cables 18 are arranged on the cable 9 at intervals along the height direction of the moisture content measuring hole, and both ends of the cable 9 extend outside the moisture content measuring hole and are respectively connected to a heating module 20 and a demodulator 21, and the cable 9 is connected to a guide hammer 19 connected by a steel strand 16, and the data obtained by the demodulator 21 is transmitted 15 by wireless signal to a precipitation control platform 22.

[0028] The cable 9 is connected to the heating module 20 to achieve heating of the measuring element. The distributed temperature sensing optical cables 18 are fixed on the cable 9 at a certain distance to obtain temperature changes and transmit signals in a distributed manner. The signals are modulated by the temperature demodulator 21 and transmitted to the precipitation control platform 22.

[0029] Before the automatic moisture content measurement system is used for field measurement, it is necessary to carry out soil moisture content classification calibration test, sample different types of soil on site, conduct test calibration, and verify the measurement accuracy under different types, different moisture contents, and different saturation conditions. The specific steps are as follows: (1) On-site sampling: Field sampling of different types of soil within the precipitation range.

[0030] (2) Soil sample preparation: Prepare soil samples with mass moisture contents of 5%, 10%, 15%, and 20% (saturated), respectively.

[0031] (3) Sample preparation: The sample box is 20 cm*20 cm*15 cm in size. A hole is opened in the middle of the 20*20 surface for inserting the sensor. The prepared soil sample is evenly filled into the sample box.

[0032] (4) Equipment connection: Connect the fiber grating sensor cable to the demodulator 21, and connect the cable to the DC regulated power supply. The heating parameters should be consistent with the on-site heating parameters.

[0033] (5) Data measurement: ① Determination of actual moisture content: drying method; ② Classification calibration: using fiber grating sensor to measure the temperature response curve of samples with different moisture contents, and calibrate by comparing with the standard value; ③ Accuracy test: measuring soil samples with any moisture content, comparing with the standard value of the moisture content of the soil sample, and verifying the measurement accuracy.

[0034] When the automatic water content measurement system is used for on-site measurement, a water content measurement hole is set up every 150m along the foundation pit. The design depth of each measurement hole is related to the thickness of the aquifer within the excavation depth, and the distance between measurement points along the depth is 1m. The specific steps are as follows: (1) Use a drilling rig to drill multiple moisture content measurement holes to the designed depth based on the locations measured and designed in advance, and collect and store the removed soil in layers.

[0035] (2) The heating cable 9 is fixed to the guide hammer 19, and the distributed temperature sensing optical cables 18 are bundled with steel strands 16 at intervals of 1 m on the cable 9.

[0036] (3) The cable 9 is lowered into the measuring hole and driven by the weight of the guide hammer 19 to the bottom of the hole.

[0037] (4) The hole is backfilled with the original soil collected and stored as above and lightly compacted.

[0038] (5) One end of the cable 9 is connected to the heating control module, and the other end of the distributed temperature sensing optical cable 18 is connected to the demodulator 21, and the monitoring data is uploaded to the precipitation control platform 22.

[0039] like Figure 4 As shown, by analyzing the real-time monitoring data of moisture content and groundwater level, control instructions are automatically generated to carry out refined management of precipitation operations.

[0040] ① The groundwater level data and water content data are wirelessly transmitted to the precipitation control platform 22, and the water level-time, water level-space, water content-time, and water content-space relationship curves are drawn and displayed respectively to monitor the water level change and water content change in real time.

[0041] ② Set the groundwater level target value and moisture content critical value in the precipitation control platform 22 system. When the moisture content is higher than the critical value, send a command to control the intelligent distribution box 8 to turn on the power of the precipitation well and start precipitation; when the groundwater level is close to the target value, send a command to control the intelligent distribution box 8 to turn off the power of some precipitation wells and implement precipitation on demand; when the moisture content of the local layer is less than the critical value, send a command to control the intelligent distribution box 8 to turn off the power of all precipitation wells, stop precipitation, and pop up a prompt box on the platform interface, prompting "The conditions for entering the site for excavation operations are met."

[0042] ③ The operating status of the precipitation well is identified through the current signal of the intelligent distribution box 8, and the start and stop status of the precipitation well is intuitively displayed on the project plan.

[0043] ④The groundwater level data and moisture content data are automatically stored, and the viewing and downloading functions are provided.

[0044] The present invention provides an active precipitation monitoring construction method for strong and weak permeable interlayer strata, and the specific implementation steps are as follows: (1) The designed precipitation implementation plan is input into the precipitation control platform 22 to form a precipitation target.

[0045] (2) Drill holes at intervals of 150 m along the centerline of the foundation pit, with the hole depth consistent with the distribution depth of the weak permeable layer within the excavation range of the foundation pit.

[0046] (3) A moisture content measurement cable (electric cable + optical cable) is placed in each hole, the heating module 20 is connected to the cable 9, and the temperature-sensitive optical cable is connected to the demodulator 21 for signal modulation.

[0047] (4) The original soil in the hole is backfilled and compacted, and the moisture content measurement data is wirelessly transmitted to the precipitation control platform 22 and displayed in real time.

[0048] (5) Several drainage wells are set up in the foundation pit. The lower part of the drainage well uses a water filter steel pipe, and the upper part uses a solid pipe 3. The space between the well pipe and the drilled hole is backfilled with medium-coarse sand to about 3m below the ground, and then sealed with clay balls.

[0049] (6) After washing the well, lower the water pump, connect the cable 9 and the drainage pipe 10, extend the vacuum tube 7 into the well, seal the wellhead with a flange and a gasket, and conduct a test pump to check the pumping effect.

[0050] (7) An observation well 12 is drilled every 300 m outside the foundation pit. An automatic water level gauge 13 is placed in the observation well 12. A wireless transmission module is fixed on the outside of the wellhead. The water level data is wirelessly transmitted to the precipitation control platform 22 and displayed in real time.

[0051] (8) The dewatering control platform 22 determines whether the dewatering wells have been drained properly based on the water content of the weakly permeable strata, and adjusts the opening conditions of the dewatering wells and the water pump flow rate according to the water content. When the water content drops to the target value, the dewatering wells in the area are gradually closed, and a prompt is given that excavation operations can be carried out.

[0052] It is understood that the present invention is described by some embodiments, and those skilled in the art are aware that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation mode, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, other modifications can be easily implemented, so without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A construction method for active precipitation monitoring in strong and weak permeable interlayer strata, characterized in that: The steps include: Step 1: Input the designed precipitation implementation plan into the precipitation control platform to form a precipitation target; Step 2: multiple moisture content measuring holes are set at intervals along the direction of the foundation pit, and an automatic moisture content measuring system is installed, and its moisture content measurement data is wirelessly transmitted to the precipitation control platform; Step 3: Drill a dewatering well inside the foundation pit and install an active dewatering system; Step 4: Observation wells are set at set intervals along the direction of the foundation pit outside the foundation pit, and automatic water level gauges are set inside the observation wells, and the water level data is wirelessly transmitted to the precipitation control platform; Step 5: The precipitation control platform monitors the moisture content data and groundwater level data in real time, and controls the active precipitation system to carry out active precipitation within the precipitation target.

2. The active precipitation monitoring construction method for strong and weak permeable interlayer strata according to claim 1 is characterized in that: In the step three, a number of precipitation wells are arranged inside the foundation pit, each of which is correspondingly provided with an active precipitation system, the active precipitation system comprises a steel pipe buried in the foundation pit and a drainage mechanism arranged in the steel pipe, the lower part of the steel pipe is opened to form a filter tube, the upper part of the steel pipe close to the ground is not opened to form a solid tube, the outer periphery of the filter tube is filled with matrix material to form a filter layer, the outer periphery of the solid tube is filled with blocking material to form a sealing layer, the top of the steel pipe is sealed, the drainage mechanism comprises a submersible pump located at the bottom of the steel pipe, a drainage pipe connected to the submersible pump and a vacuum tube arranged in the steel pipe, the submersible pump is connected to the distribution box outside the foundation pit through a cable to power supply and control opening and closing, the drainage pipe extends to a sedimentation tank arranged outside the foundation pit, and the groundwater is discharged through sedimentation in the sedimentation tank, the vacuum tube is connected to the vacuum pump outside the foundation pit, which is also powered by the distribution box and controlled to open and close, the distribution box is an intelligent distribution box and is intelligently controlled by a precipitation control platform.

3. The active precipitation monitoring construction method for strong and weak permeable interlayer strata according to claim 1 is characterized in that: In step four, the well pipe of the observation well is set as a steel pipe, a hole is opened at the bottom and an automatic water level gauge is placed thereon. The automatic water level gauge includes a water level sensor and a wireless transmission terminal. The water level data acquired by the water level sensor is transmitted to the wireless transmission terminal via a cable, and the wireless transmission terminal then transmits the data to the precipitation control platform via a wireless signal.

4. The active precipitation monitoring construction method for strong and weak permeable interlayer strata according to claim 1 is characterized in that: In the step 2, the automatic moisture content measurement system includes at least one cable line arranged in the moisture content measuring hole, wherein the upper part is armored to form an armored lead, and a plurality of distributed temperature sensing optical cables are arranged at intervals along the upper direction of the moisture content measuring hole of the cable line, and both ends of the cable line extend outside the moisture content measuring hole and are respectively connected to the heating module and the demodulator, the cable line is connected to the guide hammer connected by the steel strand, and the data obtained by the demodulator is transmitted to the precipitation control platform by wireless signal.

5. The active precipitation monitoring construction method for strong and weak permeable interlayer strata as claimed in claim 4 is characterized in that: The specific method for setting up the automatic moisture content measurement system includes: First, multiple water content measurement holes are drilled to the designed depth according to the locations measured and designed in advance, and the soil taken out from the holes is collected and stored in layers; Secondly, the cable is fixed to the guide hammer, and the distributed temperature sensing optical cables are fixedly arranged on the cable in sequence according to the set intervals; Next, in the water content measuring hole and with the help of a guide hammer, lower the cable to the bottom of the hole; Then, after the lowering is completed, the moisture content measuring hole is backfilled and compacted with the original soil collected and stored as above; Finally, one end of the cable is connected to the heating module, and the other end is connected to the demodulator. The monitoring data obtained by the demodulator is uploaded to the precipitation control platform.

6. The active precipitation monitoring construction method for strong and weak permeable interlayer strata according to claim 4 is characterized in that: The automatic moisture content measurement system carries out soil moisture content classification calibration test before field measurement, samples different types of soil on site, performs test calibration, and verifies the measurement accuracy under different types, different moisture contents, and different saturation conditions. The specific steps are as follows: Step 1: On-site sampling: Field sampling of different types of soil within the precipitation range; Step 2: Soil sample preparation: prepare soil samples with mass moisture contents of 5%, 10%, 15%, and 20% respectively; Step 3: Sample preparation: Prepare a sample box according to the designed size, and open a hole in the middle of the sample box for inserting the fiber grating sensor, and evenly fill the prepared soil sample into the sample box; Step 4: Equipment connection: Connect the fiber grating sensor cable to the demodulator, connect the cable to the DC regulated power supply, and keep the heating parameters consistent with the on-site heating parameters; Step 5. Data measurement: First, the actual moisture content is determined by the drying method; secondly, through classification calibration, the fiber grating sensor is used to measure the temperature response curve of samples with different moisture contents, and the calibration is performed by comparing with the standard value; finally, an accuracy test is performed, and soil samples with any moisture content are measured and compared with the standard value of the moisture content of the soil sample to verify the measurement accuracy.

7. The active precipitation monitoring construction method for strong and weak permeable interlayer strata according to claim 1 is characterized in that: The step 5 is as follows: the precipitation control platform automatically generates control instructions to manage the active precipitation operation by real-time monitoring of the moisture content data and the groundwater level data and performing data analysis, which specifically includes the following steps: Step 1: The groundwater level data and water content data are wirelessly transmitted to the precipitation control platform, and the water level-time, water level-space, water content-time, and water content-space relationship curves are drawn and displayed respectively to monitor the water level change and water content change in real time; Step 2: Set the precipitation target, i.e., the groundwater level target value and the moisture content critical value, in the precipitation control platform. When the monitored moisture content is higher than the set moisture content critical value, send a command through the precipitation control platform to control the distribution box to turn on the power of the precipitation well and start precipitation; when the groundwater level is close to the set groundwater level target value, send a command to control the intelligent distribution box to turn off the power of some precipitation wells and implement precipitation on demand; when the monitored moisture content is lower than the set moisture content critical value, send a command to control the intelligent distribution box to turn off the power of all precipitation wells and stop precipitation, and pop up a prompt box on the precipitation control platform interface, prompting "Conditions for entering the site for excavation are met".

8. The active precipitation monitoring construction method for strong and weak permeable interlayer strata according to claim 7 is characterized in that: The precipitation control platform obtains the current signal of the intelligent distribution box corresponding to each precipitation well, identifies the operation status of the corresponding precipitation well, and intuitively displays the start and stop status of the precipitation well on the precipitation control platform.

9. The active precipitation monitoring construction method for strong and weak permeable interlayer strata according to claim 7 is characterized in that: The groundwater level data and water content data obtained in the precipitation control platform are automatically stored, and viewing and downloading functions are provided.

10. The active precipitation monitoring construction method for strong and weak permeable interlayer strata according to claim 2, characterized in that: In the step three, after the active precipitation system is installed and the inlet is sealed, a test pump is performed to test the pumping effect and then proceed to the next step after the pumping effect is qualified.

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