Underground water level engineering investigation method and system based on well point measurement method

Abstract

The invention discloses an underground water level engineering investigation method and system based on a well point measurement method, and belongs to the technical field of engineering investigation, the method is implemented based on the system, the method comprises the steps that underground water level measurement in well logging is achieved based on a rope, a measurement module and an underwater assembly, and the underwater assembly comprises a rod barrel, a floating body and a detection module; according to the method, an underwater assembly is installed in a logging well; according to the method, a method for obtaining the underground water level comprises the steps that a measuring module obtains the position of a rod barrel in a logging well according to the length of a rope released in the logging well; the detection module obtains the position of the floating body on the rod barrel; according to the position of the rod cylinder in the well logging and the position of the floating body on the rod cylinder, the position of the floating body relative to the well logging wellhead is obtained and serves as the position of the underground water level in the well logging; the rod cylinder is lifted or released through the rope, the states of the rod hole and the floating body relative to the logging liquid level are kept, and the scheme has the advantages of being low in implementation cost and capable of guaranteeing the water level measurement precision.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering survey, and in particular to a method and system for underground water level engineering survey based on a well point measurement method. Background Art

[0002] In engineering survey, the well point measurement method is a method that uses well logging to complete groundwater level measurement and has a relatively low implementation cost. Commonly used methods include the rope method, static pressure method and float method. Among them, the rope method uses a rope or a steel ruler, and a sensor is connected to the lower end of the rope or the steel ruler. When the sensor is lowered and the sensor contacts the water surface, the groundwater level in the well logging is obtained by the amount of the rope or the steel ruler lowered when the sensor responds. The static pressure method uses a pressure sensor and converts the static pressure detection result of the pressure sensor into the water level depth in the well logging, thereby obtaining the groundwater level in the well logging. The float method uses a float floating in the well logging, and the float rises or falls with the change of the water level, and the rope movement that changes with the position of the float is used to obtain the position of the float in the well logging, thereby obtaining the groundwater level in the well logging. Compared with the rope method, the static pressure method and the float method are a method that can continuously measure the groundwater level.

[0003] In engineering construction, taking foundation pit water control as an example, one of the important means is to set up several precipitation wells, recharge wells and recharge ditches on the side of the foundation pit, and control the groundwater level to ensure the smooth progress of construction and the safety of existing buildings around the foundation pit. In the process of implementing water control, it is necessary to implement continuous water level measurement on multiple logging wells to obtain regional groundwater level and water level change trend. At the same time, in addition to the influence of aquifers, compared with the groundwater level without human intervention, due to the existence of artificial pumping and water replenishment, the groundwater level in the logging well has the characteristics of large fluctuations within a certain range. The principle of the rope method is to obtain the groundwater level by actively releasing the measuring rope and obtaining the release amount of the measuring rope length, so it is not suitable for the continuous measurement of water level in this kind of logging well. When the float method measures the groundwater level, the float pulls the rope to move, and the movement of the rope is recorded by the drum. The transmission resistance is large. When the water level changes significantly, there are problems of lagging results and poor accuracy. The implementation cost of the static pressure method is relatively high, and the accuracy is greatly affected by environmental factors such as air pressure and temperature. Water quality conditions also have a great impact on measurement accuracy and maintenance costs.

[0004] In the prior art, water level measurement in well logging is usually completed by using one of the rope method, static pressure method, float method, ultrasonic measurement method, radar measurement method, etc. From the perspective of controlling the cost and accuracy of well logging water level measurement, it is necessary to further optimize the relevant methods and systems. Summary of the invention

[0005] In view of the problem of groundwater level measurement in well logging, the present invention provides a groundwater level engineering survey method and system based on the well point measurement method. The method and system have the characteristics of low implementation cost and guaranteed water level measurement accuracy.

[0006] The present invention relates to an underground water level engineering survey method based on a well point measurement method, wherein the method realizes underground water level measurement in well logging based on a rope, a measuring module and an underwater component, wherein the underwater component is connected to the lower end of the rope, the measuring module is used to measure the length of the rope released in the well logging, the underwater component comprises a rod barrel, a floating body and a detection module, the upper end of the rod barrel is connected to the lower end of the rope, the floating body is arranged in a rod hole of the rod barrel, and the rod hole is connected to the outside of the rod barrel through a connecting hole; In this method, the underwater assembly is installed in the well logging, specifically: the rod barrel is suspended in the well logging by a rope and holds a plumb bob, the detection module is installed on the rod barrel, the rod hole has a lower end below the well logging liquid level, the upper end above the well logging liquid level, and the float floats on the well logging liquid level; In the method, the method for obtaining the groundwater level is as follows: the measuring module obtains the position of the rod barrel in the well logging by releasing the length of the rope in the well logging; the detection module obtains the position of the float on the rod barrel; according to the position of the rod barrel in the well logging and the position of the float on the rod barrel, the position of the float relative to the well logging wellhead is obtained and the position is used as the position of the groundwater level in the well logging; During the groundwater level measurement process, the rod barrel is lifted or released by the rope to maintain the state of the rod hole and the float relative to the logging fluid level.

[0007] This scheme is aimed at the use of logging wells (measuring wells for groundwater level measurement) with precipitation wells and recharge wells / recharge ditches around them. It is necessary to make the area between the precipitation well and the recharge ditch, and the area between the precipitation well and the recharge well have an inclined groundwater level line. In the process of adjusting the influence of the precipitation well and the recharge well / recharge ditch on the groundwater level, the liquid level in the logging well is affected by the precipitation well and the recharge well / recharge ditch. The logging well has obvious groundwater level changes during the measurement period. When the low-cost and high-precision measuring rope method is used to measure the liquid level position of this type of logging well, it is not convenient to complete continuous monitoring of the liquid level position. When the low-cost float method is used to continuously measure the logging liquid level, the frequent fluctuations of the liquid level will cause poor measurement accuracy. Based on the above, a technical scheme is provided to complete groundwater level engineering survey by combining the measuring rope method and the float method, aiming to provide a groundwater level measurement scheme with low implementation cost and guaranteed water level measurement accuracy.

[0008] The principle of implementing groundwater level measurement in this scheme is as follows: when the underwater component is suspended in the well logging with the rod barrel as a plumb bob based on the rope, the measuring module can obtain the position of the lower rod barrel in the well logging based on the length of the rope released in the well logging; since the rod barrel has a certain length, and the lower rod hole has a state where the lower end is below the well logging liquid level, the upper end is above the well logging liquid level, and the float floats on the well logging liquid level, when the well logging liquid level fluctuates with the change of the groundwater level line, under the condition that the rod barrel remains in the well logging position, due to The float can rise and sink to a certain extent along the rod hole with the logging fluid level. After the position of the float on the rod barrel is obtained by the detection module, the position of the float in the logging can be obtained by combining the above two positions, and this position is used as the position of the logging fluid level. When the liquid level height changes in the logging process to the point that the float cannot move further down or up along the rod hole in the rod barrel, or the float is not floating on the logging fluid level, the rod barrel can be lifted or released by a rope to restore the float to a state where it can continuously measure the logging fluid level position within a certain travel range.

[0009] Different from the float method and the rope method used in the prior art, in this solution, after the underwater component is released to a suitable position (under the state), the position of the logging liquid surface is finally obtained by utilizing the movement of the float within a certain range and the position of the float being detected by the detection module installed on the rod barrel. Therefore, compared with the existing rope method for measuring the logging liquid level, it is not necessary to lift or release the rope for obtaining a single liquid level value, that is, the underwater component can continuously measure the logging liquid level within a certain range after it is in place once; in the structural design and functional design of the underwater component, the detection module obtains the position of the float on the rod barrel without being affected by the rope, etc., that is, the problem of result lag and poor accuracy caused by transmission resistance in the process of measuring the groundwater level by the float method is eliminated; when the draft of the rod barrel changes in the logging process, resulting in the change of the state, the position of the underwater component in the logging process can be adjusted by the rope, so this solution is suitable for groundwater level measurement when the liquid surface position changes greatly in the logging process.

[0010] In a specific implementation, in order to enable the underwater components to be released and lifted smoothly and reduce the interference of factors such as well wall collapse on the movement of the floating body with the liquid surface, before the underwater components are installed in the well logging, a casing as a well logging wall protection pipe is installed in the well logging. The side wall of the casing has a pipe hole, which serves as a connecting hole between the liquid surface in the casing and the peripheral geological liquid level line. After the casing is installed, the water in the well logging is left to stand. When the water is clear, the underwater components are installed in the well logging to prevent sediment sedimentation from interfering with the smooth rise and fall of the floating body.

[0011] In a specific embodiment, the method for maintaining the state of the rod hole and the float relative to the logging liquid level is: determining the draft of the rod barrel in the logging process, when the draft is less than or equal to a lower limit threshold, releasing the rod barrel by a rope and making the draft of the rod barrel reach a set depth; when the draft is greater than or equal to an upper limit threshold, lifting the rod barrel by a rope and making the draft of the rod barrel reach a set depth; The method for determining the draft is any one of the following methods: This is achieved based on the position of the float on the rod barrel obtained by the detection module; This is achieved by installing liquid level switches at the upper and lower ends of the rod barrel.

[0012] It is easy to understand that the rod barrel adopts a structure that will sink into the well logging without the pull of a rope. After the rod barrel is maintained at a specific position in the well logging under the pull of the rope, as the liquid level in the well logging changes, the float will rise or fall along the rod hole with the liquid surface. When the liquid level drops too much, the float will form a situation where it drops to the bottom of the rod barrel, causing the float to be constrained by the rod barrel and unable to further descend with the liquid surface. When the liquid level rises too much, the float will form a situation where it rises to the top of the rod barrel, causing the float to be constrained by the rod barrel and unable to further rise with the liquid surface. The above changes in liquid level position are accompanied by changes in the draft of the rod barrel in the well logging. The above scheme provides a specific method for monitoring the state changes. Specifically, it matches the lower threshold, set depth and upper threshold associated with the draft depth. The lower threshold and upper threshold serve as trigger values ​​for triggering the rope to release the rod barrel and lift the rod barrel. When the draft depth reaches the corresponding threshold and triggers the rope action, the rod barrel is lowered or lifted to the set depth at which the float can rise or fall to adapt to the groundwater level measurement when the liquid level rises or falls.

[0013] In a specific embodiment, since the position of the float in the rod barrel changes with the draft, the detection value of the detection module can be used as the basis for determining the draft, and a separate liquid level switch can be configured for the rod barrel. For example, by respectively arranging the liquid level switches at the upper and lower ends of the rod barrel, it is possible to determine whether the upper limit threshold has been reached and whether the lower limit threshold has been reached.

[0014] In a specific embodiment, the method for the measurement module to obtain the position of the rod barrel in the well logging is: by obtaining the number of rolling circles of the roller on the measurement module that contacts the rope, the length of the rope released in the well logging is obtained, wherein the roller is configured as follows: set at the wellhead position of the well logging, the wheel surface of the roller contacts the side of the rope, when the rope is lifted and released, the roller rotates under the friction of the rope and is synchronized with the movement speed of the rope; The detection module obtains the position of the float on the rod barrel in any one or more of the following ways: A permanent magnet is arranged in the float. When the permanent magnet moves along the rod hole with the float relative to the rod barrel, the detection module obtains the position of the float on the rod barrel by sensing the magnetic field of the permanent magnet. The bottom of the float is connected to a tension sensor arranged at the bottom of the rod barrel through an elastic rope or a constant force spring. The tension sensor is used to measure the tension exerted by the float on it. The detection module converts the tension into the elongation of the elastic rope or the constant force spring, and calculates the position of the float on the rod barrel based on the elongation.

[0015] The above scheme provides a specific method for the measurement module to obtain the position of the rod barrel in the well logging. The principle is: when the rope is lifted or lowered, the friction between the rope and the roller forces the roller to move with the rope. According to the rotation direction of the roller, it can be determined whether the rope is lowered or lifted. According to the number of turns and angle of the roller, the lifting amount or lowering amount of the rope can be determined. In this measurement method, the measurement of the rod barrel position is not affected by the coiling radius of the rope on the following roller module, nor is it affected by the shape of the rope turns on the roller module. Under the premise of a simple scheme, the position of the rod barrel in the well logging can be correctly obtained. The preferred application is to clamp the rope by two rollers, each of which is a metal wheel with an annular groove on the wheel surface, and a rubber layer is arranged on the groove surface of the annular groove, and a wear-resistant cloth surface layer is arranged on the surface of the rubber layer. The rubber layer undergoes elastic deformation under the extrusion of the rope. By adopting this scheme, a reliable supporting force can be maintained between the rope and the wheel surface so that the roller can move synchronously with the rope. The wear-resistant cloth surface layer is used to adapt to the rope as a wire rope, and the performance of the measurement module is kept reliable for a long time.

[0016] The above scheme provides a specific method for the detection module to obtain the position of the float on the rod barrel, and its principle is: for a float equipped with a permanent magnet, when the float moves with the liquid surface position, the permanent magnet moves with the float in the rod barrel, so that the detection module obtains the position of the float through magnetic induction, and the detection module can adopt structures such as magnetic induction coils and waveguide wires; for a float connected to the bottom of the rod barrel by an elastic rope or a constant force spring, as the float moves, the elongation of the elastic rope or constant force spring changes, and at this time, the force of the elastic rope or constant force spring on the tension sensor changes, so the measurement result based on the tension sensor can be converted into the position of the float on the rod barrel. Compared with magnetic induction coils and waveguide wires, this structure not only has the characteristics of low cost, but also has the characteristics of simple supporting structure, measurement accuracy is not easily affected by electromagnetic fields in the environment, low power consumption, and convenient power supply. Preferably, since the draft of the float will change when the elongation of the elastic rope or constant force spring changes, the logging liquid level position is corrected using the measurement result of the tension sensor when the position of the logging liquid level is determined by the position of the float on the rod barrel. Preferably, the float is set to have an equal-diameter cylindrical structure in the draft section. Since the tension and buoyancy have a matching relationship, a correction coefficient K can be obtained through experiments. The K value is used to eliminate the influence of the float on the groundwater level measurement results under different tensions and drafts.

[0017] In a specific embodiment, the rope lifting or releasing of the rod barrel is realized under the action of the drum module, the upper end of the rope is wound around the drum module, when the position of the rod barrel in the well logging is fixed, the measurement value of the measurement module is read and stored, when the position of the rod barrel changes, the measurement value of the measurement module is re-read and stored; The detection module obtains the position of the float on the rod barrel according to the set measurement frequency. After each time the detection module completes the position detection of the float on the rod barrel, the detection module transmits the position detection result of the float on the rod barrel to the processing module. The processing module obtains the position of the groundwater level in the logging according to the currently stored measurement value and the current detection result, and uses the detection result as the basis for determining the operation of the roller module. The roller module is used to maintain the state of the rod hole and the float relative to the logging liquid level.

[0018] The above scheme provides a technical solution that the position of the rod barrel in well logging is maintained by relying on the roller module, provides a technical solution that records the measured value of the measurement module after the roller module completes a single action, so as to efficiently read the position of the rod barrel when calculating the groundwater level in well logging, and provides a technical solution that uses the position detection result of the detection module for groundwater level measurement in well logging and the basis for judging the operation of the roller module. Specifically, the storage location of the measured value can be stored on the rope processing module. After the detection module completes a float position detection, the detection result is uploaded to the processing module to calculate the groundwater level and complete a groundwater level measurement, complete a rod barrel draft depth judgment, and judge whether to adjust the position of the rod barrel relative to the liquid surface in the well logging through the roller module.

[0019] The present solution also relates to a groundwater level engineering survey system based on a well point measurement method, which is used to implement any of the groundwater level engineering survey methods described above. It is easy to understand that the groundwater level engineering survey system is a groundwater level engineering survey system that implements the above groundwater level engineering survey method.

[0020] In a specific embodiment, the underground water level engineering survey system includes a rope, a measuring module and an underwater component, the underwater component is connected to the lower end of the rope, the measuring module is used to measure the length of the rope released in the well logging, the underwater component includes a rod barrel, a float and a detection module, the upper end of the rod barrel is connected to the lower end of the rope, the float is arranged in the rod hole of the rod barrel, the rod hole is connected to the outside of the rod barrel through a connecting hole, the detection module is installed on the rod barrel, and the detection module is used to obtain the position of the float on the rod barrel; The rod barrel is a mesh tube, and further comprises a filter wrapped around the outside of the rod barrel, the mesh holes on the mesh tube serve as the communicating holes, and the filter covers each communicating hole; The upper end and the lower end of the floating body are both elliptical head-shaped structures that are convex relative to the end portions.

[0021] This scheme is different from the above schemes. It provides a technical scheme that uses a mesh tube as the rod barrel. The mesh tube can not only make the rod hole and the well logging have good water connectivity, but also is a rod barrel implementation scheme with strong structural stability. The filter is used to prevent impurities in the well logging from entering the rod hole, so as to avoid the influence of the floating body's sensitivity to the rise or fall relative to the rod barrel due to the deposition of impurities around the float, the sinking or floating objects entrained in the connecting hole, etc. The end shape of the float is used to achieve: in order to reduce the influence of the floating body shaking in the rod barrel on the detection of the floating body position, when the float and the rod hole have a small matching clearance, by avoiding the floating body being blocked at the end when moving relative to the rod barrel, the end shape can effectively ensure the sensitivity of the floating body to rise or fall relative to the rod barrel. From the perspective of the sensitivity of the floating body movement, the arc chamfer can be set at the end position of the floating body to replace the elliptical head structure, but when the top surface of the floating body is a plane, the influence of water drops falling on the plane on the floating body position will be much greater than the influence of water drops falling on the elliptical head structure on the floating body position.

[0022] In a specific embodiment, a first partition and a second partition located below the first partition are provided at the bottom of the rod barrel, the first partition and the second partition form a watertight chamber located inside the rod barrel, the detection module includes a tension sensor, the lower end of the tension sensor is fixedly connected to the second partition, the upper end of the tension sensor is fixedly connected to a pull rod, the pull rod passes through the first partition through a through hole on the first partition, and an O-ring is provided between the hole wall of the through hole and the pull rod; The lower end of the floating body is connected to the upper end of the pull rod through an elastic rope or a constant force spring.

[0023] The above scheme provides a technical scheme for sealing the electronic components of the detection module in a watertight chamber to facilitate the selection of the corresponding electronic components and ensure the reliability of their performance. Specifically, the pull rod is used as a rigid rod and as an intermediate connector for transmitting force between the tension sensor and the elastic rope or constant force spring. Compared with the elastic rope or constant force spring passing through the through hole, since the pull rod does not deform when it is pulled, from the perspective of the gap between the sealing hole wall and the pull rod, this scheme is easier to obtain reliable sealing performance and smaller pull rod movement resistance; the O-ring is used as a sealing structure at the through hole position. When the tension sensor is deformed by tension, compared with the packing sealing structure, the sealing structure can reduce the movement resistance of the pull rod to improve the measurement accuracy of the tension sensor. A better scheme is to have multiple O-rings along the axial direction of the through hole, and use the O-ring at the top to block sand particles from entering the mating surface between the O-ring below and the pull rod, thereby ensuring the sealing reliability of the watertight chamber.

[0024] In a specific embodiment, the rod barrel includes a first barrel, a second barrel and an end cap connected in sequence from top to bottom, the first barrel and the second barrel are connected in threaded connection through a connecting thread, and the second barrel and the end cap are connected in threaded connection through a connecting thread; The first baffle is fixed to the lower end of the first cylinder, the second baffle is fixed to the lower end of the second cylinder, the first baffle and the second baffle are both provided with a center hole, the center hole on the first baffle serves as the through hole, the tension sensor is fixedly connected to the second baffle by a tightening bolt, and the center hole on the second baffle serves as a bolt hole for the tightening bolt; An installation cavity for installing a signal transmission module and a battery is formed between the second partition plate and the end cap.

[0025] The present invention provides a technical solution for convenient assembly of underwater components. Specifically, after a float having an elastic rope or a constant force spring connected to its lower end is embedded into the rod hole from the upper end of the first cylinder, the lower end of the elastic rope or the constant force spring passes through the first baffle through the through hole. After the connection between the elastic rope or the constant force spring and the pull rod is completed at the lower end of the first cylinder, a tension sensor is installed from the lower end of the first cylinder, and the pull rod is passed through the first baffle through the through hole. At this time, the tension sensor is centered in the first cylinder. Then, the second cylinder is connected to the lower end of the first cylinder. After the second cylinder is docked, the bolt hole at the lower end of the tension sensor is directly opposite to the center hole on the second baffle. At this time, a tightening bolt is installed from the bottom side of the second baffle to fix the bottom of the tension sensor on the second baffle. Then, a signal transmission module and electronic devices such as a battery are placed in the enclosed space between the end cap and the second baffle, and the enclosed space is further closed by rotating the end cap. In a specific implementation, thread glue is coated on the connection surface between the first cylinder and the second cylinder, and on the connection surface between the second cylinder and the end cap, and the thread glue is used to achieve water isolation and anti-loosening.

[0026] In a specific embodiment, it further comprises a drum module, the upper end of the rope is wound around the drum module, and it further comprises a driving device for driving the drum module to rotate; It also includes a signal transmission module, which receives the float position detection result of the detection module and transmits the position detection result to the control module of the drive device. The control module is used to control the operation of the roller module and maintain the state of the rod hole and the float relative to the logging liquid level.

[0027] In the above scheme, the driving device and the drum module enable the length adjustment of the rope released during logging to be completed through automatic control, so that the system has unattended characteristics during the groundwater level monitoring process. The signal transmission module is used to establish an automatic control strategy for the float position and the rod barrel position.

[0028] In a specific embodiment, it also includes a support structure and a limiting wheel, wherein the roller module, the limiting wheel and the measuring module are all installed on the support structure, and the rope between the roller module and the measuring module is supported on the limiting wheel; The rope is a steel wire rope; A biofilm inhibition coating is arranged on the inner wall of the rod barrel and / or the outer wall of the float.

[0029] In the above scheme, the limiting wheel serves as a reversing wheel for the rope, so that when the rope is wound around different axial positions of the drum module or released from different axial positions of the drum module, the ropes on both sides of the measuring module have a stable angle. Preferably, under the action of the limiting wheel, the ropes on both sides of the measuring module are in a relatively straight state; the steel wire rope makes the rope have a relatively small elongation under the tension of the underwater component, thereby ensuring the acquisition and detection accuracy of the measuring module on the rod barrel; the biofilm inhibition coating is used to inhibit the biofilm that may be formed on the inner wall of the rod barrel and / or the outer wall of the float, thereby ensuring the reliability and sensitivity of the float as the logging fluid level rises and moves downward.

[0030] The present invention has the following beneficial effects: In this solution, after the underwater component is released to a suitable position, the movement of the float within a certain range and the position of the float are detected by the detection module installed on the rod barrel, and finally the position of the logging fluid surface is obtained. Therefore, compared with the existing rope measuring method for measuring the logging fluid level, there is no need to lift or release the rope to obtain a single liquid level value, that is, after the underwater component is in place once, the logging fluid level can be continuously measured within a certain range.

[0031] In the structural design and functional design of the underwater component, the detection module obtains the position of the float on the rod barrel without being affected by the rope, etc., which eliminates the problem of result lag and poor accuracy caused by transmission resistance during the float method of measuring groundwater level.

[0032] When the draft of the rod barrel changes in the well logging, resulting in the change of the state, the position of the underwater component in the well logging can be adjusted by the rope. Therefore, this solution is suitable for groundwater level measurement when the liquid surface position in the well logging changes significantly. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of a specific application embodiment of the groundwater level engineering survey system described in this scheme; Figure 2 This is a schematic diagram of a specific application example of the groundwater level engineering survey system described in this scheme, and Figure 1 There is a difference, the filter is omitted in this schematic diagram; Figure 3A cross-sectional view of a specific embodiment of the underwater assembly described in this solution; Figure 4 for Figure 3 A partial enlarged view of part A.

[0034] The reference numerals in the figure are: 1. roller module, 2. rope, 3. limiting wheel, 4. supporting structure, 5. measuring module, 6. casing, 7. underwater component, 71. rod barrel, 72. detection module, 73. rod hole, 74. connecting hole, 75. float, 76. pull rod, 77. watertight chamber, 78. tension sensor, 79. first partition, 710. second partition, 711. tightening bolt, 712. elastic rope. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with embodiments, but the present invention is not limited to the following embodiments: Example

[0036] like Figures 1 to 4 As shown, a groundwater level engineering survey method based on the well point measurement method is implemented based on a rope 2, a measuring module 5 and an underwater component 7 to achieve groundwater level measurement in well logging, wherein the underwater component 7 is connected to the lower end of the rope 2, the measuring module 5 is used to measure the length of the rope 2 released in the well logging, and the underwater component 7 includes a rod barrel 71, a float 75 and a detection module 72, the upper end of the rod barrel 71 is connected to the lower end of the rope 2, the float 75 is arranged in a rod hole 73 of the rod barrel 71, and the rod hole 73 is connected to the outside of the rod barrel 71 through a connecting hole 74; In this method, the underwater assembly 7 is installed in the well logging, specifically: the rod barrel 71 is suspended in the well logging by the rope 2 and holds the plumb bob, the detection module 72 is installed on the rod barrel 71, the rod hole 73 has a lower end below the well logging liquid level, an upper end above the well logging liquid level, and a float 75 floats on the well logging liquid level; In the method, the method for obtaining the groundwater level is as follows: the measuring module 5 obtains the position of the rod barrel 71 in the well logging by releasing the length of the rope 2 in the well logging; the detection module 72 obtains the position of the float 75 on the rod barrel 71; according to the position of the rod barrel 71 in the well logging and the position of the float 75 on the rod barrel 71, the position of the float 75 relative to the well logging wellhead is obtained and the position is used as the position of the groundwater level in the well logging; During the underground water level measurement, the rod barrel 71 is lifted or released by the rope 2 to keep the rod hole 73 and the float 75 in a state relative to the logging fluid surface.

[0037] This scheme is aimed at the use of logging wells (measuring wells for groundwater level measurement) with precipitation wells and recharge wells / recharge ditches around them. It is necessary to make the area between the precipitation well and the recharge ditch, and the area between the precipitation well and the recharge well have an inclined groundwater level line. In the process of adjusting the influence of the precipitation well and the recharge well / recharge ditch on the groundwater level, the liquid level in the logging well is affected by the precipitation well and the recharge well / recharge ditch. The logging well has obvious groundwater level changes during the measurement period. When the low-cost and high-precision measuring rope method is used to measure the liquid level position of this type of logging well, it is not convenient to complete continuous monitoring of the liquid level position. When the low-cost float method is used to continuously measure the logging liquid level, the frequent fluctuations of the liquid level will cause poor measurement accuracy. Based on the above, a technical scheme is provided to complete groundwater level engineering survey by combining the measuring rope method and the float method, aiming to provide a groundwater level measurement scheme with low implementation cost and guaranteed water level measurement accuracy.

[0038] The principle of the present scheme for measuring groundwater level is as follows: when the underwater assembly 7 is suspended in the well logging with the rod barrel 71 as a plumb bob based on the rope 2, the measuring module 5 can obtain the position of the lower rod barrel 71 in the well logging based on the length of the rope 2 released in the well logging; since the rod barrel 71 has a certain length, and the lower rod hole 73 has a state where the lower end is below the well logging liquid level, the upper end is above the well logging liquid level, and the float 75 floats on the well logging liquid level, when the well logging liquid level fluctuates with the change of the groundwater level line, when the rod barrel 71 is in the well logging and its position remains unchanged, the float 75 can It can float and sink to a certain extent along the rod hole 73 with the logging fluid level. After the position of the float 75 on the rod barrel 71 is obtained by the detection module 72, the position of the float 75 in the logging can be obtained by combining the above two positions, and this position is used as the position of the logging fluid level. When the liquid level height changes in the logging process to the point that the float 75 cannot further move down or up along the rod hole 73 in the rod barrel 71, or the float 75 is not floating on the logging fluid level, the rod barrel 71 can be lifted or released by the rope 2 to restore the float 75 to a state where it can continuously measure the logging fluid level position within a certain travel range.

[0039] Different from the float method and the rope measuring method used in the prior art, in this solution, after the underwater component 7 is released to a suitable position (in the state), the position of the well logging liquid surface is finally obtained by utilizing the movement of the float 75 within a certain range and the position of the float 75 being detected by the detection module 72 installed on the rod barrel 71. Therefore, compared with the existing rope measuring method for measuring the well logging liquid level, it is not necessary to lift or release the rope 2 for obtaining a single liquid level value, that is, the underwater component 7 can continuously measure the well logging liquid level within a certain range after it is in place once; the water In the structural design and functional design of the lower component 7, the detection module 72 obtains the position of the float 75 on the rod barrel 71 and is not affected by the rope 2, etc., that is, the problem of result lag and poor accuracy caused by transmission resistance during the float method of measuring groundwater level is eliminated because the float needs to pull the rope 2 to move; when the draft of the rod barrel 71 changes in the well logging, resulting in the change of the state, the position of the underwater component 7 in the well logging can be adjusted by the rope 2, so this solution is suitable for groundwater level measurement when the liquid surface position changes drastically in the well logging.

[0040] In a specific application, in order to enable the underwater component 7 to be released and lifted smoothly and reduce the interference of factors such as well wall collapse on the movement of the float 75 with the liquid surface, before the underwater component 7 is installed in the well logging, a casing 6 as a well logging wall protection pipe is installed in the well logging. The side wall of the casing 6 has a pipe hole, which serves as a connecting hole 74 between the liquid surface in the casing 6 and the peripheral geological liquid level line. After the installation of the casing 6 is completed, the water body in the well logging is left to stand. When the water body is clear, the underwater component 7 is installed in the well logging to prevent sediment sedimentation from interfering with the smooth rise and fall of the float 75. Example

[0041] This embodiment is further refined on the basis of embodiment 1: The method for maintaining the state of the rod hole 73 and the float 75 relative to the logging liquid level is as follows: the draft of the rod barrel 71 in the logging is determined, and when the draft is less than or equal to the lower limit threshold, the rope 2 releases the rod barrel 71 and makes the draft of the rod barrel 71 reach the set depth; when the draft is greater than or equal to the upper limit threshold, the rope 2 lifts the rod barrel 71 and makes the draft of the rod barrel 71 reach the set depth; The method for determining the draft is any one of the following methods: This is achieved based on the position of the float 75 on the rod barrel 71 acquired by the detection module 72; This is achieved by installing liquid level switches at the upper and lower ends of the rod barrel 71 .

[0042] It is easy to understand that the rod barrel 71 adopts a structure that will sink into the well logging without the pull of the rope 2. After the rod barrel 71 is maintained at a specific position in the well logging under the pull of the rope 2, as the liquid level in the well logging changes, the float 75 will rise or fall along the rod hole 73 with the liquid surface. When the liquid level drops too much, the float 75 will form a situation where it drops to the bottom of the rod barrel 71, causing the float 75 to be constrained by the rod barrel 71 and unable to further descend with the liquid surface. When the liquid level rises too much, the float 75 will form a situation where it rises to the top of the rod barrel 71, causing the float 75 to be constrained by the rod barrel 71 and unable to further rise with the liquid surface. The above changes in liquid level position are accompanied by changes in the draft of the rod barrel 71 in the well logging. The above scheme provides a specific method for monitoring the state changes. Specifically, it matches the lower threshold, set depth and upper threshold associated with the draft depth. The lower threshold and upper threshold serve as trigger values ​​for triggering the rope 2 to release the rod barrel 71 and lift the rod barrel 71. When the draft depth reaches the corresponding threshold and triggers the rope 2 to act, the rod barrel 71 is lowered or lifted to the set depth at which the float 75 can rise or fall to adapt to the groundwater level measurement when the liquid level rises or falls.

[0043] In this embodiment, since the position of the float 75 in the rod barrel 71 changes with the draft depth, the detection value of the detection module 72 can be used as the basis for determining the draft depth, and a separate liquid level switch can be configured for the rod barrel 71. For example, by respectively arranging the liquid level switches at the upper and lower ends of the rod barrel 71, it is possible to determine whether the upper limit threshold has been reached and whether the lower limit threshold has been reached. Example

[0044] This embodiment is further refined on the basis of embodiment 1: The method for the measuring module 5 to obtain the position of the rod barrel 71 in the well logging is: by obtaining the number of rolling circles of the roller on the measuring module 5 that contacts the rope 2, the length of the rope 2 released in the well logging is obtained, wherein the roller is configured as follows: set at the wellhead position of the well logging, the wheel surface of the roller contacts the side of the rope 2, when the rope 2 is lifted and released, the roller rotates under the friction of the rope 2 and is synchronized with the movement speed of the rope 2; The method by which the detection module 72 obtains the position of the float 75 on the rod barrel 71 is any one or more of the following methods: A permanent magnet is disposed in the float 75. When the permanent magnet moves along the rod hole 73 with the float 75 relative to the rod barrel 71, the detection module 72 obtains the position of the float 75 on the rod barrel 71 by sensing the magnetic field of the permanent magnet. The bottom of the float 75 is connected to a tension sensor 78 arranged at the bottom of the rod barrel 71 through an elastic rope 712 or a constant force spring. The tension sensor 78 is used to measure the tension exerted by the float 75 on it. The detection module 72 converts the tension into the elongation of the elastic rope 712 or the constant force spring, and calculates the position of the float 75 on the rod barrel 71 based on the elongation.

[0045] The above scheme provides a specific method for the measurement module 5 to obtain the position of the rod barrel 71 in well logging. The principle is: when the rope 2 is lifted or lowered, the friction between the rope 2 and the roller forces the roller to move with the rope 2. According to the rotation direction of the roller, it can be determined whether the rope 2 is lowered or lifted. According to the number of rotations and angles of the roller, the lifting or lowering amount of the rope 2 can be determined. In this measurement method, the measurement of the position of the rod barrel 71 is not affected by the winding radius of the rope 2 on the following drum module, nor is it affected by the shape of the rope 2 turns on the drum module. Under the premise of a simple scheme, the position of the rod barrel 71 in well logging can be correctly obtained. A better application is to clamp the rope 2 by two rollers, each of which is a metal wheel with a ring groove on the wheel surface, and a rubber layer is arranged on the groove surface of the ring groove, and a wear-resistant cloth surface layer is arranged on the surface of the rubber layer. The rubber layer undergoes elastic deformation under the extrusion of the rope 2. By adopting this solution, a reliable supporting force can be maintained between the rope 2 and the wheel surface so that the roller can move synchronously with the rope 2. The wear-resistant cloth surface layer is used to adapt to the rope 2 that is a steel wire rope, thereby maintaining the long-term reliable performance of the measurement module 5.

[0046] The above scheme provides a specific method for the detection module 72 to obtain the position of the float 75 on the rod barrel 71. The principle is: for the float 75 provided with a permanent magnet, when the float 75 moves with the liquid surface position, the permanent magnet moves with the float 75 in the rod barrel 71, so that the detection module 72 obtains the position of the float 75 through magnetic induction, and the detection module 72 can adopt structures such as magnetic induction coils and waveguide wires; for the float 75 connected to the bottom of the rod barrel 71 through an elastic rope 712 or a constant force spring, as the float 75 moves, the elongation of the elastic rope 712 or the constant force spring changes. At this time, the force of the elastic rope 712 or the constant force spring on the tension sensor 78 changes, so the measurement result based on the tension sensor 78 can be converted into the position of the float 75 on the rod barrel 71. Compared with magnetic induction coils and waveguide wires, this structure not only has the characteristics of low cost, but also has the characteristics of simple supporting structure, measurement accuracy is not easily affected by electromagnetic fields in the environment, low power consumption, and convenient power supply. Preferably, since the draft of the float 75 will change after the elongation of the elastic rope 712 or the constant force spring changes, the logging liquid level position is corrected using the measurement result of the tension sensor 78 when the position of the logging liquid level is determined by the position of the float 75 on the rod barrel 71. Preferably, the float 75 is set to have an equal-diameter columnar structure in the draft section. Since the tension and buoyancy have a matching relationship, a correction coefficient K can be obtained through experiments. The K value is used to eliminate the influence of the float 75 on the groundwater level measurement result under different tensions and drafts. Example

[0047] This embodiment is further refined on the basis of embodiment 1: The rope 2 lifts or releases the rod barrel 71 under the action of the drum module. The upper end of the rope 2 is wound around the drum module. When the rod barrel 71 is fixed in the well logging, the measurement value of the measurement module 5 is read and stored. When the position of the rod barrel 71 changes, the measurement value of the measurement module 5 is re-read and stored. The detection module 72 obtains the position of the float 75 on the rod barrel 71 according to the set measurement frequency. After each time the detection module 72 completes the position detection of the float 75 on the rod barrel 71, the detection module 72 transmits the position detection result of the float 75 on the rod barrel 71 to the processing module. The processing module obtains the position of the groundwater level in the well logging according to the currently stored measurement value and the current detection result, and uses the detection result as the basis for determining the operation of the roller module. The roller module is used to maintain the state of the rod hole 73 and the float 75 relative to the well logging liquid level.

[0048] The above scheme provides a technical solution that the position of the rod barrel 71 in the well logging is maintained by the roller module 1, provides a technical solution that records the measured value of the measuring module 5 after the single action of the roller module is completed, so as to efficiently read the position of the rod barrel 71 when calculating the groundwater level in the well logging, and provides a technical solution that uses the position detection result of the detection module 72 for the groundwater level measurement in the well logging and the basis for the determination of the operation of the roller module. Specifically, the storage location of the measured value can be stored on the rope 2 processing module, and after the detection module 72 completes a position detection of the float 75, it will upload the detection result to the processing module to calculate the groundwater level and complete a groundwater level measurement, complete a water depth judgment of the rod barrel 71, and determine whether to adjust the position of the rod barrel 71 relative to the liquid surface in the well logging through the roller module. Example

[0049] Based on Example 1, this embodiment provides a groundwater level engineering survey system based on the well point measurement method, which is used to implement any of the groundwater level engineering survey methods described above. It is easy to understand that this groundwater level engineering survey system is a groundwater level engineering survey system that implements the above groundwater level engineering survey method. Example

[0050] This embodiment is further refined on the basis of Embodiment 5: The underground water level engineering survey system includes a rope 2, a measuring module 5 and an underwater component 7. The underwater component 7 is connected to the lower end of the rope 2. The measuring module 5 is used to measure the length of the rope 2 released in the well logging. The underwater component 7 includes a rod barrel 71, a float 75 and a detection module 72. The upper end of the rod barrel 71 is connected to the lower end of the rope 2. The float 75 is arranged in a rod hole 73 of the rod barrel 71. The rod hole 73 is connected to the outside of the rod barrel 71 through a connecting hole 74. The detection module 72 is installed on the rod barrel 71. The detection module 72 is used to obtain the position of the float 75 on the rod barrel 71. The rod barrel 71 is a mesh tube, and further includes a filter wrapped around the outside of the rod barrel 71. The mesh holes on the mesh tube serve as the communication holes 74, and the filter covers each communication hole 74. The upper end and the lower end of the floating body 75 are both elliptical head-shaped structures that are convex relative to the end portions.

[0051] The present solution is different from the above solutions in that it provides a technical solution using a mesh tube as the rod barrel 71. The mesh tube not only enables the rod hole 73 and the well logging to have good water connectivity, but also is a solution for implementing the rod barrel 71 with strong structural stability. The filter is used to prevent impurities in the well logging from entering the rod hole 73, to avoid the effect of impurities deposited around the float 75, sinking objects or floating objects entrained in the connecting hole 74, etc., which may affect the sensitivity of the float 75 to rise or fall relative to the rod barrel 71. The end shape of the float 75 is used to achieve: to reduce the impact of the shaking of the float 75 in the rod barrel 71 on the position detection of the float 75, when the float 75 and the rod hole 73 have a small fitting clearance, by avoiding obstruction at the end when the float 75 moves relative to the rod barrel 71, the end shape can effectively ensure the sensitivity of the float 75 to rise or fall relative to the rod barrel 71. From the perspective of the movement sensitivity of the float 75, a circular chamfer can be set at the end position of the float 75 to replace the elliptical head structure. However, when the top surface of the float 75 is a plane, the impact of water drops falling on the plane on the position of the float 75 will be much greater than the impact of water drops falling on the elliptical head structure on the position of the float 75. Example

[0052] This embodiment is further refined on the basis of Embodiment 6: The bottom of the rod barrel 71 is provided with a first partition 79 and a second partition 710 located below the first partition 79. The first partition 79 and the second partition 710 form a watertight chamber 77 located inside the rod barrel 71. The detection module 72 includes a tension sensor 78. The lower end of the tension sensor 78 is fixedly connected to the second partition 710. The upper end of the tension sensor 78 is fixedly connected to a pull rod 76. The pull rod 76 passes through the first partition 79 through a through hole on the first partition 79. An O-ring is provided between the hole wall of the through hole and the pull rod 76. The lower end of the float 75 is connected to the upper end of the pull rod 76 through an elastic rope 712 or a constant force spring.

[0053] The above scheme provides a technical scheme for sealing the electronic components of the detection module 72 in the watertight chamber 77 to facilitate the selection of the corresponding electronic components and ensure the reliability of their performance. Specifically, the pull rod 76 is used as a rigid rod and as an intermediate connector for the tension sensor 78 and the elastic rope 712 or the constant force spring to transmit force. Compared with the elastic rope 712 or the constant force spring passing through the through hole, since the pull rod 76 does not deform when it is pulled, from the perspective of the gap between the sealing hole wall and the pull rod 76, this scheme is easier to obtain reliable sealing performance and smaller movement resistance of the pull rod 76; the O-type sealing ring is used as a sealing structure at the position of the through hole. When the tension sensor 78 is deformed by tension, compared with the packing sealing structure, the sealing structure can reduce the movement resistance of the pull rod 76 to improve the measurement accuracy of the tension sensor 78. A better scheme is to have multiple O-type sealing rings along the axial direction of the through hole, and use the O-type sealing ring at the top to block sand particles from entering the matching surface between the O-type sealing ring below and the pull rod 76, thereby ensuring the sealing reliability of the watertight chamber 77. Example

[0054] This embodiment is further refined on the basis of Embodiment 7: The rod barrel 71 includes a first barrel, a second barrel and an end cap which are sequentially connected from top to bottom. The first barrel and the second barrel are connected by connecting threads to form a threaded connection relationship, and the second barrel and the end cap are connected by connecting threads to form a threaded connection relationship. The first partition plate 79 is fixed to the lower end of the first cylinder, and the second partition plate 710 is fixed to the lower end of the second cylinder. The first partition plate 79 and the second partition plate 710 are both provided with a center hole, and the center hole on the first partition plate 79 serves as the through hole. The tension sensor 78 is fixedly connected to the second partition plate 710 by a tightening bolt 711, and the center hole on the second partition plate 710 serves as a bolt hole for the tightening bolt 711. An installation cavity for installing a signal transmission module and a battery is formed between the second partition plate 710 and the end cap.

[0055] The present invention provides a technical solution for facilitating the assembly of the underwater assembly 7. Specifically, after the upper end of the first cylinder is embedded into the rod hole 73, the lower end of the elastic rope 712 or the constant force spring is connected to the first baffle 79 through the through hole. After the elastic rope 712 or the constant force spring is connected to the pull rod 76 at the lower end of the first cylinder, a tension sensor 78 is installed from the lower end of the first cylinder, and the pull rod 76 is passed through the first baffle 79 through the through hole. At this time, the tension sensor 78 is in the first cylinder. The first cylinder is centered in the cylinder, and then the second cylinder is connected to the lower end of the first cylinder. After the second cylinder is docked, the bolt hole at the lower end of the tension sensor 78 is aligned with the center hole on the second partition 710. At this time, the tension bolt 711 is installed from the bottom side of the second partition 710 to complete the fixation of the bottom of the tension sensor 78 on the second partition 710. Then, the signal transmission module and the electronic devices such as the battery are placed in the enclosed space between the end cap and the second partition 710, and the enclosed space is further closed by rotating the end cap. In the specific implementation, thread glue is applied on the connection surface between the first cylinder and the second cylinder, and on the connection surface between the second cylinder and the end cap. The thread glue is used to achieve water isolation and loosening prevention. Example

[0056] This embodiment is further refined on the basis of Embodiment 6: It also includes a drum module, the upper end of the rope 2 is wound around the drum module, and also includes a driving device for driving the drum module to rotate; It also includes a signal transmission module, which receives the position detection result of the float 75 from the detection module 72 and transmits the position detection result to the control module of the drive device. The control module is used to control the operation of the roller module and maintain the state of the rod hole 73 and the float 75 relative to the logging liquid level.

[0057] In the above scheme, the driving device and the drum module enable the length adjustment of the rope 2 released during logging to be completed through automatic control, so that the system has unattended characteristics during the groundwater level monitoring process. The signal transmission module is used to establish an automatic control strategy for the position of the float 75 and the rod barrel 71.

[0058] Embodiment 10: This embodiment is further refined on the basis of Embodiment 9: It also includes a support structure 4 and a limiting wheel 3. The roller module, the limiting wheel 3 and the measuring module 5 are all installed on the support structure 4. The rope 2 between the roller module and the measuring module 5 is supported on the limiting wheel 3. The rope 2 is a steel wire rope; The inner wall of the rod barrel 71 and / or the outer wall of the float 75 are provided with a biofilm inhibition coating.

[0059] In the above scheme, the limiting wheel 3 serves as a reversing wheel for the rope 2, so that when the rope 2 is wound around different axial positions of the drum module 1 or released from different axial positions of the drum module 1, the rope 2 on both sides of the measuring module 5 has a stable angle. Preferably, under the action of the limiting wheel 3, the rope 2 on both sides of the measuring module 5 is in a relatively straight state; the steel wire rope makes the rope 2 have a relatively small elongation under the tension of the underwater component 7, thereby ensuring the acquisition and detection accuracy of the rod barrel 71 by the measuring module 5, and the biofilm inhibition coating is used to inhibit the biofilm that may be formed on the inner wall of the rod barrel 71 and / or the outer wall of the float 75, thereby ensuring the reliability and sensitivity of the float 75 as the logging fluid level rises and moves downward.

[0060] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific embodiments of the present invention are limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, other embodiments obtained without departing from the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for underground water level engineering survey based on a well point measurement method, the method realizing underground water level measurement in well logging based on a rope (2), a measurement module (5) and an underwater component (7), wherein: The underwater component (7) is connected to the lower end of the rope (2), and the measuring module (5) is used to measure the length of the rope (2) released in the well logging, characterized in that the underwater component (7) comprises a rod barrel (71), a float (75) and a detection module (72), the upper end of the rod barrel (71) is connected to the lower end of the rope (2), the float (75) is arranged in the rod hole (73) of the rod barrel (71), and the rod hole (73) is connected to the outside of the rod barrel (71) through a connecting hole (74); In the method, the underwater component (7) is installed in the well logging, specifically: the rod barrel (71) is suspended in the well logging by a rope (2) and holds a plumb bob, the detection module (72) is installed on the rod barrel (71), the rod hole (73) has a lower end located below the well logging liquid surface, an upper end located above the well logging liquid surface, and a float (75) floats on the well logging liquid surface; In the method, the method for obtaining the groundwater level is as follows: the measuring module (5) obtains the position of the rod barrel (71) in the well logging by releasing the length of the rope (2) in the well logging; the detection module (72) obtains the position of the float (75) on the rod barrel (71); based on the position of the rod barrel (71) in the well logging and the position of the float (75) on the rod barrel (71), the position of the float (75) relative to the well logging wellhead is obtained and the position is used as the position of the groundwater level in the well logging; During the underground water level measurement process, the rod barrel (71) is lifted or released by the rope (2) to maintain the state of the rod hole (73) and the float (75) relative to the logging fluid surface.

2. The underground water level engineering survey method based on the well point measurement method according to claim 1 is characterized in that: The method for maintaining the state of the rod hole (73) and the float (75) relative to the logging fluid surface is as follows: determining the draft of the rod barrel (71) in the logging process; when the draft is less than or equal to a lower limit threshold, the rope (2) releases the rod barrel (71) and makes the draft of the rod barrel (71) reach a set depth; when the draft is greater than or equal to an upper limit threshold, the rope (2) lifts the rod barrel (71) and makes the draft of the rod barrel (71) reach a set depth; The method for determining the draft is any one of the following methods: This is achieved according to the position of the float (75) on the rod barrel (71) acquired by the detection module (72); This is achieved by installing liquid level switches at the upper and lower ends of the rod barrel (71).

3. The underground water level engineering survey method based on the well point measurement method according to claim 1 is characterized in that: The method for the measuring module (5) to obtain the position of the rod barrel (71) in the well logging is: by obtaining the number of rolling circles of the roller on the measuring module (5) in contact with the rope (2), the length of the rope (2) released in the well logging is obtained, wherein the roller is configured as follows: arranged at the wellhead position of the well logging, the wheel surface of the roller is in contact with the side of the rope (2), and when the rope (2) is lifted and released, the roller rotates under the friction force of the rope (2) and is synchronized with the movement speed of the rope (2); The method in which the detection module (72) obtains the position of the float (75) on the rod barrel (71) is any one or more of the following methods: A permanent magnet is disposed in the floating body (75); when the permanent magnet moves along the rod hole (73) with the floating body (75) relative to the rod barrel (71), the detection module (72) obtains the position of the floating body (75) on the rod barrel (71) by sensing the magnetic field of the permanent magnet; The bottom of the float (75) is connected to a tension sensor (78) arranged at the bottom of the rod barrel (71) via an elastic rope (712) or a constant force spring. The tension sensor (78) is used to measure the tension exerted on it by the float (75). The detection module (72) converts the tension into an elongation of the elastic rope (712) or the constant force spring, and calculates the position of the float (75) on the rod barrel (71) based on the elongation.

4. The underground water level engineering survey method based on the well point measurement method according to claim 1 is characterized in that: The rope (2) lifts or releases the rod barrel (71) under the action of the drum module (1), the upper end of the rope (2) is wound around the drum module (1), and when the position of the rod barrel (71) in the well logging is fixed, the measurement value of the measurement module (5) is read and stored; when the position of the rod barrel (71) changes, the measurement value of the measurement module (5) is read and stored again; The detection module (72) obtains the position of the float (75) on the rod barrel (71) according to a set measurement frequency. After the detection module (72) completes the position detection of the float (75) on the rod barrel (71) each time, it transmits the position detection result of the float (75) on the rod barrel (71) to the processing module. The processing module obtains the position of the groundwater level in the well logging according to the currently stored measurement value and the current detection result, and uses the detection result as a basis for determining the operation of the roller module (1). The roller module (1) is used to maintain the state of the rod hole (73) and the float (75) relative to the well logging liquid surface.

5. The underground water level engineering survey system based on the well point measurement method is characterized by: The system is used to implement the groundwater level engineering survey method described in any one of claims 1 to 4.

6. The underground water level engineering survey system based on the well point measurement method according to claim 5 is characterized in that: The underground water level engineering survey system comprises a rope (2), a measuring module (5) and an underwater component (7), wherein the underwater component (7) is connected to the lower end of the rope (2), the measuring module (5) is used to measure the length of the rope (2) released in the well logging, and the underwater component (7) comprises a rod barrel (71), a floating body (75) and a detection module (72), wherein the upper end of the rod barrel (71) is connected to the lower end of the rope (2), the floating body (75) is arranged in a rod hole (73) of the rod barrel (71), the rod hole (73) is connected to the outside of the rod barrel (71) through a connecting hole (74), and the detection module (72) is installed on the rod barrel (71), and the detection module (72) is used to obtain the position of the floating body (75) on the rod barrel (71); The rod barrel (71) is a mesh tube, and further comprises a filter screen wrapped around the outside of the rod barrel (71), the mesh holes on the mesh tube serve as the communication holes (74), and the filter screen covers each communication hole (74); The upper end and the lower end of the floating body (75) are both elliptical head-shaped structures that are convex relative to the end portions.

7. The underground water level engineering survey system based on the well point measurement method according to claim 5 or 6, characterized in that: The bottom of the rod barrel (71) is provided with a first partition (79) and a second partition (710) located below the first partition (79), the first partition (79) and the second partition (710) form a watertight chamber (77) located inside the rod barrel (71), the detection module (72) includes a tension sensor (78), the lower end of the tension sensor (78) is fixedly connected to the second partition (710), the upper end of the tension sensor (78) is fixedly connected to a pull rod (76), the pull rod (76) passes through the first partition (79) through a through hole on the first partition (79), and an O-ring is provided between the hole wall of the through hole and the pull rod (76); The lower end of the floating body (75) is connected to the upper end of the pull rod (76) via an elastic rope (712) or a constant force spring.

8. The underground water level engineering survey system based on the well point measurement method according to claim 7 is characterized in that: The rod barrel (71) comprises a first barrel body, a second barrel body and an end cap which are sequentially connected from top to bottom, the first barrel body and the second barrel body forming a threaded connection relationship through a connecting thread, and the second barrel body and the end cap forming a threaded connection relationship through a connecting thread; The first baffle (79) is fixed to the lower end of the first cylinder, and the second baffle (710) is fixed to the lower end of the second cylinder. The first baffle (79) and the second baffle (710) are both provided with a central hole, and the central hole on the first baffle (79) serves as the through hole. The tension sensor (78) is fixedly connected to the second baffle (710) by a tension bolt (711), and the central hole on the second baffle (710) serves as a bolt hole for the tension bolt (711); An installation cavity for installing a signal transmission module and a storage battery is formed between the second partition plate (710) and the end cap.

9. The underground water level engineering survey system based on the well point measurement method according to claim 5 or 6, characterized in that: It also comprises a drum module (1), the upper end of the rope (2) being wound around the drum module (1), and a driving device for driving the drum module (1) to rotate; It also includes a signal transmission module, which receives the position detection result of the float (75) from the detection module (72) and transmits the position detection result to the control module of the drive device, and the control module is used to control the operation of the roller module (1) and maintain the state of the rod hole (73) and the float (75) relative to the logging liquid surface.

10. The underground water level engineering survey system based on the well point measurement method according to claim 9, characterized in that: It also comprises a supporting structure (4) and a limiting wheel (3), wherein the roller module (1), the limiting wheel (3) and the measuring module (5) are all mounted on the supporting structure (4), and the rope (2) between the roller module (1) and the measuring module (5) is supported on the limiting wheel (3); The rope (2) is a steel wire rope; A biofilm inhibition coating is provided on the inner wall of the rod barrel (71) and / or the outer wall of the float (75).

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