A piezometer with a replaceable main body structure

Abstract

The present invention provides a piezometer with a replaceable main body structure, comprising a main pipeline. The main pipeline includes an inner layer pipe, a middle layer pipe and an outer layer pipe. The middle layer pipe is sleeved outside the inner layer pipe, and the outer layer pipe is sleeved outside the middle layer pipe. The inner layer pipe includes a first water-impermeable section, a first water-permeable section and a second water-impermeable section arranged from top to bottom. First water-permeable holes are arranged on the first water-permeable section. The middle layer pipe includes a third water-impermeable section, a second water-permeable section and a fourth water-impermeable section arranged from top to bottom. Second water-permeable holes are arranged on the second water-permeable section. The outer layer pipe includes a fifth water-impermeable section, a third water-permeable section and a sixth water-impermeable section arranged from top to bottom. Third water-permeable holes are arranged on the third water-permeable section. An anti-filter material and a plugging body are arranged between the inner layer pipe and the middle layer pipe. The first water-permeable section, the second water-permeable section and the third water-permeable section are all located below the plugging body. A base is arranged at the bottom end of the main pipeline. The bottom ends of the middle layer pipe and the inner layer pipe are both connected to the base. This piezometer is beneficial to preventing the piezometer from being blocked.

Description

Technical Field

[0001] The present invention relates to the technical field of water conservancy seepage detection, and in particular to a piezometer tube with a replaceable main structure. Background Art

[0002] Seepage monitoring is an important part of the safety monitoring of water conservancy projects, and burying piezometer tubes is an important means of monitoring seepage. The working principle of traditional piezometer tubes is that a piezometer tube with a permeable flower tube section at the bottom is buried in the seepage area. Groundwater will enter the inside of the piezometer tube through the above flower tube section and rise to a certain height along the inside of the piezometer tube. The height of the water level inside the piezometer tube will reflect the water head size of the monitored area.

[0003] Although the piezometer tubes with traditional structural forms are widely used, the actual application effect is not ideal. In the actual use process, the piezometer tubes are very easy to be blocked. The blockage causes the piezometer tubes to be slow to respond, and even causes the piezometer tubes to fail. Moreover, it is very difficult to clean and repair after being blocked. The problem of blockage and failure of piezometer tubes is widespread in many water conservancy projects and has become a common problem in the industry. Summary of the Invention

[0004] The purpose of the present invention is to provide a piezometer tube with a replaceable main structure to solve the above technical problems.

[0005] The technical solution of the present application is: a piezometer tube with a replaceable main structure, including a main pipe. The main pipe includes an inner layer pipe, a middle layer pipe, and an outer layer pipe. The middle layer pipe is sleeved outside the inner layer pipe, and the outer layer pipe is sleeved outside the middle layer pipe. The inner layer pipe includes a first impermeable section, a first permeable section, and a second impermeable section arranged in sequence from top to bottom. The first permeable section is provided with a first permeable hole. The middle layer pipe includes a third impermeable section, a second permeable section, and a fourth impermeable section arranged in sequence from top to bottom. The second permeable section is provided with a second permeable hole. The outer layer pipe includes a fifth impermeable section, a third permeable section, and a sixth impermeable section arranged in sequence from top to bottom. The third permeable section is provided with a third permeable hole. An anti-filter material and a sealing body are arranged between the inner layer pipe and the middle layer pipe. The first permeable section, the second permeable section, and the third permeable section are all located below the sealing body. A base is arranged at the bottom end of the main pipe, and the bottom ends of the middle layer pipe and the inner layer pipe are both connected to the base.

[0006] Preferably, the plugging body includes a first plugging body and a second plugging body. A sealed sandwich layer is formed between the first plugging body and the second plugging body. The first plugging body is located at the top of the main pipeline, and the second plugging body is located below the first plugging body. The first water-permeable section, the second water-permeable section, and the third water-permeable section are all located below the first plugging body. The bottom ends of the middle layer pipe and the inner layer pipe are both detachably connected to the base. The filter material is located between the base and the first plugging body.

[0007] Preferably, the first water-impermeable section, the third water-impermeable section, and the fifth water-impermeable section are correspondingly arranged. The first water-permeable section, the second water-permeable section, and the third water-permeable section are correspondingly arranged. The second water-impermeable section, the fourth water-impermeable section, and the sixth water-impermeable section are correspondingly arranged.

[0008] Preferably, there are multiple first water-permeable holes, which are circumferentially arranged on the first water-permeable section. There are multiple second water-permeable holes, which are circumferentially arranged on the second water-permeable section. There are multiple third water-permeable holes, which are circumferentially arranged on the third water-permeable section.

[0009] Preferably, the filter material is granular material. The inner layer pipe is coated with a first wire mesh at the position corresponding to the first water-permeable section, and the middle layer pipe is coated with a second wire mesh at the position corresponding to the second water-permeable section. The pore sizes of the first wire mesh and the second wire mesh are both smaller than the minimum particle size of the filter material. The pore sizes of the first water-permeable hole, the second water-permeable hole, and the third water-permeable hole are all larger than the maximum particle size of the filter material.

[0010] Preferably, a plurality of fixed sliders are arranged on the outer surface of the middle layer pipe in the circumferential direction. Chamfers are provided at the top and bottom ends of the fixed sliders. Preferably, the fixed sliders are located on the fourth water-impermeable section.

[0011] Preferably, the first water-impermeable section includes a bottom section and a top section. The plugging body is located outside the bottom section. The bottom section and the top section are detachably connected, and the connection position is close to the plugging body. The top of the third water-impermeable section is constricted from bottom to top to form a constriction, and the top end of the constriction is hermetically connected to the bottom section.

[0012] Preferably, a protective cover is provided at the top end of the main pipeline. The protective cover includes a straight cylinder and a ring-shaped protrusion provided on the surface of the straight cylinder. The bottom of the straight cylinder is located between the middle layer pipe and the outer layer pipe, and the ring-shaped protrusion covers the outer layer pipe.

[0013] Preferably, an outer sleeve is sleeved outside the outer layer pipe. The outer sleeve covers the third water permeable section. A sleeve bottom plate is fixed at the bottom end of the outer sleeve, and a sleeve top plate is fixed at the top end of the outer sleeve. An accommodation space is formed between the sleeve bottom plate, the sleeve top plate, the outer sleeve and the outer layer pipe. The accommodation space is filled with outer filter material; a water permeable structure is arranged on the outer sleeve.

[0014] Preferably, the outer sleeve is made of a water permeable material; the outer filter material is made of granular material.

[0015] During the use of the piezometer tube with a replaceable main structure provided by the present invention, water flow enters through the third water permeable section, then sequentially passes through the second water permeable section, the filter material, and the first water permeable section, and finally enters the inside of the inner layer pipe. A sensor is arranged inside the inner layer pipe, and the water level inside the inner layer pipe can be monitored by using this sensor. The water level information inside the inner layer pipe reflects the seepage state of this measuring point. During the process of water flow entering the inner layer pipe, soil particles enter the inner layer pipe and then fall into the second water impermeable section, and here the second water impermeable section can also be called the precipitation section. After using for a period of time, if the piezometer tube shows a slow response, the middle layer pipe can be hoisted out. Under the action of the base, the inner layer pipe and the middle layer pipe form a whole, including the filter material. Therefore, during the process of hoisting out the middle layer pipe 2, the inner layer pipe and the filter material will be hoisted out simultaneously. In this state, after cleaning the inner layer pipe and the filter material, they are put back inside the outer layer pipe, and thus the piezometer tube will regain its sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is one of the overall longitudinal sectional structure diagrams of the piezometer tube with a replaceable main structure in Embodiment 1;

[0017] Figure 2 is the transverse sectional structure diagram of the piezometer tube with a replaceable main structure in Embodiment 1;

[0018] Figure 3 is the structure diagram of the base in Embodiment 1;

[0019] Figure 4 is the installation structure diagram of the fixed slider in Embodiment 1;

[0020] Figure 5 is the installation structure diagram of the protective sleeve in Embodiment 1;

[0021] Figure 6 is the overall structure diagram of the protective sleeve in Embodiment 1;

[0022] Figure 7 is the second overall longitudinal sectional structure diagram of the piezometer tube with a replaceable main structure in Embodiment 1

[0023] Figure 8 It is a schematic diagram of the overall longitudinal sectional structure of the piezometer tube with a replaceable main body structure in Embodiment 2;

[0024] Figure 9 It is a schematic diagram of the transverse sectional structure of the piezometer tube with a replaceable main body structure in Embodiment 2;

[0025] Figure 10 It is a schematic diagram of the installation structure of the outer casing in Embodiment 2;

[0026] In the figure: inner layer tube 1, first water-impermeable section 11, section 111, top section 112, thread 113, first water-permeable section 12, second water-impermeable section 13, middle layer tube 2, third water-impermeable section 21, reduced opening 211, second water-permeable section 22, fourth water-impermeable section 23, outer layer tube 3, fifth water-impermeable section 31, third water-permeable section 32, sixth water-impermeable section 33, filter material 4, sealing body 5, first sealing body 51, second sealing body 52, protective sleeve 6, straight tube 61, annular protrusion 62, filter media 7, outer side casing 8, bottom plate 9, top plate 10, fixed slider 24, base 25, first bolt 251, second bolt 252, sealing and water-stopping material 101. Detailed implementation manners

[0027] The present invention will be further described below in conjunction with the drawings and embodiments.

[0028] Embodiment 1, the present invention provides a piezometer tube with a replaceable main body structure. Refer to Figure 1 and Figure 2 , which includes a main pipeline. The main pipeline includes an inner layer tube 1, a middle layer tube 2, and an outer layer tube 3. The middle layer tube is sleeved outside the inner layer tube, and the outer layer tube is sleeved outside the middle layer tube; the inner layer tube includes a first water-impermeable section 11, a first water-permeable section 12, and a second water-impermeable section 13 arranged in sequence from top to bottom. The first water-permeable section is provided with a first water-permeable hole; the middle layer tube includes a third water-impermeable section 21, a second water-permeable section 22, and a fourth water-impermeable section 23 arranged in sequence from top to bottom. The second water-permeable section is provided with a second water-permeable hole; the outer layer tube includes a fifth water-impermeable section 31, a third water-permeable section 32, and a sixth water-impermeable section 33 arranged in sequence from top to bottom. The third water-permeable section is provided with a third water-permeable hole; an anti-filter material 4 and a sealing body are arranged between the inner layer tube and the middle layer tube. The first water-permeable section, the second water-permeable section, and the third water-permeable section are all located below the sealing body. In this embodiment, the sealing body is a filled sealing material, and the material of the sealing material can be polyurethane, rubber, etc. A base 25 is arranged at the bottom end of the main pipeline, and the bottom ends of the middle layer tube and the inner layer tube are both connected to the base.

[0029] During the use of the piezometer tube with the replaceable main body structure described above, water flow enters through the third permeable section, then sequentially passes through the second permeable section, the filter material, and the first permeable section, and finally enters the interior of the inner tube. A sensor is arranged inside the inner tube 1, and the water level inside the inner tube 1 can be monitored by using this sensor. The water level information inside the inner tube 1 reflects the seepage state of this measuring point. During the process of water flow entering the inner tube, soil particles enter the inner tube 1 and then fall into the second impermeable section, where the second impermeable section can also be called the sedimentation section. After using it for a period of time, if the piezometer tube shows a slow response, the middle tube can be lifted out. Under the action of the base, the inner tube and the middle tube form a whole, including the filter material 4. Therefore, when lifting out the middle tube 2, the inner tube 1 and the filter material 4 will be lifted out at the same time. In this state, after cleaning the inner tube and the filter material 4, they are put back into the interior of the outer tube 1, and thus the piezometer tube will regain its sensitivity.

[0030] In this embodiment, the sealing body includes a first sealing body 51 and a second sealing body 52. A sealed sandwich layer is formed between the first sealing body and the second sealing body. The first sealing body is located at the top of the main pipeline, and the second sealing body is located below the first sealing body. The first permeable section, the second permeable section, and the third permeable section are all located below the first sealing body. Among them, the main function of the first sealing body material 51 is to fix the filter material 4, and the main function of the second sealing body 52 is to prevent rainwater, garbage, etc. in the external environment from falling into the gap between the inner tube 1 and the middle tube 2. In addition, the second sealing body can also be used to prevent the sealing performance of the first sealing body from weakening during long-term use, resulting in the infiltration of rainwater, etc. into the filter material and affecting the accuracy of actual measurement. In addition, the air pressure inside the sealed sandwich layer can prevent the first sealing body from loosening during long-term use, especially when there is a certain air pressure in the sandwich layer after sealing, the effect is remarkable; the bottom ends of the middle tube and the inner tube are both detachably connected to the base. Refer to Figure 3 , in this embodiment, the diameter of the base 25 can be set to be approximately the same as the outer diameter of the middle tube 2. The inner tube 1 is fixed to the base 25 through the first bolt 251, and the inner tube 1 is fixed in the middle of the base 25. The middle tube 2 is fixed to the base 25 through the second bolt 252. The filter material is located between the base and the first sealing body. In this way, when the piezometer tube shows a slow response and the middle tube is lifted out, the base 25 can be detached. After cleaning the inner tube 1 and the filter material 4, they are reassembled and put back into the interior of the outer tube 1, which is more convenient for cleaning.

[0031] For the convenience of manufacturing and use, the first impermeable section, the third impermeable section, and the fifth impermeable section are correspondingly arranged; the first permeable section, the second permeable section, and the third permeable section are correspondingly arranged; the second impermeable section, the fourth impermeable section, and the sixth impermeable section are correspondingly arranged. Among them, the inner layer pipe 1, the middle layer pipe 2, and the outer layer 3 pipe can be a single pipe of full length, or can be segmented and connected by multiple pipe materials. The pipe materials of the inner layer pipe, the middle layer pipe, and the outer layer pipe can all adopt materials that are not easily rusted and have relatively high strength, such as stainless steel, PVC (Polyvinylchlorid), etc. The pipe diameter is generally 120 mm to 500 mm of the outer layer pipe, the pipe diameter of the middle layer pipe is 100 mm to 480 mm, and the pipe diameter of the inner layer pipe is 20 mm to 80 mm.

[0032] As a medium deformation, refer to Figure 7 , the first impermeable section includes a bottom section 111 and a top section 112, and the plugging body 5 is located outside the bottom section; the bottom section and the top section are detachably connected. In this embodiment, the bottom section and the top section are connected by a thread 113, and the connection position is close to the position of the plugging body 5; the top of the third impermeable section is contracted upward to form a reduced opening 211, and the top end of the reduced opening is hermetically connected to the bottom section. This structure divides the energy layer pipe into two sections at the thread. During use, the part below the thread can be replaced, and the part above the thread can be reused, saving resources; in addition, the height of the third impermeable section is reduced, and a reduced opening is formed at the top end. In this way, when the middle layer pipe and the inner layer pipe need to be lifted out, the friction between the middle layer pipe and the outer layer pipe is greatly reduced, which is convenient for lifting out the middle layer pipe and the inner layer pipe as a whole.

[0033] In order to make the above permeable sections permeate more uniformly, there are multiple first permeable holes, which are circumferentially arranged on the first permeable section; there are multiple second permeable holes, which are circumferentially arranged on the second permeable section; there are multiple third permeable holes, which are circumferentially arranged on the third permeable section.

[0034] In this embodiment, the filter material is granular material, and generally granular materials such as medium and coarse sand can be used. In order to prevent the loss of the filter material and improve the filtering effect of the external soil particles, the inner layer pipe is coated with a first wire mesh corresponding to the position of the first permeable section, and the middle layer pipe is coated with a second wire mesh corresponding to the position of the second permeable section. In this embodiment, the first wire mesh and the second wire mesh use stainless steel wire mesh; the aperture of the first wire mesh and the aperture of the second wire mesh are both smaller than the minimum particle size of the filter material; the aperture of the first permeable hole, the aperture of the second permeable hole, and the aperture of the third permeable hole are all larger than the maximum particle size of the filter material. In this way, small particles of the filter material 4 can be prevented from flowing out from the first permeable hole and the second permeable hole. In addition, during use, the stainless steel wire mesh will filter most of the soil particles, reducing the filtering pressure of the filter material and being beneficial to preventing the piezometer tube from being blocked.

[0035] In one embodiment, refer to Figure 2 and Figure 4 , on the outer surface of the middle layer pipe, a plurality of fixed sliders 24 are circumferentially arranged, generally more than three. The material of the fixed sliders 24 is the same as that of the middle layer pipe 2, and it can also be arranged in the form of convex ribs with a smooth outer surface. Chamfers are provided at the top and bottom of the fixed sliders. The fixed sliders are located on the fourth water-impermeable section. Due to a certain gap between the outer diameter of the middle layer pipe 2 and the inner diameter of the outer layer pipe 3, when the middle layer pipe 2 is installed into the outer layer pipe 3, the fixed sliders 24 can always keep the middle layer pipe 2 at the central position inside the outer layer pipe 3, and there is always a certain gap between the outer wall of the middle layer pipe 2 and the inner wall of the outer layer pipe 3, without being in close contact.

[0036] In one embodiment, refer to Figure 5 and Figure 6 , a protective sleeve 6 is provided at the top of the main pipeline. The material of the protective sleeve 6 can be the same as that of the middle layer pipe 2. The protective sleeve includes a straight cylinder 61 and a ring-shaped protrusion 62 provided on the surface of the straight cylinder, which can be made integrally during production. The bottom of the straight cylinder is located between the middle layer pipe and the outer layer pipe, and the ring-shaped protrusion covers the outer layer pipe. During use, water-stop materials such as foam boards and rubber boards are designed between the protective sleeve 6, the middle layer pipe, the outer layer pipe, and the ground. The protective sleeve 6 has two functions: one is to cooperate with the bottom slider 24 to keep the middle layer pipe 2 at the central position inside the outer layer pipe 3 and vertically plumb; the other is to block the gap between the outer wall of the middle layer pipe 2 and the inner wall of the outer layer pipe 3 at the top of the piezometer tube to prevent flowing water and sundries in the external environment from entering and affecting the monitoring results.

[0037] The usage method of the piezometer tube with a replaceable main structure in the above embodiment is as follows:

[0038] (1) Arrange the positions of seepage monitoring according to the actual engineering needs, and determine the designed depths of the piezometer tubes at each monitoring point.

[0039] (2) Drill a hole to the designed depth at each seepage monitoring point. The diameter of the drill hole is slightly larger than the outer diameter of the outer layer pipe 3.

[0040] (3) Install the outer layer pipe 3. After wrapping the third permeable section of the outer layer pipe 3 with a stainless steel wire mesh, place it into the drill hole. The outer layer pipe 3 is fixed at the monitoring point by materials such as cement mortar. Before fixing, a blocking structure should be designed at the upper part of the third permeable section to prevent materials such as cement mortar from flowing to the third permeable section and causing blockage. For example, an expansion water-stop strip can be wound in advance at the upper part of the third permeable section. During the installation process, after the outer layer pipe 3 is placed into the drill hole, wait for the expansion water-stop strip to fully expand, and then pour cement mortar into the gap between the outer layer pipe 3 and the drill hole.

[0041] (4) Assemble the internal main structure of the piezometer tube composed of the inner layer pipe 1, the middle layer pipe 2, the filter material 4, etc. After assembly, place the main structure into the outer layer pipe 3.

[0042] (5) Install the protective sleeve 6, place the sensor into the inner layer pipe 1, and complete the installation work of the piezometer tube.

[0043] (6) During the later use process, if the sensitivity of the piezometer tube decreases, the overall structure composed of the inner layer pipe 1, the middle layer pipe 2, and the filter material 4 in the middle is hoisted out, disassembled, cleaned, and then reinstalled.

[0044] This piezometer tube is mainly used for existing completed projects.

[0045] Example 2, see Figures 8 - 10 , the piezometer tube with a replaceable main structure in this embodiment is roughly the same as the structure in Example 1, the difference is that: an outer sleeve 8 is sleeved outside the outer layer pipe, the outer sleeve covers the third permeable section 32, a sleeve bottom plate 9 is fixed at the bottom end of the outer sleeve, and a sleeve top plate 10 is fixed at the top end of the outer sleeve. Among them, the bottom plate 9 and the top plate 10 are made of impermeable materials, such as precast reinforced concrete slabs. A receiving space is formed between the sleeve bottom plate, the sleeve top plate, the outer sleeve and the outer layer pipe. To further ensure the seal between the top plate and the outer layer pipe, a sealing and water-stop material 101 is provided between the top plate 10 and the outer layer pipe 3, and epoxy structural adhesive, cement mortar, etc. can be used. The receiving space is filled with outer filter material 7; a permeable structure is provided on the outer sleeve. In this embodiment, the outer sleeve is made of permeable material, such as non-sand concrete, and the inner diameter of the outer sleeve 8 is generally limited to 550 mm to 1000 mm; the outer filter material is made of granular material, and generally medium and coarse sand and other granular materials can be used. In this embodiment, the vertical lengths of the first permeable section, the second permeable section, and the third permeable section are all less than 0.5 m. The reason is that: the main purpose of the piezometer tube in this case is to measure the uplift pressure of the foundation, and it is required that the permeable part of the piezometer tube is as close to the foundation as possible and not too long, so that the water level in the piezometer tube can accurately reflect the uplift pressure of the foundation. In this embodiment, the outer sleeve 8 and the filter material 7 improve the soil conditions around the bottom of the piezometer tube, form the first filtration barrier for the surrounding soil particles, and can provide good protection for the bottom of the piezometer tube during the construction stage, reducing the possibility of the piezometer tube being blocked.

[0046] The working principle of the above-mentioned piezometer tube with a replaceable main structure is roughly the same as the usage process in Example 1, the difference is that the water flow first enters through the outer sleeve 8 and the outer filter material 7, and then sequentially passes through the third permeable section, the second permeable section, the filter material, and the first permeable section for subsequent operation.

[0047] The usage method of the above-mentioned piezometer tube with a replaceable main structure is as follows:

[0048] (1) Arrange the positions of the seepage monitoring points according to the actual engineering needs.

[0049] (2) Before pouring the base concrete, embed the outer sleeve 8, the outer filter material 7, the bottom plate 9 of the outer sleeve, the top plate 10 of the outer sleeve and the outer layer pipe 3. Seal the gap between the top plate 10 and the outer layer pipe 3 with a sealing and water-stop material to prevent the cast-in-place concrete from flowing in.

[0050] (3) Pour the base and the upper structure, and pay attention to the protection of the embedded structure.

[0051] (4) Assemble the internal main structure of the piezometer tube composed of structures such as the inner layer pipe 1, the middle layer pipe 2, and the filter material 4 indoors. After the assembly is completed, place the main structure into the outer layer pipe 3.

[0052] (5) Install the protective sleeve 6, place the sensor into the inner layer pipe 1, and complete the installation of the piezometer tube.

[0053] (6) During the later use process, if the sensitivity of the piezometer tube decreases, lift out the overall structure composed of the inner layer pipe 1, the middle layer pipe 2, and the filter material 4 in the middle, disassemble, clean and reinstall it.

[0054] This piezometer tube is mainly used for new projects and is embedded during the project construction process.

[0055] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Terms such as first and second are only used for name distinction and are not limitations on technical terms. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A piezometer with a replaceable main body structure, comprising a main pipeline, Characterized in that, The main pipeline includes an inner layer pipe (1), a middle layer pipe (2) and an outer layer pipe (3). The middle layer pipe is sleeved outside the inner layer pipe, and the outer layer pipe is sleeved outside the middle layer pipe; The inner layer pipe includes a first water-impermeable section (11), a first water-permeable section (12) and a second water-impermeable section (13) arranged in sequence from top to bottom. The first water-permeable section is provided with first water-permeable holes; The middle layer pipe includes a third water-impermeable section (21), a second water-permeable section (22) and a fourth water-impermeable section (23) arranged in sequence from top to bottom. The second water-permeable section is provided with second water-permeable holes; The outer layer pipe includes a fifth water-impermeable section (31), a third water-permeable section (32) and a sixth water-impermeable section (33) arranged in sequence from top to bottom. The third water-permeable section is provided with third water-permeable holes; An anti-filter material (4) and a plugging body are arranged between the inner layer pipe and the middle layer pipe. The first water-permeable section, the second water-permeable section and the third water-permeable section are all located below the plugging body; A base (25) is arranged at the bottom end of the main pipeline. The bottom ends of the middle layer pipe and the inner layer pipe are both connected to the base; The plugging body includes a first plugging body (51) and a second plugging body (52). A sealed interlayer is formed between the first plugging body and the second plugging body. The first plugging body is located at the top of the main pipeline, the second plugging body is located below the first plugging body, and the first water-permeable section, the second water-permeable section and the third water-permeable section are all located below the first plugging body; The bottom ends of the middle layer pipe and the inner layer pipe are both detachably connected to the base; The anti-filter material is located between the base and the first plugging body; A plurality of fixed sliders (24) are arranged on the outer surface of the middle layer pipe in the circumferential direction. Chamfers are arranged at the top and bottom ends of the fixed sliders. The fixed sliders are located on the fourth water-impermeable section.

2. A piezometer with a replaceable main body structure according to claim 1, Characterized in that, The first water-impermeable section, the third water-impermeable section and the fifth water-impermeable section are correspondingly arranged; The first water-permeable section, the second water-permeable section and the third water-permeable section are correspondingly arranged; The second water-impermeable section, the fourth water-impermeable section and the sixth water-impermeable section are correspondingly arranged.

3. A piezometer with a replaceable main body structure according to claim 1, Characterized in that, There are a plurality of the first water-permeable holes, which are circumferentially arranged on the first water-permeable section; There are a plurality of the second water-permeable holes, which are circumferentially arranged on the second water-permeable section; There are a plurality of the third water-permeable holes, which are circumferentially arranged on the third water-permeable section.

4. A piezometer with a replaceable main body structure according to claim 1, Characterized in that, The anti-filter material is a granular material. The inner layer pipe is coated with a first wire mesh at the position corresponding to the first water-permeable section, and the middle layer pipe is coated with a second wire mesh at the position corresponding to the second water-permeable section. The pore diameters of the first wire mesh and the second wire mesh are both smaller than the minimum particle size of the anti-filter material; The pore diameters of the first water-permeable holes, the second water-permeable holes, and the third water-permeable holes are all larger than the maximum particle size of the filter material.

5. A piezometer tube with a replaceable main body structure according to claim 1, characterized in that the first water-impermeable section includes a bottom section (111) and a top section (112), and the plugging body (5) is located outside the bottom section; the bottom section and the top section are detachably connected, and the connection position is close to the position of the plugging body; the top of the third water-impermeable section is tapered upward to form a constriction (211), and the top end of the constriction is hermetically connected to the bottom section.

6. A piezometer tube with a replaceable main body structure according to claim 1, characterized in that a protective sleeve (6) is provided at the top end of the main pipe, the protective sleeve includes a straight tube (61) and a ring-shaped protrusion (62) provided on the surface of the straight tube, the bottom of the straight tube is located between the middle layer tube and the outer layer tube, and the ring-shaped protrusion covers the outer layer tube.

7. A piezometer tube with a replaceable main body structure according to any one of claims 1-6, characterized in that an outer sleeve (8) is sleeved outside the outer layer tube, the outer sleeve shields the third water-permeable section (32), a sleeve bottom plate (9) is fixed at the bottom end of the outer sleeve, a sleeve top plate (10) is fixed at the top end of the outer sleeve, and a receiving space is formed between the sleeve bottom plate, the sleeve top plate, the outer sleeve and the outer layer tube, and an outer filter material (7) is filled in the receiving space; a water-permeable structure is provided on the outer sleeve.

8. A piezometer tube with a replaceable main body structure according to claim 7, characterized in that the outer sleeve is made of a water-permeable material; the outer filter material is made of granular material.

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