Single-well double-channel piezometric tube structure and construction process

Abstract

The invention relates to a single-well double-channel piezometer tube structure and a construction technology, and belongs to the field of dam pore water pressure detection.The piezometer tube structure is characterized in that a tube body is lowered into a pressure measuring well, the tube body is provided with two channels which are mutually independent and not communicated, the two channels are different in length, and the bottom end of the channel with the shorter length extends into a dam body; the bottom end of the channel with the longer length extends into the dam foundation; the side wall of the pipe body corresponding to the channel is provided with a permeable section and a filter screen; the two limiting plates are located between the two permeable sections, water expansion materials are arranged on the periphery of the pipe body corresponding to the position between the two limiting plates, the pipe body is divided into two channels, one channel is used for measuring the dam body, the other channel is used for measuring the dam foundation, and by means of the structure, it can be guaranteed that the dam body water level water pressure and the dam foundation water level water pressure cannot affect each other when measured; and the work amount and the damage to the dam body can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of dam void water pressure detection, and in particular to a single-well double-channel pressure measuring tube structure and a construction process. Background Art

[0002] During the operation stage of water conservancy projects, water pressure in hydraulic structures and foundations is often measured by piezometers. This data is essential for the calculation of seepage pressure, seepage and uplift pressure, and is necessary for calculating the stability of buildings, and is very important for judging the safety status of hydraulic structures. Earth dams are one of the most commonly used water retaining structures. During design and engineering operation, it is generally necessary to measure the water level in the dam body and the water level in the dam foundation to calculate safety-related factors such as landslides, seepage, and seepage pressure. At present, the measurement of water level and water pressure in the dam body and dam foundation is generally done by burying piezometers in the dam body and dam foundation respectively, and measuring them separately. The advantage of this is that there is no interference with each other, but the disadvantages are also very obvious: first, the measurement location is not on the same section, and the water level of the dam body and dam foundation on the same section is not measured, resulting in low accuracy of the measured data; second, the engineering volume is large, and different wells need to be drilled; third, since the dam foundation measurement well also needs to pass through the dam body when drilling, the damage to the dam body is relatively large.

[0003] Therefore, it is necessary to design a pressure measuring tube structure that can solve the above problems. Summary of the invention

[0004] The existing dam body and dam foundation water pressure and water level are generally measured separately. The accuracy of this method is difficult to guarantee. In addition, the separate measurement leads to a large amount of construction work and causes great damage to the dam body. At least one aspect or one purpose of the present application can solve the above problems. A single-well dual-channel pressure measuring tube structure and construction process are specifically designed. A single-well dual-channel pressure measuring tube structure is protected, and its technical solution is:

[0005] A single-well dual-channel pressure measuring tube structure, comprising:

[0006] The tube body has at least two channels with closed bottom ends, at least two channels are arranged in parallel and are independent of each other, each channel is arranged along the length direction of the tube body, and at least two channels have different lengths; the first channel and the second channel are arranged in parallel along the length direction of the tube body, the first channel and the second channel are independent of each other and are not connected, and the length of the first channel is less than the length of the second channel;

[0007] The side wall of the tube body corresponding to each channel has a water-permeable section, and a filter screen is arranged on the periphery of the water-permeable section;

[0008] Two limit plates are arranged at intervals on the outer wall of the tube body along the length direction of the tube body, the two limit plates are located between the two water-permeable sections, and water-swelling material is arranged on the periphery of the tube body corresponding to the two limit plates.

[0009] Preferably, the expansion material is expansion rubber.

[0010] Preferably, the two limiting plates are circular plates with equal diameters.

[0011] Preferably, it also includes: a protective cover, which is detachably arranged on the upper end of the tube body.

[0012] The present application also protects a single-well dual-channel pressure measuring tube structure construction process, which includes the above-mentioned single-well dual-channel pressure measuring tube structure, including the following steps:

[0013] s1. Drill a pressure well. The diameter of the pressure well is larger than the diameter of the limit plate. The drilling depth of the pressure well is to the position required for the dam foundation seepage pressure measurement;

[0014] s2. Lower the pressure measuring tube into the pressure measuring well until the two limit plates are located on both sides of the interface between the dam body and the foundation, and the bottom end of the relatively short channel is located inside the dam body, and the bottom end of the relatively long channel is located inside the dam foundation;

[0015] s3. Fill the dam foundation filter material into the space between the pressure measuring well and the pipe body at the bottom end of the channel with a relatively long length, until the dam foundation filter material fills the space between the limit plate, the pressure measuring well and the pipe body in the dam foundation;

[0016] s4. Inject water into the space between the pressure measuring well and the pipe body, so that the water-swellable material blocks the space between the two limit plates, the pressure measuring well and the pipe body;

[0017] s5. Fill the space between the pressure measuring well and the pipe body at the bottom of the channel with a relatively short length with filter material of the dam body until the highest position of the filter material of the dam body is higher than the highest position of the permeable section at this location;

[0018] s6. Seal the hole between the pressure measuring well and the pipe body.

[0019] s7. Put the protective cover on the top of the tube.

[0020] Preferably, the dam base filter material in step 3 and the dam body filter material in step 5 are a mixture of fine sand or coarse sand.

[0021] Preferably, the sealing material in step 6 is clay balls.

[0022] Preferably, the swelling time of the water-swellable material in step 4 is greater than 6 hours.

[0023] Preferably, in step 2, the distances between the two limit plates and the interface of the dam body and foundation are equal.

[0024] The present invention has the following technical effects through the above technical solution:

[0025] ① By setting the pipe body into at least two channels, when two channels are set, one channel is used to measure the dam body and the other channel is used to measure the dam foundation. This structure can ensure that the water level and water pressure of the dam body and the water level and water pressure of the dam foundation will not affect each other when measuring them, and can also reduce the amount of engineering. Of course, it can also be set into multiple channels, such as three, four, etc., to measure the pressure between different layers of the dam.

[0026] ② One pipe body can be drilled with a pressure measuring well to reduce damage to the dam body. In addition, the two channels in one pressure measuring well are approximately on the same section, which improves the accuracy of measurement.

[0027] ③ The two channels are independent and not connected to each other, and water-swelling materials are used to isolate the permeable section between the dam body and the foundation during the construction process, which completely blocks the dam body and the foundation, avoids the mutual leakage of pore water between the dam body and the foundation, ensures the accuracy of the measurement of the dam body water level and water pressure, and provides more reliable data for calculating the stability of the dam. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the construction process structure diagram of the pressure measuring tube;

[0029] Figure 2 It is the front view of the pressure measuring tube;

[0030] Figure 3 This is the cross-sectional structure diagram of the pressure measuring tube.

[0031] In the figure, 1, protective cover, 2, tube body, 201, second channel, 202, first channel, 3, clay ball, 4, dam body filter material, 5, first filter screen, 6, first permeable section, 7, permeable hole, 8, plugging head, 9, upper limit plate, 10, expansion rubber, 11, lower limit plate, 12, second filter screen, 13, second permeable section, 14, dam base filter material, 15, pressure measuring well. DETAILED DESCRIPTION

[0032] In order to clearly illustrate the technical features of the present invention, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0033] In addition, in the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0034] like Figure 1-3 As shown, a single-well dual-channel pressure measuring tube structure includes a tube body 2. The tube body 2 can be made of a gold-plated steel tube or a hard plastic tube. The tube body 2 has at least two channels with closed bottom ends. This embodiment is described by taking two channels as an example. For the convenience of description, the two channels are referred to as the first channel 202 and the second channel 201 in this application. The channel with closed bottom ends can be a tube with openings at both top and bottom, and a plugging head 8 is arranged at the bottom thereof to achieve closure, or it can be a directly processed channel, and the bottom end and the side wall are an integral structure. The first channel 202 and the second channel 201 are arranged in parallel along the length direction of the tube body 2. The first channel 202 and the second channel 201 are independent of each other and not connected. The length of the first channel 202 is less than the length of the second channel 201. When the tube body 2 is buried in the dam, the bottom end of the first channel 202 is arranged in the dam body, and the bottom end of the second channel 201 is arranged in the dam foundation. In this way, the water level and water pressure in the dam body and the dam foundation can be measured respectively.

[0035] The side walls of the tube body 2 corresponding to each channel have a permeable section. For the sake of convenience of description, the two permeable sections are referred to as the first permeable section 6 and the second permeable section 13 in this application. The first permeable section 6 is arranged on the side wall of the tube body 2 corresponding to the first channel 202, close to the bottom end of the first channel 202. The so-called permeable section is realized by drilling a plurality of permeable holes 7 on the side wall of the tube body 2. A first filter screen 5 is arranged on the periphery of the first permeable section 6. The first filter screen 5 is wrapped around and wrapped on the tube body 2. The first filter screen 5 can prevent gravel or coarse and fine sand from entering the tube body 2 when the tube body 2 is buried in the dam, and at the same time ensure that the pore water in the dam foundation can enter the first channel 202, thereby measuring the pore water level and seepage pressure in the dam foundation.

[0036] At the same time, the second water-permeable section 13 is arranged on the side wall of the pipe body 2 corresponding to the second channel 201, near the bottom end of the second channel 201. The second water-permeable section 13 is formed by drilling a plurality of water-permeable holes 7 on the side wall of the pipe body 2. A second filter screen 12 is arranged on the periphery of the second water-permeable section 13. The second filter screen 12 and the first filter screen 5 are respectively two layers of 60-mesh filter screens wound in two layers and wrapped on the pipe body 2. Similarly, the second filter screen 12 can prevent gravel or coarse and fine sand from entering the pipe body 2 when the pipe body 2 is buried in the dam.

[0037] It also includes two limit plates. For the convenience of description, in this application, the above two limit plates are referred to as an upper limit plate 9 and a lower limit plate 11. The upper limit plate 9 and the lower limit plate 11 are located between the first permeable section 6 and the second permeable section 13. At the same time, the upper limit plate 9 and the lower limit plate 11 are spaced along the length direction of the tube body 2. The upper limit plate 9 and the lower limit plate 11 are horizontally arranged and fixed on the outer wall of the tube body 2 by welding or processing flanges on the outer wall of the tube body 2. A water-expandable material is arranged on the periphery of the tube body 2 corresponding to the two limit plates. The water-swelling material here is an expansion rubber 10, which is wound around the tube body 2. It expands when it encounters water. After a period of time, its volume can be increased to 2 to 3 times. The existence of the upper limit plate 9 and the lower limit plate 11 can limit the expansion direction, making the expansion direction horizontal. When the tube body 2 is buried in the dam, the expansion rubber 10 can, on the one hand, fix the tube body 2, and on the other hand, block the first channel 202 and the second channel 201 of the tube body 2 on both sides of the dam body and the foundation, thereby playing a water-blocking role.

[0038] It should be noted that the length of the above-mentioned tube body 2 can be determined according to the required depth of the dam foundation seepage pressure measurement and pre-processed. The different lengths of the above-mentioned first channel 202 and the second channel 201 can be processed using a tube body 2 with two channels of equal lengths. Specifically, the first channel 202 is cut off according to the dam body seepage pressure measurement depth (note that the first channel 202 and the second channel 201 cannot be pierced during cutting), and then the bottom of the upper section is sealed with a plugging head 8, and the top of the lower section is sealed with a plugging head 8. At this time, only the cut-off upper section is used to measure the pore water level and seepage pressure of the dam body, and the lower section can be cut off or carried, and it does not affect the use of the pressure measuring tube when carried.

[0039] Furthermore, the upper limit plate 9 and the lower limit plate 11 are circular plates with equal diameters. They are set as circular plates so that they can match the drill hole during construction. Since the expansion rubber 10 is wrapped around the outer periphery of the tube body 2, its wrapping thickness is consistent in the upper and lower directions. In order to ensure uniform upper and lower limits of the expansion rubber 10, the upper limit plate 9 and the lower limit plate 11 have equal diameters.

[0040] Furthermore, in addition to the above-mentioned components, the pressure measuring tube structure also includes a protective cover 1 , which is detachably arranged on the upper end of the tube body 2 , and the protective cover 1 can prevent external debris from entering the tube body 2 .

[0041] The present application also protects a single-well dual-channel pressure measuring tube structure construction process, which includes the above-mentioned single-well dual-channel pressure measuring tube structure, and includes the following steps:

[0042] s1. Drill a pressure measuring well 15. The diameter of the pressure measuring well 15 is larger than the diameter of the limit plate to ensure that the dam foundation filter material 14 and the dam body filter material 4 can descend smoothly. The drilling depth of the pressure measuring well 15 is to the position required for measuring the dam foundation permeability pressure.

[0043] s2. Pre-process the pressure measuring tube and lower it into the pressure measuring well 15 until the upper limit plate 9 is located on the upper side of the dam body and foundation interface, and at the same time, the second permeable section 13 is higher than the upper limit plate 9, the lower limit plate 11 is located on the lower side of the dam body and foundation interface, the first permeable section 6 is lower than the lower limit plate 11, the first permeable section 6 is located in the dam foundation, the second permeable section 13 is located in the dam body, the bottom end of the first channel 202 is located in the dam body, and is used to measure the water level and water pressure of the dam body, and the bottom end of the second channel 201 is located in the dam foundation, and is used to measure the water level and water pressure of the dam foundation.

[0044] s3. Fill the dam foundation filter material 14 into the space between the pressure measuring well 15 and the pipe body 2 at the bottom end of the corresponding second channel 201. The dam foundation filter material 14 is made of a mixture of fine sand or coarse sand. For clay loam or sandy loam, fine sand can be used as a filter material, and for gravel layers, a mixture of fine sand and coarse sand can be used. After calculating the volume of the filter material, the dam foundation filter material 14 fills the space between the limit plate, the pressure measuring well 15 and the pipe body 2 located in the dam foundation. The pore water in the dam can pass through the dam foundation filter material 14 and enter the pipe body 2.

[0045] s4. Inject a small amount of water into the space between the pressure measuring well 15 and the pipe body 2. The expansion rubber 10 swells when it comes into contact with water. The expansion time and expansion rate of the expansion rubber 10 should be selected based on the test. The expansion time cannot be too short, and is generally selected to be greater than 6 hours, otherwise it will affect the filling of the dam foundation filter material 14, until the expansion rubber 10 blocks the space between the two limit plates, the pressure measuring well 15 and the pipe body 2, separates the dam body and the dam foundation, and isolates the porous water layer between the dam body and the dam foundation to ensure that the measurements do not affect each other.

[0046] s5. Fill the dam body filter material 4 into the space between the pressure measuring well 15 and the pipe body 2 at the bottom end of the corresponding first channel 202. The dam body filter material 4 is still made of a mixture of fine sand or coarse sand according to the geological conditions. The dam body filter material 4 is filled here until its highest position is higher than the highest position of the first permeable section 6, generally 2-3 meters above the first permeable section 6. In this way, the dam body filter material 4 can completely submerge the first permeable section 6, playing a role in permeability to prevent mud from entering the pipe.

[0047] s6. The pressure measuring well 15 and the pipe body 2 are sealed with 5-10 mm clay balls 3 to prevent upper water from entering the permeable section through the gap in the pipe wall and then entering the pressure measuring tube, which would affect the measurement accuracy.

[0048] s7. Finally, fix the protective cover 1 to the dam body by bolts and cover the top of the tube body 2. When the tube body 2 needs to be operated, screw the bolts to remove the protective cover 1. The presence of the protective cover 1 can protect the opening of the tube body 2 and prevent external debris from entering the tube body 2.

[0049] Furthermore, in the above step 2, the distances between the two limit plates and the interface of the dam body and foundation are equal, thus ensuring that the distances between the two ends of the expansion rubber 10 and the interface of the dam body and foundation are equal, avoiding the problem of pore water on one side entering that side due to the shorter length of the expansion rubber 10 on the other side.

[0050] After the construction of the above-mentioned pressure measuring tube is completed, the corresponding measuring instrument can be lowered into the corresponding first channel and second channel to measure the water pressure.

[0051] The above specific implementation manner cannot be used as a limitation on the protection scope of the present invention. For those skilled in the art, any substitution, improvement or change made to the implementation manner of the present invention falls within the protection scope of the present invention.

[0052] The matters not described in detail in the present invention are all known technologies to those skilled in the art.

Claims

1. A single-well dual-channel pressure measuring tube structure, It is characterized in that include: A tube body, wherein the tube body has at least two channels with closed bottom ends, at least two of the channels are arranged in parallel and are independent of each other and not connected, each of the channels is arranged along the length direction of the tube body, and at least two of the channels have different lengths; The side wall of the tube body corresponding to each of the channels has a water-permeable section, and a filter screen is arranged on the periphery of the water-permeable section; Two limit plates are arranged at intervals on the outer wall of the tube body along the length direction of the tube body, the two limit plates are located between the two water-permeable sections, and water-swelling material is arranged on the periphery of the tube body between the two limit plates.

2. A single-well dual-channel pressure measuring tube structure according to claim 1, It is characterized in that The water-swellable material is swellable rubber.

3. A single-well dual-channel pressure measuring tube structure according to claim 1, It is characterized in that The two limiting plates are circular plates with equal diameters.

4. A single-well dual-channel pressure measuring tube structure according to claim 1, It is characterized in that Also includes: A protective cover is detachably arranged on the upper end of the tube body.

5. A single-well dual-channel pressure measuring tube structure construction process, comprising the single-well dual-channel pressure measuring tube structure according to any one of claims 1 to 4, It is characterized in that The steps include: s1. Drilling a pressure measuring well, the diameter of which is larger than the diameter of the limit plate, and the drilling depth of which is to the position required for measuring the dam foundation permeability pressure; s2. Lower the pressure measuring tube into the pressure measuring well until the two limit plates are located at the two sides of the interface between the dam body and the foundation, and the bottom end of the relatively short channel is located in the dam body, and the bottom end of the relatively long channel is located in the dam foundation; s3, filling the dam foundation filter material into the space between the pressure measuring well and the pipe body at the bottom end of the channel with a relatively long length, until the dam foundation filter material fills the space between the limit plate located in the dam foundation, the pressure measuring well and the pipe body; s4, injecting water into the space between the pressure measuring well and the pipe body, so that the water-swellable material blocks the space between the two limit plates, the pressure measuring well and the pipe body; s5. Fill the space between the pressure measuring well and the pipe body at the bottom of the channel with a relatively short length with filter material of the dam body until the highest position of the filter material of the dam body is higher than the highest position of the permeable section at this location; s6. Sealing the hole between the pressure measuring well and the pipe body; s7. Cover the top of the tube with a protective cover.

6. The single-well dual-channel pressure measuring tube structure construction process according to claim 5, It is characterized in that The dam base filter material in step 3 and the dam body filter material in step 5 are a mixture of fine sand or coarse sand.

7. The single-well dual-channel pressure measuring tube structure construction process according to claim 5, It is characterized in that The sealing material in step 6 is clay balls.

8. The single-well dual-channel pressure measuring tube structure construction process according to claim 5, It is characterized in that The swelling time of the water-swellable material in step 4 is greater than 6 hours.

9. The single-well dual-channel pressure measuring tube structure construction process according to claim 5, It is characterized in that In step 2, the distances between the two limit plates and the interface of the dam body and foundation are equal.

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