Construction method for ultra-deep burying of pore pressure meter

Abstract

The invention relates to the technical field of pore pressure meter burying, and discloses a construction method for ultra-deep burying of a pore pressure meter, which comprises the following steps: step S1, drilling according to the specific position of the underground water level to be monitored; s2, a pore pressure device is buried in the hole obtained in the step S1, a pore pressure meter is arranged in the pore pressure device, and a plurality of through holes are formed in the periphery of the pore pressure device; s3, a pore pressure meter in the pore pressure device is connected with the automatic acquisition device through a signal line, and data acquisition is carried out; the depth of the drill hole is larger than 30 meters. The method provided by the invention not only can realize dynamic change monitoring of underground water which is more than 30 meters away from the ground surface, but also can realize simultaneous monitoring of pore water pressure at a plurality of position points in the same hole, and the obtained monitoring data is more accurate.

Description

Technical Field

[0001] The invention relates to the technical field of burial piezometers, and in particular to a construction method for ultra-deep buried piezometers. Background Art

[0002] In the fields of geological engineering, geotechnical engineering and water conservancy engineering, pore water pressure is a key indicator for evaluating soil stability and monitoring the dynamic changes of groundwater. When conducting pore water pressure tests, the piezometer must be in a static state to achieve accurate monitoring of water dynamics. However, the existing technology can only monitor surface water up to 30 meters from the surface. Since groundwater flows horizontally and vertically, the impact of the vertical water flow on the piezometer increases as the monitoring position decreases. Therefore, as the test position decreases, the piezometer will eventually break due to the flow of water, and the flow of water will also cause inaccurate test results.

[0003] Therefore, it is particularly critical and urgent to develop an efficient, high-precision and low-cost piezometer installation technology. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a construction method for an ultra-deep buried piezometer. The method of the present invention can not only realize the dynamic change monitoring of groundwater more than 30 meters away from the surface, but also obtain more accurate monitoring data.

[0005] The present invention provides a construction method for an ultra-deep buried piezometer, comprising the following steps: Step S1: drilling a hole according to the specific location of the groundwater level to be monitored; Step S2: burying a pore pressure device in the hole obtained in step S1, wherein a pore pressure gauge is arranged inside the pore pressure device, and a plurality of through holes are arranged around the pore pressure device; Step S3: connecting the pore pressure gauge in the pore pressure device to the automatic data acquisition device through a signal line to collect data; The depth of the borehole is greater than 30 meters.

[0006] Furthermore, the pore pressure device includes a monitoring unit and a connecting pipe; the monitoring unit includes a hollow first pipe and a second pipe, and a plurality of penetrating holes are arranged on the pipe wall of the second pipe.

[0007] Furthermore, along the length direction of the second pipe, the holes are arranged in multiple layers on the pipe wall of the second pipe, and the holes in adjacent layers are staggered.

[0008] Furthermore, in the length direction of the second pipe, the hole is arranged on the pipe wall at 2 / 3 of the distance from the upper end of the second pipe.

[0009] Furthermore, seals are provided at the upper and lower ends of the interior of the second pipeline to isolate the piezometer in the second pipeline.

[0010] Furthermore, the outside of the second pipe is wrapped by filter paper, and the pore size of the filter paper is 0.02 mm.

[0011] Furthermore, the piezometer is in the second pipeline and is surrounded by holes arranged on the pipe wall.

[0012] Furthermore, the second pipe is also filled with fine sand.

[0013] Furthermore, the sealing arrangement of the upper and lower ends inside the second pipe is specifically as follows: in the length direction of the second pipe, expansion glue is used for sealing at a distance of 150 mm from both ends of the piezometer.

[0014] Furthermore, a water stop strip is provided on the outer wall of the second pipe at a distance of 150 mm from both ends of the piezometer.

[0015] Furthermore, the first pipeline is above the second pipeline, and a connecting ring interference fit is adopted between the second pipeline and the first pipeline.

[0016] Furthermore, the signal line extends from the connection between the second pipe and the connection ring connecting the first pipe and the second pipe.

[0017] Furthermore, the connecting pipe and the first pipeline are connected by an interference fit of a connecting ring.

[0018] Furthermore, the connecting pipe can be composed of multiple monitoring units, or it can be composed of one or more connecting pipes. The connecting pipes can be connected by interference fit through connecting rings. Those skilled in the art should know that the connecting pipe is used to place the monitoring unit at the position where the pore water pressure needs to be monitored, and the connecting pipe can achieve the purpose.

[0019] Furthermore, the material of the first pipeline and the second pipeline includes inclinometer casing.

[0020] Furthermore, the material of the connecting pipe includes inclinometer casing.

[0021] Furthermore, the material of the connecting ring includes a rubber joint.

[0022] Furthermore, the length ratio of the second pipeline to the first pipeline is 3:1.

[0023] Furthermore, the data collection is performed once every 15 minutes.

[0024] The embodiments of the present invention have the following technical effects: 1. In the method of the present invention, the pore pressure device used can firstly ensure that the pore pressure gauge will not be broken and can fix the position of the pore pressure gauge in the hole; on this basis, a closed space is formed in the pore pressure device, which can reduce the influence of the longitudinal water flow on the accuracy of the test, and holes are arranged on the pore pressure device to ensure the lateral water flow, so as to accurately monitor the pore water pressure.

[0025] 2. In the process of ensuring monitoring, filter paper is also arranged on the outside of the pore pressure device to prevent the fine sand inside the pore pressure device from being washed out, thereby causing the displacement of the pore pressure gauge and affecting the accuracy of monitoring; in addition, the arrangement of the holes on the wall of the second pipeline in the pore pressure device ensures the stability of the entire structure while ensuring the lateral water flow.

[0026] 3. This method uses water-stop strip isolation technology to ensure that each piezometer can accurately reflect the pore water pressure at its depth. Isolation through materials such as permeable fillers and bentonite balls prevents pore water pressures at different depths from interfering with each other, thereby improving the accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic diagram of the structure of a monitoring unit provided in an embodiment of the present invention.

[0029] Figure 2 It is a comparison between the embodiment of the present invention and the observation well data.

[0030] The above drawings include the following reference numerals: 1-monitoring unit, 2-piezometer, 3-signal line, 11-first pipeline, 12-second pipeline, 13-water stop strip, 14-connecting ring, 121-hole, 122-filter paper. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0032] In a first aspect, some embodiments of the present invention provide a construction method for an ultra-deep buried piezometer, comprising the following steps: Step S1: drilling a hole according to the specific location of the groundwater level to be monitored; Step S2: burying a pore pressure device in the hole obtained in step S1, wherein a pore pressure gauge is arranged inside the pore pressure device, and a plurality of through holes are arranged around the pore pressure device; Step S3: connecting the pore pressure gauge in the pore pressure device to the automatic data acquisition device through a signal line to collect data; The depth of the borehole is greater than 30 meters.

[0033] In some embodiments, the pore pressure device includes a monitoring unit 1 and a connecting pipe; the monitoring unit 1 includes a hollow first pipe 11 and a second pipe 12 , and a plurality of penetrating holes 121 are arranged on the pipe wall of the second pipe 12 .

[0034] In some embodiments, along the length direction of the second pipe, the holes 121 are arranged in multiple layers on the pipe wall of the second pipe 12, and the holes 121 in adjacent layers are staggered.

[0035] In some embodiments, in the length direction of the second pipe 12 , the hole 121 is disposed on the pipe wall at 2 / 3 of the distance from the upper end of the second pipe 12 .

[0036] In some embodiments, seals are provided at the upper and lower ends of the second pipe 12 to isolate the piezometer 2 in the second pipe 12 .

[0037] In some embodiments, the exterior of the second pipe 12 is wrapped by a filter paper 122 , and the pore size of the filter paper 122 is 0.02 mm.

[0038] In some embodiments, the piezometer 2 is in the second pipeline and is surrounded by holes 121 provided on the pipeline wall.

[0039] In some embodiments, the second pipe 12 is also filled with fine sand.

[0040] In some embodiments, the sealing arrangement of the upper and lower ends inside the second pipe 12 is specifically as follows: in the length direction of the second pipe 12, expansion glue is used for sealing at a distance of 150 mm from both ends of the piezometer 2.

[0041] In some embodiments, a water stop strip 13 is provided on the outer wall of the second pipe 12 at a distance of 150 mm from both ends of the piezometer.

[0042] In some embodiments, the first pipe 11 is above the second pipe 12 , and an interference fit is formed between the second pipe 12 and the first pipe 11 using a connecting ring 14 .

[0043] In some embodiments, the signal line 3 extends from the connection between the second pipe 12 and the connecting ring 14 connecting the first pipe 11 and the second pipe 12 .

[0044] In some embodiments, the connecting pipe and the first pipe 11 are connected by interference fit via a connecting ring 14 .

[0045] In some embodiments, the material of the first pipeline 11 and the second pipeline 12 includes inclinometer casing.

[0046] In some embodiments, the material of the connecting pipe includes an inclinometer casing.

[0047] In some embodiments, the material of the connecting ring 14 includes a rubber joint.

[0048] In some embodiments, the length ratio of the second pipe 12 to the first pipe 11 is 3:1.

[0049] In some embodiments, the data collection is performed once every 15 minutes.

[0050] The method of the present invention is also applied in practical engineering: Embodiment 1: (1) The monitoring unit 1 in the pore pressure device is assembled. The specific steps include: selecting a 30 cm long inclinometer tube as the second pipe 12, drilling holes 121 on the pipe wall 2 / 3 of the distance from the upper end of the second pipe 12, and the holes 121 on the second pipe 12 are arranged in multiple layers, and the holes 121 in adjacent layers are staggered. The arrangement of the holes 121 is as follows: Figure 1As shown. Subsequently, the piezometer 2 is installed at the drilling position inside the second pipeline 12, so that the piezometer 2 is surrounded by the hole 121 set on the pipe wall in the second pipeline 12, and the piezometer is filled with engineering sand to ensure its stability and accuracy. Next, the expansion glue is used to seal the second pipeline 12 at 150mm from both ends of the piezometer. On the outer wall of the second pipeline 12, a water stop strip 13 is set at 150mm from both ends of the piezometer 2 to isolate the piezometer 2 in the second pipeline 12, and the second pipeline 12 is sealed to prevent the intrusion of external substances. At the upper part of the second pipeline 12, the rubber joint is connected to the second pipeline 12 and the first pipeline 11 through an interference fit, wherein the first pipeline 11 also uses an inclinometer tube, and the length of the first pipeline 11 is 10cm, ensuring the air tightness and water tightness of the connection, and the signal line 3 of the piezometer 2 is extended from the second pipeline 12 to the connection ring 14 connecting the first pipeline 11 and the second pipeline 12, and the monitoring unit 1 is assembled.

[0051] (2) Drilling operation: Based on the geological survey data, the typical soil layer distribution of the foundation pit site is determined, and then drilling operations are carried out. The drilling depth must reach 45 meters to ensure that the shallow water layer and the first pressure-bearing layer can be covered, thereby reaching the predetermined groundwater level monitoring depth.

[0052] (3) The pore pressure device works downwards, and monitors at a predetermined depth (42 meters) in the drilled hole. The specific operation steps are as follows: first, place the monitoring unit 1 at the bottom in the hole, and then use a press to press the pore pressure device to a depth of 20 cm underground. Use a 2-meter inclinometer pipe as a connecting pipe. The connecting pipes are also connected by rubber joints through interference fit. The first pipeline 11 in the monitoring unit 1 and the connecting pipe are connected by rubber joints through interference fit. Use an air compressor to continue to press the connected monitoring unit downward. Finally, press the pore pressure device to a position flush with the ground. The pore pressure device is assembled and placed in the drilled hole to transmit the pore water pressure at a predetermined depth.

[0053] (4) Automatic data collection and processing: Connect the signal line connector in the pore pressure device above the ground to the corresponding interface of the automatic data collection box, and use solar panels for power supply. The data collection frequency is set to once every 15 minutes, and the collected data will be uploaded to the cloud to achieve real-time monitoring of groundwater levels and remote data processing.

[0054] Results and Analysis: In order to verify whether the measurement results of the device are consistent with the actual situation, we conducted a detailed comparative analysis. First, we conducted an in-depth study on the changes in the pore water pressure gauge recorded by the device over time, and compared it with the water level changes observed in conventional observation wells. Through the comparison, we obtained the following analysis results, which are presented in Figure 2 middle.

[0055] During the monitoring process, the result recorded by the pore water piezometer is in kilopascals (kPa). In order to compare and analyze the water level in the observation well with the pore water pressure tested in Example 1, we calculated the depth h of the groundwater level based on the measured value of the pore water pressure. The specific calculation formula is as follows: ; Among them, h represents the depth of groundwater level (unit: m); H represents the buried depth of pore water pressure measuring point (unit: m); r w Represents the weight of water (unit: kilonewton / m 3 ), usually taken as 9.8kN / m³; μ represents the measured value of pore water pressure (unit: kPa).

[0056] After conversion, we set the data measured in the embodiment and the observation well on August 6, 2024 as the initial water level and set it to 0 meters as the reference point. Figure 2 In the figure, the straight line part represents the water level change at 42 meters underground monitored by the piezometer, while the scattered part represents the data monitored at 42 meters underground by the conventional monitoring well. Through comparative analysis, we found that the use of this device can effectively replace the conventional monitoring well. This means that the device of the present invention can effectively observe the change of the groundwater level at a depth of more than 35 meters, while ensuring the accuracy of the monitoring data.

[0057] It should be noted that the terms used in the present invention are only for describing specific embodiments, rather than limiting the scope of the present application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of more restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0058] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A construction method for an ultra-deep buried piezometer, characterized in that: The steps include: Step S1: drilling a hole according to the specific location of the groundwater level to be monitored; Step S2: burying a pore pressure device in the hole obtained in step S1, wherein a pore pressure gauge is arranged inside the pore pressure device, and a plurality of through holes are arranged around the pore pressure device; Step S3: connecting the pore pressure gauge in the pore pressure device to the automatic data acquisition device through a signal line to collect data; The depth of the borehole is greater than 30 meters.

2. The construction method according to claim 1, characterized in that: The pore pressure device comprises a monitoring unit (1) and a connecting pipe. The monitoring unit (1) comprises a hollow first pipe (11) and a second pipe (12). A plurality of penetrating holes (121) are arranged on the pipe wall of the second pipe (12).

3. The construction method according to claim 2, characterized in that: Along the length direction of the second pipe, the holes (121) are arranged in multiple layers on the pipe wall of the second pipe (12), and the holes (121) in adjacent layers are distributed in a staggered manner.

4. The construction method according to claim 2, characterized in that: In the length direction of the second pipe (12), the hole (121) is arranged on the pipe wall at 2 / 3 of the distance from the upper end of the second pipe (12); The piezometer (2) is in the second pipeline and is surrounded by holes (121) arranged on the pipeline wall.

5. The construction method according to claim 2, characterized in that: Sealing means are provided at the upper and lower ends of the interior of the second pipe (12) for isolating the piezometer (2) in the second pipe (12); The outside of the second pipe (12) is wrapped by filter paper (122), and the pore size of the filter paper (122) is 0.02 mm.

6. The construction method according to claim 2, characterized in that: The second pipe (12) is also filled with fine sand.

7. The construction method according to claim 2, characterized in that: The sealing arrangement of the upper and lower ends inside the second pipe (12) is specifically as follows: in the length direction of the second pipe (12), a sealing treatment is performed using expansion glue at a distance of 150 mm from both ends of the piezometer (2); A water stop strip (13) is provided on the outer wall of the second pipe (12) at a distance of 150 mm from both ends of the piezometer (2).

8. The construction method according to claim 2, characterized in that: The first pipeline (11) is above the second pipeline (12), and a connecting ring (14) is used for interference fit between the second pipeline (12) and the first pipeline (11).

9. The construction method according to claim 2, characterized in that: The connecting pipe and the first pipeline (11) are connected by interference fit via a connecting ring (14).

10. The construction method according to claim 8, characterized in that: The signal line (3) extends from the connection point between the second pipe (12) and the connection ring (14) connecting the first pipe (11) and the second pipe (12).

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