A deep foundation deep hole in-situ pore pressure testing device and method

Abstract

The application discloses a deep foundation deep hole in-situ pore pressure testing device and method. The device comprises a plurality of extension pipes which are sequentially screwed to form a long connecting pipe, and an in-situ pore pressure monitoring pipe which is screwed to the head of the long connecting pipe. The method comprises a deep foundation deep hole in-situ pore pressure testing device assembling and monitoring method and a foundation horizontal consolidation coefficient obtaining method based on the deep foundation deep hole in-situ pore pressure testing device. The device and method can accurately and quickly measure the pore pressure time history curve of the deep overburden layer, the device has good working performance in the underground super-deep environment, the horizontal consolidation coefficient obtained by reasonably analyzing the in-situ pore pressure data has clear physical meaning and high accuracy, and the problems that the conventional pore pressure measuring equipment cannot normally work for a long time in the super-deep environment and cannot accurately obtain the foundation horizontal consolidation coefficient and other parameters are solved.

Description

Technical Field

[0001] This invention belongs to the field of in-situ pore pressure measurement in deep foundations, and specifically relates to a device and method for in-situ pore pressure testing in deep holes in deep foundations. Background Technology

[0002] During the construction of deep foundations, accurate monitoring of dynamic changes in pore water pressure is crucial for assessing foundation stability and long-term safety. Currently, there are two main methods for measuring pore pressure: one is to directly bury pore pressure gauges at the design depth, which, although not affecting surface vibration operations, makes the sensors prone to damage and difficult to operate stably for extended periods; the other is to use a static pore pressure penetration test device, but during vibration liquefaction tests, the vibration of the probe and protective shell can affect the test accuracy.

[0003] For measuring changes in pore pressure during construction, buried borehole gauges are generally used. The particle content and size of the mud and water in the borehole affect the measurement accuracy, but there is a lack of standardized methods for cleaning the borehole and standards for protecting the filter layer. Furthermore, there are no unified requirements for the types of directional backfill soil and construction methods after installation.

[0004] Construction in deep strata involves complex processes, generating significant pore water stress in the soil due to static plastic deformation and dynamic forces. However, existing monitoring and analysis methods do not fully understand the mechanism and extent of pore pressure generation, leading to inaccuracies in subsequently measured soil parameters such as the consolidation coefficient. Summary of the Invention

[0005] To address the problems existing in the background technology, this invention provides a device and method for in-situ pore pressure testing in deep foundations, which solves the technical problems of the lack of standardized methods for cleaning holes and standards for the protection of filter layers; the lack of unified requirements for the types and construction methods of directional backfill soil after installation; and the lack of accurate methods for measuring the consolidation coefficient.

[0006] The technical solution adopted in this invention includes:

[0007] I. A deep borehole in-situ pore pressure testing device for deep foundations:

[0008] The system includes several extension tubes and an in-situ pore pressure monitoring tube. Multiple extension tubes are sequentially threaded together to form a long connecting tube, with the in-situ pore pressure monitoring tube threaded to the head of the long connecting tube. Each extension tube is a hollow steel pipe, with one end having an external thread and the other an internal thread. The open and closed ends of multiple extension tubes are sequentially threaded together to form the long connecting tube. Each in-situ pore pressure monitoring tube includes a hollow monitoring steel pipe and a pore pressure sensor. The two ends of the monitoring steel pipe are a sealed end with an external thread and an open end with an internal thread, with the open end of the in-situ pore pressure monitoring tube threaded to the closed end of one extension tube of the long connecting tube. The pore pressure sensor is located in the middle of the monitoring steel pipe, and the space between the pore pressure sensor and the inner wall of the monitoring steel pipe is filled with quartz sand.

[0009] The in-situ pore pressure monitoring tube also includes gauze and a support hole plug; several perforations and a wiring hole are opened on the outer periphery of the monitoring steel tube, and a support hole plug is installed on the wiring hole. The signal line of the pore pressure sensor is led out to the outside of the in-situ pore pressure monitoring tube through the support hole plug; a layer of gauze is wrapped around the outer periphery of the monitoring steel tube to form a filter layer, and the signal line is wound around the outer periphery of the monitoring steel tube wrapped with gauze and the outer periphery of the long connecting pipe in a spiral upward wiring manner and finally electrically connected to the data acquisition instrument.

[0010] II. An assembly and monitoring method for a deep borehole in-situ pore pressure testing device for deep foundations:

[0011] S1. Drill a hole at the monitoring site. After drilling, fill the hole with clean water until clean water returns from the hole, then stop filling.

[0012] S2. Determine the number of extension tubes based on the required monitoring depth, and connect the open and closed ends of multiple extension tubes sequentially by thread to form a long connecting tube.

[0013] S3. After saturating the pore pressure sensor, assemble the deep foundation deep hole in-situ pore pressure testing device.

[0014] S4. After arranging the assembled deep foundation deep hole in-situ pore pressure testing device at the preset position, monitoring is performed to obtain the pore pressure time history curve at the monitoring position.

[0015] Step S3 specifically involves:

[0016] S31. Remove the filter from the head of the pore pressure sensor and immerse both the filter and the pore pressure sensor without the filter in clean water for several hours to saturate them.

[0017] S32. Install the saturated filter on the head of the pore pressure sensor and place the saturated pore pressure sensor with the filter in the middle of the monitoring steel pipe. The data line is led out through the support pore plug.

[0018] S33. Add quartz sand to the monitoring steel pipe until it is full, and wrap the outer circumference of the monitoring steel pipe with gauze to form a filter layer. The data line of the pore pressure sensor is spirally wrapped on the surface of the gauze on the outer circumference of the monitoring steel pipe. The data line is protected and fixed with cable ties and tape to obtain the in-situ pore pressure monitoring tube.

[0019] S34. Connect the in-situ pore pressure monitoring tube to the head of the long connecting tube, and spirally wind the data line of the pore pressure sensor around the outer circumference of the long connecting tube. Finally, connect it to the data acquisition instrument to obtain the assembled in-situ pore pressure testing device for deep holes in deep foundations.

[0020] Step S4 specifically involves:

[0021] S41. Lower the deep foundation deep hole in-situ pore pressure testing device to the designated position.

[0022] S42. Calculate the volume difference between the monitoring hole and the deep foundation deep hole in-situ pore pressure testing device, and backfill the corresponding volume difference of soil between the deep foundation deep hole in-situ pore pressure testing device and the monitoring hole after it is lowered to the designated position.

[0023] S43. After backfilling is completed, the deep foundation deep hole in-situ pore pressure testing device performs real-time monitoring to obtain the pore pressure time history curve at the monitoring location.

[0024] III. A method for obtaining the horizontal consolidation coefficient of a deep-hole in-situ pore pressure testing device for deep foundations:

[0025] D1. Construct a formation numerical model using numerical simulation analysis software to obtain the completed formation numerical model; obtain several influencing factors and input all influencing factors into the completed formation numerical model to obtain a formation numerical model containing all influencing factors.

[0026] D2. The deep foundation deep hole in-situ pore pressure testing device is used to monitor the location to be tested and obtain the pore pressure time history curve of the location to be tested. Based on the formation numerical model containing all influencing factors and the pore pressure time history curve of the location to be tested, an interference-free pore pressure time history curve is obtained.

[0027] D3. Obtain the horizontal consolidation coefficient of the foundation based on the undisturbed pore pressure time history curve.

[0028] Step D1 specifically involves:

[0029] D11. Grid the monitoring site and construct a stratigraphic numerical model using a finite difference grid in the numerical simulation analysis software. Set the size of the monitoring site, the grid size, and the constitutive model in the stratigraphic numerical model, as well as the boundary conditions and initial conditions of the stratigraphic numerical model.

[0030] D12. Obtain preliminary geological survey data, determine soil parameters such as the distribution, density, Poisson's ratio, and permeability coefficient of the foundation strata, and input the soil parameters into the stratum numerical model to obtain the completed stratum numerical model.

[0031] D13. Based on the field data and construction methods, determine the multiple influencing factors that affect the change of pore pressure during the construction process, and input all influencing factors into the formation numerical model to obtain a formation numerical model that includes all influencing factors.

[0032] Step D2 specifically involves:

[0033] D21. Conduct pore pressure test simulation experiments for each influencing factor in the formation numerical model that includes all influencing factors, and obtain the pore pressure time history curve of each individual influencing factor.

[0034] D22. After assembling the deep foundation deep hole in-situ pore pressure testing device, place it in a preset position and monitor to obtain the pore pressure time history curve of the position to be tested.

[0035] D23. Subtract the pore pressure time history curves of all individual influencing factors from the pore pressure time history curves measured at the location to be measured in turn to obtain the pore pressure time history curve without interference.

[0036] The influencing factors include seepage, high-pressure water jets from the machine, hole enlargement, extrusion, and vibration energy input.

[0037] The horizontal consolidation coefficient of the foundation is obtained by formulating the following undisturbed pore pressure time history curve:

[0038]

[0039] Where u is the pore pressure, t is the dissipation time, and C is the pore pressure. h denoted as the horizontal consolidation coefficient of the foundation, and r is the radial distance between the construction center and the pore pressure sensor.

[0040] The beneficial effects of this invention are:

[0041] 1. The assembly and monitoring method of the present invention can be carried out without disturbing the surrounding soil, and is simple to operate. The test results are highly reliable and accurate, providing a basis for further in-situ characteristic parameter testing of deep soil foundations.

[0042] 2. The device of the present invention places the pore pressure sensor into the monitoring steel pipe and wraps it with gauze for back filtration, so that the sand filling inside the monitoring steel pipe will not be lost, the pore pressure sensor will not shift or cross-hole, and the data accuracy of the pore pressure sensor during long-term service is guaranteed.

[0043] 3. The depth to which the pore pressure sensor is placed in the device of the present invention is controlled by the extension tube connected to it. The number and length of the extension tubes can be continuously and freely adjusted. The vertical lowering method of the device can better control the posture of the overall structure of the pore pressure sensor and the in-situ pore pressure monitoring tube. Therefore, the pore pressure sensor can be accurately and conveniently lowered to the preset depth.

[0044] 4. This invention uses a layered backfilling method, which solves the problem of backfilling the gap between the soil around the in-situ pore pressure monitoring pipe and the in-situ pore pressure monitoring pipe, improves the accuracy of pore pressure measurement, and avoids the problem of cross-hole between the inside and outside.

[0045] 5. The method for obtaining the horizontal consolidation coefficient of the foundation in this invention includes numerical simulation and static-dynamic analysis coupling to separate the influencing factors of pore pressure source, and in-situ pore pressure time history curve fitting to obtain the horizontal consolidation coefficient of the foundation. The physical meaning of the result is clear and the accuracy is high. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the in-situ pore pressure monitoring tube.

[0047] Figure 2 This is a schematic diagram of the pore pressure sensor.

[0048] The components include an in-situ pore pressure monitoring tube 1, a support pore plug 2, a pore pressure sensor 3, a filter 31, and a sensor body 32. Detailed Implementation

[0049] The present invention will now be described in more detail with reference to the accompanying drawings and embodiments. However, the present invention is not limited thereto. For those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

[0050] like Figure 1 As shown, this embodiment presents an in-situ pore pressure testing device for deep foundations:

[0051] The system includes several extension tubes and an in-situ pore pressure monitoring tube 1. Multiple extension tubes are sequentially threaded together to form a long connecting tube, extending its length. The in-situ pore pressure monitoring tube 1 is threaded to the head of the long connecting tube. Each extension tube is a hollow galvanized steel pipe, with one end having an external thread and the other an internal thread. The open and closed ends of multiple extension tubes are sequentially threaded together to form a long connecting tube, extending its length. Each in-situ pore pressure monitoring tube 1 includes a hollow monitoring steel pipe and a pore pressure sensor 3. The two ends of the monitoring steel pipe are a sealed end with an external thread and an open end with an internal thread. The open end of the in-situ pore pressure monitoring tube 1 is threaded to the closed end of one extension tube of the long connecting tube. The pore pressure sensor 3 is located in the middle of the monitoring steel pipe, and the space between the pore pressure sensor 3 and the inner wall of the monitoring steel pipe is filled with quartz sand to ensure that the pore pressure sensor 3 is always located in the middle of the monitoring steel pipe.

[0052] The in-situ pore pressure monitoring tube 1 also includes gauze and a support hole plug 2; several perforations and a wiring hole are opened on the outer circumference of the monitoring steel tube, and the support hole plug 2 is installed on the wiring hole. The signal line of the pore pressure sensor 3 is led out to the outside of the in-situ pore pressure monitoring tube 1 through the support hole plug 2; a layer of gauze is wrapped around the outer circumference of the monitoring steel tube to form a filter layer, preventing the internal quartz sand from flowing out and causing the sensor's fixed position to change. The signal line is wound around the outer circumference of the monitoring steel tube wrapped with gauze and the outer circumference of the long connecting pipe in a spiral upward wiring manner, and finally connected to the data acquisition instrument. Figure 2 As shown, the pore pressure sensor 3 consists of a filter 31 at the head and a sensor body 32.

[0053] In this embodiment, the support plug 2 is designed as a circular anti-static rubber protective pad, placed in the wiring hole of the monitoring steel pipe. The data cable of the pore pressure sensor 3 passes through it, providing buffer protection for easily broken parts. It is used to reinforce the opening when the data cable runs outside the hole, preventing the cable corners from being scratched by the outer sleeve during the lowering of the pore pressure sensor 3 and when the in-situ pore pressure testing device is pulled out of the deep foundation, thus providing shear protection. The pore pressure sensor 3 is a BGK-4500S vibrating wire pore pressure sensor, which can be used for monitoring pressures such as osmotic pressure, pore water pressure, uplift pressure, and pipeline pressure. The extension tube is not perforated and comes in various sizes such as 1m and 2m. Its main purpose is to connect with the in-situ pore pressure monitoring pipe 1 containing the pore pressure sensor 3 via a threaded connection, allowing the pore pressure sensor 3 to be lowered to a specified depth. The data acquisition instrument is model BGK-G2-DVW-8 / 16. It connects to the G cloud platform (BGKLogger software) to transmit data to the G cloud platform for processing. The integrated monitoring station, consisting of the data acquisition instrument, pore pressure sensor 3, and G cloud platform, can perform automatic measurement, data processing, chart generation, and abnormal value alarm for various engineering safety monitoring instruments.

[0054] The assembly and monitoring method of this embodiment is implemented according to the following steps:

[0055] S1. Drill a hole at the monitoring site. After drilling, fill the hole with clean water until clean water comes out of the hole and then stop filling. This ensures that the permeable stone on the head of the pore pressure sensor 3 will not be blocked by soil particles after the sensor is installed, thus affecting the measurement accuracy. The filling time should be 30-45 minutes.

[0056] S2. Based on the actual conditions of the foundation soil and the required monitoring depth, determine the number of extension pipes, thereby determining the length of the long connecting pipe. Then, connect the open and closed ends of multiple extension pipes sequentially with threads to form a long connecting pipe.

[0057] S3. After saturating the pore pressure sensor 3, assemble it with a deep foundation deep hole in-situ pore pressure testing device.

[0058] S31. Remove the filter 31 that comes with the head of the pore pressure sensor 3, and immerse both the filter 31 and the pore pressure sensor 3 without the filter 31 in clean water for several hours to saturate them; in practice, they are usually left to stand in clean water for 24 hours.

[0059] S32. Install the saturated filter 31 on the head of the pore pressure sensor 3 without the filter 31, and place the saturated pore pressure sensor 3 with the filter 31 in the middle of the monitoring steel pipe. The data line is led out through the support hole plug 2.

[0060] In practice, the front cavity of the pore pressure sensor 3 must be vented before installation to avoid measurement errors during operation. A simple venting method is to gently pull out the front filter 31 along the axis of the sensor body 32, then immerse the sensor body 32 and filter 31 completely in a container filled with clean water, and then slowly push the filter 31 into the sensor body 32 in the water until the water in the front cavity of the pore pressure sensor 3 is saturated.

[0061] S33. Add quartz sand to the monitoring steel pipe until it is full, and wrap the outer circumference of the monitoring steel pipe with gauze to form a filter layer. The data line of the pore pressure sensor 3 is spirally wrapped on the surface of the gauze on the outer circumference of the monitoring steel pipe. The data line is protected and fixed with cable ties and tape. At the same time, apply an appropriate amount of petroleum jelly to the surface of the monitoring steel pipe for lubrication, and the in-situ pore pressure monitoring tube 1 is obtained.

[0062] In practice, when filling the quartz sand, the quartz sand is slowly and densely poured in from the top of the monitoring steel pipe to ensure that the pore pressure sensor 3 is placed vertically without shifting.

[0063] S34. Connect the in-situ pore pressure monitoring tube 1 to the head of the long connecting tube, and spirally wind the data line of the pore pressure sensor 3 around the outer circumference of the long connecting tube. Finally, connect it to the data acquisition instrument to obtain the assembled in-situ pore pressure testing device for deep holes in deep foundations.

[0064] Connecting the in-situ pore pressure monitoring tube 1 to the head of the long connecting tube specifically involves threading the unsealed internal thread end of the in-situ pore pressure monitoring tube 1 to the sealed external thread end of the long connecting tube.

[0065] S4. After the assembled deep foundation deep hole in-situ pore pressure testing device is set up at the preset position, monitoring is carried out to obtain the pore pressure time history curve at the monitoring position.

[0066] S41. Lower the in-situ pore pressure testing device for deep foundation deep holes to the designated location.

[0067] S42. Calculate the volume difference between the monitoring hole and the deep foundation deep hole in-situ pore pressure testing device. After the deep foundation deep hole in-situ pore pressure testing device is lowered to the designated position, backfill the soil volume corresponding to the volume difference between the two holes to ensure that the backfill gap is consistent with the properties of the surrounding soil and improve the measurement accuracy.

[0068] S43. After backfilling is completed, the deep foundation deep hole in-situ pore pressure testing device is used for real-time monitoring to obtain the pore pressure time history curve at the monitoring location.

[0069] Before formal monitoring during the lowering and subsequent static process of the deep-hole in-situ pore pressure testing device in deep foundations, the pore pressure sensor 3 measures and collects water level data at a frequency of 10Hz to check for sensor failure and damage. The pore pressure sensor 3 transmits the data to an external data acquisition instrument, which then stores the data in the computer's data storage system.

[0070] The method for obtaining the horizontal consolidation coefficient of the foundation in this embodiment is implemented according to the following steps:

[0071] D1. Construct a formation numerical model using numerical simulation analysis software on a computer to obtain the completed formation numerical model; obtain several influencing factors and input all influencing factors into the completed formation numerical model to obtain a formation numerical model containing all influencing factors.

[0072] Influencing factors include, but are not limited to, seepage, high-pressure water jets from the machine, hole enlargement, extrusion, and vibration energy input.

[0073] D11. Grid the monitoring site and construct a stratigraphic numerical model using a finite difference grid in the numerical simulation analysis software. Set the size of the monitoring site, the grid size, and the constitutive model in the stratigraphic numerical model, as well as the boundary conditions and initial conditions of the stratigraphic numerical model.

[0074] The initial conditions of the formation numerical model are determined based on different influencing factors; the boundary conditions of the formation numerical model are determined based on the site conditions.

[0075] D12. Obtain preliminary geological survey data, determine soil parameters such as soil strata distribution, density, Poisson's ratio, and permeability coefficient, and input the soil parameters into the geological numerical model to obtain the completed geological numerical model.

[0076] Furthermore, the rationality of the model parameter settings is determined through indoor tests and on-site construction data analysis; in specific implementation, for example, a segment of the measured pore pressure time history curve without interference is taken and compared with the pore pressure time history curve in the numerical model to see how well they match.

[0077] D13. Based on the field data and construction methods, determine the multiple influencing factors that affect the change of pore pressure during the construction process, and input all influencing factors into the formation numerical model to obtain a formation numerical model that includes all influencing factors.

[0078] D2. Use a deep-foundation in-situ pore pressure testing device to monitor the location to be tested and obtain the pore pressure time history curve of the location to be tested. Based on the formation numerical model containing all influencing factors and the pore pressure time history curve of the location to be tested, obtain an interference-free pore pressure time history curve.

[0079] In practice, the pore pressure time history curve is mainly selected from the time history curve of the pore pressure dissipation stage to obtain the horizontal consolidation coefficient of the foundation.

[0080] D21. Conduct pore pressure test simulation experiments for each influencing factor in the formation numerical model that includes all influencing factors, and obtain the pore pressure time history curve of each individual influencing factor.

[0081] D22. After assembling the in-situ pore pressure testing device for deep foundations, place it in the preset position and monitor to obtain the pore pressure time history curve of the position to be tested.

[0082] D23. Subtract the pore pressure time history curves of all individual influencing factors from the pore pressure time history curves measured at the location to be measured in turn to obtain the pore pressure time history curve without interference.

[0083] D3. Obtain the horizontal consolidation coefficient of the foundation based on the undisturbed pore pressure time history curve.

[0084] The horizontal consolidation coefficient of the foundation is obtained by formulating the following undisturbed pore pressure time history curve:

[0085]

[0086] Where u is the pore pressure, t is the dissipation time, and C is the pore pressure. hdenoted as the horizontal consolidation coefficient of the foundation, and r is the radial distance between the construction center and the pore pressure sensor 3.

[0087] In practice, the formula for the above-mentioned interference-free pore pressure time history curve is mainly the time history curve during the pore pressure dissipation period.

[0088] The apparatus and method of this invention place the pore pressure sensor 3 at a specified burial depth. The design and assembly of the apparatus take into account factors such as internal and external perforations, sensor back-filter protection, survivability in harsh construction environments, and long-term service. This invention achieves the beneficial effects of normal pore pressure response after long-term service and the removal of pore pressure time history curves that are unaffected by subsequent static-dynamic coupling analysis of data.

[0089] The device and method of this invention can accurately and quickly measure the pore pressure time history curve of deep overburden. The device has good working performance in ultra-deep underground environments. The horizontal consolidation coefficient obtained from the in-situ pore pressure data through reasonable data analysis methods has clear physical meaning and high accuracy. It solves the problem of conventional pore pressure measuring equipment working normally for a long time in ultra-deep environments and accurately obtaining parameters such as the horizontal consolidation coefficient of the foundation.

[0090] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A method for obtaining the horizontal consolidation coefficient of a foundation based on the assembly and monitoring method of an in-situ pore pressure testing device for deep foundations, characterized in that, Includes the following steps: D1. Construct a formation numerical model using numerical simulation analysis software to obtain the completed formation numerical model; obtain several influencing factors and input all influencing factors into the completed formation numerical model to obtain a formation numerical model containing all influencing factors. D2. Using the deep foundation deep borehole in-situ pore pressure testing device, monitor the location to be tested to obtain the pore pressure time history curve of the location to be tested. Based on the formation numerical model including all influencing factors and the pore pressure time history curve of the location to be tested, obtain an interference-free pore pressure time history curve; Step D2 specifically includes: D21. Conduct pore pressure test simulation experiments for each influencing factor in the formation numerical model that includes all influencing factors, and obtain the pore pressure time history curve of each individual influencing factor. D22. After assembling the deep foundation deep hole in-situ pore pressure testing device, place it in a preset position and monitor to obtain the pore pressure time history curve of the position to be tested. D23. Subtract the pore pressure time history curves of all individual influencing factors from the pore pressure time history curves measured at the location to be measured in turn, and finally obtain the pore pressure time history curve without interference. D3. Obtain the horizontal consolidation coefficient of the foundation based on the undisturbed pore pressure time history curve; The assembly and monitoring method of the deep-hole in-situ pore pressure testing device for deep foundations specifically includes the following steps: S1. Drill a hole at the monitoring site. After drilling is completed, fill the hole with clean water until clean water comes out of the hole and then stop filling. S2. Determine the number of extension tubes based on the required monitoring depth, and connect the open and closed ends of multiple extension tubes sequentially by thread to form a long connecting tube; S3. After saturating the pore pressure sensor (3), assemble the deep foundation deep hole in-situ pore pressure testing device. Step S3 specifically involves: S31. Remove the filter (31) that comes with the head of the pore pressure sensor (3). Soak both the filter (31) and the pore pressure sensor (3) without the filter (31) in clean water for several hours to saturate them. S32. Install the saturated filter (31) on the head of the pore pressure sensor (3) and place the pore pressure sensor (3) with the filter (31) in the middle of the monitoring steel pipe. The data line of the pore pressure sensor (3) is led out through the support pore plug (2). S33. Add quartz sand to the monitoring steel pipe until it is full, and wrap the outer circumference of the monitoring steel pipe with gauze to form a filter layer. The data line of the pore pressure sensor (3) is wrapped in a spiral on the surface of the gauze on the outer circumference of the monitoring steel pipe. The data line is protected and fixed with cable ties and tape to obtain the in-situ pore pressure monitoring tube (1). S34. Connect the in-situ pore pressure monitoring tube (1) to the head of the long connecting tube, and spiral the data line of the pore pressure sensor (3) around the outer circumference of the long connecting tube, and finally connect it to the data acquisition instrument to obtain the assembled deep foundation deep hole in-situ pore pressure testing device. S4. After the assembled deep foundation deep hole in-situ pore pressure testing device is placed at the preset position, monitoring is performed to obtain the pore pressure time history curve at the monitoring position. Step S4 specifically involves: S41. Lower the deep foundation deep hole in-situ pore pressure testing device to the designated position; S42. Calculate the volume difference between the monitoring hole and the deep foundation deep hole in-situ pore pressure testing device, and backfill the corresponding volume difference of soil between the deep foundation deep hole in-situ pore pressure testing device and the monitoring hole after it is lowered to the designated position. S43. After backfilling is completed, the deep foundation deep hole in-situ pore pressure testing device performs real-time monitoring to obtain the pore pressure time history curve at the monitoring location.

2. The method for obtaining the horizontal consolidation coefficient of a foundation based on the assembly and monitoring method of a deep-hole in-situ pore pressure testing device for deep foundations according to claim 1, is characterized in that, Step D1 specifically involves: D11. Grid the monitoring site and construct a stratigraphic numerical model using a finite difference grid in the numerical simulation analysis software. Set the size of the monitoring site, the grid size, and the constitutive model in the stratigraphic numerical model, as well as the boundary conditions and initial conditions of the stratigraphic numerical model. D12. Obtain preliminary geological survey data, determine soil parameters such as the distribution, density, Poisson's ratio, and permeability coefficient of the foundation strata, and input the soil parameters into the stratum numerical model to obtain the completed stratum numerical model. D13. Based on the field data and construction methods, determine the multiple influencing factors that affect the change of pore pressure during the construction process, and input all influencing factors into the formation numerical model to obtain a formation numerical model that includes all influencing factors.

3. The method for obtaining the horizontal consolidation coefficient of a foundation based on the assembly and monitoring method of a deep-hole in-situ pore pressure testing device for deep foundations as described in claim 1, characterized in that: The influencing factors include seepage, high-pressure water jets from the machine, hole enlargement, extrusion, and vibration energy input.

4. The method for obtaining the horizontal consolidation coefficient of a foundation based on the assembly and monitoring method of a deep-hole in-situ pore pressure testing device for deep foundations according to claim 1, characterized in that: The horizontal consolidation coefficient of the foundation is obtained by formulating the following undisturbed pore pressure time history curve: Where u is the pore pressure. t For dissipation time, C h This is the horizontal consolidation coefficient of the foundation. r The radial distance between the construction center and the pore pressure sensor (3) is given.

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