Automatic pressurization type soil consolidation method, system and device for multidimensional pore pressure monitoring

Abstract

The application discloses a multi-dimensional pore pressure monitoring automatic pressurization type soil body consolidation method, system and device, and relates to the technical field of soil body consolidation engineering. A plurality of soil pressure cells are arranged on the same plane and the same vertical direction of a soil sample to synchronously collect pore water pressure data at different positions in the soil sample; an automatic and step-by-step axial pressure is applied through a preset program of a measurement control system; based on the continuous drainage boundary theory, the time and space variation trends of the pore water pressure and the settlement data are combined to comprehensively determine the consolidation state and invert the interface parameters. The system and the device integrate a consolidation pressure chamber, an axial loading system, a water pressure control device, a multi-channel data acquisition system and a measurement control system to realize automatic and collaborative loading, monitoring and control, and the application can efficiently and reliably acquire multi-point time and space data of the whole soil body consolidation process, thereby providing an advanced test method for evaluating the consolidation space uniformity, determining soil engineering parameters and verifying the continuous drainage boundary theory.

Description

Technical Field

[0001] This invention relates to the field of soil consolidation engineering technology, specifically to an automatic pressurized soil consolidation method, system, and device with multi-dimensional pore pressure monitoring. Background Technology

[0002] In the fields of civil engineering, geological engineering, and geotechnical engineering, soil consolidation is one of the core aspects affecting the safety and long-term stability of engineering structures. Soil in its natural state typically contains a certain amount of pore water. When subjected to external pressures such as building loads, roadbed compaction, and foundation pit support, this pore water gradually drains, reducing pore volume and causing soil compression deformation—a process known as consolidation. The adequacy of the consolidation process directly affects the amount of settlement in the later stages of the project. Insufficient consolidation can lead to uneven settlement, causing serious problems such as wall cracking, roadbed deformation, and damage to underground pipelines, affecting not only the service life of the project but also causing safety accidents. Furthermore, accurately understanding the characteristics of soil consolidation is a crucial basis for engineering design. For example, in soft soil foundation treatment, the construction schedule needs to be determined based on the consolidation rate; in foundation pit excavation, the stress state of the support structure needs to be assessed based on the degree of consolidation. Therefore, conducting experimental research and technological development related to soil consolidation has significant practical importance and engineering value for ensuring project quality, reducing safety risks, and optimizing design schemes.

[0003] Traditional soil consolidation testing techniques mainly revolve around two types of consolidation apparatus: lever-type consolidation apparatus and fully automatic pneumatic consolidation apparatus. Lever-type consolidation apparatus, as an early and widely used device, operates on the principle of lever balance, applying pressure to the soil sample by adding weights to one end of the lever. It boasts advantages such as simple structure, low manufacturing cost, and low operational threshold, making it widely used in various laboratories. However, this type of instrument has significant limitations: firstly, the volume of soil samples used in the test is usually small, making it difficult to reflect the spatial distribution characteristics of soil in actual engineering projects. Furthermore, disturbances to the soil sample during collection and preparation are easily amplified, leading to significant deviations between the test data and the actual field conditions. Secondly, the loading process relies on manual operation, requiring personnel to manually add weights for staged loading. This is not only time-consuming and labor-intensive, but also makes precise control of the loading rate difficult, easily introducing errors due to human error. Additionally, the test process requires continuous monitoring, making unattended operation impossible and resulting in low work efficiency. The fully automatic pneumatic consolidation apparatus is an improvement on the loading method of the lever-type consolidation apparatus. It uses a pneumatic system to replace weights for loading, and can simulate stress changes in actual engineering with continuously changing loads. Theoretically, it is closer to the on-site working conditions and reduces the need for manual intervention to a certain extent. However, this type of instrument also has its shortcomings: the equipment is expensive, the maintenance cost is high, the operating environment requirements are strict, and the operation process is complex. Professional technicians need to undergo systematic training to use it proficiently. Therefore, it is only used in a few research institutions or large engineering laboratories with special requirements and is difficult to popularize in ordinary laboratories or small and medium-sized engineering units.

[0004] With the development of geotechnical engineering testing technology, existing soil consolidation testing techniques have improved in terms of automation and data acquisition accuracy, but there are still many areas for improvement. In terms of data monitoring, most existing technologies still rely on single monitoring indicators, such as measuring soil sample settlement using displacement sensors or collecting local pore water pressure data using only a few pore pressure sensors. This makes it difficult to comprehensively reflect the spatial distribution and dynamic changes of pore water pressure within the soil, leading to an incomplete assessment of the consolidation process. For example, relying solely on settlement might mistakenly classify "temporarily stable soil compression" as "consolidation complete," ignoring the fact that pore water pressure has not yet dissipated. Furthermore, relying solely on local pore pressure data, due to insufficient monitoring points, fails to capture the consolidation differences at different depths and horizontal positions within the soil. Regarding pressurization control logic, while some existing technologies have achieved automated pressurization, the pressurization gradient is mostly a fixed value, failing to fully consider the differences in compressibility characteristics of different types of soil (such as soft soil, silty clay, and sand). For example, using the same pressurization gradient for soft soil with high compressibility as for sand with low compressibility leads to insufficient consolidation of soft soil or low efficiency of sand tests. In addition, existing technologies also have shortcomings in data preprocessing and stability assessment. For example, the raw pore water pressure signal is not effectively denoised, making it susceptible to environmental interference (such as vibration and temperature changes) that affects data accuracy. Furthermore, stability assessment often relies on a single threshold (such as settlement rate threshold), lacking comprehensive consideration of multiple indicators, and the reliability of the assessment results needs to be improved.

[0005] Chinese patent (CN106198376A) discloses a consolidation apparatus for measuring pore pressure. The core structure of this technical solution includes a soil sample holding device, a pressure head, a displacement sensor, an earth pressure cell, and a measurement and control system. The soil sample holding device holds the soil sample to be tested, and multiple earth pressure cells are set on the same plane and vertical direction of the soil sample to collect pore water pressure data at different locations. The pressure head pressurizes the soil sample through a lifting mechanism (such as a hydraulic jack), and the displacement sensor is located on the pressure head to measure the deformation of the soil sample. The measurement and control system is connected to the earth pressure cell, lifting mechanism, and displacement sensor, and can automatically pressurize and collect data through program settings. While this technical solution improves the automation level of consolidation testing to some extent, it has serious technical defects, specifically including:

[0006] 1. The monitoring dimension is singular and one-sided. Soil pressure cells are only set up on the same plane and vertical direction of the soil sample. A three-dimensional monitoring network with multiple cross sections and multiple points is not formed. It is impossible to fully capture the spatial distribution differences of pore water pressure at different depths and horizontal positions of the soil. It is easy to misjudge the consolidation uniformity due to local data.

[0007] 2. The pressure control lacks flexibility. The pressure gradient is not dynamically adjusted based on the initial void ratio and compression coefficient of the soil. Only a fixed mode is used for step-by-step loading, which cannot adapt to the differences in compression characteristics of different types of soil (such as soft soil and sand). This can easily lead to insufficient consolidation of soft soil or low test efficiency of sand.

[0008] 3. Insufficient data processing precision: No effective data noise reduction and outlier removal mechanisms were set up. The original signal is easily affected by environmental vibration and temperature fluctuations. Furthermore, the data was not optimized by methods such as moving average, resulting in insufficient accuracy of pore water pressure data and affecting subsequent judgment results.

[0009] 4. The stability determination method is crude, only indirectly reflecting the consolidation process through pore pressure and deformation. It has not established a quantitative determination model with multiple coupled indicators, lacks comprehensive consideration of the coefficient of variation of pore water pressure and dissipation rate, and the determination criteria are vague, with a high probability of misjudgment.

[0010] 5. No steady-state verification at the end of consolidation: After loading is completed, the long-term stability of pore water pressure is not verified. Consolidation is judged to be completed based on short-term data only. This is prone to problems such as pressure rebound or excessive settlement in the later stage, and the long-term stability of the project cannot be guaranteed.

[0011] 6. Poor sensor compatibility; it uses a traditional earth pressure cell and does not clearly define the design for tight contact between the sensor and the soil, which can easily lead to data deviation due to contact gaps. Furthermore, it does not mention sealing and protection measures for sensor signal transmission, which poses a risk of pressure leakage.

[0012] 7. Low level of automation and collaboration: Although it can achieve automatic pressurization and data acquisition, the modules (pressurization, monitoring, and judgment) lack closed-loop collaborative logic. It cannot dynamically adjust the pressurization rhythm based on real-time monitoring data and still needs to rely on manual preset parameters, resulting in insufficient flexibility.

[0013] To address the aforementioned technical challenges, the industry urgently needs a soil consolidation method that can achieve precise monitoring of pore pressure across multiple dimensions, automated pressurization control, and comprehensive stability assessment of multiple indicators. This would improve the quality and efficiency of soil consolidation and ensure the long-term safety and stability of engineering structures under complex geological conditions. Summary of the Invention

[0014] To address the aforementioned technical problems, this invention provides an automatic pressure-based soil consolidation method, system, and apparatus for multi-dimensional pore pressure monitoring. The automatic pressure-based soil consolidation method for pore pressure spatial monitoring includes:

[0015] Select soil samples to be consolidated, and simultaneously collect pore water pressure data at different depths and horizontal positions inside the soil samples by using multiple earth pressure cells arranged on the same plane and in the same vertical direction.

[0016] Based on the preset consolidation target pressure of the soil sample, it is divided into multiple gradient pressures. Through the preset program of the measurement and control system, the lifting mechanism is automatically controlled to pressurize the soil sample step by step. Under each pressure level, the pore water pressure data measured by the earth pressure cell and the settlement deformation data measured by the displacement sensor are collected and recorded in real time. Combined with the continuous drainage boundary theory, the consolidation development state and boundary drainage characteristics under the pressure level are comprehensively evaluated.

[0017] The first-level axial pressure is applied to the soil sample through the lifting mechanism, and the measurement and control system connected to each soil pressure cell and displacement sensor data synchronously and continuously collects the pore water pressure changes and vertical displacement data of the soil sample at each point inside the soil sample.

[0018] Based on the collected pore water pressure data, the dissipation law of pore pressure at different depths in the same vertical direction and the difference in pore pressure dissipation at different points on the same plane are analyzed. Based on the continuous drainage boundary theory, the spatial distribution characteristics of pore pressure and the influence of boundary parameters during soil consolidation are studied.

[0019] Observe and determine whether the pore water pressure data has been fully dissipated and tended to stabilize. At the same time, combine the settlement deformation rate recorded by the displacement sensor to determine whether it has slowed down significantly. Combine the interface parameter inversion results in the continuous drainage boundary theory to comprehensively determine whether the soil sample has reached the state of consolidation under the current pressure level and can be loaded at the next level.

[0020] Under the current pressure level, once the soil sample is determined to be consolidated to the point where the next level of loading can be applied, the measurement and control system automatically controls the lifting mechanism to raise the axial pressure to the next level of load according to the preset program. This process is repeated step by step until all preset pressure levels have been applied.

[0021] Once the final axial pressure is applied and the soil sample is determined to have largely consolidated under that pressure based on observations of pore water pressure and settlement data, consolidation is complete.

[0022] Preferably, the acquisition of pore water pressure data inside the soil sample specifically involves: embedding soil pressure cells at preset positions in the soil sample within the soil sample holding device; the sensor signals of the soil pressure cells are led out through a wire from a preset sealed interface on the wall of the consolidation pressure chamber and connected to the measurement and control system; the measurement and control system continuously acquires and records the voltage or frequency signals output by each soil pressure cell at a set sampling frequency, and this signal is proportional to the pore water pressure of the soil, thereby obtaining the real-time pore water pressure data sequence at each monitoring point.

[0023] Preferably, the setting of the multi-stage loading pressure is specifically as follows: according to the geotechnical test procedures or simulated engineering load conditions, a series of progressively increasing axial pressure values ​​are pre-set in the measurement and control system to form a multi-stage loading sequence. When the test is conducted using continuous drainage boundary conditions, the dissipation law of the boundary pore water pressure follows the following theoretical expression. ,in t is the boundary pore pressure at time t; p(t0) is the initial boundary pore pressure after the loading increment ends at time t0; t0 is the current time for discussing the boundary problem; b is the interface parameter reflecting the boundary drainage characteristics. The holding time of each pressure level in the experiment must ensure that sufficient pore pressure data reflecting the above dissipation law can be collected. The measurement and control system automatically executes the step-by-step loading according to the preset pressure sequence and the time control logic based on the continuous drainage boundary theory.

[0024] Preferably, the acquisition of pore water pressure data from each earth pressure cell is achieved through the measurement and control system. This system synchronously records the output of each sensor at a constant sampling frequency using a multi-channel data acquisition instrument. The output is directly represented as a pore water pressure value after internal analog-to-digital conversion and calibration calculation, forming a multi-channel synchronous raw observation dataset corresponding to a strict timestamp.

[0025] Preferably, the analysis of the spatial distribution characteristics of pore water pressure within the soil specifically involves: based on the pore water pressure data of each monitoring point changing over time, plotting and comparing pore pressure dissipation curves at different depths in the same vertical direction, as well as pore pressure dissipation curves at different locations on the same horizontal plane. This qualitatively and semi-quantitatively assesses the spatial non-uniformity of the consolidation process. For further quantitative analysis, a one-dimensional consolidation theory solution under continuous drainage boundary conditions can be introduced. This theoretical solution gives the distribution of excess pore water pressure u within the soil layer with depth z and time t under the control of interface parameters b (characterizing the drainage capacity of the upper boundary) and c (characterizing the drainage capacity of the lower boundary). In the formula, p is the applied load, H is the soil layer thickness, and C is the soil layer thickness. v is the consolidation coefficient of the soil. As a time factor, By comparing the measured pore pressure-time data at different depths with the theoretical distribution described above, the applicability of the theoretical model can be evaluated, and the consolidation parameter C of the soil can be obtained under known boundary conditions. v Alternatively, verify the values ​​of boundary parameters b and c.

[0026] Preferably, the analysis of the uniformity of pore pressure distribution at different depth sections in conjunction with continuous drainage boundary parameters specifically involves: based on the continuous drainage boundary theory, the boundary drainage capacity is characterized by the interface parameters b (upper boundary) and c (lower boundary), which directly affect the pore pressure dissipation process. By comparing the measured pore pressure dissipation curves at different depth sections, the consolidation uniformity can be analyzed. If the upper and lower boundary parameters are asymmetrical (b≠c), the theoretical solution indicates that the pore pressure is asymmetrically distributed along the depth, with different dissipation rates. By comparing the measured pore pressure-time data at different depth sections with the theoretical solution, the consistency between the spatial distribution uniformity predicted by the theoretical model and the actual observation can be evaluated, thereby reflecting the influence of boundary conditions or the soil itself on the spatial uniformity of consolidation.

[0027] Preferably, the assessment of soil consolidation state specifically involves: based on the continuous drainage boundary theory, evaluating consolidation progress by analyzing the dissipation law of measured pore water pressure at the drainage boundary over time; and comparing the measured pore pressure data u with the solution from the continuous drainage boundary theory. Fitting is performed, where b is the interface parameter to be inverted; when the pore pressure dissipation process conforms to the exponential decay trend described by the theoretical model, and the interface parameter b obtained by inversion through the least squares method tends to a stable value during the calculation period, and the settlement deformation rate of the soil sample has also slowed down significantly, it can be comprehensively determined that the consolidation of the soil sample under this pressure level has been basically completed.

[0028] Preferably, the determination of the completion of the consolidation test is as follows: after the last stage of axial pressure is applied and maintained for a sufficient time, a comprehensive judgment is made based on whether the pore water pressure-time curves at each major monitoring point tend to flatten and the dissipation rate is lower than a preset threshold, and whether the settlement deformation rate of the soil sample has dropped to a negligible level. When the above conditions are met simultaneously, it can be determined that the consolidation under that pressure level is basically completed.

[0029] Its pore pressure space monitoring automatic pressurization soil consolidation system based on the continuous drainage boundary theory includes a consolidation pressure chamber, an axial loading system, a water pressure control system, a multi-channel data acquisition system, and a measurement and control system.

[0030] The consolidation pressure chamber is used to contain soil samples. It is equipped with drainage channels and control valves at the top and bottom, respectively, and multiple sealed interfaces for threading sensor wires through the side walls.

[0031] The axial loading system includes a servo motor-driven lifting mechanism and a pressure head, used to apply multi-level gradient axial pressure to the soil sample in the consolidation pressure chamber.

[0032] The water pressure control system uses a pressure / volume controller, which is connected to the drainage channel of the consolidation pressure chamber through a pipeline, and is used to realize back pressure control, boundary pore pressure monitoring and drainage volume measurement.

[0033] The multi-channel data acquisition system includes multiple earth pressure cells, displacement sensors, and a multi-channel data acquisition instrument, all buried at different monitoring points inside the soil sample. The earth pressure cells and displacement sensors are connected to the data acquisition instrument via lead wires from the sealed interface of the consolidation pressure chamber, for the synchronous acquisition of pore water pressure signals and vertical displacement signals.

[0034] The measurement and control system is communicatively connected to the multi-channel data acquisition system, the axial loading system, and the water pressure control system, respectively. The measurement and control system is used to: execute a preset test program; control the axial loading system to automatically pressurize according to a multi-level gradient; control the water pressure control system to adjust the back pressure; receive, process, and store pore water pressure and settlement data from the data acquisition system; and, based on the data and in conjunction with the continuous drainage boundary theory, determine the consolidation state and automatically control the loading process according to the determination result.

[0035] An automatic pressurized soil consolidation device for multi-dimensional pore pressure monitoring, characterized in that the device specifically comprises:

[0036] The consolidation pressure chamber is used to contain and seal the soil sample. The chamber wall is equipped with a sealed interface for passing sensor wires through it. Drainage control valves are provided at the top and bottom to achieve single / double-sided drainage control.

[0037] The axial loading mechanism, driven by a servo motor or hydraulic jack, applies axial load by contacting the upper surface of the soil sample in the consolidation pressure chamber through a rigid pressure head.

[0038] The water pressure control device uses a high-precision pressure / volume controller, which is connected to the drainage channel of the consolidation pressure chamber through a pipeline. It is used to apply and adjust the back pressure and accurately measure the drainage volume.

[0039] The pore water pressure monitoring component consists of multiple earth pressure cells, which are embedded in different locations inside the soil sample according to the design. The signal lines are led out through the sealed interface of the consolidation pressure chamber.

[0040] Displacement sensors, mounted on the indenter or fixed frame of the axial loading mechanism, are used to measure the vertical deformation of soil samples.

[0041] The data acquisition unit includes a multi-channel data acquisition instrument, whose input end is connected to the earth pressure cell, displacement sensor, load sensor of axial loading mechanism and water pressure control device, for multi-channel synchronous acquisition and analog-to-digital conversion of various analog signals;

[0042] The measurement and control system consists of an industrial computer and dedicated control software running on it. The industrial computer is communicatively connected to the data acquisition unit, the servo controller of the axial loading mechanism, and the water pressure control device. The control software is used to execute a preset test program, which is set based on the continuous drainage boundary theory. The test program includes: controlling the axial loading mechanism to apply pressure according to a set gradient, controlling the water pressure control device to adjust the back pressure, synchronously acquiring and storing all monitoring data at a constant sampling frequency, performing real-time determination of the consolidation state and automatic control of the loading process based on the acquired pore water pressure and settlement data and in combination with the continuous drainage boundary theory, and providing a human-machine interface to display and monitor the test process in real time.

[0043] Compared with the prior art, the technical solution of this application has the following technical effects:

[0044] This invention achieves simultaneous, multi-point monitoring of pore water pressure within soil at both depth and planar locations by arranging multiple earth pressure cells on the same plane and vertical direction of the soil sample. Compared to traditional consolidation apparatuses that monitor pore pressure at only a single location or boundary, this invention can acquire richer spatially discrete pore pressure data, allowing for comparative analysis of differences in pore pressure dissipation patterns at different depths and at different locations within the same depth. This helps to more comprehensively assess the spatial non-uniformity of soil consolidation and provides crucial multi-location test data support for verifying consolidation theories considering complex boundary conditions (such as continuous drainage boundary theory). Combined with an automated loading and data acquisition system, the efficiency and reliability of consolidation tests are significantly improved.

[0045] This invention achieves automatic, step-by-step application of axial pressure through a preset loading program in the measurement and control system. This replaces the traditional lever-type consolidation apparatus that relies on manual weight manipulation, significantly improving experimental efficiency and the consistency of the loading process. The system can stably execute a pre-set multi-level load sequence and, combined with real-time collected pore water pressure and settlement data, provides operators with intuitive information to monitor the consolidation process and determine the appropriate loading timing within the automated workflow. Thus, while ensuring experimental quality, it achieves an automated process from loading to data acquisition.

[0046] This invention utilizes an integrated data acquisition system to achieve synchronous, continuous, and automatic acquisition and recording of earth pressure cell signals at various monitoring points within soil samples, directly obtaining a raw pore water pressure observation dataset that strictly corresponds to the time series. This system avoids the errors and asynchrony issues that may arise from traditional manual readings, ensuring data continuity in the time dimension and synchronous comparability across multiple spatial points. The acquired complete and systematic pore pressure-time series provides a direct and reliable raw data foundation for in-depth research into the spatiotemporal evolution of pore pressure during soil consolidation, particularly for quantitative analysis using continuous drainage boundary theory (such as pore pressure dissipation curve plotting and interface parameter inversion).

[0047] This invention provides multi-source, real-time observation data for assessing consolidation status by simultaneously acquiring pore water pressure and settlement deformation data. Operators or the control system can comprehensively judge the consolidation development state of the soil sample under the current load based on the trend of the pore water pressure dissipation curve (e.g., whether it tends to flatten) and the rate of settlement deformation change. This method overcomes the limitations of past methods that relied solely on a single settlement index or fixed time intervals, enabling a more timely reflection of the actual response of the soil in assessing consolidation stability. This allows for the rational determination of the holding time for each load level and improves experimental efficiency while ensuring test quality.

[0048] This invention, through an automated loading and data acquisition system, ensures continuous and complete recording of soil sample consolidation data at each load level (including the final level) until consolidation is deemed essentially complete based on preset standards or observations. The complete and continuous pore water pressure and settlement time series data obtained by the system not only reflect the instantaneous consolidation characteristics under each load level but also provide a comprehensive dataset for evaluating the final soil compression, calculating the consolidation coefficient, and verifying the continuous drainage boundary theoretical model (including inverted interface parameters). This achieves a complete closed loop from loading and process monitoring to data acquisition, laying a solid foundation for subsequent geotechnical parameter determination and theoretical analysis.

[0049] This invention selects an earth pressure cell, known for its stability and high reliability, as the pore water pressure sensing element. By embedding it inside the soil sample at a designed location and using a pre-sealed interface on the inner wall of the consolidation pressure chamber to lead out signal wires, contact between the sensor and the soil is effectively ensured, while preventing water seepage and pressure leakage from the pressure chamber. This design ensures continuous and stable transmission of monitoring signals during long-term pressurization and consolidation drainage, providing hardware support for obtaining high-quality, repeatable pore water pressure time-series data.

[0050] This invention uses the measurement and control system as the core control and data center, establishing bidirectional communication with the axial loading system, water pressure control system, and data acquisition system. This system receives pore water pressure and displacement data from the data acquisition system in real time and monitors the consolidation process accordingly. Simultaneously, according to a preset test procedure, it automatically issues control commands to the axial loading system and water pressure control system, precisely executing multi-stage loading and back pressure regulation. This closed-loop control architecture, with the measurement and control system at its center, achieves automated integration and coordinated operation of loading, data acquisition, and process monitoring, significantly improving the standardization, execution efficiency, and process controllability of the consolidation test, providing a system guarantee for obtaining highly reliable test data.

[0051] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0052] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0054] Based on the description of the figures and their corresponding technical content in the document, the titles of the figures are as follows:

[0055] Figure 1 A schematic diagram of the process for an automated pressurized soil consolidation method with multi-dimensional pore pressure monitoring;

[0056] Figure 2 A schematic diagram of the unit connection of an automatic pressurized soil consolidation system for multi-dimensional pore pressure monitoring;

[0057] Figure 3 A schematic diagram of the consolidation chamber structure of an automatic pressurized soil consolidation device based on multi-dimensional pore pressure monitoring.

[0058] Figure 4 This is a schematic diagram of an automatic pressurized soil consolidation device for multi-dimensional pore pressure monitoring. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0060] It should be understood that the phrase "an embodiment" or "this embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "an embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0061] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0062] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.

[0063] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0064] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.

[0065] Example 1

[0066] This embodiment mainly describes an automated pressurized soil consolidation method based on multi-dimensional pore pressure monitoring. Soil consolidation tests are conducted using the aforementioned consolidation apparatus. Figure 1 As shown, it specifically includes:

[0067] Select soil samples to be consolidated, and simultaneously collect pore water pressure data at different depths and horizontal positions inside the soil samples by using multiple earth pressure cells arranged on the same plane and in the same vertical direction.

[0068] Based on the preset consolidation target pressure of the soil sample, it is divided into multiple gradient pressures. Through the preset program of the measurement and control system, the lifting mechanism is automatically controlled to pressurize the soil sample step by step. Under each pressure level, the pore water pressure data measured by the earth pressure cell and the settlement deformation data measured by the displacement sensor are collected and recorded in real time. Combined with the continuous drainage boundary theory, the consolidation development state and boundary drainage characteristics under the pressure level are comprehensively evaluated.

[0069] The first-level axial pressure is applied to the soil sample through the lifting mechanism, and the measurement and control system connected to each soil pressure cell and displacement sensor data synchronously and continuously collects the pore water pressure changes and vertical displacement data of the soil sample at each point inside the soil sample.

[0070] Based on the collected pore water pressure data, the dissipation law of pore pressure at different depths in the same vertical direction and the difference in pore pressure dissipation at different points on the same plane are analyzed. Based on the continuous drainage boundary theory, the spatial distribution characteristics of pore pressure and the influence of boundary parameters during soil consolidation are studied.

[0071] Observe and determine whether the pore water pressure data has been fully dissipated and tended to stabilize. At the same time, combine the settlement deformation rate recorded by the displacement sensor to determine whether it has slowed down significantly. Combine the interface parameter inversion results in the continuous drainage boundary theory to comprehensively determine whether the soil sample has reached the state of consolidation under the current pressure level and can be loaded at the next level.

[0072] Under the current pressure level, once the soil sample is determined to be consolidated to the point where the next level of loading can be applied, the measurement and control system automatically controls the lifting mechanism to raise the axial pressure to the next level of load according to the preset program. This process is repeated step by step until all preset pressure levels have been applied.

[0073] Once the final axial pressure is applied and the soil sample is determined to have largely consolidated under that pressure based on observations of pore water pressure and settlement data, consolidation is complete.

[0074] Furthermore, the preparation of the soil sample and the monitoring of pore water pressure are specifically as follows:

[0075] The consolidation apparatus is adaptable to specimens of different sizes, with typical sizes including a diameter of 250 mm and a height of 80 mm. During specimen preparation, the placement of earth pressure cells is pre-planned according to monitoring requirements. Multiple earth pressure cells are placed at different depths (upper, middle, and lower) and radial positions within the same section, as well as multiple earth pressure cells in the same vertical direction, to obtain pore pressure data at different depths and planar positions. Specifically, during placement, the earth pressure cells can be buried in the preset positions and directions (ensuring the sensing surface faces the expected direction of pore pressure) and in close contact with the soil when filling soil in layers at different heights of the specimen.

[0076] The prepared sample is placed on the base of the consolidation pressure chamber, ensuring good contact between the bottom of the sample and the drainage channel. The gaps around the sample should be filled with a sealing and friction-reducing material such as petroleum jelly to reduce sidewall friction and enhance sealing. The signal wires of the soil pressure cell should be carefully bundled and led out through pre-set wire holes with rubber sealing rings on the sidewall of the consolidation pressure chamber, connecting to the corresponding channel of the data acquisition system.

[0077] After the measurement and control system is started, it controls the data acquisition system to synchronously and continuously acquire the electrical signals output by all earth pressure cells at a set sampling frequency (e.g., 1Hz). After analog-to-digital conversion and calibration calculations within the system, these signals are directly recorded as the raw pore water pressure-time series data for each monitoring point. The system continuously acquires and stores data throughout the entire consolidation test, forming a complete raw observation dataset.

[0078] The raw pore water pressure-time series data collected and stored by the measurement and control system constitute direct observation data for studying the soil consolidation process.

[0079] These data can be directly used to plot the dissipation curves of pore water pressure over time at each monitoring point. For further analysis, this raw data, especially the pore pressure data at the drainage boundary, can be compared and fitted with consolidation theory models. For example, to apply the continuous drainage boundary theory, the measured pore pressure data u at the drainage boundary can be compared with the solution from the continuous drainage boundary theory. By fitting the data and inverting it using an optimization algorithm (such as the least squares method), the interface parameter b is obtained, thereby verifying the theory and obtaining the drainage characteristics parameters of the soil boundary.

[0080] Furthermore, the determination of the multi-level loading and consolidation state is specifically as follows:

[0081] The multi-stage axial loading pressure sequence is pre-set according to the "Standard for Geotechnical Testing Methods" (GB / T 50123) or the simulated specific engineering load conditions, and input into the measurement and control system. Based on the preset pressure values ​​and the pressure holding logic for each stage based on the continuous drainage boundary theory, the system automatically controls the axial loading mechanism to perform progressive loading.

[0082] During each load application and maintenance period, the consolidation state is monitored and evaluated using real-time acquired pore water pressure and settlement data. During evaluation, the measurement and control system automatically analyzes whether the pore water pressure dissipation curve has flattened, and simultaneously considers whether the settlement rate has significantly decreased. For experiments employing the continuous drainage boundary theory, the system can automatically compare the measured pore pressure-time data at the drainage boundary with the theoretical model. Fitting and inversion are performed. If the fit is good, the interface parameter b obtained by inversion tends to be stable during the calculation period, and the settlement rate simultaneously meets the preset threshold. This can be used as a quantitative basis for judging that the pore pressure dissipation conforms to the theoretical law and the consolidation tends to be stable.

[0083] Based on the above automated analysis and judgment of pore pressure dissipation trend and settlement rate, when it is considered that the consolidation of the soil sample under this load level is basically completed, the measurement and control system will automatically or be manually triggered by the operator to switch to the next load level.

[0084] Once the final load has been applied and consolidation has been determined to be essentially complete, the test can be stopped.

[0085] The analysis of the spatial distribution characteristics of pore water pressure inside the soil is as follows:

[0086] Based on the pore water pressure data of each monitoring point over time, pore pressure dissipation curves at different depths in the same vertical direction (depth direction) and at different locations in the same horizontal plane (radial direction) were plotted and compared. By comparing the differences in dissipation rate, time required to reach stability, and final stable value among these curves, the spatial non-uniformity of the consolidation process within the soil can be assessed intuitively and quantitatively.

[0087] To further quantify the distribution of pore pressure along the depth direction, a one-dimensional consolidation theory solution under continuous drainage boundary conditions can be introduced. This theoretical solution gives the distribution of excess pore water pressure u in the soil layer with depth z and time t under the control of interface parameters b (upper boundary) and c (lower boundary): In the formula, p is the applied load, H is the soil layer thickness, and C is the soil layer thickness. v is the consolidation coefficient of the soil. As a time factor, By comparing the measured pore pressure-time data at different depths with the theoretical distribution described above, the applicability of the theoretical model can be evaluated, and the consolidation parameter C of the soil can be obtained under known boundary conditions. v Alternatively, verify the values ​​of boundary parameters b and c.

[0088] By comparing and analyzing the measured pore pressure-time data at different depths with the theoretical distribution mentioned above, the applicability of the theoretical model to describe the spatial distribution of pore pressure under specific experimental conditions can be evaluated.

[0089] The analysis of the spatial distribution characteristics of pore pressure using the continuous drainage boundary theory is as follows:

[0090] Based on the continuous drainage boundary theory, the boundary drainage capacity is characterized by interface parameters b (upper boundary) and c (lower boundary). The theoretical solution shows that when the upper and lower boundary parameters are asymmetrical (i.e., b≠c), the excess pore water pressure in the soil is asymmetrically distributed along the depth direction, and the pore pressure dissipation rate is different at different depths.

[0091] In the experiment, by comparing the pore water pressure dissipation curves measured at monitoring points at different depths along the same vertical direction (depth direction), the uniformity of the consolidation process along depth can be visually analyzed. If these dissipation curves show significant differences in morphology and dissipation rate, it indicates that the consolidation is spatially non-uniform. This non-uniformity may originate from the actual differences in drainage capacity at the upper and lower boundaries (characterized by b and c), or it may be related to the spatial variation in the soil's permeability or compressibility.

[0092] To further quantify and diagnose the causes of non-uniformity, the measured pore pressure-time data at different depths can be systematically compared and fitted with the theoretical solution of the continuous drainage boundary. This can effectively determine the extent to which the observed spatial non-uniformity can be explained by the actual differences in boundary conditions (i.e., the difference between parameters b and c), or whether it mainly stems from the spatial variation of the soil's permeability or compressibility. This analysis provides direct experimental evidence for optimizing drainage boundary design or identifying weak areas within the soil.

[0093] The determination of the consolidation state of the soil sample under the current pressure level is based on a comprehensive analysis of real-time monitoring data. Specifically, the operator (or the system based on simple logic) mainly relies on the following observations:

[0094] (1) Stability determination of pore water pressure dissipation: The system calculates the pore water pressure dissipation rate at each key monitoring point (especially at the drainage boundary) in real time. When the rate is consistently lower than the preset threshold and the pore water pressure-time curve tends to flatten, the primary stability condition is met.

[0095] (2) Stability determination of settlement deformation development: The system calculates the settlement rate of the soil sample in real time. When the settlement rate is continuously lower than the preset threshold and tends to zero, the secondary stability condition is met.

[0096] For experiments employing the continuous drainage boundary theory, the measured pore pressure dissipation data at the drainage boundary can be compared with the theoretical model. Perform a fitting. If the fitting is good and the interface parameter b obtained by inversion tends to a stable value in the recent time period, this can provide an auxiliary quantitative reference for determining whether the pore pressure dissipation conforms to the theoretical law.

[0097] Based on the above observations of pore pressure and settlement, and combined with possible theoretical models for analysis, when it is considered that the consolidation of the soil sample under the current load is basically completed, the test can be triggered to enter the next level of loading or end.

[0098] The consolidation test is completed as follows:

[0099] When the final axial pressure is applied, based on the comprehensive judgment that the pore water pressure dissipation curve tends to flatten and the settlement deformation rate decreases significantly, it is considered that the consolidation of the soil sample under this load level is basically completed. At this point, the measurement and control system automatically terminates the loading and data acquisition process, marking the completion of the consolidation test.

[0100] After the experiment, the complete, continuous, and spatiotemporally synchronized pore water pressure-time series and settlement-time series data acquired by the system constituted the core data for analyzing the consolidation characteristics of the soil. This data can be directly used for:

[0101] (1) Plot the ep curves under various load levels to determine the soil's compression index, compression coefficient, etc.;

[0102] (2) Calculate the consolidation coefficient based on the pore pressure dissipation curve;

[0103] (3) Fit the pore pressure data, especially the data at the boundary, with the continuous drainage boundary theoretical model, and invert the interface parameters b and c that characterize the boundary drainage capacity to complete the verification of the theoretical model and provide key parameters for the simulation and optimization of boundary conditions in actual engineering.

[0104] The above analysis provides key parameters and verification basis for settlement prediction, foundation treatment design, and consolidation theory research in practical engineering.

[0105] This embodiment details a soil consolidation test method and system based on multi-point synchronous pore pressure monitoring and automated loading. By implementing a multi-dimensional distributed earth pressure cell layout within the soil sample, direct observation of spatial differences in pore water pressure during consolidation is achieved, overcoming the limitations of traditional single-point monitoring. Combined with an automatic step-by-step loading system based on a pre-programmed continuous drainage boundary theory, test efficiency and loading consistency are significantly improved. By synchronously acquiring pore pressure and settlement data and combining them with a quantitative model based on continuous drainage boundary theory for comprehensive determination of consolidation state, the evaluation process shifts from experience-based to data-driven scientific decision-making, making the assessment of consolidation state more comprehensive and timely. The high-quality, complete spatiotemporal data acquired by the method and system are particularly suitable for verifying and parameter inversion of modern consolidation theories such as continuous drainage boundary theory, providing an effective experimental means for in-depth research on soil consolidation mechanisms and solving related engineering problems.

[0106] Example 2

[0107] This embodiment describes in detail an automatic pressurized soil consolidation system capable of multi-dimensional pore pressure monitoring, and its hardware configuration and connection relationships are as follows: Figures 2-4 As shown, it mainly includes: a consolidation pressure chamber, an axial loading mechanism, a water pressure control device, a pore water pressure monitoring component, a displacement sensor, a data acquisition unit, and a measurement and control system, specifically:

[0108] The sample preparation and installation serve as the basis for the experiment. Representative soil samples are selected and pretreated through processes such as impurity removal, saturation, and reshaping. Cylindrical samples are then prepared using the ring cutter method or static pressure method. The sample dimensions must be compatible with the consolidation pressure chamber; typical dimensions include a diameter of 250 mm and a height of 80 mm. During preparation, it should be ensured that the upper and lower end faces of the sample are parallel, the texture is uniform, and there are no visible cracks or delaminations. The prepared sample is transferred to the base of the consolidation pressure chamber, and its position is adjusted to align with the base. According to the monitoring plan, earth pressure cell embedding points are pre-set at the corresponding locations on the sample. A friction-reducing material such as petroleum jelly is applied between the sample sidewall and the inner wall of the pressure chamber to reduce sidewall friction and ensure a seal.

[0109] Based on monitoring requirements, the locations for embedding earth pressure cells in the samples are pre-defined. The placement follows the principle of setting multiple monitoring points on the same horizontal plane and in the same vertical direction. In practice, depending on the research objective, earth pressure cells can be embedded at predetermined depths during layered backfilling at different heights. Within the same layer, earth pressure cells can be positioned at different radial distances from the sample center. This allows for the simultaneous acquisition of pore water pressure data at different depths and at different radial positions within the same depth.

[0110] After the earth pressure cell placement locations are planned, they are deployed during sample preparation. Specifically, when the sample is compacted to the preset depth in layers, the earth pressure cells are placed in the soil according to the designed orientation, ensuring good contact between their sensing surfaces and the soil. After sample preparation is complete, the cells are carefully moved into the consolidated pressure chamber, placed on the base, and centered to ensure good contact between the bottom of the sample and the drainage channel. The gap between the sample sidewall and the inner wall of the pressure chamber is filled with a sealing and friction-reducing material such as petroleum jelly to prevent pressure leakage and reduce friction. All signal wires of the earth pressure cells are carefully organized and led out through the preset sealed wiring holes on the sidewall of the pressure chamber, preparing for connection to the data acquisition system.

[0111] The pore water pressure monitoring and acquisition function is achieved by multiple earth pressure cells buried inside the soil sample, as well as a multi-channel data acquisition instrument and measurement and control system connected to them.

[0112] During sensor deployment, soil pressure cells are placed in the soil at predetermined positions and orientations during sample layering, ensuring close contact between their sensing surfaces and the soil. Signal wires from each soil pressure cell are properly fixed inside the sample, then converge and lead out from the top surface or side of the sample. After the sample is placed in the consolidation pressure chamber, these signal wires are led out to the outside through sealed wiring interfaces on the pressure chamber wall. These sealed interfaces utilize structures such as rubber sealing rings to ensure no leakage under pressure. All led-out signal wires are connected to the corresponding input channels of the data acquisition system. The measurement and control system controls the data acquisition system to synchronously sample each channel, converting the analog signals from the soil pressure cells into digital signals and recording them, thereby forming a complete pore water pressure monitoring network.

[0113] In the data acquisition phase, the measurement and control system controls the data acquisition system to synchronously and continuously acquire the output signals of all earth pressure cells and displacement sensors at a preset sampling frequency. These analog signals are converted from analog to digital signals and then converted in real time into pore water pressure and displacement values, which are dynamically displayed as time-varying curves on the control software interface. The acquired raw data is completely stored in the computer, forming a raw dataset containing timestamps and physical quantity values ​​for each monitoring point. This system ensures the continuity of data in time and the synchronization of data at various points in space. Operators can observe the dissipation trend of pore water pressure and the development of settlement in real time through the interface. This observation information provides an intuitive basis for judging the consolidation process and deciding whether to proceed to the next level of loading. All stored raw data provides a foundation for plotting consolidation curves, calculating soil parameters, and performing theoretical inversion after the experiment.

[0114] The axial loading and counter-pressure control function is jointly realized by the axial loading system driven by the servo motor and the water pressure control device controlled by pressure / volume, and the two work together under the coordination of the measurement and control system.

[0115] The core function of the axial loading system is to precisely apply multi-level axial pressure to the soil sample according to a preset program. Operators pre-set the target pressure sequence and loading parameters in the measurement and control system based on the experimental design. During loading, a servo motor, through a ball screw and other transmission mechanisms, converts rotational motion into high-precision axial linear motion, driving the indenter to pressurize the sample. The system monitors the applied pressure in real time using a high-precision load sensor and employs closed-loop feedback control to dynamically adjust the motor output, ensuring the pressure stably reaches the set value and avoiding overshoot.

[0116] The hydraulic control chamber is primarily responsible for back pressure regulation and volume monitoring. During the consolidation process, the pressure / volume controller monitors the sample volume changes caused by pore water discharge in real time and simultaneously adjusts the back pressure acting on the sample to maintain tight contact between the sample and the chamber wall, preventing gaps. The back pressure value can be set and adjusted according to experimental requirements. Simultaneously, the hydraulic control chamber transmits the real-time back pressure value and volume change data, along with the applied pressure value collected by the axial loading system, to the measurement and control system. This data is displayed and stored in real time on the control software interface, providing crucial information for operators to monitor the consolidation process and assess sample conditions (such as saturation retention and boundary condition stability).

[0117] The determination of the consolidation state of the soil sample under the current pressure is performed by the operator based on the real-time monitoring data provided by the measurement and control system, or automatically by the system according to the preset simple logic. The main basis for the determination is: (1) The dissipation trend of pore water pressure: observe the pore water pressure-time curve of each key monitoring point (especially the drainage boundary) displayed in real time by the system. When the curve tends to flatten with time and there is no obvious continuous decline, it can be considered that the pore pressure dissipation is basically stable. (2) The development rate of settlement deformation: observe the settlement-time curve of the soil sample displayed in real time by the system. When the settlement rate decreases significantly and tends to a very small stable value, it can be considered that the deformation development is basically stable.

[0118] Based on the above observations of the pore water pressure dissipation trend and settlement deformation rate, when it is considered that the consolidation of the soil sample under the current load level is basically complete, it can be decided to proceed to the next loading level. The measurement and control system then automatically controls the axial loading system to increase the axial pressure to the next set value according to a preset program, and simultaneously adjusts the back pressure of the water pressure control device. If, based on observations, consolidation is not yet complete, the system continues to maintain loading at the current pressure and collect data until the set stability conditions are met.

[0119] After the experiment, the complete and continuous pore water pressure and settlement time series data acquired by the system can be used for comprehensive consolidation characteristic analysis. These data provide direct evidence for calculating soil compressibility parameters, compression index, consolidation coefficient, and for verifying the continuous drainage boundary theory.

[0120] Through the aforementioned automated loading, multi-dimensional data synchronous acquisition, and comprehensive judgment process, the system described in this invention completed a full consolidation test. The high-quality, spatiotemporally synchronized monitoring data obtained from the test provides a reliable experimental means for accurately analyzing the consolidation properties of soil, determining key geotechnical parameters, and verifying and developing consolidation theories.

[0121] The measurement and control system (i.e., the host computer software and the industrial computer running it) serves as the core of the entire consolidation apparatus system for control and data processing. It establishes bidirectional communication connections with the servo controller of the axial loading system, the hydraulic control device (pressure / volume controller), and the data acquisition system via industrial buses (such as RS485, EtherCAT) or other standard communication interfaces, forming a centralized control and data network.

[0122] In terms of data reception and processing, the measurement and control system receives and processes data from various hardware subsystems in real time: including pore water pressure signals from each earth pressure cell and displacement sensor signals synchronously uploaded by the data acquisition system; real-time axial load values ​​fed back by the axial loading system; and back pressure values ​​and volume changes fed back by the water pressure control device. All received data is displayed graphically in real time in the control software interface (such as load-time curves, pore pressure-time curves, and settlement-time curves), and is synchronously stored in the computer's storage device to form a structured test database, supporting post-test query, export, and analysis.

[0123] Regarding control command issuance, the measurement and control system sends control commands to various hardware subsystems based on preset test procedures or real-time instructions from operators: it issues pressure setpoints, loading rates, and start / stop commands to the servo controller of the axial loading system; it issues back pressure setpoints and control mode commands to the water pressure control device; and it issues sampling start / stop and sampling frequency settings to the data acquisition system. By executing these commands, the system automatically completes the entire test process from loading and back pressure adjustment to data acquisition. Simultaneously, the measurement and control system is equipped with a graphical human-machine interface. Operators can use this interface to monitor all sensor data and equipment status in real time, and, when necessary, interrupt the automatic program to manually adjust loading pressure, back pressure values, sampling parameters, etc., or directly control equipment actions. All operating commands, parameter modifications, and system status are recorded and stored along with the acquired test data, ensuring the entire consolidation test process is complete and traceable.

[0124] The system and method described in this embodiment achieve synchronous monitoring of spatial differences in pore water pressure during consolidation by implementing a multi-dimensional distributed earth pressure cell layout inside the sample. The pre-programmed automatic step-by-step loading system significantly improves the efficiency and consistency of load application. An integrated data acquisition and measurement control system enables synchronous acquisition, real-time display, and complete recording of multi-source monitoring data. Operators can make timely judgments on the consolidation state based on the real-time curves provided by the system, considering both the pore water pressure dissipation trend and the settlement deformation rate. This system integrates loading control, data acquisition, and process monitoring into a unified software platform, significantly improving the standardization and process controllability of consolidation tests while ensuring experimental quality. The acquired high-quality, complete spatiotemporal data provides a powerful experimental tool for in-depth research on soil consolidation characteristics, determination of key geotechnical parameters, and verification and development of consolidation theories (such as the continuous drainage boundary theory).

[0125] Example 3

[0126] The automatic pressurized soil consolidation method with multi-dimensional pore pressure monitoring is characterized by comprising a consolidation pressure chamber, an axial loading system, a water pressure control system, a multi-channel data acquisition system, and a measurement and control system.

[0127] The consolidation pressure chamber is used to contain soil samples. It is equipped with drainage channels and control valves at the top and bottom, respectively, and multiple sealed interfaces for threading sensor wires through the side walls.

[0128] The axial loading system includes a servo motor-driven lifting mechanism and a pressure head, used to apply multi-level gradient axial pressure to the soil sample in the consolidation pressure chamber.

[0129] The water pressure control system uses a pressure / volume controller, which is connected to the drainage channel of the consolidation pressure chamber through a pipeline, and is used to realize back pressure control, boundary pore pressure monitoring and drainage volume measurement.

[0130] The multi-channel data acquisition system includes multiple earth pressure cells, displacement sensors, and a multi-channel data acquisition instrument, all buried at different monitoring points inside the soil sample. The earth pressure cells and displacement sensors are connected to the data acquisition instrument via lead wires from the sealed interface of the consolidation pressure chamber, for the synchronous acquisition of pore water pressure signals and vertical displacement signals.

[0131] The measurement and control system is communicatively connected to the multi-channel data acquisition system, the axial loading system, and the water pressure control system, respectively. The measurement and control system is used to: execute a preset test program, control the axial loading system to automatically pressurize according to a multi-level gradient, and control the water pressure control system to adjust the back pressure; receive, process, and store pore water pressure and settlement data from the data acquisition system; and, based on the data and in conjunction with the continuous drainage boundary theory, determine the consolidation state and automatically control the loading process according to the determination result.

[0132] This embodiment details the specific hardware configuration of an automatic pressurized soil consolidation device capable of monitoring pore pressure space. The consolidation pressure chamber provides a stable and sealed testing environment for large soil samples; the servo motor-driven axial loading system enables high-precision, programmed multi-stage pressure application; the pressure / volume control device ensures precise control of back pressure and high-resolution measurement of volume changes; and the distributed earth pressure cells and high-precision displacement sensors enable direct sensing of key parameters in the consolidation process. The collaborative operation of the data acquisition system and the measurement and control system (industrial computer and host computer software) enables synchronous acquisition, real-time display, continuous storage, and centralized control of multi-channel data. This hardware system provides a stable and reliable physical carrier for the consolidation method. Its automated and integrated design effectively overcomes the shortcomings of traditional lever-type consolidation apparatuses, such as cumbersome operation, low efficiency, and asynchronous data, ensuring efficient and controllable testing processes and laying a solid foundation for obtaining high-quality test data suitable for in-depth analysis.

[0133] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter changes made to these embodiments within the spirit and principles of the present invention, without departing from the principles and spirit of the present invention, through conventional substitutions or to achieve the same function, fall within the scope of protection of the present invention.

Claims

1. An automatic pressurized soil consolidation method based on multi-dimensional pore pressure monitoring, characterized in that, include: Select soil samples to be consolidated, and simultaneously collect pore water pressure data at different depths and horizontal positions inside the soil samples by using multiple earth pressure cells arranged on the same plane and in the same vertical direction. Based on the preset consolidation target pressure of the soil sample, it is divided into multiple gradient pressures. Through the preset program of the measurement and control system, the lifting mechanism is automatically controlled to pressurize the soil sample step by step. Under each pressure level, the pore water pressure data measured by the earth pressure cell and the settlement deformation data measured by the displacement sensor are collected and recorded in real time. Combined with the continuous drainage boundary theory, the consolidation development state and boundary drainage characteristics under the pressure level are comprehensively evaluated. The first-level axial pressure is applied to the soil sample through the lifting mechanism, and the measurement and control system connected to each soil pressure cell and displacement sensor data synchronously and continuously collects the pore water pressure changes and vertical displacement data of the soil sample at each point inside the soil sample. Based on the collected pore water pressure data, the dissipation law of pore pressure at different depths in the same vertical direction and the difference in pore pressure dissipation at different points on the same plane are analyzed. Based on the continuous drainage boundary theory, the spatial distribution characteristics of pore pressure and the influence of boundary parameters during soil consolidation are studied. Observe and determine whether the pore water pressure data has been fully dissipated and tended to stabilize. At the same time, combine the settlement deformation rate recorded by the displacement sensor to determine whether it has slowed down significantly. Combine the interface parameter inversion results in the continuous drainage boundary theory to comprehensively determine whether the soil sample has reached the state of consolidation under the current pressure level and can be loaded at the next level. Under the current pressure level, once the soil sample is determined to be consolidated to the point where the next level of loading can be applied, the measurement and control system automatically controls the lifting mechanism to raise the axial pressure to the next level of load according to the preset program. This process is repeated step by step until all preset pressure levels have been applied. Once the final axial pressure is applied and the soil sample is determined to have largely consolidated under that pressure based on observations of pore water pressure and settlement data, consolidation is complete.

2. The automatic pressurized soil consolidation method with multi-dimensional pore pressure monitoring according to claim 1, characterized in that, The acquisition of pore water pressure data inside the soil sample is specifically as follows: soil pressure cells are buried in the soil sample in the soil sample holding device at preset positions; the sensor signals of the soil pressure cells are led out through the preset sealed interface of the consolidation pressure chamber wall and connected to the measurement and control system; the measurement and control system continuously collects and records the voltage or frequency signals output by each soil pressure cell at a set sampling frequency, which are proportional to the pore water pressure of the soil, thereby obtaining the real-time pore water pressure data sequence of each monitoring point.

3. The automatic pressurized soil consolidation method with multi-dimensional pore pressure monitoring according to claim 1, characterized in that, The setting of the multi-stage loading pressure is specifically as follows: based on the geotechnical test procedures or simulated engineering load conditions, a series of progressively increasing axial pressure values ​​are pre-set in the measurement and control system to form a multi-stage loading sequence. When conducting the test using continuous drainage boundary conditions, the dissipation law of the boundary pore water pressure follows the following theoretical expression. ,in p(t0) is the boundary pore pressure at time t; p(t0) is the initial boundary pore pressure after the loading increment ends at time t0. t0 is the current moment for discussing the boundary problem; b is the interface parameter reflecting the boundary drainage characteristics. The holding time of each pressure level in the experiment must ensure that sufficient pore pressure data reflecting the above dissipation law can be collected. The measurement and control system automatically executes step-by-step loading according to the preset pressure sequence and the time control logic based on the continuous drainage boundary theory.

4. The automatic pressurized soil consolidation method with multi-dimensional pore pressure monitoring according to claim 1 or 3, characterized in that, The pore water pressure data of each earth pressure cell is collected through the measurement and control system. The system synchronously records the output of each sensor at a constant sampling frequency through a multi-channel data acquisition instrument. The output is directly represented as the pore water pressure value after analog-to-digital conversion and calibration calculation within the system, forming a multi-channel synchronous raw observation dataset corresponding to a strict timestamp.

5. The automatic pressurized soil consolidation method based on multi-dimensional pore pressure monitoring according to claim 1, characterized in that, The analysis of the spatial distribution characteristics of pore water pressure within the soil is specifically as follows: Based on the pore water pressure data of each monitoring point over time, pore pressure dissipation curves at different depths in the same vertical direction and at different locations on the same horizontal plane are plotted and compared. This is used to qualitatively and semi-quantitatively assess the spatial non-uniformity of the consolidation process. For further quantitative analysis, a one-dimensional consolidation theory solution under continuous drainage boundary conditions can be introduced. This theoretical solution gives the distribution of excess pore water pressure u in the soil layer with depth z and time t under the control of interface parameters b and c as follows: In the formula, p is the applied load, H is the soil layer thickness, and C is the soil layer thickness. v is the consolidation coefficient of the soil. As a time factor, b represents the drainage capacity of the upper boundary, and c represents the drainage capacity of the lower boundary. By comparing the measured pore pressure-time data at different depths with the theoretical distribution, the applicability of the theoretical model is evaluated. Under known boundary conditions, the consolidation parameter C of the soil is obtained through inversion. v Alternatively, verify the values ​​of boundary parameters b and c.

6. The automatic pressurized soil consolidation method with multi-dimensional pore pressure monitoring according to claim 1, characterized in that, The analysis of the uniformity of pore pressure distribution at different depth sections using continuous drainage boundary parameters is as follows: Based on the continuous drainage boundary theory, the boundary drainage capacity is characterized by the upper boundary b and the lower boundary c. This parameter directly affects the pore pressure dissipation process. By comparing the measured pore pressure dissipation curves at different depth sections, the consolidation uniformity can be analyzed. If the upper and lower boundary parameters are asymmetrical (b≠c), the theoretical solution shows that the pore pressure is asymmetrically distributed along the depth, with different dissipation rates. By comparing the measured pore pressure-time data at different depth sections with the theoretical solution, the consistency between the spatial distribution uniformity predicted by the theoretical model and the actual observation can be evaluated, thereby reflecting the influence of boundary conditions or the soil itself on the spatial uniformity of consolidation.

7. The automatic pressurized soil consolidation method for pore pressure space monitoring according to claim 1 or 6, characterized in that, The assessment of soil consolidation state specifically involves: based on the continuous drainage boundary theory, evaluating consolidation progress by analyzing the dissipation law of measured pore water pressure at the drainage boundary over time; and comparing the measured pore pressure data u with the solution from the continuous drainage boundary theory. Fitting is performed, where b is the interface parameter to be inverted; when the pore pressure dissipation process conforms to the exponential decay trend described by the theoretical model, and the interface parameter b obtained by inversion through the least squares method tends to a stable value during the calculation period, and the settlement deformation rate of the soil sample has also slowed down significantly, it can be comprehensively determined that the consolidation of the soil sample under this pressure level has been basically completed.

8. The automatic pressurized soil consolidation method with multi-dimensional pore pressure monitoring according to claim 1, characterized in that, The determination of the completion of the consolidation test is as follows: after the last stage of axial pressure is applied and maintained for a sufficient time, a comprehensive judgment is made based on whether the pore water pressure-time curves at each major monitoring point tend to flatten and the dissipation rate is lower than a preset threshold, and whether the settlement deformation rate of the soil sample has dropped to a negligible level. When the above conditions are met simultaneously, it can be determined that the consolidation under that pressure level is basically completed.

9. An automatic pressure-based soil consolidation method based on multi-dimensional pore pressure monitoring, applicable to any of the automatic pressure-based soil consolidation methods based on continuous drainage boundary theory according to claims 1-8, characterized in that, It includes a consolidation pressure chamber, an axial loading system, a hydraulic control system, a multi-channel data acquisition system, and a measurement and control system; The consolidation pressure chamber is used to contain soil samples. It is equipped with drainage channels and control valves at the top and bottom, respectively, and multiple sealed interfaces for threading sensor wires through the side walls. The axial loading system includes a servo motor-driven lifting mechanism and a pressure head, used to apply multi-level gradient axial pressure to the soil sample in the consolidation pressure chamber. The water pressure control system uses a pressure / volume controller, which is connected to the drainage channel of the consolidation pressure chamber through a pipeline, and is used to realize back pressure control, boundary pore pressure monitoring and drainage volume measurement. The multi-channel data acquisition system includes multiple earth pressure cells, displacement sensors, and a multi-channel data acquisition instrument, all buried at different monitoring points inside the soil sample. The earth pressure cells and displacement sensors are connected to the data acquisition instrument via lead wires from the sealed interface of the consolidation pressure chamber, for the synchronous acquisition of pore water pressure signals and vertical displacement signals. The measurement and control system is communicatively connected to the multi-channel data acquisition system, the axial loading system, and the water pressure control system, respectively. The measurement and control system is used to: execute a preset test program, control the axial loading system to automatically pressurize according to a multi-level gradient, control the water pressure control system to adjust the back pressure, and receive, process, and store pore water pressure and sedimentation data from the data acquisition system. Based on the data, the consolidation state is determined using the continuous drainage boundary theory, and the loading process is automatically controlled according to the determination result.

10. An automatic pressurized soil consolidation device for multi-dimensional pore pressure monitoring, characterized in that, The device is specifically: The consolidation pressure chamber is used to contain and seal the soil sample. The chamber wall is equipped with a sealed interface for passing sensor wires through it. Drainage control valves are provided at the top and bottom to achieve single / double-sided drainage control. The axial loading mechanism, driven by a servo motor or hydraulic jack, applies axial load by contacting the upper surface of the soil sample in the consolidation pressure chamber through a rigid pressure head. The water pressure control device uses a high-precision pressure / volume controller, which is connected to the drainage channel of the consolidation pressure chamber through a pipeline. It is used to apply and adjust the back pressure and accurately measure the drainage volume. The pore water pressure monitoring component consists of multiple earth pressure cells, which are embedded in different locations inside the soil sample according to the design. The signal lines are led out through the sealed interface of the consolidation pressure chamber. Displacement sensors, mounted on the indenter or fixed frame of the axial loading mechanism, are used to measure the vertical deformation of soil samples. The data acquisition unit includes a multi-channel data acquisition instrument, whose input end is connected to the earth pressure cell, displacement sensor, load sensor of axial loading mechanism and water pressure control device, for multi-channel synchronous acquisition and analog-to-digital conversion of various analog signals; The measurement and control system consists of an industrial computer and dedicated control software running on it. The industrial computer is communicatively connected to the data acquisition unit, the servo controller of the axial loading mechanism, and the water pressure control device. The control software is used to execute a preset test program, which is set based on the continuous drainage boundary theory. The test program includes: controlling the axial loading mechanism to apply pressure according to a set gradient, controlling the water pressure control device to adjust the back pressure, synchronously acquiring and storing all monitoring data at a constant sampling frequency, performing real-time determination of the consolidation state and automatic control of the loading process based on the acquired pore water pressure and settlement data and in combination with the continuous drainage boundary theory, and providing a human-machine interface to display and monitor the test process in real time.

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