Layered soft soil thermal drainage consolidation test method considering interface contact thermal resistance effect

Abstract

The invention provides a layered soft soil thermal drainage consolidation test method considering an interface contact thermal resistance effect, which comprises the following steps: S11, filling layered soft soil into a soil sample box according to a design thickness layer by layer, laying a heat conduction film between layers, and connecting a heat flow meter; s12, applying a preset pressure to compact the soil body, starting the heating base, raising the temperature according to a set gradient, and synchronously monitoring the thermal resistance of each layer; s13, when the temperature reaches a set value, a vacuum pump is started to maintain the preset vacuum degree, the heating power is automatically adjusted through a control algorithm based on the real-time heat flow data, and the interface thermal resistance change is compensated; s14, synchronously acquiring temperature, pressure, vacuum degree and displacement data, and establishing a heat-water-force coupling model to invert interface thermal resistance parameters; and S2, based on the interface thermal resistance parameters obtained in S1, executing a thermal drainage consolidation test stage. The problems that in the prior art, due to the fact that the interface contact thermal resistance effect is not fully considered, heat conduction efficiency evaluation is deviated, and consolidation process prediction is inaccurate are solved.

Description

Technical Field

[0001] The invention relates to a thermal drainage consolidation test method for layered soft soil, in particular to a thermal drainage consolidation test method for layered soft soil taking into account the interface contact thermal resistance effect, and belongs to the technical field of geotechnical testing. Background Art

[0002] In the field of soft soil foundation treatment, thermal drainage consolidation is a highly effective reinforcement technology that accelerates soil consolidation by combining multiple fields such as temperature, pressure, and vacuum. Existing technologies have developed test devices that can automatically control temperature, pressure load, and vacuum. These devices achieve multi-parameter monitoring through pre-embedded pore water pressure sensors and drainage mechanisms, providing important support for theoretical research on soft soil reinforcement. However, such devices have significant flaws when simulating actual projects: they fail to fully consider the contact thermal resistance effects within the soil and between the soil and the structure, resulting in deviations in the evaluation of heat conduction efficiency, which in turn affects the accurate prediction of the consolidation process.

[0003] Interfacial contact thermal resistance is a key factor that restricts thermal conduction efficiency. Existing studies have shown that the interfacial thermal resistance of saturated soft soil will change due to water migration during the heating process, and traditional test equipment has not designed a compensation mechanism for this phenomenon, resulting in a large error between the thermal resistance measurement results and the actual working conditions. In addition, the interfacial thermal resistance characteristics of layered soil require a high-precision temperature control device to achieve stable heating, but existing equipment is only for single thermal resistance measurement and cannot meet the dynamic thermal resistance monitoring needs under multi-field coupling conditions. The current thermal drainage consolidation method has the following defects: 1. A dynamic compensation mechanism for interfacial contact thermal resistance has not been established, resulting in distorted thermal conduction efficiency evaluation; 2. There is a lack of collaborative monitoring capabilities for thermal-hydraulic-mechanical parameters under multi-field coupling conditions; 3. Existing thermal resistance measurement devices cannot be directly embedded in multi-factor joint test systems. Summary of the Invention

[0004] Based on the above background, the purpose of the present invention is to provide a thermal drainage consolidation test method for layered soft soil taking into account the interface contact thermal resistance effect, so as to solve the problem that the prior art does not fully consider the interface contact thermal resistance effect, resulting in deviations in the evaluation of thermal conduction efficiency and inaccurate predictions of the consolidation process.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect comprises the following steps:

[0007] S1, measuring the interface contact thermal resistance stage, including:

[0008] S11. Fill the soil sample box with layered soft soil according to the designed thickness, lay thermal conductive film between the layers and connect a heat flow meter;

[0009] S12, applying a predetermined pressure to compact the soil, starting the heating base to increase the temperature according to the set gradient and simultaneously monitoring the thermal resistance of each layer;

[0010] S13. When the temperature reaches the set value, the vacuum pump is turned on to maintain the predetermined vacuum degree, and the heating power is automatically adjusted through the control algorithm based on the real-time heat flow data to compensate for the change in interface thermal resistance;

[0011] S14, synchronously collect temperature, pressure, vacuum and displacement data, establish a thermal-hydraulic-mechanical coupling model to invert the interface thermal resistance parameters;

[0012] S2. Based on the interface thermal resistance parameters obtained in S1, perform the thermal drainage consolidation test phase, including:

[0013] S21. Cut the original soft soil into layered samples according to the actual layering ratio of the project, and bury micro heat flow meters and temperature sensors at the contact surfaces of adjacent soil layers;

[0014] S22. Fill the soil sample box in layers, using compaction equipment after each layer to ensure uniform contact between layers;

[0015] S23. Arrange pore water pressure sensors and vacuum sensors at different soil depths and calibrate the heating system to ensure that the temperature field uniformity error is ≤±0.5°C;

[0016] S24, inputting the interface thermal resistance parameters obtained in step S1 into the dynamic thermal resistance compensation module, setting the heating temperature gradient, vacuum degree and vertical stress, and setting the contact thermal resistance threshold;

[0017] S25. Start the heating system, maintain the target temperature field, apply vacuum load and mechanical load synchronously, and collect interface heat flow data, pore water pressure changes and soil deformation in real time.

[0018] Preferably, in step S12, the predetermined pressure is 50-100 kPa and lasts for 20-24 hours; and the gradient heating rate is set to 1-5°C / min.

[0019] Preferably, in step S13, the predetermined vacuum degree is -70 kPa to -90 kPa.

[0020] Preferably, in step S13, the control algorithm is a fuzzy control algorithm, and dynamic compensation of interface thermal resistance is achieved through the following steps:

[0021] Establish a fuzzy rule base for heat flow change rate, temperature gradient, and pore water pressure;

[0022] Collect interface heat flow values in real time and calculate their deviation from theoretical values;

[0023] Automatically adjust the heating power output according to the deviation size.

[0024] Preferably, in step S14, establishing a thermal-hydraulic-mechanical coupling model to invert interface thermal resistance parameters includes the following steps:

[0025] Based on the finite element method, a multi-physics field control equation group including heat conduction, water pressure transmission and mechanical deformation is established;

[0026] The measured temperature field, pore water pressure and deformation are used as boundary conditions;

[0027] The equivalent thermal resistance coefficient of each interface is obtained through inverse analysis.

[0028] Preferably, in step S21, the thickness of each layer of the layered sample is 5-10 cm.

[0029] Preferably, in step S24, the contact thermal resistance threshold is determined by the following method:

[0030] Conduct preliminary tests on the interface thermal resistance of similar soils under different moisture content and density conditions;

[0031] Establish the relationship curve between moisture content, density and thermal resistivity;

[0032] According to the actual engineering soil parameters, the corresponding thermal resistance reference value is obtained from the relationship curve as the threshold.

[0033] Preferably, in step S24, the heating temperature gradient is 15-50°C, the vacuum degree is -80 kPa to -100 kPa, and the vertical stress is 50-300 kPa.

[0034] Preferably, in step S25, the rate of applying the mechanical load is controlled to be 0.2-1.0 kPa / min.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] The present invention proposes a thermal drainage consolidation test method for layered soft soil that takes into account the interfacial contact thermal resistance effect. This method integrates multi-parameter monitoring, including temperature, pressure, vacuum, and pore water pressure, to simultaneously acquire dynamic variation data of thermal, hydraulic, and mechanical parameters under multi-field coupling conditions. By establishing a multi-parameter coupling database and comprehensively analyzing this data, relationship curves, maps, and response surfaces that comprehensively reflect the consolidation process of layered soft soil can be drawn, providing rich and accurate data support for in-depth research on soft soil reinforcement theory.

[0037] The dynamic compensation mechanism for interfacial thermal resistance of the present invention effectively solves the problem of thermal conduction efficiency evaluation deviation caused by interfacial thermal resistance changes by monitoring heat flow changes in real time and automatically adjusting heating power. This makes the results of thermal drainage consolidation tests more accurate and accurate than actual engineering conditions, significantly improving the accuracy and reliability of the tests.

[0038] The present invention first measures the interface contact thermal resistance and then applies the measured thermal resistance parameters to the subsequent thermal drainage consolidation test. It can accurately grasp the impact of the interface thermal resistance on the heat conduction efficiency and improve the accuracy of the test through a dynamic compensation mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0040] Figure 1 It is a schematic structural diagram of the test device used in the present invention;

[0041] In the figure: 1. Device console; 2. Operation display screen; 3. Knob; 4. Power supply; 5. Relay; 6. Heating base; 7. Bottom of test chamber; 8. Temperature controller; 9. Soil sample box; 10. Heating tube. DETAILED DESCRIPTION

[0042] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any form of modification and / or change made to the present invention will fall within the scope of protection of the present invention.

[0043] In the present invention, unless otherwise specified, all parts and percentages are by weight. The equipment and raw materials used are commercially available or commonly used in the art. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art. The components or equipment in the following embodiments, unless otherwise specified, are all universal standard parts or components known to those skilled in the art. Their structures and principles are known to those skilled in the art through technical manuals or routine experimental methods.

[0044] The following detailed description of the embodiments of the present invention is made in conjunction with the accompanying drawings. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, one or more embodiments may be implemented by those skilled in the art without these specific details.

[0045] An embodiment of the present invention discloses a thermal drainage consolidation test method for layered soft soil that takes into account the interface contact thermal resistance effect. This method first measures the interface contact thermal resistance and then applies the measured thermal resistance parameters to the thermal drainage consolidation test, thereby achieving accurate consideration of the interface thermal resistance effect and improving the accuracy and reliability of the test results.

[0046] The test device used in the present invention includes a multi-field coupling control unit, a thermal resistance compensation test chamber and a dynamic thermal resistance monitoring system. Figure 1 shown.

[0047] The multi-field coupling control unit includes a device console (1), an integrated operation display (2), a knob (3), and a power supply (4), which realizes independent control of temperature (adjustable from 0 to 200°C), pressure (0 to 500 kPa), and vacuum (-100 kPa to normal pressure). The temperature controller (8) adopts a PID algorithm with an accuracy of ±0.1°C and supports multi-channel synchronous temperature control. A relay (5) is provided inside the multi-field coupling control unit for converting different control signals.

[0048] The thermal resistance compensation test chamber includes a layered soil sample box (9) and a heating base (6). The layered soil sample box (9) is made of transparent organic glass with a wall thickness of 8-10mm and has good compressive resistance and thermal stability. The inner wall of the soil sample box is treated with a special coating to reduce friction with the soil and improve heat conduction efficiency. The layered soil sample box (9) is composed of 3-5 layers of detachable units, and a high-precision connection structure is used between the units to ensure that the verticality error after assembly is ≤0.1°. A flexible thermal conductive film (thickness 0.1-0.3mm) is set between the layers, and a micro thermocouple (accuracy ±0.2℃) is integrated in the film. The heating base (6) has a built-in spiral heating tube (10), which adopts a double helix structure to achieve rapid heating and cooling of ±5℃ / min, and a heating uniformity of ≥98%. A drainage channel is set at the bottom (7) of the thermal resistance compensation test chamber, equipped with an electromagnetic flowmeter (accuracy ±0.5%FS) and a pressure sensor (accuracy ±0.1%FS). The drainage channel adopts a porous plate design with a pore size of 0.5-1.0mm and a coverage rate of about 40%, ensuring uniform drainage.

[0049] In the dynamic thermal resistance monitoring system, a heat flow meter (range 0-200W / m 2 , accuracy ±3%), used to monitor heat flux changes in real time. The dynamic thermal resistance monitoring system uses distributed fiber optic temperature measurement technology, with temperature measurement points arranged along the height of the soil sample (with 5mm spacing) to achieve three-dimensional temperature field reconstruction.

[0050] The test device is assembled as follows.

[0051] Each layer unit of the layered soil sample box (9) is vertically spliced according to the designed number of layers (3-5 layers), a flexible thermal conductive film (thickness 0.2 mm) is embedded between the layers, and a micro thermocouple (±0.2°C) in the film is connected to a dynamic thermal resistance monitoring system through a wire;

[0052] Apply thermal conductive silicone grease (thickness ≤ 0.1 mm) on the surface of the spiral heating tube (10) of the heating base (6), and fix the soil sample box (9) on the heating base (6) to ensure that the contact area is ≥ 95%;

[0053] The drainage channel at the bottom of the test chamber (7) is connected to an electromagnetic flow meter (accuracy ±0.5% FS) and a pressure sensor (accuracy ±0.1% FS), and is connected to an external vacuum pump through a silicone tube;

[0054] A distributed optical fiber temperature measurement array (5 mm spacing) is vertically buried along the height direction of the soil sample box (9), and the end of the optical fiber is connected to the temperature controller (8);

[0055] The signals of each sensor are connected to the device console (1) via a shielded cable and are transmitted to the data acquisition terminal via an analog-to-digital conversion module (with a precision of 16 bits).

[0056] To ensure structural stability, stainless steel fasteners are used, with a torque limit of 3-5 N·m. All contact surfaces must be cleaned to ensure there are no dust or impurities that could affect heat transfer performance. Signal cables use twisted-pair shielded cables to reduce external electromagnetic interference. Each sensor is calibrated using a standard calibrator to ensure system measurement accuracy.

[0057] After assembly, key components need to be debugged.

[0058] Heating system calibration: start the spiral heating tube (10), heat it to 100°C at a rate of 5°C / min, and use an infrared thermal imager to detect heating uniformity (deviation ≤±2°C); detect thermal response time, the time from room temperature to the set temperature should be controlled within 5 minutes; conduct a thermal stability test, maintain it at the set temperature for 2 hours, and the temperature fluctuation should be ≤±0.5°C.

[0059] Vacuum system sealing test: Close the drainage channel, start the vacuum pump to -100kPa, and maintain a pressure drop of ≤1kPa for 30 minutes; check whether there are any leaks at each connection, and replace the sealing ring or strengthen the sealing treatment if necessary; use an ultrasonic leak detector for detailed testing to ensure that the system is completely sealed.

[0060] Sensor calibration: Use a standard thermocouple (accuracy ±0.1°C) and a pressure calibrator (accuracy ±0.05% FS) to perform three-point linear calibration on each monitoring module; complete thermocouple consistency testing to ensure that the temperature deviation between each measuring point is ≤±0.2°C; perform pressure sensor response time testing, and the response time should be ≤0.5 seconds.

[0061] Data acquisition system test: Perform analog signal input test to verify the linearity and stability of the system; test the system's anti-interference ability, and the signal fluctuation should be ≤±1% under external electromagnetic interference conditions; perform data transmission rate test to ensure that it meets the requirements of high-frequency data acquisition.

[0062] The test method implementation steps are as follows.

[0063] S11. Collect undisturbed samples from the site, seal them, and transport them to the laboratory. After unsealing, use a soil cutter to create specimens with a diameter of 61.8 mm and a height of 125 mm. Two specimens are required for each thermal resistivity measurement test. Immediately after removing the specimens, measure and record basic physical properties such as moisture content and density. Fill the soil sample box with layered soft soil according to the designed thickness. Lay a thermal conductive film between the layers and connect a heat flux meter.

[0064] The thermal film is made of highly conductive silicone material with a thermal conductivity coefficient of ≥1.5W / (m·K) and a thickness uniformity error of ≤5%. Ensure full contact between the heat flow meter and the soil layer during installation. Use thermal adhesive to secure the heat flow meter if necessary. After installation, test the signal output of each sensor to ensure proper operation of the data acquisition system.

[0065] S12. Apply a predetermined pressure of 50-100 kPa for 20-24 hours to compact the soil. The pressure should be applied in stages, increasing by 10-20 kPa each time, with each stage lasting at least 30 minutes to ensure uniform compression of the soil. During the compaction process, record the change in soil height and calculate the compression ratio.

[0066] S13. Start the heating base and increase the temperature at a set gradient of 1-5°C / min (recommended rate 2°C / min), while simultaneously monitoring the thermal resistance of each layer. Temperature control uses a PID algorithm with parameters set to P = 5.0, I = 0.5, and D = 0.1 to ensure a smooth temperature rise without overshoot. When the temperature reaches the set value (usually 60°C), start the vacuum pump and maintain the vacuum between -70kPa and -90kPa.

[0067] Based on real-time heat flow data, a fuzzy control algorithm automatically adjusts heating power to compensate for changes in interface thermal resistance. This algorithm uses a triangular membership function, with the input variables being the heat flow deviation and the rate of change of the deviation, and the output variable being the heating power adjustment. The rule base contains 25 fuzzy rules covering various thermal resistance variations. The controller's response time is ≤ 1 second, ensuring real-time compensation for thermal resistance changes.

[0068] S14. Simultaneously collects temperature (once per second), pressure (five times per second), vacuum (twice per second), and displacement (once per second) data. Data is stored in binary format and automatically backed up hourly. The system features a real-time monitoring interface that displays trend and distribution graphs of key parameters.

[0069] Finite element software (such as COMSOL) was used to establish a coupled thermal-hydraulic-mechanical model and inversely estimate the interfacial thermal resistance parameters. The model employed a three-dimensional unsteady-state heat conduction equation, accounting for the effects of moisture migration on heat conduction. Adaptive meshing was used, with localized meshing performed in the interface region, using a cell size of 0.5-1.0 mm. Boundary conditions were set to the measured temperature and pressure values, and the initial conditions were the temperature and pressure fields at the start of the experiment.

[0070] The equivalent thermal resistance coefficient of each interface is obtained by reverse analysis. The thermal resistance coefficient R is calculated as follows: R = ΔT / q, where R is the thermal resistance coefficient, unit is m 2 K / W; ΔT is the temperature difference across the interface, in K; q is the heat flux through the interface, in W / m 2 .

[0071] The calculated results were statistically analyzed, including mean, standard deviation, and coefficient of variation, to assess the stability and reliability of the thermal resistance parameters. Furthermore, the correlation between the thermal resistance parameters and factors such as soil moisture content, density, and temperature was analyzed, and a multivariate regression model was established.

[0072] S21. Cut the original soft soil into layered specimens according to the actual project layering ratio, with each layer being 5-10 cm thick. When cutting the specimens, keep the cutting tool sharp and the cut surface smooth to avoid disturbing the soil structure. Measure and record basic physical parameters such as initial moisture content, density, and liquid / plastic limit for each layer.

[0073] A micro heat flow meter (accuracy ±0.5W / m 2 ) and a temperature sensor (accuracy ±0.1°C). The sensor should be buried away from possible dominant flow paths to ensure representative measurements. The sensor wires should be led out horizontally to avoid forming vertical channels that affect water flow and heat conduction.

[0074] S22. Fill the soil into the organic glass soil sample box (9) in layers. After each layer is filled, use a pneumatic compactor (pressure 0.1-0.3MPa) to ensure uniform contact between layers. The compaction time is controlled within 1-2 minutes, and the compaction force is evenly distributed. After each layer is filled, the surface flatness needs to be checked to ensure good contact with the next layer.

[0075] S23. Place pore-water pressure sensors (accuracy ±0.1 kPa) and vacuum sensors (accuracy ±0.05 kPa) at different soil depths. Sensor placement should take into account soil structural characteristics. Key locations include the center of each soil layer, near soil interfaces, and at drainage boundaries. Sensor spacing should generally be 2-5 cm to ensure complete pressure distribution data.

[0076] The heating tube (10) is gradient calibrated by the temperature controller (8) to ensure that the temperature field uniformity error is ≤±0.5°C. The calibration process includes three steps: no-load heating test, standard medium addition test and actual soil sample test, which comprehensively evaluates the temperature control performance of the system.

[0077] S24. Input the interface thermal resistance parameters obtained in step S1 into the dynamic thermal resistance compensation module, set the heating temperature gradient (adjustable from 15 to 50°C), vacuum degree (-80 kPa to -100 kPa) and vertical stress (50 to 300 kPa), and set the contact thermal resistance threshold.

[0078] The contact thermal resistance threshold is determined by the following method: First, the contact thermal resistance is determined by different water content (20%-60%), density (1.5-1.9g / cm 3 ) conditions, and record the thermal resistance coefficient under each condition. Then, a relationship curve between moisture content, density and thermal resistance coefficient is established using a polynomial fitting method. Finally, based on the actual engineering soil parameters, the corresponding thermal resistance reference value is obtained from the relationship curve as the threshold.

[0079] The thermal resistance compensation module utilizes a real-time closed-loop control strategy consisting of feedforward compensation and feedback correction. Feedforward compensation, based on a thermal resistance prediction model, pre-adjusts heating power according to current soil conditions. Feedback correction dynamically fine-tunes heating power based on the deviation between measured and ideal heat flux. Compensation accuracy reaches ±5%, with a response time of ≤2 seconds.

[0080] S25. Start the heating system and maintain the target temperature field (control accuracy ±0.2°C) using the PID algorithm. Simultaneously apply vacuum load and graded mechanical load at a rate of 0.2-1.0 kPa / min (0.5 kPa / min recommended). Load application follows the principle of graded loading, maintaining each level until deformation stabilizes (deformation rate ≤ 0.005 mm / h) before moving on to the next level.

[0081] Real-time data collection is used to collect interface heat flow data, pore water pressure changes, and soil deformation. The acquisition frequency is dynamically adjusted according to the test phase: high-frequency acquisition (5-10Hz) is used during the initial loading phase, and reduced to 1-2Hz during the stabilization phase to balance data volume and information integrity. Collected data includes: temperature field distribution at each interface, heat flux density, pore water pressure, drainage, soil deformation, etc.

[0082] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect, characterized by: The method comprises the following steps: S1, measuring the interface contact thermal resistance stage, including: S11. Fill the soil sample box with layered soft soil according to the designed thickness, lay thermal conductive film between the layers and connect a heat flow meter; S12, applying a predetermined pressure to compact the soil, starting the heating base to increase the temperature according to the set gradient and simultaneously monitoring the thermal resistance of each layer; S13. When the temperature reaches the set value, the vacuum pump is turned on to maintain the predetermined vacuum degree, and the heating power is automatically adjusted through the control algorithm based on the real-time heat flow data to compensate for the change in interface thermal resistance; S14, synchronously collect temperature, pressure, vacuum and displacement data, establish a thermal-hydraulic-mechanical coupling model to invert the interface thermal resistance parameters; S2. Based on the interface thermal resistance parameters obtained in S1, perform the thermal drainage consolidation test phase, including: S21. Cut the original soft soil into layered samples according to the actual layering ratio of the project, and bury micro heat flow meters and temperature sensors at the contact surfaces of adjacent soil layers; S22. Fill the soil sample box in layers, using compaction equipment after each layer to ensure uniform contact between layers; S23. Arrange pore water pressure sensors and vacuum sensors at different soil depths and calibrate the heating system to ensure that the temperature field uniformity error is ≤±0.5°C; S24, inputting the interface thermal resistance parameters obtained in step S1 into the dynamic thermal resistance compensation module, setting the heating temperature gradient, vacuum degree and vertical stress, and setting the contact thermal resistance threshold; S25. Start the heating system, maintain the target temperature field, apply vacuum load and mechanical load synchronously, and collect interface heat flow data, pore water pressure changes and soil deformation in real time.

2. The thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect according to claim 1 is characterized by: In step S12, the predetermined pressure is 50-100 kPa and lasts for 20-24 hours; and the gradient temperature increase rate is set to 1-5°C / min.

3. The thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect according to claim 1 is characterized by: In step S13, the predetermined vacuum degree is -70 kPa to -90 kPa.

4. The thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect according to claim 1 is characterized by: In step S13, the control algorithm is a fuzzy control algorithm, and dynamic compensation of interface thermal resistance is achieved through the following steps: establishing a fuzzy rule base of heat flow change rate, temperature gradient, and pore water pressure; Collect interface heat flow values in real time and calculate their deviation from theoretical values; Automatically adjust the heating power output according to the deviation size.

5. The thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect according to claim 1 is characterized by: In step S14, establishing a thermal-hydraulic-mechanical coupling model to invert interface thermal resistance parameters includes the following steps: Based on the finite element method, a multi-physics field control equation group including heat conduction, water pressure transmission and mechanical deformation is established; The measured temperature field, pore water pressure and deformation are used as boundary conditions; The equivalent thermal resistance coefficient of each interface is obtained through inverse analysis.

6. The thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect according to claim 1 is characterized by: In step S21, the thickness of each layer of the layered sample is 5-10 cm.

7. The thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect according to claim 1, characterized in that: In step S24, the contact thermal resistance threshold is determined by the following method: Conduct preliminary tests on the interface thermal resistance of similar soils under different moisture content and density conditions; Establish the relationship curve between moisture content, density and thermal resistivity; According to the actual engineering soil parameters, the corresponding thermal resistance reference value is obtained from the relationship curve as the threshold.

8. The thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect according to claim 1 is characterized by: In step S24, the heating temperature gradient is 15-50° C., the vacuum degree is -80 kPa to -100 kPa, and the vertical stress is 50-300 kPa.

9. The thermal drainage consolidation test method for layered soft soil considering the interfacial contact thermal resistance effect according to claim 1, characterized in that: In step S25, the rate of applying the mechanical load is controlled to be 0.2-1.0 kPa / min.

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