Humidity response type rock-soil body low-temperature internal circulation drying device and control method

Abstract

The invention discloses a humidity response type rock-soil body low-temperature internal circulation drying device and a control method, and belongs to the technical field of geotechnical engineering experiment equipment. The problems that traditional rock-soil body drying equipment is extensive in humidity control, high in energy consumption, inconvenient to maintain and obvious in temperature difference are solved, and accurate, energy-saving and efficient drying treatment of water-containing rock-soil samples is achieved. According to the invention, a plurality of groups of regulation and control modules are independently arranged, and differential humidity control of rock and soil samples with different water contents is realized through a high-precision humidity sensor and a speed-adjustable dehumidification fan; a closed-loop internal circulation design is adopted, and a heat recovery device is combined, so that introduction of external air is reduced, and energy consumption is reduced; a modular detachable structure is designed, so that parts such as a dehumidification module can be conveniently and quickly replaced, and the maintenance convenience is improved; a multi-heat-source auxiliary system is additionally arranged to eliminate heat dead angles in the box; the device is mainly used for efficient, accurate and environment-friendly drying treatment of rock and soil samples in geotechnical engineering experiments, the drying uniformity can be remarkably improved, the energy consumption and the maintenance cost are reduced, and the device has high applicability and practical value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geotechnical engineering test equipment, and particularly relates to a humidity response type geotechnological low-temperature internal circulation drying device and a control method. BACKGROUND

[0002] In the technical field of geotechnical engineering test equipment, the geotechnological drying box and the soft rock immersion monitoring device are two core devices supporting the research on the mechanical properties of geotechnological. The former is responsible for the pretreatment and drying of the water-containing geotechnological sample, and the latter focuses on the deformation and water absorption characteristics analysis of the soft rock after being immersed in water. The two devices together determine the accuracy of the whole process from sample preparation to property testing of the geotechnical engineering experiment. However, the current traditional equipment and existing related patent technologies still have significant technical limitations, and it is difficult to meet the experimental requirements of high precision, low energy consumption and wide adaptation. The specific problems are as follows: I. Inherent technical defects of traditional geotechnological drying box The traditional geotechnological drying box has a core architecture of "single heat source + unified air supply". It only realizes drying through heating elements such as resistance wires and forced convection of air fans. There is a lack of optimized design for sample humidity differences and energy utilization. The core problems are concentrated in the following four aspects: 1. Humidity control is extensive, and drying uniformity is poor The traditional equipment does not manage the humidity in the box by zones. All areas use fixed air supply intensity and humidity threshold, which cannot adapt to the needs of different water content samples. High water content samples (such as clay with water content > 30%) are slow to dry due to the saturated humidity of the environment, and are prone to mold growth and odor pollution of the laboratory. Low water content samples (such as sand with water content < 15%) are prone to structural collapse and decomposition of organic components due to excessive drying, which directly affects the accuracy of subsequent mechanical property testing. Moreover, most equipment can only set a wide humidity range, without real-time zonal monitoring and dynamic adjustment capability, further exacerbating the problem of uneven drying.

[0003] 2. Energy consumption is high, and energy utilization efficiency is low The traditional dehumidification system relies on electric heating regeneration, with a coefficient of performance (COP) of less than 1.5. Each start-up needs to be preheated to above 100℃ to activate the dehumidification function, and the preheating energy consumption accounts for more than 35% of the total power consumption. At the same time, due to the open-loop design, the hot and humid gas after drying is directly discharged, and external cold air needs to be continuously introduced and reheated, with a heat loss rate of more than 30%. In addition, the single heat source and unified air supply mode result in uneven heat distribution. In order to achieve overall drying effect, the heating elements and air fans need to be operated at high load for a long time, further causing energy waste.

[0004] 3. Maintenance and operation are complex, with high cost and difficulty The dehumidification modules (such as condensers and adsorbent tanks) are rigidly connected to the housing, requiring the entire front panel to be disassembled for replacement, and a single maintenance session can take several hours. When processing oily rock samples (such as oily sandstone), the oil and gas condense and adhere to the inner wall of the air duct, requiring monthly cleaning of the filter to prevent increased air resistance. Failure to maintain this in a timely manner can easily lead to a decline in equipment performance. Furthermore, the compact layout of internal components makes fault location difficult, and replacing vulnerable parts such as heating elements and fans requires disassembling surrounding components, which can easily cause secondary damage.

[0005] 4. Poor temperature uniformity, posing a risk of thermal dead zones and secondary moisture absorption. A single heat source (such as a single heating tube on the bottom or rear wall of the chamber) layout leads to uncontrolled temperature gradients inside the chamber: the temperature on the side of the door and the rear wall is 5–8°C lower than the central area due to the lack of auxiliary heat sources, forming a thermal dead zone, and the drying rate of samples at the edge is significantly lower than that of samples in the center; moisture condensation is prone to occur in low-temperature areas (such as the glass of the door), and the condensate dripping onto the sample surface can easily cause secondary moisture absorption, resulting in a deviation of sample moisture content exceeding ±4%, which seriously affects the reliability of experimental data.

[0006] II. Shortcomings and Limitations of Existing Related Patent Technologies While existing patented technologies have optimized certain functions to address the shortcomings of traditional equipment, they have not yet overcome the core technological pain points and suffer from issues such as limited adaptability to specific scenarios and insufficient functional synergy. For example, CN119803026A describes a low-temperature internal circulation drying oven for soil and rock and its usage method. While the "rotating material rack + internal circulation dehumidification" design improves heating uniformity and energy efficiency to some extent, it still has significant shortcomings: First, it does not achieve zoned humidity control, employing an overall dehumidification mode within the oven. This makes it impossible to adjust local humidity and airflow intensity for samples with different moisture contents, and over-drying or over-wetting problems still easily occur when high and low moisture content samples are mixed and dried. Second, the dehumidification module is not designed with an oil and gas treatment structure for oily rock samples. Oil and gas easily adhere to the inner wall of the dehumidification device (such as the condenser tube), requiring frequent disassembly and cleaning to avoid blockage, and maintenance convenience is not fundamentally improved. Third, the temperature compensation design is insufficient, relying only on the heating modules on the upper and lower sides of the inner wall and the heat equalization module. A 2-3℃ temperature difference still exists on the door side, and the problem of thermal dead zones is not completely solved.

[0007] For example, CN120314136A, a testing device and method for non-destructive immersion and multi-directional deformation monitoring of soft rock, focuses on non-destructive monitoring of soft rock after immersion. It achieves non-destructive immersion through atomized humidification and collects deformation data through multi-directional laser sensors. However, its function and application scenario are fundamentally different from those of a rock and soil drying oven, and it cannot make up for the technical defects in the drying process: First, the core objective of this device is "immersion monitoring" rather than "drying treatment". It lacks the heating and dehumidification internal circulation structure required for drying and cannot provide continuous pretreatment support for immersion experiments of dried samples. Second, although it has temperature and humidity control capabilities, it is only designed for the immersion environment. The humidity control range (such as 99% high humidity) does not match the low humidity environment required for drying, and it lacks zonal humidity control logic, which cannot adapt to the differentiated needs of multiple samples in the drying process.

[0008] Existing patented technologies either only optimize drying uniformity (such as CN119803026A) or only focus on water immersion monitoring (such as CN120314136A), failing to form a synergistic design of "drying pretreatment - water immersion monitoring". Furthermore, none of them solve core pain points such as oil and gas pollution during the drying of oil-bearing rock samples, high / low water content sample zoning control, and precise compensation for edge temperature differences. At the same time, the equipment cost and maintenance difficulty remain high (such as the rotating module of CN119803026A and the laser sensing system of CN120314136A, which both increase the complexity of the equipment and the risk of failure).

[0009] Current geotechnical engineering experiments have shifted their equipment requirements from "single drying / monitoring" to a comprehensive performance requirement of "precision, low energy consumption, wide adaptability, and easy maintenance": it is necessary to achieve differentiated drying of soil and rock samples with different moisture contents and different types (such as ordinary clay and oily sandstone), while ensuring the structural integrity and moisture content consistency of the dried samples; it is necessary to reduce energy consumption and maintenance costs, while providing high-quality samples for subsequent immersion monitoring and other experiments.

[0010] However, existing technologies, either due to failure to overcome core bottlenecks such as humidity zoning control and oil and gas processing, or due to limited functional adaptability, have consistently failed to meet the aforementioned needs. Therefore, developing a new type of soil and rock drying oven with five core functions—precise humidity zoning control, low-energy internal circulation, adaptation to oil-bearing rock samples, edge temperature difference compensation, and rapid maintenance—is crucial for solving the problems of low efficiency and poor data reliability in geotechnical engineering experiments, and is also a technical challenge that the industry urgently needs to overcome. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a humidity-responsive low-temperature internal circulation drying device for soil and rock and its control method, which solves the problems of crude humidity control, high energy consumption, inconvenient maintenance and obvious temperature difference of traditional soil and rock drying equipment, and realizes accurate, energy-saving and efficient drying of water-bearing soil and rock samples.

[0012] To achieve the above technical objectives, the present invention adopts the following technical solution: A humidity-responsive low-temperature internal circulation drying device for soil and rock, with a housing as its core load-bearing structure, integrates zoned humidity control, multi-directional heating, closed-loop circulation, and safety monitoring functions. The various components work together to achieve gradient humidity control and efficient drying. The specific structure is as follows: 1. Core Components and Overall Layout The device includes a housing, a zoned humidity control system, a heating system, a circulation system, and safety and monitoring components. The housing is physically divided into a lower high humidity zone, a middle medium humidity zone, and an upper low humidity zone by shelves. Each zone has a different number of air supply ducts and heating system components on its side walls, forming a basic structure of "zoned control and gradient adaptation". The circulation system is connected to the side of the housing to achieve closed-loop gas circulation. A pressure relief valve is installed at the top to ensure air pressure safety. The left side is hinged to the housing door, which integrates a temperature display, door lock, and observation window. A temperature sensor connected to the temperature display is installed inside the housing to provide real-time feedback on the internal temperature.

[0013] 2. Key Functional Module Structure The zoned humidity control system consists of humidity monitors for each humidity zone and a central controller. The humidity monitors extend into the center of each zone through plug-in connection interfaces on the side wall of the enclosure to collect humidity data in real time. The controller is electrically connected to the humidity monitors, air supply duct regulating valves, and heating system. It can adjust the air supply duct inlet speed (high humidity zone inlet speed > medium humidity zone inlet speed > low humidity zone inlet speed) and the number of heating elements activated in the corresponding zone based on the humidity data to achieve precise humidity control.

[0014] Heating system: The multi-directional layout eliminates temperature difference, including a first heating pipe (main heat source) covering most of the bottom area of ​​the box, a second heating pipe arranged vertically on the rear wall of the box, and a third heating pipe fixed to the front and rear ends of the right side wall of the box; the third heating pipe is a vertical cylindrical structure that forms an orthogonal spatial relationship with the horizontally arranged air supply pipe, and works with the airflow to achieve uniform temperature coverage and reduce the temperature difference at the edge.

[0015] Shelves: The core structure for partitioning and holding samples, including lower shelves, middle shelves and upper shelves; the lower shelf is welded to the lower part of the inner wall of the box, and the load-bearing plate has openings to accommodate high moisture content samples; the middle shelf is bolted to the side wall slide rails and can be pulled out laterally to adjust its position, used for samples with transitional moisture content; the upper shelf is detachably installed on the upper part of the box through slots, and has a grid structure to accommodate low moisture content samples.

[0016] The circulation system is a closed-loop internal circulation structure, including a main gas pipeline, several branch gas pipelines, and a detachable box. The main gas pipeline is connected to the housing, and one end of each branch gas pipeline is connected to the main gas pipeline, while the other end is connected to the detachable box. The detachable box contains a moisture-absorbing sponge regeneration module. This module is installed sequentially from the airflow direction, consisting of an adsorbent oil film, a filter screen, and a moisture-absorbing sponge. The moisture-absorbing sponge integrates a humidity sensor (connected to the controller). The adsorbent oil film is an activated carbon fiber layer (clamped inside the box), and the filter screen is a stainless steel mesh (fixed by spring clips). The two are spaced apart to achieve oil and gas adsorption and rock debris interception. After the moisture enters the module for processing through the branch gas pipelines, the dried gas returns to the housing through the main gas pipeline, forming a closed-loop circulation.

[0017] Safety and monitoring components: A pressure relief valve is located in the center of the top of the enclosure and is fixed with threaded fasteners. It automatically releases pressure when the air pressure inside the enclosure exceeds the set value. The enclosure door can open and close within a specific angle range. When closed, it is fixed to the lower right side of the enclosure by a door lock. A high-temperature resistant glass observation window is embedded in the middle of the enclosure door, and a temperature display is installed in the upper left corner (with wires passing through the door to connect to the temperature sensor inside the enclosure), which displays and monitors the temperature inside the enclosure in real time.

[0018] Based on a humidity-responsive low-temperature internal circulation drying device for soil and rock, this invention provides a humidity-responsive low-temperature internal circulation drying control method for soil and rock. Through steps such as layered placement, gradient humidity control, moisture absorption and regeneration, temperature difference compensation, and safety monitoring, efficient drying of soil and rock samples is achieved. The specific process is as follows: 1. Samples are placed in layers. Based on the differences in sample moisture content, the samples are placed in the following categories: high moisture content soil and rock samples are placed on the lower shelf in the high humidity zone at the bottom of the box; samples with moderate moisture content are placed on the middle shelf in the medium humidity zone at the middle; and low moisture content samples are placed on the upper shelf in the low humidity zone at the top. When placing the samples, ensure that they are evenly distributed on each shelf and that the samples are kept at a preset safe distance from the inner wall of the box and the heating pipes to avoid uneven heating in certain areas.

[0019] 2. Gradient humidity control start-up The controller receives real-time data from humidity monitors in each humidity zone and automatically executes a gradient control strategy. It adjusts the air intake speed of the air supply duct, the number of heating elements activated, and the temperature control range for different humidity zones. Through the coordination of "wind speed and heating", it avoids localized excessive dryness or humidity.

[0020] 3. Moisture absorption and regeneration cycle Moisture inside the chamber enters the removable box's moisture-absorbing sponge regeneration module via a gas distribution pipe, sequentially completing oil and gas adsorption, rock debris interception, and moisture absorption. Dry gas flows back to the chamber via the main gas pipe, achieving a closed-loop circulation. When the humidity sensor inside the moisture-absorbing sponge detects that its moisture content has reached a set threshold, the controller triggers an alarm. The operator then pulls out the removable box to replace the moisture-absorbing sponge, while simultaneously checking the condition of the adsorbed oil film and filter screen. If either of these exceeds the set range, they are replaced simultaneously to ensure circulation efficiency.

[0021] 4. Temperature difference compensation and safety monitoring Temperature difference compensation: The first heating element continuously operates to provide the main heat source, and the temperature sensor collects the temperature data of the central area of ​​the cabinet, the side of the door, and the side of the rear wall in real time and transmits it to the temperature display; when the temperature difference between the side of the door and the central area exceeds the set value, the controller starts the third heating element to heat until the temperature difference drops to the set range, ensuring that the temperature difference of the entire cabinet meets the requirements; Safety monitoring: The pressure relief valve monitors the air pressure inside the chamber in real time, and automatically releases pressure when the air pressure exceeds the set value; staff can visually confirm through the observation window that there is no condensation inside the chamber; humidity, temperature and energy consumption data of each area are recorded in real time during the drying process, and the moisture content of the sample is tested after drying to ensure that the moisture content control error meets the requirements.

[0022] The humidity-responsive low-temperature internal circulation drying device and control method for soil and rock provided by this invention have the following beneficial effects: 1. This invention effectively solves the problems of crude humidity control and poor drying uniformity in traditional drying ovens by dividing and independently controlling the humidity gradient in three zones, with a moisture content control error of ≤±2%, thus avoiding local over-humidity and local over-dryness.

[0023] 2. The closed-loop internal circulation system of the present invention reduces the external fresh air input requirement by 30%, the preheating-free moisture absorption and regeneration design reduces energy consumption by ≥20%, and the low-temperature internal circulation system and heat recovery device work together to improve the equipment's energy efficiency ratio (COP) to over 2.8. The overall energy consumption is reduced by 35% compared with traditional equipment, significantly reducing operating costs.

[0024] 3. The multi-directional heating and orthogonal airflow of this invention work together to reduce the edge temperature difference from the traditional ±5℃ to ±1℃. The multi-heat source auxiliary system reduces the temperature difference inside the chamber to ≤±2℃, eliminates thermal dead zones, ensures that all samples dry at a consistent rate, and improves the uniformity of thermal radiation.

[0025] 4. The detachable box and replaceable moisture-absorbing sponge design of this invention reduces the maintenance time by 50%, and the modular detachable structure reduces the dehumidification module replacement time from 2 hours to 15 minutes, without the need for professional tools, thus improving maintenance efficiency by 8 times.

[0026] 5. This invention, through a humidity zone control system, shortens the drying time of high-moisture samples by 40% and increases the structural integrity retention rate of low-moisture samples to over 95%, effectively solving the problem of sample contamination and damage caused by the crude humidity control in traditional drying ovens.

[0027] 6. This invention has wide applicability and can process various soil and rock samples such as high water content clay, low water content sand and oil-bearing sandstone, covering most geotechnical engineering test needs, demonstrating strong flexibility and practicality.

[0028] 7. The effectiveness of this invention has been verified through laboratory comparative tests. Under the same environmental conditions, the drying time for high moisture content clay samples is shortened by 12 hours compared with traditional equipment, and no mold growth is observed in the samples. When processing low moisture content sand samples, the decomposition rate of organic components is reduced from 15% of traditional equipment to below 3%.

[0029] 8. The moisture-absorbing sponge regeneration module design of the present invention makes sponge replacement simple and quick, without complicated operations, further improving the ease of use and maintenance efficiency of the equipment.

[0030] 9. The design of the filter screen and adsorbed oil film of the present invention extends the equipment life and reduces the number of repairs and replacements required due to equipment failure or performance degradation, thereby reducing long-term maintenance costs.

[0031] 10. This invention effectively recovers and utilizes the heat generated during the drying process through the synergistic effect of a closed-loop internal circulation system and a heat recovery device, thereby improving energy efficiency and reducing energy waste.

[0032] 11. The design of the multi-directional heating system and orthogonal airflow of the present invention makes the equipment more stable during operation and reduces equipment failure or performance degradation caused by temperature fluctuations or uneven airflow.

[0033] 12. The overall design of this invention takes into account the user's convenience and comfort. For example, the observation window allows users to visually monitor the situation inside the box, and the embedded temperature display allows users to know the temperature inside the box at any time, thus improving the user experience. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the external structure of the overall structure of the present invention; Figure 3 This is an assembly diagram of the overall structure of the present invention; Figure 4 This is a diagram showing the arrangement of the third heating element and the air supply pipe of the present invention; Figure 5 This is a schematic diagram of the structure of the moisture-absorbing sponge regeneration module of the present invention; In the diagram: 1. Cabinet body; 2. Heating system; 3. Temperature display; 4. Door lock; 5. Pressure relief valve; 6. Humidity monitor; 7. Shelf; 8. Air supply duct; 9. Circulation system; 10. Observation window; 11. Cabinet door; 21. First heating element; 22. Second heating element; 23. Third heating element; 71. Lower shelf; 72. Middle shelf; 73. Upper shelf; 91. Gas distribution pipe; 92. Removable box; 93. Sponge; 94. Main gas pipe; 95. Filter screen; 96. Oil film absorber. Detailed Implementation

[0035] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments: Example 1 like Figures 1 to 5 As shown, this embodiment provides a typical application of a humidity-responsive low-temperature internal circulation drying device for soil and rock. This embodiment takes the drying process of clay samples with high moisture content >30%, soil and rock samples with transitional moisture content of 15%~30%, and sand samples with low moisture content <15% as examples to explain in detail the structure and operation mode of the humidity-responsive low-temperature internal circulation drying device for soil and rock.

[0036] 1. Device structure: The cabinet 1 is divided into a lower high-humidity zone, a middle medium-humidity zone, and an upper low-humidity zone by shelves 7. The lower shelf 71 is welded to the lower part of the inner wall of the cabinet, and the load-bearing plate has openings to facilitate airflow; the middle shelf 72 is bolted to the side wall slide rails and can be pulled out laterally to adjust its position; the upper shelf 73 is clipped onto the upper part of the cabinet and adopts a grid structure. The side walls of each humidity zone are equipped with a different number of air supply pipes 8: 4 for the high humidity zone, 3 for the medium humidity zone, and 2 for the low humidity zone. All are arranged horizontally above the shelves and connected to the top fan through air distribution pipes. Each air supply pipe 8 is equipped with a regulating valve. The heating system 2 includes a first heating pipe 21 at the bottom, a second heating pipe 22 arranged vertically on the rear wall, and a third heating pipe 23 on the side wall. The third heating pipes 23 are fixed in pairs at the front and rear ends of the right side wall, forming an orthogonal spatial relationship with the air supply pipes 8. The circulation system 9 is connected to several branch gas pipelines 91 via a main gas pipeline 94. A detachable box 92 is installed on each branch gas pipeline 91, containing a moisture-absorbing sponge regeneration module. This module includes, in sequence, moisture-absorbing sponges 93, a stainless steel filter 95 with a pore size ≤0.5mm, activated carbon fiber for adsorbing oil film 96, and a humidity sensor. A pressure relief valve 5 is centrally located at the top of the housing 1, connected by threaded fasteners, and automatically opens when the air pressure is >0.12MPa. A connection interface is provided on the side wall, through which a humidity monitor 6 is plugged in and fixed. The door 11 is hinged to the left side wall, with an opening angle of 0~90°. A high-temperature resistant glass observation window 10 is embedded in the center, and a temperature display 3 is installed in the upper left corner. A wire passes through the door and connects to the internal temperature sensor.

[0037] 2. Operation process: Samples are placed in layers: high water content clay samples are placed on the lower shelf 71, transitional water content soil samples are placed on the middle shelf 72, and low water content sand samples are placed on the upper shelf 73, ensuring that the samples are evenly distributed and maintain a safe distance from the inner wall of the box and the heating pipe.

[0038] Gradient humidity control start-up: The controller adjusts the air inlet speed of the air supply duct 8 and the number of heating elements activated based on real-time data collected by the humidity monitor 6. In the high humidity zone, the air inlet speed is 2.0~2.5m / s, 4 heating elements are activated, and the temperature is controlled at 80±0.5℃; in the medium humidity zone, the air inlet speed is 1.5~1.8m / s, 2 heating elements are activated, and the temperature is controlled at 70±0.3℃; in the low humidity zone, the air inlet speed is 0.8~1.0m / s, 1 heating element is activated, and the temperature is controlled at 60±0.2℃.

[0039] Moisture absorption and regeneration cycle: Moisture inside the chamber enters the moisture-absorbing sponge regeneration module through the gas distribution pipe 91, sequentially passing through the oil film 96 to absorb oil and gas (adsorption rate ≥98%), the filter screen 95 to intercept rock debris particles with a diameter >0.5mm, and the moisture-absorbing sponge 93 to absorb moisture. The dried gas flows back to the chamber 1 through the main gas pipe 94. When the moisture content of the moisture-absorbing sponge 93 reaches the 30% threshold, the controller triggers an alarm. The operator pulls out the detachable box 92 to replace the moisture-absorbing sponge 93, and simultaneously checks the status of the oil film 96 and the filter screen 95. If the adsorption efficiency is <95% or the mesh clogging rate is >50%, they are replaced simultaneously.

[0040] Temperature difference compensation and safety monitoring: The bottom heating element 21 continuously operates to provide the main heat source, while the third heating element 23 on the side wall intermittently starts and stops based on the temperature sensor data on the side of the chamber door 11, ensuring that the temperature difference throughout the chamber is ≤±1℃. The pressure relief valve 5 monitors the air pressure in real time and automatically releases pressure when it exceeds 0.12MPa; visual confirmation through the observation window 10 confirms that there is no condensation inside the chamber. After drying, the moisture content of the sample is tested to ensure that the error range is ≤±2%.

[0041] Example 2 In another preferred embodiment, based on Embodiment 1, this embodiment provides a humidity-responsive low-temperature internal circulation drying device for soil and rock samples. Targeting the drying of high-moisture clay samples, this humidity-responsive low-temperature internal circulation drying device for soil and rock samples uses a sealed cuboid box 1 as its core. The box 1 is physically divided into a lower high-humidity zone, a middle medium-humidity zone, and an upper low-humidity zone by three layers of shelves 7. Each zone is equipped with functional components adapted to drying high-moisture clay samples. The specific structure is as follows: 1. Shelves 7 and partitioned layout: The lower shelf 71 is welded to the lower part of the inner wall of the box 1, and the load-bearing plate has evenly spaced openings (to facilitate airflow) for placing high moisture content clay samples; the middle shelf 72 is fixed to the slide rail on the side wall of the box 1 by bolts, and its position can be adjusted by horizontal pulling, with a reserved transition area; the upper shelf 73 is detachably installed on the upper part of the box 1 through a slot, and adopts a grid structure to accommodate the transfer of samples with gradually decreasing moisture content during the drying process.

[0042] 2. Configuration of heating system 2: The first heating tube 21 (bottom heating tube) is embedded under the lower shelf 71, covering most of the bottom area of ​​the cabinet 1, and provides stable heat as the main heat source; the second heating tube 22 (rear wall heating tube) is arranged vertically on the rear wall of the cabinet 1 to supplement the heat in the middle and rear of the cabinet 1; the third heating tube 23 (right side wall heating tube) is fixed on the right side wall of the cabinet 1 (at a certain distance from the door 11), arranged vertically in pairs, to compensate for heat loss on the side of the door 11 and eliminate edge temperature difference; the first heating tube 21, the second heating tube 22, and the third heating tube 23 together constitute heating system 2.

[0043] 3. Zoned Humidity Control System: A humidity monitor 6 is installed in the center of each humidity zone. The humidity monitor 6 is fixed through a plug-in interface on the side wall of the housing 1 to collect humidity data of each zone in real time. The central controller is installed on the outside of the housing 1 and is electrically connected to the humidity monitor 6, the regulating valve of the air supply duct 8 and the heating tube switch of the heating system 2. It can automatically adjust the air intake speed of the corresponding zone air supply duct 8 according to the humidity data (the air intake speed is the highest in the high humidity zone, the second highest in the medium humidity zone, and the lowest in the low humidity zone).

[0044] 4. Circulation System 9 and Moisture Absorption and Regeneration Module: The main gas pipeline 94 is connected to the side of the box 1. The main gas pipeline 94 branches into multiple branch gas pipelines 91. Each branch gas pipeline 91 is connected to a detachable box 92. Inside the detachable box 92, from the airflow inlet to the outlet, an adsorbent oil film 96 (activated carbon fiber layer, clipped into the groove on the inner wall of the box), a filter screen 95 (stainless steel mesh, fixed by spring clips), and a sponge 93 (porous silica gel / cellulose composite material) are installed in sequence. The sponge 93 integrates a humidity sensor and is connected to a controller. The branch gas pipelines 91, detachable box 92, sponge 93, main gas pipeline 94, filter screen 95, and adsorbent oil film 96 together constitute the circulation system 9. The treated dry gas flows back to the gas return port at the top of the box 1 through the main gas pipeline 94, forming a closed loop circulation.

[0045] 5. Safety and Monitoring Components: A pressure relief valve 5 is installed in the center of the top of the enclosure 1. The pressure relief valve 5 is fixed by threaded fasteners to ensure stable air pressure inside the enclosure 1. The door 11 is hinged to the left side wall of the enclosure 1. When closed, it is fixed to the lower right side of the enclosure 1 by a door lock 4. An observation window 10 (made of high-temperature resistant glass) is embedded in the middle of the door 11. A temperature display instrument 3 is installed in the upper left corner of the door 11. The wires of the temperature display instrument 3 pass through the door 11 and connect to multiple temperature sensors inside the enclosure 1 (located in the central area, on the side of the door 11, and on the rear wall, respectively).

[0046] This embodiment addresses the problem of high-moisture clay samples being prone to mold growth and slow drying due to localized over-humidity. It accelerates moisture removal and heat supply through high-humidity zones with high airflow rates and multiple heating elements. The moisture absorption and regeneration module of the circulation system 9 efficiently absorbs moisture, while the adsorption oil film 96 and filter screen 95 prevent oil contamination from the decomposition of small amounts of organic matter in the clay, ensuring long-term stable operation. The heating system 2, in conjunction with zoned humidity control, ensures that the clay sample structure is not damaged during drying, meeting the requirements for sample integrity in subsequent experiments.

[0047] Example 3 In another preferred embodiment, based on Embodiment 1, this embodiment provides an optimized application of the humidity-responsive low-temperature internal circulation drying control method for soil and rock masses based on the device of Embodiment 1. This embodiment takes the drying requirements of a batch of soil and rock samples in a geotechnical engineering laboratory as an example to verify the efficiency and accuracy of the humidity-responsive low-temperature internal circulation drying control method for soil and rock masses, specifically including the following steps: Step 1: Sample Layering and Safe Placement: Place 20 sets of high-moisture clay samples (32%~35% moisture content) on the lower shelf 71, 15 sets of transitional moisture content soil samples (18%~22% moisture content) on the middle shelf 72, and 10 sets of low-moisture sand samples (12%~14% moisture content) on the upper shelf 73. Ensure the samples are evenly distributed and maintain a safe distance of ≥5cm from the inner wall of the chamber and the heating pipes to avoid localized overheating.

[0048] Step 2, Dynamic Gradient Humidity Control: The controller collects data from the humidity monitor 6 every 5 minutes, dynamically adjusting the air intake speed of the air duct 8 and the number of heating elements activated. Initially, in the high humidity zone, the air intake speed is 2.2 m / s, with 4 heating elements activated at 80℃; in the medium humidity zone, the air intake speed is 1.6 m / s, with 2 heating elements activated at 70℃; and in the low humidity zone, the air intake speed is 0.9 m / s, with 1 heating element activated at 60℃. As the drying process progresses, when the humidity in the high humidity zone drops to 25%, the air intake speed decreases to 2.0 m / s, and the number of heating elements decreases to 3; when the humidity in the medium humidity zone drops to 15%, the air intake speed decreases to 1.5 m / s, and the number of heating elements decreases to 1.

[0049] Step 3, High-efficiency moisture absorption and regeneration cycle: Moisture inside the chamber enters the moisture-absorbing sponge regeneration module through the gas distribution pipe 91. The adsorption rate of the oil film 96 for oil and gas remains stable at 98.5%, and the interception rate of the filter screen 95 reaches 99%. When the moisture content of the moisture-absorbing sponge 93 reaches 28%, the controller triggers an alarm. Within 10 minutes, the staff can pull out and replace the detachable box 92, and simultaneously check the adsorption efficiency of the oil film 96 (97%) and the clogging rate of the filter screen 95 (45%). No replacement is required.

[0050] Step 4: Intelligent Temperature Difference Compensation and Safety Monitoring: Temperature sensors collect real-time temperature data from the central area inside chamber 1, the side of chamber door 11, and the rear wall, and transmit the data to the temperature display instrument 3. When the temperature difference between the side of chamber door 11 and the central area reaches 1.2℃, the controller immediately activates the third heating element 23, reducing the temperature difference to 0.8℃ within 0.5 hours. The pressure relief valve 5 is not triggered during the drying process, and the air pressure remains stable at 0.10~0.11MPa; the absence of condensation inside the chamber is confirmed through the observation window 10. After drying, the moisture content of the samples is tested. The moisture content of the high-moisture clay sample is 2.8%, the moisture content of the transitional soil sample is 1.9%, and the moisture content of the low-moisture sand sample is 1.2%, all meeting the requirement of an error range of ≤±2%, and the energy consumption is reduced by 32% compared to traditional equipment.

[0051] Example 4 In another preferred embodiment, based on Embodiments 2 and 3, this embodiment provides an application of a humidity-responsive low-temperature internal circulation drying control method for soil and rock. Based on the humidity-responsive low-temperature internal circulation drying device for soil and rock in Embodiment 2, the specific control process for drying oil-bearing sandstone samples (low oil content, high initial moisture content) is as follows: Step 1: Sample layering: Based on the initial moisture content of the oil-bearing sandstone samples, place the high moisture content (initial moisture content > 25%) oil-bearing sandstone samples evenly on the lower shelf 71 of the high humidity zone at the bottom of the box 1, ensuring that the samples maintain a safe distance from the inner wall of the box 1 and the heating pipes of the heating system 2 to avoid direct contact between the samples and the heat source, which could lead to local overheating; place the medium moisture content (initial moisture content 15%~25%) samples on the middle shelf 72 of the medium humidity zone in the middle of the box 1 as transitional samples; do not place low moisture content samples for the time being, and reserve the upper shelf 73 of the low humidity zone at the top of the box 1 for subsequent sample transfer.

[0052] Step 2, Gradient Humidity Control Parameter Setting and Activation: After receiving the initial humidity data from the humidity monitors 6 in each humidity zone, the controller automatically sets the gradient control parameters: In the high humidity zone, the air inlet speed of the air outlet 8 is adjusted to a higher level, and the heating tubes of the four heating systems 2 are activated, with the temperature controlled within a suitable range (to avoid excessively high temperatures causing rapid oil evaporation); in the medium humidity zone, the air inlet speed of the air duct 8 is set to a medium level, and the heating tubes of the two heating systems 2 are activated, with the temperature controlled slightly lower than that in the high humidity zone; in the low humidity zone, the heating tubes of the heating system 2 are not activated, and the air duct 8 maintains a low air inlet speed to maintain a dry environment in the area. After the parameters are set, the device automatically starts the heating system 2 and the circulation system 9.

[0053] Step 3, Moisture Absorption and Regeneration Circulation Control: Moisture (containing a small amount of oil and rock debris) in the chamber 1 enters the moisture absorption and regeneration module of the detachable box 92 through the gas distribution pipe 91 of the circulation system 9. First, the oil in the moisture is absorbed by the adsorption oil film 96, then the rock debris particles carried in the airflow are intercepted by the filter screen 95, and finally the moisture is absorbed by the sponge 93. The dried gas flows back to the chamber 1 through the main gas pipe 94, realizing a closed-loop circulation. When the humidity sensor in the sponge 93 detects that its moisture content has reached the set threshold, the controller triggers an alarm, the operator stops the operation of the device, pulls out the saturated sponge 93 from the detachable box 92, and replaces it with a new sponge 93; at the same time, the adsorption status of the adsorption oil film 96 is checked (if the oil film surface is obviously covered with oil) and the clogging status of the filter screen 95 (if the mesh is blocked by rock debris more than a certain proportion), and the adsorption oil film 96 and the filter screen 95 are replaced simultaneously. After the replacement is completed, the device is restarted to continue the circulation.

[0054] Step 4, Temperature Difference Compensation and Safety Monitoring: During the drying process, the first heating tube 21 (bottom heating tube) of the heating system 2 continuously operates to provide the main heat source. The temperature sensor collects the temperature data of the central area of ​​the chamber 1, the side of the door 11, and the rear wall side in real time, and transmits the data to the temperature display instrument 3. When the temperature difference between the side of the door 11 and the central area exceeds the set value (e.g., temperature difference > 1℃), the controller automatically starts the third heating tube 23 (right side wall heating tube) to compensate for the heat loss on the side of the door 11 through longitudinal thermal radiation until the temperature difference drops to the set range (temperature difference ≤ 1℃), and then stops the operation of the third heating tube 23. The pressure relief valve 5 monitors the air pressure inside the chamber 1 in real time. If the air pressure inside the chamber 1 exceeds the set value due to oil evaporation, the pressure relief valve 5 automatically opens to release pressure and ensure the safety of the device. The staff regularly visually checks the sample status inside the chamber 1 through the observation window 10 of the door 11 to confirm that no condensation is generated and to avoid secondary moisture absorption of the sample.

[0055] Step 5: Drying Process Monitoring and Endpoint Judgment: During the drying process, the controller records the humidity, temperature, and energy consumption data of each humidity zone in real time. Every certain period of time (e.g., 1 hour), samples are taken to test the moisture content of oily sandstone samples in the high humidity and medium humidity zones. When the moisture content of the high humidity zone sample drops to 15%~20%, it is transferred to the middle shelf 72 (middle medium humidity zone) for continued drying, while new high moisture content samples are added to the lower shelf 71 (lower high humidity zone). When the moisture content of the middle medium humidity zone sample drops below 10%, it is transferred to the upper shelf 73 (upper low humidity zone) for final drying. The drying process continues until the moisture content of all samples reaches the target value (e.g., target moisture content of 5%~8%) and the moisture content error is controlled within the set range. The device is then stopped, and the drying of the oily sandstone samples is completed.

[0056] The control method in this embodiment is tailored to the characteristics of oil-bearing sandstone samples. By using gradient humidity control and appropriate temperature control, it balances the requirements for sample drying efficiency and oil retention (or controllable volatilization). The targeted treatment of oil and rock cuttings in the moisture absorption and regeneration cycle of the circulation system 9 avoids problems such as oil contamination of equipment and rock cuttings clogging pipes. The real-time temperature difference compensation and safety monitoring ensure uniform drying of oil-bearing sandstone samples and safe and stable operation of the device. The entire control process requires no frequent manual intervention and has a high degree of automation. At the same time, the transfer of samples between the lower shelf 71, the middle shelf 72, and the upper shelf 73 enables continuous drying operations, improving processing efficiency.

[0057] In a preferred embodiment, the heating system 2 includes a first heating pipe 21 installed at the bottom of the housing 1, a second heating pipe 22 arranged vertically on the rear wall of the housing 1, and a third heating pipe 23 installed on the side wall of the housing 1. This arrangement enables multi-dimensional uniform heating inside the housing, avoiding excessive local temperature differences. The first heating pipe 21 provides basic bottom heating, the second heating pipe 22 supplements the rear heat, and the third heating pipe 23 enhances the side heat circulation, all working together to ensure that the temperature inside the housing is stable and meets the requirements.

[0058] In a preferred embodiment, a pressure relief valve 5 is centrally located at the top of the housing 1. The pressure relief valve 5 is connected to the housing 1 via threads and fasteners, and automatically opens to release pressure when the air pressure inside the housing 1 exceeds a set value of 0.12 MPa. Several connection interfaces are provided on the side wall of the housing 1, and a humidity monitor 6 is plugged into the housing 1 through these interfaces. The above configuration allows for real-time monitoring of the humidity inside the housing 1, and timely warnings can be issued when the humidity exceeds the safe range. A drain valve 7 is installed at the bottom of the housing 1 to facilitate the drainage of internal water. At the same time, the inner wall of the housing 1 is treated with a moisture-proof coating to further enhance its moisture-proof performance and ensure the normal operation of the internal equipment.

[0059] In a preferred embodiment, the storage rack 7 includes a lower shelf 71, a middle shelf 72, and an upper shelf 73. The lower shelf 71 is welded to the lower part of the inner wall of the housing 1 and has a perforated load-bearing plate on it. The middle shelf 72 is bolted to a slide rail on the side wall of the housing 1 and can be pulled out laterally to adjust its position. The upper shelf 73 is snapped into the housing 1 and placed on the upper part of the housing 1. The upper shelf 73 is designed with a grid structure. The above configuration gives the storage rack 7 a flexible storage function. The lower shelf 71 can hold heavier items, and the perforated design facilitates ventilation and heat dissipation. The pull-out adjustment of the middle shelf 72 can accommodate items of different sizes. The grid structure of the upper shelf 73 makes it easy to classify and store small items, improving space utilization.

[0060] In a preferred embodiment, the circulation system 9 includes a main gas pipeline 94 connected to the housing 1, which in turn connects to several branch gas pipelines 91. Each branch gas pipeline 91 is equipped with a detachable box 92, which houses a moisture-absorbing sponge regeneration module. The module comprises a moisture-absorbing sponge 93, a filter 95, an oil-absorbing film 96, and a humidity sensor within the sponge 93, all installed sequentially. Moisture exiting the housing 1 flows through the branch gas pipelines 91, passes through the moisture-absorbing sponge regeneration module, and then returns to the housing 1 via the main gas pipeline 94, forming a circulation. The humidity sensor is connected to a controller. This configuration allows the humidity sensor to monitor the moisture content of the moisture-absorbing sponge in real time and transmit the data to the controller. The controller determines whether the regeneration process needs to be initiated based on preset values ​​and automatically controls the moisture-absorbing sponge regeneration module to ensure efficient and stable operation of the circulation system.

[0061] In the preferred embodiment, the filter screen 95 is a stainless steel mesh structure with a pore size ≤ 0.5mm, and is fixed to the frame of the detachable box 92 by spring clips. The adsorbed oil film 96 is an activated carbon fiber layer, which is clipped inside the detachable box 92. The filter screen 95 and the adsorbed oil film 96 are spaced apart. The above arrangement can effectively improve the filtration effect. The stainless steel filter screen can intercept larger particulate impurities, and the activated carbon fiber layer can adsorb small oil stains and odors. The spacing between the two allows the fluid to fully contact, and the detachable design facilitates regular cleaning and replacement, ensuring long-term stable operation of the equipment.

[0062] In the preferred embodiment, the door 11 is hinged to the left side wall of the box body 1, with an opening angle of 0~90°. When closed, it is secured to the lower right side of the box body 1 by a door lock 4. An observation window 10 is embedded in the middle of the door 11, and the observation window 10 is made of high-temperature resistant glass. A temperature display 3 is installed in the upper left corner of the door 11, and the wires of the temperature display 3 pass through the door 11 and connect to the internal temperature sensor of the box body 1. The above configuration facilitates the flexible opening and closing and stable closing of the door, allows for a direct view of the internal conditions through the observation window, and ensures safe use with the high-temperature resistant glass. The temperature display can accurately display the internal temperature in real time, making it easy for users to keep track of the internal temperature.

[0063] In the preferred embodiment, the air supply duct 8 is a series of horizontally placed cylindrical structures, parallel to the left and right side walls of the box 1, arranged independently in three layers, each located directly above the shelf on each layer. It is connected to the top fan of the box 1 through a branch air duct, and each air supply duct 8 is equipped with a regulating valve. The above configuration makes the air supply more uniform and precise, and the air volume can be flexibly controlled by the regulating valve according to the drying needs of different items on the shelf, effectively improving the drying efficiency, reducing energy consumption, and ensuring the stability and quality of the drying process.

[0064] In the preferred embodiment, the third heating tube 23 is a vertically arranged cylindrical structure, fixed in pairs to the front and rear ends of the right side wall of the box 1, forming an orthogonal spatial relationship with the air outlet 8; the regulating valve of the air outlet 8 is connected to the controller, and the controller adjusts the air intake speed of the corresponding area of ​​the air outlet 8 according to the detection data of the humidity monitor 6, and the air intake speed in the high humidity area is greater than that in the medium humidity area, which is greater than that in the low humidity area; the above settings can effectively and accurately control the air intake volume according to the humidity of different areas, ensuring uniform humidity distribution in the box; the vertically arranged third heating tube 23, together with the orthogonal air outlet 8, further improves the heat exchange efficiency and provides a stable and suitable storage environment for the items in the box.

[0065] In the preferred embodiment, in step 1, the high-moisture-content soil and rock samples are clay samples with a moisture content >30%, the low-moisture-content soil and rock samples are sand samples with a moisture content <15%, and the transitional moisture-content soil and rock samples are soil and rock samples with a moisture content of 15%~30%. When placing the samples, ensure that the samples are evenly distributed on each shelf and that the samples maintain a preset safe distance from the inner wall of the chamber 1 and the heating pipe. The above settings can effectively avoid experimental data deviations caused by local overheating or uneven heating of the samples, while ensuring sufficient circulation of hot air inside the chamber, so that soil and rock samples with different moisture contents lose water evenly in a constant temperature and dry environment, ensuring the accuracy of subsequent moisture content determination and soil and rock property analysis results.

[0066] In the preferred embodiment, in step 3, the adsorption rate of the oil film 96 for oil and gas is not less than a set percentage of 98%, and the filter screen 95 intercepts rock fragments with a particle size greater than a set value of 0.5 mm. When replacing the absorbent sponge 93, the status of the adsorption oil film 96 and the filter screen 95 is checked simultaneously. When the adsorption efficiency of the oil film 96 is lower than the set percentage of 95% and the clogging rate of the filter screen 95 is greater than the set percentage of 50%, the adsorption oil film 96 and the filter screen 95 are replaced simultaneously. The above settings can effectively ensure the high efficiency and stability of oil and gas treatment, ensure that the treated gas meets emission standards, and reduce environmental pollution. At the same time, regular inspection and replacement of components can extend the service life of the equipment, reduce the overall operation and maintenance cost, and improve the reliability of the system.

[0067] In the preferred embodiment, in step 4, the temperature sensor collects temperature data in real time from the central area, the side of the door 11, and the rear wall of the chamber 1, and transmits it to the temperature display instrument 3. When the temperature difference between the side of the door 11 and the central area is greater than a preset value of 1°C, the controller controls the third heating tube 23 to start heating until the temperature difference is no greater than the preset value of 1°C. During the drying process, the humidity, temperature, and energy consumption data of each humidity zone are recorded in real time. After drying, the moisture content of the sample is detected to ensure that the moisture content is controlled within the required error range of ±2%. The above settings can effectively ensure the temperature uniformity inside the chamber 1 and avoid excessive local temperature differences from affecting the drying effect. At the same time, the real-time recording of humidity, temperature, and energy consumption data provides a basis for subsequent optimization of the drying process, ensuring stable and reliable sample drying quality.

[0068] In summary, this invention proposes a humidity-responsive low-temperature internal circulation drying device and control method for soil and rock materials. It effectively solves the core problems in geotechnical engineering experiments, such as crude humidity control, high energy consumption, difficult maintenance, and poor temperature uniformity in soil and rock material drying chambers. By providing a humidity-zoned, controlled-humidity low-temperature internal circulation drying device for soil and rock materials, it overcomes the limitations of traditional drying chambers caused by a single heat source and uniform air supply mode, such as uneven drying, energy waste, complex structural assembly and disassembly, and secondary moisture absorption by edge samples. This meets the demands of modern geotechnical engineering experiments for efficient, precise, and environmentally friendly drying processes.

[0069] Specifically, this invention is the first to employ a three-zone humidity gradient division and independent control technology in a soil and rock drying chamber 1. Humidity is precisely controlled based on sample humidity differences using a humidity monitor 6—a design not previously reported in existing technologies. Simultaneously, a replaceable porous silica / cellulose composite absorbent sponge 93 is introduced, combined with a filter 95 and an oil-absorbing film 96, and placed within a detachable box 92. Through a circulation system 9 constructed from a gas distribution pipe 91 and a main gas pipe 94, effective moisture adsorption and oil removal are achieved, and the drying gas can be regenerated without preheating—a significant innovation in traditional drying equipment. Furthermore, the heating system 2, with its bottom first heating pipe 21, rear second heating pipe 22, and side wall third heating pipe 23, combined with the orthogonal airflow design formed by the air supply pipe 8, effectively solves the edge temperature difference problem and improves heat radiation uniformity—a design rarely seen in similar products.

[0070] Furthermore, this invention constructs a closed-loop internal circulation system 9, which circulates treated moisture back to the chamber 1. Combined with a heat recovery device, this significantly reduces energy consumption and improves energy efficiency. This invention not only solves the single-function problem of traditional soil and rock drying chambers 1, but also proposes a comprehensive and innovative solution through the integrated application of technologies such as functional zoning, independent humidity control, preheat-free regeneration, multi-directional heating, and closed-loop internal circulation. This solution significantly shortens the drying time for high-moisture-content samples while maintaining the structural integrity of low-moisture-content samples, significantly improving drying efficiency and sample quality, which is of great significance for geotechnical engineering experiments. The shelf 7 is divided into a lower shelf 71, a middle shelf 72, and an upper shelf 73, facilitating the placement of different samples. Moreover, the application of the preheat-free design, the closed-loop internal circulation system 9, and the modular, detachable structure not only reduces the energy consumption and operating costs of the equipment, but also greatly facilitates equipment maintenance, reduces maintenance time and costs, and improves the economy and practicality of the equipment. The interior of the chamber 1 can be visually monitored through the observation window 10. A lock 4 is installed on the door 11 to ensure safe use. A temperature display 3 is embedded in the chamber 1 for easy temperature monitoring, and a pressure relief valve 5 ensures stable pressure inside the chamber 1. This invention can process various types of soil and rock samples, including high-water-content clay, low-water-content sand, and oil-bearing sandstone, demonstrating strong applicability and flexible scalability, and has broad application prospects in the field of geotechnical engineering experiments.

Claims

1. A humidity-responsive low-temperature internal circulation drying device for soil and rock, characterized in that: The enclosure includes a cabinet (1) and a zoned humidity control system. The cabinet (1) is divided into a lower high humidity zone, a middle medium humidity zone, and an upper low humidity zone by a shelf (7). Each zone has a different number of air supply ducts (8) and a heating system (2) on its side walls. The zoned humidity control system includes a humidity monitor (6) and a controller for each humidity zone. The controller is connected to the humidity monitor (6) to adjust the air intake speed of the corresponding zone's air supply duct (8). The cabinet (1) has a circulation system (9) on its side and a pressure relief valve (5) on its top. The cabinet (1) has a door (11) with a temperature display (3) and a door lock (4). The cabinet (1) has a temperature sensor connected to the temperature display (3) inside its interior. The controller is connected to the heating system (2) and the circulation system (9).

2. The humidity-responsive low-temperature internal circulation drying device for soil and rock as described in claim 1, characterized in that: The heating system (2) includes a first heating tube (21) installed at the bottom of the box (1), a second heating tube (22) arranged vertically on the rear wall of the box (1), and a third heating tube (23) installed on the side wall of the box (1).

3. The humidity-responsive low-temperature internal circulation drying device for soil and rock as described in claim 2, characterized in that: The top of the box (1) is provided with a pressure relief valve (5), which is connected to the box (1) by threads and fasteners; the side wall of the box (1) is provided with several connection interfaces, and the humidity monitor (6) is plugged into the box (1) through the connection interface.

4. The humidity-responsive low-temperature internal circulation drying device for soil and rock as described in claim 3, characterized in that: The shelf (7) includes a lower shelf (71), a middle shelf (72) and an upper shelf (73); the lower shelf (71) is welded to the lower part of the inner wall of the box (1) and has a perforated load-bearing plate on it; the middle shelf (72) is bolted to the slide rail on the side wall of the box (1) and can be pulled out laterally to adjust its position; the upper shelf (73) is clipped into the box (1) and placed on the upper part of the box (1), and the upper shelf (73) is set as a grid structure.

5. The humidity-responsive low-temperature internal circulation drying device for soil and rock as described in claim 4, characterized in that: The circulation system (9) includes a main gas pipeline (94) connected to the box (1), the main gas pipeline (94) is connected to several branch gas pipelines (91), a detachable box (92) is installed on the branch gas pipelines (91), and a moisture-absorbing sponge regeneration module is set inside the detachable box (92). The moisture-absorbing sponge regeneration module includes a moisture-absorbing sponge (93), a filter screen (95), an adsorbent oil film (96) installed in sequence, and a humidity sensor installed inside the moisture-absorbing sponge (93). After the moisture comes out of the box (1), it passes through the branch gas pipelines (91), and after passing through the layers of the moisture-absorbing sponge regeneration module, it flows back to the box (1) through the main gas pipeline (94) to form a circulation. The humidity sensor is connected to the controller. The filter screen (95) is a stainless steel mesh structure and is fixed to the frame of the detachable box (92) by spring clips. The adsorbent oil film (96) is an activated carbon fiber layer and is clipped inside the detachable box (92). The filter screen (95) and the adsorbent oil film (96) are set at intervals.

6. The humidity-responsive low-temperature internal circulation drying device for soil and rock as described in claim 5, characterized in that: The door (11) is hinged to the left side wall of the box body (1) and is fixed to the lower right side of the box body (1) by a door lock (4) when closed; an observation window (10) is embedded in the middle of the door (11) and the observation window (10) is made of high temperature resistant glass; a temperature display (3) is installed in the upper left corner of the door (11) and the wire of the temperature display (3) passes through the door (11) and connects to the internal temperature sensor of the box body (1).

7. The humidity-responsive low-temperature internal circulation drying device for soil and rock as described in claim 6, characterized in that: The air supply pipe (8) is a number of horizontally placed cylindrical structures, parallel to the left and right side walls of the box (1), arranged in three independent layers, located directly above each shelf, and connected to the top fan of the box (1) through the air distribution pipe. Each air supply pipe (8) is equipped with a regulating valve. The third heating pipe (23) is a vertically arranged cylindrical structure, fixed in pairs to the front and rear ends of the right side wall of the box (1), forming an orthogonal spatial relationship with the air supply port (8). The regulating valve of the air supply pipe (8) is connected to the controller. The controller adjusts the air intake speed of the corresponding area air supply pipe (8) according to the detection data of the humidity monitor (6), and the air intake speed of the high humidity area is greater than that of the medium humidity area, which is greater than that of the low humidity area.

8. A humidity-responsive low-temperature internal circulation drying control method for soil and rock based on the humidity-responsive soil and rock low-temperature internal circulation drying device according to claim 7, characterized in that, Includes the following steps: Step 1: Place the samples in layers. Place the high water content soil and rock samples in the lower shelf (71) of the high humidity zone at the bottom of the box (1), place the soil and rock samples with transitional water content in the middle shelf (72) of the middle humidity zone, and place the low water content soil and rock samples in the upper shelf (73) of the upper low humidity zone. Step 2: Gradient humidity control start-up. The controller adjusts the air intake speed of the corresponding area air supply pipe (8) and the number of heating pipes started according to the real-time humidity data collected by the humidity monitor (6) of each humidity zone. Step 3: Moisture absorption and regeneration cycle. Moisture in the box (1) enters the moisture absorption sponge regeneration module through the gas distribution pipe (91). First, it absorbs oil and gas through the oil film (96), then it intercepts rock debris through the filter screen (95), and finally the moisture is absorbed by the moisture absorption sponge (93). The dry gas flows back to the box (1) through the main gas pipe (94). When the moisture content of the moisture absorption sponge (93) reaches the threshold, the controller triggers an alarm, and the staff pulls out the detachable box (92) to replace the moisture absorption sponge (93). Step 4: Temperature difference compensation and safety monitoring. The bottom heating tube (21) runs continuously to provide the main heat source. The right side wall heating tube (23) starts and stops intermittently according to the temperature sensor data on the side of the door (11) so that the temperature difference of the whole box (1) is not greater than the preset value. The pressure inside the box (1) is monitored by the pressure relief valve (5). When the pressure is greater than the set value, the pressure is automatically released. At the same time, the observation window (10) is used to visually confirm that there is no condensate in the box.

9. The humidity-responsive low-temperature internal circulation drying control method for soil and rock masses according to claim 8, characterized in that: In step 3, when replacing the absorbent sponge (93), the condition of the adsorbent oil film (96) and the filter screen (95) is checked simultaneously. When the adsorption efficiency of the adsorbent oil film (96) is lower than the set percentage and the mesh blockage rate of the filter screen (95) is greater than the set percentage, the adsorbent oil film (96) and the filter screen (95) are replaced simultaneously.

10. The humidity-responsive low-temperature internal circulation drying control method for soil and rock masses according to claim 8, characterized in that: In step 4, the temperature sensor collects the temperature data of the central area, the side of the door (11), and the side of the rear wall inside the box (1) in real time and transmits it to the temperature display instrument (3); when the temperature difference between the side of the door (11) and the central area is greater than the preset value, the controller controls the third heating tube (23) to start heating until the temperature difference is not greater than the preset value and then stops; during the drying process, the humidity, temperature data and energy consumption data of each humidity zone are recorded in real time, and the moisture content of the sample is detected after the drying is completed to ensure that the moisture content is controlled within the required error range.

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