A cooling capacity monitoring control system and method based on frozen parameters

Abstract

The present application relates to a kind of freezing parameter-based cooling capacity monitoring control system and method.The system at least includes total control platform and sensor module.Sensor module is arranged at freezing pipe of contact passage and temperature measuring pipe to obtain the pressure condition of contact passage and the formation condition of frozen wall.Total control platform divides the preferred process of frozen wall thickness into preliminary selection, calibration and selection based on the pressure condition of contact passage detected by sensor module before active freezing, and controls the freezing efficiency of freezing station based on the frozen wall formation condition detected by sensor module in active freezing.The present application indirectly controls the thickness of frozen wall by controlling the cooling capacity of freezing machine, and the above control process is the targeted control scheme based on the pressure condition of contact passage and the frozen wall formation condition obtained by sensor module arranged in urban underground contact passage.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a cooling capacity monitoring and control system based on freezing parameters. Background Technology

[0002] With the continuous development of urbanization, the construction of urban underground engineering is constantly advancing. However, due to the complex working conditions of underground construction of main urban roads, the excavation of subway connecting passages in water-rich layers usually adopts the freezing method. During the construction of connecting passages, the thickness of the frozen wall used in the freezing method is often designed with a large safety margin to ensure construction safety as much as possible. However, such a large increase in safety margin leads to increased freezing time and energy consumption at the freezing station, while also affecting construction work and increasing construction difficulty. Therefore, how to balance the safety and efficiency of the freezing method, so that the frozen wall thickness can ensure construction safety while shortening the construction period, reducing costs and energy consumption, is a problem that urgently needs to be solved by existing technologies.

[0003] Chinese patent CN 113153312B discloses a construction and monitoring method for freezing soft and hard strata in subway connecting passages, including: Step 1, measuring the designed position of the freezing pipes outside the outline (limit of the connecting passage) of the connecting passage; Step 2, drilling: drilling holes on site for several freezing pipes to be inserted; Step 3, inserting the freezing pipes into the holes drilled in Step 2 and sealing them, and setting up annular corrosion-resistant tempered glass protective shells and conical corrosion-resistant tempered glass outer shells to obtain an outer shell protection system; Step 4, setting up various measuring points (monitoring unit system) around the connecting passage, and setting up a freezing circulation system, a multi-segment temperature sensing system, a camera system, and a controller inside the outer shell protection system, and setting up a central control system outside the outer shell protection system on the ground to form a monitoring system; Step 5, freezing and monitoring. The above patent designs the position of the freezing pipes to detect the construction parameters of the connecting passage, but does not test whether the thickness of the frozen wall meets the required requirements, nor does it consider the impact of different frozen wall thicknesses on construction.

[0004] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0005] Due to the complex conditions of underground construction on urban arterial roads, the thickness of the frozen walls used in connecting tunnel construction is often designed with a significant safety margin. However, this design has the problem that increasing the thickness of the frozen wall significantly increases the freezing time, and excessively thick frozen walls lead to increased frozen soil, affecting the soil hardness at the construction face, increasing construction difficulty, and impacting the construction cycle. The increased construction cycle and freezing time also significantly increase construction costs. Therefore, how to minimize the thickness of the frozen wall while ensuring safe construction is a problem that urgently needs to be solved by existing technologies.

[0006] To address the shortcomings of existing technologies, this invention provides a cooling capacity monitoring and control system based on freezing parameters, comprising at least a central control platform and sensor modules. The sensor modules are deployed at the freezing pipes and temperature measuring pipes of the connecting passage to acquire information about the pressure conditions of the connecting passage and the formation of the frozen wall. The central control platform, based on the pressure conditions of the connecting passage detected by the sensor modules before active freezing, divides the optimization process for the frozen wall thickness into initial selection, calibration, and comparison. Furthermore, it controls the freezing efficiency of the freezing station based on the frozen wall formation detected by the sensor modules during active freezing. The sensor modules monitor the entire active freezing period to ensure that the frozen wall parameters during excavation meet construction requirements, and to prevent the frozen wall thickness from increasing before and during construction, thus preventing increased difficulty at the working face.

[0007] According to a preferred embodiment, the central control platform initially selects the frozen wall thickness based on the pressure conditions of the connecting channel obtained by the sensor modules; the sensor modules are at least installed in the wedge-shaped areas on both sides of the connecting channel to obtain the magnitude of the forces that ensure stability of the connecting channel; the central control platform constructs a face model based on the sensor modules installed in the connecting channel to obtain the stress distribution of the frozen wall. This invention, considering the actual construction environment of underground connecting channels in aquifers, proposes a construction method suitable for urban underground connecting channels, taking into account the arched top of the frozen wall. The minimum frozen wall thickness is obtained by detecting the pressure conditions of the connecting channel using sensor modules.

[0008] According to a preferred embodiment, the central control platform performs finite element analysis on the frozen wall based on the external load acquired by the sensor module and the frozen wall thickness obtained from the initial selection process to calibrate the initial selection of the frozen wall thickness. Calibrating the initially selected frozen wall thickness through finite element analysis prevents the calculated thickness from failing to meet construction standards due to abnormal parameters or other special circumstances during the initial selection.

[0009] According to a preferred embodiment, the overall control platform establishes at least a three-dimensional model of the connecting passage for comparison; the overall control platform establishes a three-dimensional model based on the physical and mechanical parameters of the soil layer; the overall control platform compares the thickness of the frozen wall of the water-rich connecting passage based at least on the fluid-structure interaction theory; wherein, the overall control platform activates the frozen wall structure by assigning values ​​to the established three-dimensional model and completes the construction simulation; the overall control platform compares the minimum thickness based on the results of the assigned simulation.

[0010] According to a preferred embodiment, the overall control platform compares the initially selected minimum thickness based on a three-dimensional model to ensure that the final minimum thickness meets the construction characteristics of the aquifer. The overall control platform determines the required thickness of the frozen wall through deformation monitoring points of the three-dimensional model. These deformation monitoring points include abrupt changes in the model's crown settlement, arch base heave, and arch waist convergence. Existing technologies only consider the frozen wall structure within the geostress field when establishing the three-dimensional spatial structure of the connecting passage, without considering the influence of the seepage stress field on the connecting passage within the aquifer. The comparison method of this invention fully considers the redistribution of the geostress field in the aquifer under the influence of the seepage stress field, making the selection of the frozen wall thickness for connecting passages at a depth in aquifers a crucial technical means.

[0011] According to a preferred embodiment, the central control platform controls the freezing efficiency of the freezing station based on at least the minimum thickness of the frozen wall and the formation status of the frozen wall. The freezing station is configured with at least a freezing module and a brine module. The freezing module includes a freezing machine, a freezing tower, a water tank, and a water pump. The freezing machine, freezing tower, water tank, and water pump are connected by pipes to form a circulation pipeline. Control valves are provided at the inlet and outlet of the freezing machine and water pump, and at the inlet of the freezing tower. The brine module includes a brine tank and a brine pump. The brine tank, brine pump, freezing machine, and conduit are connected by a brine pipe. Control valves are provided at the inlet and outlet of the brine pump. During active freezing, the central control platform adjusts the operating parameters of the freezing machine based at least on the cooling water temperature and the brine temperature to ensure that the frozen wall meets the freezing conditions. This invention indirectly controls the thickness of the frozen wall by controlling the cooling capacity of the freezing machine. Furthermore, the control process is a targeted control scheme based on the pressure conditions of the underground connecting passage and the formation status of the frozen wall obtained by the sensor module 3 installed in the urban underground connecting passage.

[0012] According to a preferred embodiment, the central control platform adjusts the brine temperature accordingly based on the formation of the frozen wall to ensure that the frozen wall formation conforms to the calculated minimum frozen wall thickness. Specifically, the central control platform dynamically adjusts the brine temperature variation curve based at least on the curve of frozen wall thickness increase. During active freezing, the edges of the frozen wall furthest from the freezing tube cool down more slowly, but as the core temperature at the freezing tube decreases, the cooling rate at the edges gradually increases. The brine temperature variation curve is designed to conform to this curve change, thus slowing down the heating rate of the brine temperature variation curve at the end of active freezing, thereby preventing the frozen wall thickness from exceeding the preset standard.

[0013] According to a preferred embodiment, the central control platform performs finite element analysis on the frozen wall temperature curve based on frozen wall temperature monitoring to predict the formation of frozen wall thickness; the finite element analysis is used to detect the development trend of frozen wall thickness so as to control the refrigeration efficiency of the freezing machine through the central control platform; the finite element analysis is also used to detect the frost heave deformation of the connecting channel to prevent the supporting force of the connecting channel from failing to meet the requirements due to temperature changes; wherein, the central control platform summarizes the freezing data and temperature change curve detected by the sensor module set on the temperature measuring tube to calculate the average development speed of the frozen wall; the central control platform calculates the maximum hole spacing of the frozen wall based on the freezing hole deviation to calculate the freezing wall overlap time, thereby obtaining the frozen wall thickness; the central control platform compares the detected frozen wall thickness with the calculated minimum frozen wall thickness to adjust the freezing efficiency of the freezing station.

[0014] This invention also relates to a cooling capacity monitoring and control method based on freezing parameters. The method includes the following steps: acquiring the pressure status of the connecting channel and the formation status of the frozen wall. Specifically, the central control platform divides the process of optimizing the frozen wall thickness into initial selection, calibration, and comparison based on the pressure status of the connecting channel detected by the sensor module before active freezing. Furthermore, it controls the freezing efficiency of the freezing station based on the frozen wall formation status detected by the sensor module during active freezing. The pressure status of the connecting channel and the formation status of the frozen wall are monitored before, during, and after active freezing. The central control platform calculates the minimum required frozen wall thickness under the current construction conditions and the freezing machine parameters to ensure the required thickness, enabling automatic adjustment. This is particularly beneficial for staff or superiors to obtain information about the connecting channel's status before and during construction from the central control platform using intelligent devices.

[0015] According to a preferred embodiment, the method further includes: the central control platform performing a preliminary selection of the frozen wall thickness based on the pressure conditions of the communication channel obtained by the sensor module; the central control platform performing finite element analysis on the frozen wall based on the external load obtained by the sensor module and the frozen wall thickness obtained from the preliminary selection process to calibrate the preliminary selection of the frozen wall thickness; and the central control platform comparing the frozen wall thickness of the water-rich layer communication channel based at least on fluid-structure interaction theory. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the communication channel in a preferred embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of a preferred embodiment of the cooling capacity monitoring and control system based on freezing parameters provided by the present invention.

[0018] List of reference numerals

[0019] 1: Connecting passage; 2: Freezing pipe; 3: Sensor module; 4: Temperature measuring pipe; 6: Existing tunnel; 7: Brine pipe; 8: Freezing station; 9: Central control platform; 10: Working face; 11: Freezing wall. Detailed Implementation

[0020] The following is a detailed explanation with reference to the accompanying drawings.

[0021] Example 1

[0022] This invention relates to a cooling capacity monitoring and control system and method based on freezing parameters. The invention relates to the construction of long-distance connecting tunnels in aquifers using the freezing method. More specifically, the invention relates to an apparatus, system, and method for determining cooling capacity using sensor devices to measure the thickness and temperature of the frozen wall relative to the soil surrounding the connecting tunnel. The sensors used in this invention include, but are not limited to, wired or wireless sensor devices, as well as sensor devices that may incorporate both wired and wireless features.

[0023] According to a preferred embodiment, freezing pipes 2 and sensor modules 3 are installed on both sides of the connecting passage 1, and temperature measuring pipes 4 and sensor modules 3 are also installed. These pipes are connected to a freezing station 8 in the existing tunnel 6 via brine pipes 7. The freezing station is controlled by a central control platform 9, and active freezing is performed based on calculation results. Preferably, excavation is carried out after active freezing is completed. During excavation, temperature measuring points are placed on the tunnel face 10, and each temperature measuring point is monitored during excavation. Preferably, the monitoring data is uploaded to the central control platform 9 in real time. The central control platform 9 automatically adjusts the cooling capacity of the freezing station after analysis and processing based on the monitoring data, geological conditions, tunnel conditions, etc., so that the frozen wall 11 is at a thickness that meets the freezing conditions without affecting the excavation state of the tunnel face 10. Preferably, the above control process is repeated until the entire retaining wall freezing stage is completed.

[0024] According to a preferred embodiment, the freezing station is configured with at least a freezing module and a brine module. The freezing module includes a freezer, a freezing tower, a water tank, and a water pump. The freezer, freezing tower, water tank, and water pump are connected by pipes to form a circulation pipeline. Control valves are provided at the inlet and outlet of the freezer and water pump, and at the inlet of the freezing tower. A pressure gauge and a thermometer are also provided at the outlet of the water pump. The brine module includes a brine tank and a brine pump. The brine tank, brine pump, freezer, and conduit are connected by a brine pipe. Control valves are provided at the inlet and outlet of the brine pump. A pressure gauge and a thermometer are also provided at the outlet of the brine pump. Preferably, during active freezing, the central control platform adjusts the operating parameters of the freezer based at least on the cooling water temperature and the brine temperature to ensure that the frozen wall meets the freezing conditions. The central control platform's control of the freezer's operating parameters also improves the freezer's cooling efficiency. Preferably, the central control platform also adjusts the control valves based on the freezer's frosting condition to prevent uneven frosting or melting, thereby ensuring a uniform brine flow rate in the freezer. Preferably, the sensor module 3, located on the freezing pipe 2 and the temperature measuring pipe 4, is used to collect data on the pressure conditions of the connecting channel to analyze the required frozen wall parameters, and also to collect data on the formation of the frozen wall after freezing begins. This formation data includes the average temperature and thickness of the frozen wall. Preferably, the central control platform controls the freezing efficiency of the freezing machine based at least on the frozen wall parameters and the frozen wall formation data detected by the sensor module 3. This process is continuous and repeated multiple times, without a specific order. Preferably, the sensor module 3 detects the entire freezing period to ensure that the frozen wall parameters during excavation meet construction requirements, and to ensure that the frozen wall thickness does not increase before and during construction, preventing increased difficulty at the working face.

[0025] Due to the complex working conditions of underground construction on main urban roads, the thickness of the frozen walls used in connecting tunnel construction is often designed with a large safety margin. However, this design has the problem that increasing the thickness of the frozen wall significantly increases the freezing time, and excessively thick frozen walls lead to increased frozen soil, affecting the soil hardness at the construction face, increasing construction difficulty, and affecting the construction cycle. The increased construction cycle and freezing time also significantly increase construction costs. Therefore, how to minimize the thickness of the frozen wall while ensuring safe construction is a problem that existing technologies urgently need to solve. First, let's introduce the existing freezing method technology: The freezing method uses artificial refrigeration technology. By compressing the refrigerant, the temperature of brine is lowered to below zero degrees Celsius. Brine at below zero degrees Celsius is the main medium for adjusting underground temperature. The sub-zero brine releases the lower temperature to the underground soil, causing the water in the soil to freeze fully, thereby increasing the hardness of the underground soil. This freezes the water in the strata, turning loose water-bearing soil and rock into frozen soil, increasing its strength and stability, isolating groundwater, so that underground engineering excavation and construction operations can be carried out under the protection of the frozen wall. Currently, the freezing method is widely used in subway construction due to its high safety and strong water-sealing properties. While the freezing method offers good safety during excavation, it consumes a significant amount of energy because it requires a large number of freezing units for prolonged cooling. Furthermore, traditional freezing methods employ constant-temperature freezing during the maintenance freezing phase, resulting in large-area freezing of the tunnel face and increased strength, which significantly increases the difficulty of excavation.

[0026] To address the aforementioned issues, this invention proposes a cooling capacity monitoring and control system based on freezing parameters. This system indirectly controls the thickness of the frozen wall by controlling the cooling capacity of the freezing machine. Furthermore, the control process is based on a targeted control scheme derived from the pressure conditions of the underground connecting passage and the formation of the frozen wall obtained by sensor module 3. The system optimizes the frozen wall thickness based on the soil characteristics of the construction site, achieving automatic adjustment of the frozen wall thickness and cooling capacity. This ensures that the connecting passage is in a frozen state in the outer soil layer while the working face 10 remains unfrozen, thereby improving construction efficiency. This system not only ensures the safety of the construction process but also significantly shortens the construction period, meeting the requirements of cost, quality, and safety in the construction of the connecting passage.

[0027] Preferably, the method and system of the present invention can utilize wireless or wired sensor devices, including sensors applied to the working face 10, in several embodiments to control the cooling capacity in an automatic and continuous manner. The object of the present invention is to provide a cooling capacity control system that enables high-precision, low-cost, and easy-to-operate construction of connecting passages, even under urban main roads including aquifers. Preferably, the central control platform at least divides the optimization process of the frozen wall thickness and / or cooling capacity into preliminary selection, calibration, and comparison.

[0028] Preferably, the central control platform 9 can employ a general-purpose central processing unit (CPU), an application-specific integrated circuit (ASIC), a microprocessor, or one or more integrated circuits to execute relevant instructions or programs to implement the technical solution of the present invention. The central control platform 9 includes at least a computing module and a storage module. The storage module can be a component of the central control platform 9 or considered an independent element. For example, the storage device can be implemented using a read-only memory (ROM), a random access memory (RAM), a static storage device, a dynamic storage device, etc. The storage unit can store the input / output operating system, data storage management system, and running operating system of the central control platform 9. When implementing the technical solution of the present invention through software or hardware, the relevant program code can be stored in the storage unit and executed by the computing module. Preferably, a communication bus enables communication transmission between the aforementioned components. The central control platform 9 is connected to the sensor module 3 and the freezing station 8 via wired or wireless means. The central control platform 9 receives data from the sensor module 3 regarding the pressure conditions of the connecting channel and the formation of the frozen wall. It then processes this data through a calculation module for initial selection, calibration, and comparison, thereby controlling the freezing station 8 to output an appropriate cooling capacity. Preferably, the sensor module 3 can employ one or more of a load sensor, force sensor, torque sensor, and weight sensor to detect the external load on the connecting channel. Preferably, the sensor module 3 also includes a temperature sensor to obtain the temperature of the frozen wall. The data detected by the sensor module 3 is stored in a time-series format in the storage module of the central control platform 9.

[0029] Preferably, the central control platform performs a preliminary selection of the frozen wall thickness based at least on the pressure conditions of the connecting passage obtained by the sensor module. Preferably, the pressure conditions of the connecting passage include at least the external loads it experiences. Existing technologies still focus on the component directions of the external loads on the frozen wall. The frozen wall thickness is designed by dividing the external loads into vertical and horizontal forces. However, since the vertical part of the frozen wall is arched, and different soil types have different calculation characteristics, it is difficult to accurately calculate the frozen wall thickness. This often requires an excessively large safety margin to ensure the implementation of the project, which in turn leads to longer construction periods and increased costs. This invention, considering the arched top of the frozen wall and the actual construction environment of underground connecting passages in aquifers, proposes a construction method suitable for urban underground connecting passages. The minimum thickness of the frozen wall is obtained by detecting the pressure conditions of the connecting passage through the sensor module 3. Preferably, the central control platform calculates the actual stress conditions of the frozen wall based on the external loads obtained by the sensor module 3, and performs a preliminary selection of the frozen wall thickness based on these actual stress conditions. Preferably, the external load acquired by sensor module 3 refers to the magnitude of the force experienced by the connecting passage when it reaches support equilibrium. Sensor module 3 is at least positioned in the wedge-shaped areas on both sides of the connecting passage to acquire the magnitude of the force that ensures the stability of the connecting passage. In many existing frozen wall design schemes, the required support force of the connecting passage is calculated by measuring the pressure on the top of the frozen wall, i.e., the weight of the overburden above the connecting passage, the weight of the ground load, and the lateral pressure based on active earth pressure theory. However, this method is typically used for calculating frozen walls in clay layers and is not applicable to connecting passages in deeply buried water-rich layers under urban main roads. The calculated frozen wall thickness is often greater than the actual requirement, leading to increased construction costs and significantly increased construction difficulty. In response, the external load acquired by the lateral sensor module 3 of this invention differs from the existing method of calculating the pressure on the top of the frozen wall. By considering the construction environment, the required support force of the connecting channel is calculated, and the working face 10 of the connecting channel is treated as a whole to obtain a more realistic stress condition of the frozen wall, thereby planning a frozen wall thickness scheme for initial selection.

[0030] According to a preferred embodiment, the central control platform 9 constructs a cross-sectional model of the connecting channel based on the sensor module 3 installed in the connecting channel to obtain the stress distribution of the frozen wall. Preferably, the central control platform 9 derives a stress distribution plan for the frozen wall based on the constructed cross-sectional model of the connecting channel to obtain a preliminary selection scheme for the thickness of the frozen wall. Compared with existing calculations that numerically equate the pressure at the top of the frozen wall to the total weight of the overlying soil and ground load, this invention delves into the stress during the construction process of the connecting channel in the deeply buried water-rich layer to obtain a preliminary selection. Preferably, after obtaining the external load, the central control platform 9 performs structural internal force calculations on the cross-section of the connecting channel based on structural mechanics. Preferably, the central control platform 9 calculates the bending moment, shear force, and axial force at the frozen wall cross-section based on the elastic modulus of the frozen soil, flexibility coefficient, moment of inertia of the cross section, cross-sectional radius, and the included angle of the top arch according to the superposition principle, thereby obtaining the minimum thickness of the top arch and bottom rectangle that satisfies bending, shear, and compressive resistance. Specifically, the formula for the thickness of the frozen wall in the preliminary selection scheme is as follows:

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037] Where h1, h2, and h3 are the minimum thicknesses of the straight walls on both sides of the frozen wall; h4, h5, and h6 are the minimum thicknesses of the top wall of the frozen wall; [q1], [q2], and [q3] are the compressive, flexural, and shear strengths of the frozen wall at the average temperature; Q1, Q1, and Q1 are the construction safety factors for the compressive, flexural, and shear strengths of the frozen wall; F1, F2, and F3 are the axial force, shear force, and bending moment of the straight walls on both sides of the frozen wall; and F4, F5, and F6 are the axial force, shear force, and bending moment of the top wall of the frozen wall.

[0038] According to a preferred embodiment, the central control platform performs finite element analysis on the frozen wall based on external loads and the frozen wall thickness obtained above to calibrate the initial selection of the frozen wall thickness. Preferably, the finite element analysis uses the compression conditions of the connecting passage obtained by the sensor module to construct the model. The parameters of the compression conditions include: soil elastic modulus, average temperature of the frozen wall, compressive strength parameters, bending strength parameters, shear strength parameters, and cross-sectional geometric parameters. Preferably, the central control platform determines whether the initially selected frozen wall thickness meets the construction standards based on the established finite element model. If the finite element model meets the construction standards, the minimum thickness obtained by the central control platform 9 is used as the initial selection. If the finite element model does not meet the construction standards, the central control platform 9 controls the sensor module 3 to perform parameter calibration and re-performs the initial selection. The above-mentioned finite element model meeting the construction standards means that the deformation degree of the top settlement and bottom bulge of the frozen wall is less than the requirements of the construction specifications. This invention is particularly applicable to the construction of connecting passages with large burial depths. The above-mentioned minimum thickness of the frozen wall refers to the minimum thickness of the frozen wall required without affecting the excavation state of the tunnel face, under the premise of meeting the construction requirements for supporting the connecting passage. The initially selected minimum thickness has multiple dimensions, including the minimum thickness at the top, sides, and bottom. It is the minimum thickness derived for external loads, without considering the influence of the water-rich layer, and has multiple definite options.

[0039] The aforementioned preliminary selection and calibration are calculations based on external loads detected by the sensor module. However, the construction conditions of connecting passages vary, for example, in urban underground construction, it is often necessary to construct connecting passages beneath water-rich layers. Different soil types also bring different construction conditions, requiring further comparison of frozen wall parameters based on these soil characteristics. Preferably, the central control platform establishes at least a three-dimensional model of the connecting passage for comparison. Preferably, the central control platform establishes a three-dimensional model based on the physical and mechanical parameters of the soil layers. These soil physical and mechanical parameters can be obtained from the sensor module or from on-site surveys. The actual working conditions of the connecting passage are simulated and analyzed using the aforementioned three-dimensional model to achieve comparison. The purpose of the above comparison is also to comprehensively consider all structural issues in actual engineering. In the aforementioned preliminary selection process, the frozen wall is equivalent to a regular cross-section in the calculation process. However, in actual construction, it is impossible to maintain a regular cross-section. Therefore, this invention proposes to establish a three-dimensional model to compare the thickness of the frozen wall. The purpose of the above comparison is also that existing technologies only consider the frozen wall structure in the geostress field when establishing the three-dimensional spatial structure of the connecting passage, without considering the influence of the seepage stress field on the connecting passage when it is in a water-rich layer. The comparison of the present invention fully considers the redistribution of the geostress field in the water-rich layer under the influence of the seepage stress field, and the selection of the frozen wall thickness of the connecting passage at the burial depth of the water-rich layer is a very important technical means.

[0040] According to a preferred embodiment, the overall control platform 9 compares and selects the thickness of the frozen wall of the water-rich layer connecting channel based at least on the fluid-structure interaction theory. Preferably, the overall control platform 9 uses the extension direction of the connecting channel as the first direction, the direction perpendicular to the first direction in the horizontal plane as the second direction, and the vertical direction as the third direction. Preferably, the overall control platform 9 uses the first direction, the second direction, and the third direction as the Y-axis, X-axis, and Z-axis, respectively. To avoid the influence of boundary effects and to maintain high calculation accuracy, the modeling data for the X-axis, Y-axis, and Z-axis are (80m, 240m, 100m). Preferably, the overall control platform 9 selects the initial geostress field as the pressure of the overlying 5m water body, and generates it according to the stepwise gravity of the soil. Preferably, the overall control platform 9 selects the initial seepage stress field as the fixed water head of the upper surface of 5m, and generates the hydrostatic pressure according to the stepwise gravity field of the water body. Preferably, the overall control platform 9 establishes a model based on the physical and mechanical parameters of the soil layer. Preferably, the physical and mechanical parameters of the soil layer include bulk modulus, shear modulus, cohesion, and natural density, etc. For example, the physical and mechanical parameters of silty clay are: bulk modulus 106 MPa, shear modulus 58 MPa, cohesion 0.3 MPa, and natural density 1880 kg·m³. -3 The physical and mechanical parameters of the gravelly clay soil are as follows: bulk modulus 114 MPa, shear modulus 61 MPa, cohesion 0.4 MPa, and natural density 1890 kg·m³. -3 The physical and mechanical parameters of the soil layer of completely weathered granite are: bulk modulus 404 MPa, shear modulus 230 MPa, cohesion 0.3 MPa, and natural density 2040 kg·m³. -3 Preferably, the physical and mechanical parameters of the soil layer can be obtained by sensor module 3 or by on-site geological survey. Preferably, the overall control platform 9 sets the fluid density within the frozen wall to 1000 kg·m³. -3 The fluid modulus is taken as 2.10. 9 Pa. It should be noted that the above parameters are exemplary parameters, which are theoretical physical and mechanical parameters of a water-rich layer at a burial depth of 30m. In actual applications, the physical and mechanical parameters of the soil layer will vary depending on the geology of different locations.

[0041] Preferably, the central control platform 9 activates the frozen wall structure by assigning values ​​to the established 3D model and completes the construction simulation. Preferably, the central control platform 9 compares and selects the minimum thickness based on the simulation results. Preferably, the central control platform 9 judges the changes in the model's crown settlement, arch bottom heave, and arch waist convergence. Preferably, the central control platform 9 obtains the construction characteristics of the aquifer by comparing the structural internal forces of frozen wall models of the same thickness in the geostress field and seepage stress field; then, it judges the stress of frozen walls of different thicknesses in the combined construction environment of geostress field and seepage stress field, so as to optimize the minimum thickness obtained in the initial selection. Preferably, the central control platform 9 compares and selects the minimum thickness obtained in the initial selection based on the above 3D model so that the obtained final minimum thickness meets the construction characteristics of the aquifer. The comparison result shows that the obtained minimum thickness meets the water-stopping requirements. Preferably, the central control platform 9 determines the required thickness of the frozen wall through the deformation monitoring points of the above 3D model. This invention establishes a three-dimensional model to compare and judge the deformation trends and mechanical changes of the frozen wall under different soil layer construction environments, enabling verification of the initially selected minimum thickness and further comparison, thereby saving construction time and costs and improving construction efficiency. Addressing the problem that existing methods for determining cooling capacity and frozen wall thickness do not consider the influence of soil layers, resulting in insufficient accuracy and practicality, this invention uses a sensor module 3 to detect the temperature of the working face 10 and the frozen wall throughout the entire freezing method construction process, increasing the reference basis and construction safety. Based on the general process of judging the thickness of connecting passages in existing technologies, this invention proposes initial selection, calibration, and comparison, further considering soil layer properties, especially the construction properties of underground connecting passages in water-rich layers, and creatively proposes a cooling capacity detection and control system. Relying on the cooling capacity and frozen wall thickness, the frozen wall thickness during construction meets the construction strength requirements without affecting the excavation state of the working face 10, balancing construction safety and economy. The aforementioned minimum thickness of the frozen wall refers to the minimum thickness required to support the connecting passage construction without affecting the excavation state of the working face. The minimum thickness selected through comparison is the minimum thickness of the frozen wall that meets the construction standards, after further comparison of several determined schemes after initial selection and calibration, taking into account the influence of the soil quality of the water-rich layer.

[0042] The above-mentioned methods of preliminary selection, calibration, and comparison reasonably and conveniently calculate the mechanical changes during the construction of the frozen wall, providing basic construction parameters, fully utilizing the bearing capacity of the frozen wall, and ensuring that the thickness and cooling requirements of the frozen wall designed by the above methods meet the engineering needs, achieving the goal of freezing the soil around the tunnel while the excavated soil does not freeze, thus realizing the technical effects of reducing construction difficulty, improving construction efficiency, shortening the construction period, and energy conservation and environmental protection.

[0043] According to a preferred embodiment, the central control platform controls the freezing efficiency of the freezing machine based on at least the minimum thickness of the frozen wall and the formation status of the frozen wall. During active freezing, the thickness of the frozen wall in the connecting channel increases non-linearly, and the temperature varies at different locations, causing the temperature of the frozen wall far from the freezing pipe to fail to meet construction requirements, and even resulting in a frozen wall thickness that does not meet the minimum thickness. Preferably, the central control platform adjusts the brine temperature accordingly based on the frozen wall formation status to ensure that the frozen wall formation conforms to the calculated minimum thickness. The temperature difference between the outgoing and return brine is no greater than 2°C. The minimum temperature of the brine is -30°C, and the maximum temperature is -10°C. The brine temperature change is non-linear and conforms to the frozen wall thickness increase curve. During active freezing, the edge of the frozen wall far from the freezing pipe cools down more slowly, but as the core temperature at the freezing pipe decreases, the cooling rate at the edge gradually increases. The brine temperature change curve is designed to conform to this curve change, slowing down the heating rate of the brine temperature change curve at the end of active freezing, thereby preventing the frozen wall thickness from exceeding the preset standard. Preferably, the central control platform adjusts the operating parameters of the freezing machine based at least on the cooling water temperature and brine temperature to improve the freezing efficiency of the freezing machine. Preferably, the brine temperature variation curve is a control curve established based on the time-related average temperature of the frozen wall detected by the sensor module. Preferably, the central control platform 9 controls the brine temperature based on the brine temperature variation curve. Preferably, in the time series, when there is a difference between the brine temperature variation curve and the average temperature of the frozen wall (or the difference between the edge temperature and the center temperature of the frozen wall), the central control platform updates the brine temperature variation curve to ensure that the thickness and temperature of the frozen wall are at the construction standard and / or minimum thickness and temperature standard. Preferably, the detection frequency of the sensor module is set to shorten the detection time cycle as the construction progresses and / or the frozen wall development trend increases. Due to the difference between the center temperature and the edge temperature of the frozen wall, when the center temperature of the frozen wall reaches the required construction standard, the edge temperature has not yet reached the construction standard. However, as the brine temperature continues to decrease at this time, the soil outside the edge will also be affected by the cooling and form frozen soil, resulting in an increase in the actual thickness of the frozen wall. Therefore, this invention sets up a brine temperature variation curve to monitor the temperature difference between the center and edge of the brine. By slowing down or pausing the brine temperature drop rate, the freezing impact on the soil outside the edge is reduced, ensuring the construction progress. Simultaneously, the additional thickness of the frozen wall causes the soil at the construction face to harden, increasing the construction difficulty. This invention automatically controls the brine temperature by using the frozen wall formation detected by sensor module 3 and controlling the freezing efficiency of freezing station 8 through a central control platform, achieving precise control over the thickness of the formed frozen wall.

[0044] According to a preferred embodiment, the central control platform performs finite element analysis on the frozen wall temperature curve based on frozen wall temperature monitoring to predict the formation of the frozen wall thickness. The aforementioned finite element numerical analysis is used at least to detect the development trend of the frozen wall thickness, so as to control the cooling efficiency of the freezing machine through the central control platform. The finite element numerical analysis is also used to detect the frost heave deformation of the connecting channel, preventing temperature changes from causing the supporting force of the connecting channel to fail to meet requirements. Preferably, after the frozen wall thickness meets the construction requirements, the average temperature of the frozen wall detected by its sensor module is less than -10℃, the surface temperature of the frozen wall is less than -5℃, and the brine temperature is less than -28℃. Preferably, the central control platform summarizes the freezing data and temperature change curves detected by the sensor modules installed on the temperature measuring tube to calculate the average development speed of the frozen wall. Preferably, the central control platform calculates the maximum hole spacing of the frozen wall based on the freezing hole deviation to calculate the freezing wall overlap time, thereby obtaining the frozen wall thickness. Preferably, the central control platform compares the detected frozen wall thickness with the calculated minimum frozen wall thickness to adjust the cooling efficiency of the freezing machine. Preferably, construction personnel also conduct borehole inspections within the connecting passage to determine the temperature changes of the frozen wall, thereby assessing whether the frozen wall meets construction safety requirements. The borehole locations are chosen at points with larger gaps or abnormal areas within the connecting passage. Preferably, the sensor module also detects the surface temperature and displacement of the frozen wall; if a localized temperature increase or deformation occurs in the frozen wall, the water flow rate at the abnormal location is increased. Preferably, after active freezing, the brine temperature is maintained below -25°C. Preferably, after active freezing, the central control platform monitors the freezing process based on the sensor module's detection data to ensure the effective operation of the freezing system.

[0045] Through these preferred embodiments of the present invention, the pressure condition of the connecting passage and the formation of the frozen wall are monitored before, during, and after active freezing. The central control platform calculates the minimum required thickness of the frozen wall under the current construction conditions and the freezing machine parameters to ensure that the frozen wall reaches the required thickness, and then automatically adjusts the system. This is particularly beneficial for staff or superiors to use smart devices to obtain the status of the connecting passage before and during construction from the central control platform. Construction sites often result in unstable network communication conditions; therefore, the central control platform summarizes and calculates the monitoring data from the construction site, reducing communication overhead. While the minimum frozen wall thickness calculated by the central control platform of this invention meets construction requirements, it often requires construction personnel to report to superiors for further confirmation, and the construction site conditions need to be monitored to determine emergency measures. Due to the numerous parameters at the construction site, if the frost heave of the connecting passage or the formation of the frozen wall exceeding a predetermined threshold cannot be reported in a direct and low-bandwidth manner, it is difficult for superiors to provide scientific solutions remotely and on-site. By utilizing the aforementioned design of this invention, the thickness of the frozen wall can be designed and the subsequent formation of the frozen wall can be monitored. This allows for comprehensive planning of the construction process and the transmission of critical abnormal data to higher authorities, preventing the latter from making difficult decisions due to information asymmetry.

[0046] Throughout the text, the features indicated by “preferred” are only optional and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete the relevant preferred features at any time.

[0047] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; terms such as "preferredly," "according to a preferred embodiment," or "optionally" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept.

Claims

1. A cooling capacity monitoring and control system based on freezing parameters, characterized in that, It includes at least a central control platform (9) and a sensor module (3), wherein, The sensor module (3) is installed at the freezing pipe (2) and the temperature measuring pipe (4) of the communication channel (1) to obtain the pressure condition of the communication channel (1) and the formation of the freezing wall. The overall control platform (9) divides the process of optimizing the thickness of the frozen wall into preliminary selection, calibration and comparison based on the pressure condition of the communication channel (1) detected by the sensor module (3) before active freezing, and controls the freezing efficiency of the freezing station (8) based on the formation of the frozen wall detected by the sensor module (3) during active freezing. The overall control platform (9) performs finite element analysis on the frozen wall temperature curve based on frozen wall temperature monitoring to predict the formation of frozen wall thickness; wherein, The central control platform (9) summarizes the freezing data and temperature change curves detected by the sensor module (3) set on the temperature measuring tube (4) to calculate the average speed of the frozen wall development; the central control platform (9) calculates the maximum hole spacing of the frozen wall based on the deviation of the freezing hole to calculate the freezing wall overlap time, thereby obtaining the frozen wall thickness; the central control platform (9) compares the detected frozen wall thickness with the calculated minimum frozen wall thickness to adjust the freezing efficiency of the freezing station (8).

2. The system according to claim 1, characterized in that, The central control platform (9) performs a preliminary selection of the thickness of the frozen wall based on the pressure condition of the communication channel (1) obtained by the sensor module (3); The sensor module (3) is at least disposed in the wedge-shaped areas on both sides of the communication channel (1) to obtain the magnitude of the force that makes the communication channel (1) stable. The central control platform (9) constructs a face model based on the sensor module (3) set in the communication channel (1) to obtain the force distribution of the frozen wall.

3. The system according to claim 1, characterized in that, The overall control platform (9) performs finite element analysis on the frozen wall based on the external load obtained by the sensor module (3) and the frozen wall thickness obtained from the preliminary selection process in order to calibrate the preliminary selection of the frozen wall thickness.

4. The system according to claim 1, characterized in that, The overall control platform (9) shall at least establish a three-dimensional model of the connecting passage (1) for comparison; the overall control platform (9) shall establish a three-dimensional model based on the physical and mechanical parameters of the soil layer; the overall control platform (9) shall at least compare the frozen wall thickness of the water-rich connecting passage (1) based on the fluid-solid coupling theory; wherein, The overall control platform (9) activates the frozen wall structure by assigning values ​​to the established three-dimensional model and completes the construction simulation; the overall control platform (9) compares and selects the minimum thickness based on the results of the assignment simulation.

5. The system according to claim 4, characterized in that, The overall control platform (9) compares the minimum thickness obtained in the preliminary selection based on the three-dimensional model, so that the final minimum thickness obtained meets the construction characteristics of the water-rich layer; the overall control platform (9) determines the required thickness of the frozen wall through the deformation monitoring points of the three-dimensional model, wherein, The deformation monitoring points of the three-dimensional model include abrupt change points in the process of changes in the model's arch crown settlement, arch base heave, and arch waist convergence.

6. The system according to claim 5, characterized in that, The overall control platform (9) controls the freezing efficiency of the freezing station (8) based at least on the minimum thickness of the frozen wall and the formation of the frozen wall, wherein, The freezing station (8) is configured with at least a freezing module and a brine module. The freezing module includes a freezing machine, a freezing tower, a water tank, and a water pump. The freezing machine, freezing tower, water tank, and water pump are connected by pipes to form a circulation pipeline. The inlet and outlet of the freezing machine and water pump, and the inlet of the freezing tower are all equipped with control valves. The brine module includes a brine tank and a brine pump. The brine tank, brine pump, freezing machine, and conduit are connected by brine pipes. The inlet and outlet of the brine pump are equipped with control valves. During active freezing, the central control platform (9) adjusts the operating parameters of the freezing machine based at least on the cooling water temperature and the brine temperature to ensure that the frozen wall meets the freezing conditions.

7. The system according to claim 6, characterized in that, The overall control platform (9) adjusts the brine temperature accordingly based on the formation of the frozen wall to ensure that the formation of the frozen wall conforms to the calculated minimum thickness of the frozen wall; wherein... The overall control platform (9) dynamically adjusts the brine temperature change curve based at least on the curve of the increase in frozen wall thickness.

8. A method for monitoring and controlling cooling capacity based on freezing parameters according to any one of claims 1 to 7, characterized in that, The method steps include: Obtain information on the pressure conditions of the communication channel (1) and the formation of the frozen wall, wherein, The overall control platform (9) divides the process of optimizing the thickness of the frozen wall into preliminary selection, calibration and comparison based on the pressure condition of the communication channel (1) detected by the sensor module (3) before active freezing, and controls the freezing efficiency of the freezing station (8) based on the formation of the frozen wall detected by the sensor module (3) during active freezing.

9. The method according to claim 8, characterized in that, The method steps also include: The central control platform (9) performs a preliminary selection of the thickness of the frozen wall based on the pressure condition of the communication channel (1) obtained by the sensor module (3); The overall control platform (9) performs finite element analysis on the frozen wall based on the external load obtained by the sensor module (3) and the frozen wall thickness obtained by the preliminary selection process to calibrate the preliminary selection of the frozen wall thickness. The overall control platform (9) at least compares the thickness of the frozen wall of the water-rich layer connecting channel (1) based on the fluid-structure interaction theory.

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