A cold energy automatic control system and method for construction of a liaison channel freezing method

Abstract

The present application relates to a kind of cold automatic control system and method for communication passage freezing method construction, system at least includes total control unit and sensor unit.Sensor unit is set at the freezing pipe of communication passage and temperature measuring tube to obtain freezing construction data, and total control unit calculates required cold and required freezing wall thickness based on the freezing construction data obtained to carry out active freezing.Total control unit at least the selection process of freezing wall thickness and / or required cold is divided into first preliminary selection, second selection and third preferred.The present application is aimed at the problem that prior art cannot objectively and truly reflect the required cold and required freezing wall thickness of long-distance communication passage freezing method construction in water-rich layer, freezing wall thickness design scheme of communication passage is divided into three stages, to propose a kind of different from prior art, more suitable for water-rich layer underground communication passage excavation cold automatic control system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of communication passage construction, in particular to a cold quantity automatic control system and method for communication passage freezing method construction. BACKGROUND

[0002] With the continuous development of subway engineering scale, the depth of subway tunnel is increasing, and the content of groundwater is increasing with the increase of depth. At the same time, the subway line is generally arranged under the city trunk road. Due to the continuous increase of the width of the city trunk road, the distance between the subway lines is gradually widened. At present, the freezing method is usually used for excavation of the rich water layer of the subway communication passage. The freezing method is to use artificial refrigeration technology. The temperature of brine is reduced to below zero Celsius by compression treatment of refrigeration material. The brine with temperature below zero Celsius is the main medium for adjusting underground temperature. The brine with negative temperature will release lower temperature to the underground soil, so that the water in the soil is fully frozen, thereby improving the hardness of the underground soil. The water in the stratum is frozen, the loose water-bearing rock-soil is changed into frozen soil, the strength and stability are increased, and the groundwater is isolated, so that the underground engineering excavation operation can be carried out under the protection of the freezing wall. At present, the freezing method is widely used in subway engineering construction due to its high safety, strong water sealing and other characteristics.

[0003] Although the freezing method has good safety during excavation, a large number of freezing units are used for long-time cooling, which consumes a large amount of energy. On the other hand, the traditional freezing method uses constant temperature freezing method in the maintenance freezing stage, which causes large-area freezing of the working face and increases the strength, greatly increasing the excavation difficulty. In order to solve the above problems, the purpose of the present application is to provide a cold quantity control method for long-distance communication passage freezing method construction in rich water layer of subway. The core of the method is the automatic regulation and control of cold quantity, so that the communication passage is in the peripheral soil freezing state and the working face is in the unfrozen state, thereby improving the construction efficiency. The method not only has the advantages of safety and stability in freezing method construction, but also has the characteristics of energy saving and environmental protection, improving construction efficiency, shortening construction period and other characteristics, which can meet the needs of communication passage construction period, cost, quality and other aspects. The key point of the present application is to solve the problem that the existing technology cannot objectively and truly reflect the required cold quantity and required freezing wall thickness of the long-distance communication passage freezing method construction in rich water layer. The freezing wall thickness design scheme of the communication passage is divided into three stages, so as to propose a control system different from the prior art and more suitable for excavation of rich water layer underground communication passage.

[0004] Chinese patent CN111734416A discloses a construction method of ordinary freezing method for deep water-rich rock shaft, and discloses seven specific steps, including designing the freezing hole, temperature isolation hole and hydrological hole of the shaft, and determining the depth of each hole; before the hole forming construction, the leakage is blocked to prevent hole collapse, drill sticking, drill burying and reduce the amount of slurry leakage; the freezing hole, temperature isolation hole and hydrological hole are constructed, after the drilling of the freezing hole outside the shaft excavation and lining is completed, the ground refrigeration station continuously supplies cold to the freezing hole, so that the stratum is frozen to form a closed frozen soil wall, ensuring that the frozen wall of the stratum of the formed shaft and the stratum of the unexcavated and lined section is interlocked to seal water, the freezing hole continues to supply cold, so that the closed frozen soil wall continuously expands to a certain thickness and strength, ensuring that the shaft excavation of the lower freezing section is not affected by the water and quicksand in the stratum. The patent is safe, high in reliability and small in environmental pollution; not only realizes the safe and smooth excavation of the shaft, but also ensures the quality of the shaft wall, providing reliable protection for the construction of deep water-rich soft rock shaft. However, the patent does not consider the influence of ground stress change on the construction of the frozen wall during the construction of the water-rich layer, and simply uses the freezing method for the construction of the deep water-rich soft rock shaft, resulting in improper freezing thickness of the construction working face and improper cold supply, increasing the construction difficulty, construction cost and construction period, and even having certain construction risks.

[0005] In addition, on the one hand, there are differences in the understanding of those skilled in the art; on the other hand, a large number of literatures and patents have been studied by the applicant when making the present application, but due to the limitation of space, all the details and contents are not listed in detail, which does not mean that the present application does not have these characteristics of the prior art, on the contrary, the present application has all the characteristics of the prior art, and the applicant reserves the right to add relevant prior art in the background art. SUMMARY

[0006] The present application is aimed at the problem that the prior art cannot objectively and truly reflect the required cold and the required frozen wall thickness of the freezing method construction of the long-distance connecting passage in the water-rich layer, and divides the connecting passage frozen wall thickness design scheme into three stages to propose a control system different from the prior art and more suitable for the excavation of the underground connecting passage in the water-rich layer.

[0007] In view of the deficiencies of the prior art, the present application provides a cold quantity automatic control system for the construction of a communication passage freezing method, which comprises at least a total control unit and a sensor unit. The sensor unit is arranged at the freezing pipe and the temperature measuring pipe of the communication passage to obtain freezing construction data, and the total control unit calculates the required cold quantity and the required freezing wall thickness based on the obtained freezing construction data to actively freeze. The total control unit divides the selection process of the freezing wall thickness and / or the required cold quantity into at least a first preliminary selection, a second intermediate selection and a third preferred selection. The above-mentioned first preliminary selection, second intermediate selection and third preferred selection reasonably and conveniently calculate the mechanical changes during the freezing wall construction, provide the basic parameters of the construction, fully exert the bearing capacity of the freezing wall, so that the freezing wall thickness and the required cold quantity designed by the above-mentioned method meet the engineering requirements, achieve the purpose of freezing the soil around the tunnel and not freezing the excavated soil, and realize the technical effects of reducing the construction difficulty, improving the construction efficiency, shortening the construction period and saving energy and protecting the environment.

[0008] According to a preferred embodiment, the freezing construction data at least includes the external load, temperature change and soil layer physical and mechanical parameters. The total control unit at least performs the first preliminary selection of the freezing wall thickness based on the freezing construction data obtained by the sensor unit. The total control unit at least calculates the external load as the actual stress of the freezing wall based on the geological characteristics of the water-rich layer, and performs the first preliminary selection of the freezing wall thickness of the communication passage based on the calculated actual stress of the freezing wall. The present application arranges the sensor unit to obtain the external load of the freezing wall, considers the stratum properties and the buried depth of the water-rich layer, calculates the high-precision internal force of the structure, and performs the first preliminary selection of the freezing wall thickness, which has important practical significance.

[0009] According to a preferred embodiment, the total control unit plans the freezing wall thickness in the first preliminary selection based on the stress distribution of the freezing wall. After obtaining the external load, the total control unit calculates the internal force of the structure of the communication passage based on structural mechanics. The total control unit calculates the bending moment, shear force and axial force at the cross section of the freezing wall according to the superposition principle based on the elastic modulus of frozen soil, flexibility coefficient, cross-sectional moment of inertia, cross-sectional radius and the arch angle of the top of the height, and further obtains the minimum thickness of the top arch and the bottom rectangle that meet the bending resistance, shear resistance and compression resistance. The external load obtained by the lateral sensor unit is different from the way of calculating the top pressure and the side pressure separately in the prior art. By considering the stratum environment, the balance relationship between the top pressure and the side pressure is calculated, the working face of the communication passage is taken as a whole, and the stress distribution of the freezing wall is obtained, so that the freezing wall thickness scheme for the first preliminary selection is planned.

[0010] According to a preferred embodiment, the general control unit performs finite element analysis on the freezing wall based on at least the external load and the obtained freezing wall thickness to calibrate the minimum thickness. In the established finite element model, the general control unit determines whether the freezing wall thickness meets the construction standard; in the case that the finite element model meets the construction standard, the minimum thickness obtained by the general control unit is the first preliminary selection; in the case that the finite element model does not meet the construction standard, the general control unit controls the sensor unit to perform parameter calibration, and the first preliminary selection is re-performed.

[0011] According to a preferred embodiment, the general control unit performs the second selection based on at least the temperature change detected by the sensor unit, wherein the general control unit calculates the cooling demand based on at least the freezing pipe parameters and the refrigeration pipe parameters, and adjusts the cooling demand based on the third preferred freezing wall thickness, and the calculation formula of the cooling demand is:

[0012] Q = 1.25 x π x h1 x d1 x K + 1.3 x π x h2 x d2 x K

[0013] The general control unit calculates the cooling demand based on the formula, and controls the cooling supply based on the obtained cooling demand and the temperature change obtained by the sensor unit, so that the freezing wall temperature is maintained under the freezing condition. The cooling supply is temperature-variable frozen with the change of the temperature, prevents large-area freezing of the working face in the case of saving energy of the freezing unit, and reduces the construction difficulty. The general control unit adjusts the cooling supply based on at least the required freezing wall thickness, so that the freezing wall is in a state that meets the freezing condition and does not affect the excavation state of the working face.

[0014] According to a preferred embodiment, the general control unit establishes a three-dimensional spatial structure of the connection channel based on at least the freezing construction data obtained by the sensor unit, to truly reproduce the stress environment of the stratum; and then, through the three-dimensional spatial structure and material parameters, simulates and analyzes the thickness of the freezing wall in the connection channel of the water-rich layer; thereby further optimizing the first preliminary selection. As can be seen from the above first preliminary selection, the thickness of the freezing wall of the connection channel of the water-rich layer can be preliminarily selected by the external load detected by the sensor unit through the calculation and modeling of the general control unit. However, due to the limitation of the parameters, all structural problems in actual engineering cannot be considered comprehensively, for example, only the cross-section problem is considered in the calculation of the internal force of the structure; the cross-section regularization problem. It is necessary to further optimize the above first preliminary selection to obtain a third preferred selection with higher rationality and reliability.

[0015] According to a preferred embodiment, the total control unit is based on the freezing wall structure under the influence of the water-rich layer seepage stress field and the ground stress field to perform a third optimization, wherein the total control unit sets the connection passage extension direction as a first direction, a direction perpendicular to the first direction in the horizontal plane as a second direction, and a vertical direction as a third direction, and takes the first direction, the second direction and the third direction as Y-axis, X-axis and Z-axis; the total control unit establishes the three-dimensional space structure model based on the soil layer physical and mechanical parameters, the Y-axis, the X-axis and the Z-axis.

[0016] According to a preferred embodiment, the total control unit activates the freezing wall structure in a manner of assigning values to the established three-dimensional space structure model, and completes construction simulation, and the total control unit performs a third optimization on the minimum thickness based on the simulation result of the assignment. Wherein the total control unit at least judges the change process of the model vault settlement, vault bottom heave and arch waist convergence. Wherein the total control unit obtains the water-rich layer construction characteristics by respectively comparing the internal forces of the freezing wall model with the same thickness in the ground stress field and the seepage stress field; and further judges the stress of the freezing wall with different thicknesses in the combined construction environment of the ground stress field and the seepage stress field, so as to realize the third optimization on the minimum thickness obtained by the first preliminary selection. The three-dimensional space structure model established by the present application compares and judges the deformation trend and mechanical change of the freezing wall in different soil layer construction environments, realizes the minimum thickness checking and further selection of the first preliminary selection, thereby saving the construction period and construction cost, and improving the construction efficiency. The present application considers the influence of the soil layer on the required cooling capacity and the thickness of the freezing wall, which solves the problems of insufficient accuracy and practicability. The sensor unit is arranged to detect the temperature of the working face and the freezing wall during the whole freezing construction process, so as to increase the reference basis and construction safety. Based on the general process of the existing technology for judging the thickness of the connection passage, the present application proposes a three-step method, further considers the properties of the soil layer, especially the construction properties of the water-rich layer underground connection passage, and creatively proposes a cold quantity automatic control system for the freezing construction of the connection passage. The required cooling capacity and the thickness of the freezing wall make the thickness of the freezing wall during the construction process meet the construction strength requirement and not affect the excavation state of the working face, and the safety and economy of the construction are considered.

[0017] The application also relates to a cold automatic control method for construction of a contact passage freezing method, and the method steps comprise the following: freezing pipes are arranged on both sides of the contact passage, and a freezing pipe sensor unit is arranged; a temperature measuring pipe is arranged, and a temperature measuring pipe sensor unit is arranged; a salt water pipe is connected with a freezing station in an existing tunnel, the freezing station is controlled by a general control unit, and active freezing is carried out according to a calculation result; after the active freezing is completed, excavation is carried out; during the excavation, a working face temperature measuring point is arranged on a working face, and each temperature measuring point is monitored during the excavation; monitoring data are uploaded to the general control unit in real time, and the general control unit automatically adjusts the cold supply capacity of the freezing station according to monitoring data, geological conditions, tunnel working conditions and the like after analysis and processing, so that the freezing wall is in a thickness that meets freezing conditions and does not affect the working face excavation state.

[0018] According to a preferred embodiment, the method steps further comprise that the general control unit divides at least the selection process of the freezing wall thickness and / or the cold demand into a first preliminary selection, a second intermediate selection and a third preferred selection, wherein: the general control unit calculates the obtained external load as the actual stress of the freezing wall based on at least the geological characteristics of the water-rich layer, and performs the first preliminary selection on the thickness of the freezing wall of the contact passage based on the calculated actual stress of the freezing wall; the general control unit performs the second intermediate selection based on at least the temperature change detected by the sensor unit; the general control unit establishes a three-dimensional space structure of the contact passage based on at least the freezing construction data obtained by the sensor unit, so as to reproduce the stress environment of the stratum; and then, the stress of the freezing wall with different thicknesses in the combined construction environment of the ground stress field and the seepage stress field is judged, so as to realize the third preferred selection on the minimum thickness obtained by the first preliminary selection. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic diagram of a cold automatic control system for construction of a contact passage freezing method according to a preferred embodiment of the application;

[0020] Figure 2 is a working face sectional view of a cold automatic control system for construction of a contact passage freezing method according to a preferred embodiment of the application.

[0021] LIST OF REFERENCE NUMBERS

[0022] 1: contact passage; 2: freezing pipe; 3: sensor unit; 4: temperature measuring pipe; 6: existing tunnel; 7: salt water pipe; 8: freezing station; 9: general control unit; 10: working face; 11: freezing wall. DETAILED DESCRIPTION

[0023] The application will be described in detail below with reference to the drawings.

[0024] Example 1

[0025] The present invention relates to a cold energy automatic control system for the construction of a connection passage freezing method. The present invention relates to the construction of a long distance connection passage freezing method in a water-rich layer. More specifically, the present invention relates to a device, system, and method for determining the required cold energy using a sensor device that measures the freezing wall thickness and temperature associated with the peripheral soil layer of the connection passage. The sensors used in the present invention include, but are not limited to, wired or wireless sensor devices and sensor devices that can include wired and wireless features.

[0026] In conventional underground tunnel excavation projects, due to the continuous development of urbanization, the tunnel depth is increasing, and the groundwater content increases with the increase in depth. At the same time, the width of the main road of the city is increasing with the development, and the tunnel line spacing is gradually widening. Currently, the excavation of the underground connection passage in the water-rich layer usually uses the freezing method. The freezing method uses artificial refrigeration technology to reduce the temperature of the brine to below zero degrees Celsius by compressing the refrigeration material. The brine with a temperature below zero degrees Celsius is the main medium for adjusting the underground temperature, and the negative temperature brine releases lower temperature to the underground soil, causing the water in the soil to freeze, thereby improving the hardness of the underground soil. The water in the ground freezes, and the loose water-containing rock-soil becomes frozen soil, increasing its strength and stability, and isolating groundwater, so that underground engineering excavation work can be carried out under the protection of the freezing wall. Currently, the freezing method is widely used in subway engineering construction due to its high safety, strong water sealing, and other characteristics. Although the freezing method has good safety during excavation, it requires a large amount of energy due to the use of a large number of freezing units for a long time. On the other hand, the traditional freezing method uses constant temperature freezing during the maintenance freezing stage, causing a large area of the working face to freeze and increase in strength, greatly increasing the excavation difficulty.

[0027] To solve the above problems, the purpose of the present invention is to provide a cold energy automatic control system for the construction of a long distance connection passage freezing method in a water-rich layer. The automatic control of the freezing wall and temperature of the system makes the connection passage in the peripheral soil layer frozen and the working face in the unfrozen state, thereby improving the construction efficiency. The system not only has the advantages of safety and stability in the freezing method construction, but also has the characteristics of energy saving and environmental protection, improving construction efficiency, shortening construction period, etc., which can meet the needs of connection passage construction period, cost, quality, etc.

[0028] Preferably, the method and system of the present application can utilize wireless or wired sensor devices in several embodiments, including sensors applied to the face 10, etc., to control the cooling in an automatic and continuous manner. The purpose of the present application is to provide a cooling control system that enables high-precision, low-cost, and low-difficulty construction of a cross passage even under a city trunk road including a water-rich layer. Preferably, the system includes a sensor unit 3 and a master control unit 9. Preferably, the sensor unit 3 is provided at the freezing pipe 2 of the cross passage. Preferably, the master control unit 9 acquires freezing construction data acquired by the sensor unit 3. Preferably, the sensor unit 3 is also provided at a temperature measuring pipe. Preferably, the master control unit 9 calculates the required cooling and the required freezing wall thickness to perform active freezing based on the acquired freezing construction data. Preferably, the master control unit 9 divides the selection process of the freezing wall thickness and / or the required cooling into at least a first preliminary selection, a second intermediate selection, and a third preferred selection.

[0029] The present application is directed to the problem that the prior art cannot objectively and truly reflect the required cooling and the required freezing wall thickness for long-distance cross passage construction by the freezing method in a water-rich layer, and divides the cross passage freezing wall thickness design scheme into three stages to propose a control system that is different from the prior art and is more suitable for the excavation of an underground cross passage in a water-rich layer.

[0030] Preferably, the general control unit 9 can adopt a general 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 realize the technical solutions of the present application. The general control unit 9 at least includes a computing module and a storage module. The storage module can be a component of the general control unit 9, or be considered as an element independent of the general control unit 9. For example, the storage device can be realized in the form of a read-only memory ROM, a random access memory RAM, a static storage device, a dynamic storage device, etc. The storage unit can store an input / output operating system, a data storage management system, a running operating system, etc. of the general control unit 9. When the technical solutions of the present application are realized by software or hardware, the relevant program codes can be kept in the storage unit and executed by the computing module. Preferably, a communication bus is used for communication transmission between the above components. The general control unit 9 is connected with the sensor unit 3 and the freezing station 8 in a wired or wireless manner. The general control unit 9 receives the freezing construction data monitored by the sensor unit 3, and processes the data by the computing module to perform the first preliminary selection, the second intermediate selection and the third preferred selection, so as to control the freezing station 8 to output an appropriate cooling capacity. Preferably, the sensor unit 3 can adopt one or more of a load sensor, a force sensor, a torque sensor and a load cell to detect the external load of the connecting passage. Preferably, the sensor unit 3 further includes a temperature sensor to obtain the freezing wall temperature. The data detected by the sensor unit 3 is stored in the storage module of the general control unit 9 in time sequence.

[0031] Preferably, the total control unit 9 performs a first preliminary selection of the thickness of the frozen wall based on the frozen construction data obtained by the sensor unit 3. Preferably, the frozen construction data at least includes the external load, temperature change and physical and mechanical parameters of the soil layer. The prior art lacks in-depth exploration of the actual external load of the frozen wall, and usually simply provides the thickness of the frozen wall to increase the reliability of the structural design. This results in the problems of high cost and great difficulty in construction of the subsequent frozen wall structure. Therefore, in view of the actual construction environment of the underground connecting passage in the water-rich layer, the present application sets the sensor unit 3 to obtain the external load of the frozen wall, considers the stratum properties and buried depth of the water-rich layer, and calculates the high-precision internal force of the structure to perform the first preliminary selection of the thickness of the frozen wall, which has important practical significance. Preferably, the total control unit 9 calculates the actual stress of the frozen wall based on the obtained external load at least based on the geological characteristics of the water-rich layer, and performs the first preliminary selection of the thickness of the frozen wall of the connecting passage based on the calculated actual stress of the frozen wall. Preferably, the external load obtained by the sensor unit 3 represents the force required for the connecting passage to reach equilibrium. The sensor unit 3 is at least arranged in the wedge-shaped area on both sides of the connecting passage to obtain the size of the force with stability of the connecting passage. In the prior art design scheme of the frozen wall, the pressure on the top of the frozen wall is usually detected, i.e. the weight of the overburden soil above the connecting passage and the weight of the ground load and the side pressure based on the active earth pressure theory. However, the above method is usually used for the frozen wall calculation of the clay layer, and has no reference significance for the deep-buried water-rich layer connecting passage under the urban trunk road. The calculated thickness of the frozen wall is often greater than the actual demand, which greatly increases the construction difficulty. Therefore, the external load obtained by the lateral sensor unit 3 of the present application is different from the prior art method of calculating the top pressure and the side pressure respectively. By considering the stratum environment, the balance relationship between the top pressure and the side pressure is calculated, the working face 10 of the connecting passage is taken as a whole, and the actual stress condition of the frozen wall is obtained to plan the thickness scheme of the frozen wall for the first preliminary selection. It should be noted that during the first preliminary selection, the frozen construction has not been formally carried out, and only the external surrounding rock of the frozen wall is detected, and the cold requirement of the frozen wall is not selected.

[0032] According to a preferred embodiment, the total control unit 9 builds a model of the working face 10 based on at least the sensor unit 3 arranged in the connecting tunnel to obtain the stress distribution of the frozen wall. Preferably, the total control unit 9 plans the thickness of the frozen wall in the first preliminary selection based on the stress distribution of the frozen wall. Compared with the prior art that numerically equates the top pressure to the total weight of the overburden and ground load, the present application deeply studies the stress in the construction process of the connecting tunnel in the deep buried water-rich layer to obtain the first preliminary selection. In the actual construction of the freezing method, the frozen wall under normal circumstances is divided into Class III and Class II. According to the construction regulations, the thickness of the frozen wall of Class II and Class III should be determined according to the bearing capacity requirement, that is, the support force of the thickness of the frozen wall needs to meet the strength requirement. Preferably, after obtaining the external load, the total control unit 9 performs structural internal force calculation on the cross section of the connecting tunnel based on structural mechanics. Preferably, the total control unit 9 calculates the bending moment, shear force and axial force at the cross section of the frozen wall according to the superposition principle based on the elastic modulus of frozen soil, flexibility coefficient, cross-sectional moment of inertia, cross-sectional radius and height of the top arch angle, and further obtains the minimum thickness of the top arch and the bottom rectangle that meet the bending, shear and compression resistance.

[0033] Preferably, the total control unit 9 performs finite element analysis on the frozen wall based on at least the external load and the obtained thickness of the frozen wall to calibrate the minimum thickness. Preferably, the finite element analysis uses the frozen construction data obtained by the sensor unit 3 to build a model. Preferably, the frozen construction data further includes soil parameters (elastic modulus of soil layer), average temperature of the frozen wall, frozen soil parameters (compression, bending and shear parameters) and cross-sectional geometric parameters. Preferably, in the established finite element model, the total control unit 9 judges whether the thickness of the frozen wall meets the construction standard. Preferably, in the case that the finite element model meets the construction standard, the minimum thickness obtained by the total control unit 9 is taken as the first preliminary selection. Preferably, in the case that the finite element model does not meet the construction standard, the total control unit 9 controls the sensor unit 3 to perform parameter calibration and re-performs the first preliminary selection. The above-mentioned finite element model meeting the construction standard means that the deformation degree of the top settlement and the bottom heave of the frozen wall is less than the requirement of the construction specification. The present application is especially used for the construction of the connecting tunnel with large burial depth. The above-mentioned minimum thickness of the frozen wall means the minimum thickness required for the frozen wall that does not affect the state of the working face excavation under the premise of meeting the construction requirements of supporting the connecting tunnel. The minimum thickness in the first preliminary selection has multiple dimensions, including the minimum thickness of the top, the minimum thickness of the side and the minimum thickness of the bottom, etc., and is the minimum thickness obtained for the external load without considering the influence of the water-rich layer, which has multiple determination schemes.

[0034] According to a preferred embodiment, the total control unit 9 performs the second selection based on at least the temperature change detected by the sensor unit 3. Preferably, the total control unit 9 calculates the cooling demand based on at least the freezing pipe parameters and the freezing pipe array parameters. Preferably, the total control unit 9 further adjusts the cooling demand based on the third preferred freezing wall thickness. The freezing pipe parameters include the freezing pipe length, the freezing pipe diameter and the freezing pipe heat dissipation coefficient. The freezing pipe array parameters include the freezing pipe array length and the freezing pipe array diameter. Preferably, the formula for calculating the cooling demand is as follows:

[0035] Q = 1.25 x π x hi x di x K + 1.3 x π x h2 x d2 x K

[0036] wherein hi is the freezing pipe length, di is the freezing pipe diameter, K is the freezing pipe heat dissipation coefficient, h2 is the freezing pipe array length, and d2 is the freezing pipe array diameter.

[0037] Preferably, the total control unit 9 calculates the cooling demand based on the above formula, and controls the cooling supply based on the obtained cooling demand and the temperature change obtained by the sensor unit 3, so that the freezing wall temperature is maintained under the freezing condition. The cooling supply is adjusted according to the temperature change for temperature-variable freezing, which prevents large-area freezing of the working face 10, reduces the construction difficulty, and saves the energy of the freezing unit. Preferably, the total control unit 9 adjusts the cooling supply based on at least the required freezing wall thickness, so that the freezing wall is in a state that meets the freezing condition and does not affect the excavation state of the working face 10.

[0038] According to the above first selection, the thickness of the freezing wall of the water-rich layer connecting channel can be preliminarily selected by detecting the external load by the sensor unit 3 and calculating and modeling by the total control unit 9. However, due to the limitation of the parameters, it cannot comprehensively consider all structural problems in actual engineering, for example, only the cross-section problem is considered in the calculation of the structural internal force; the cross-section is regularized. Further optimization is needed for the above first selection to obtain a third selection with higher rationality and reliability. Preferably, the total control unit 9 establishes a three-dimensional spatial structure of the connecting channel based on at least the freezing construction data obtained by the sensor unit 3, to truly reproduce the stress environment of the stratum; and then, through the above three-dimensional spatial structure and material parameters, the thickness of the freezing wall in the water-rich layer buried connecting channel is simulated and analyzed; thereby realizing further optimization of the first selection. Preferably, the total control unit 9 performs the third selection based on the freezing wall structure under the influence of the seepage stress field and the ground stress field in the water-rich layer.

[0039] The prior art only considers the freezing wall structure in the ground stress field when establishing the three-dimensional spatial structure of the connecting channel, and does not consider the influence of the seepage stress field on the connecting channel in the water-rich layer. The third selection of the present application fully considers the redistribution of the ground stress field in the water-rich layer under the influence of the seepage stress field, and is a very important technical means for selecting the thickness of the freezing wall of the water-rich layer buried connecting channel.

[0040] Preferably, the total control unit 9 selects the freezing wall structure of the water-rich layer connecting channel based on the fluid-solid coupling theory. Preferably, the total control unit 9 sets the extending direction of the connecting channel as the first direction, sets the direction perpendicular to the first direction in the horizontal plane as the second direction, and sets the vertical direction as the third direction. Preferably, the total control unit 9 takes the first direction, the second direction, and the third direction as the Y-axis, the X-axis, and the Z-axis. In order to avoid the influence of boundary effects and to maintain high accuracy of calculation, the modeling data of the X-axis, the Y-axis, and the Z-axis are (80m, 240m, 100m). Preferably, the total control unit 9 selects the initial geostress field as the pressure of the overlying 5m water body and generates it in a stepwise manner according to the gravity of the soil body. Preferably, the total control unit 9 selects the initial seepage stress field as the fixed water head of the upper surface 5m and generates the static water pressure in a stepwise manner according to the gravity field of the water body. Preferably, the total control unit 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 the silt clay are: bulk modulus 106MPa, shear modulus 58MPa, cohesion 0.3MPa, and natural density 1880kg·m -3 . The physical and mechanical parameters of the gravel clay are: bulk modulus 114MPa, shear modulus 61MPa, cohesion 0.4MPa, and natural density 1890kg·m -3 . The physical and mechanical parameters of the fully weathered granite are: bulk modulus 404MPa, shear modulus 230MPa, cohesion 0.3MPa, and natural density 2040kg·m -3 . Preferably, the physical and mechanical parameters of the soil layer can be obtained by the sensor unit 3 or obtained by on-site geological exploration. Preferably, the total control unit 9 takes the fluid density in the freezing wall as 1000kg·m -3 , and takes the fluid modulus as 2·10 9 Pa. It should be noted that the above parameters are exemplary parameters, which are the theoretical parameters of the physical and mechanical parameters of the water-rich layer with a burial depth of 30m. In actual application, the geological conditions are different, and the physical and mechanical parameters of the soil layer are also different.

[0041] Preferably, the total control unit 9 activates the frozen wall structure in a manner of assigning the established three-dimensional space structure model, and completes the construction simulation. Preferably, the total control unit 9 performs a third optimization on the minimum thickness based on the result of the assignment simulation. Preferably, the total control unit 9 at least judges the change process of the model vault settlement, arch bottom heave and arch waist convergence. Preferably, the total control unit 9 obtains the water-rich layer construction characteristics by respectively comparing the internal forces of the frozen wall model of the same thickness in the stress field and the seepage stress field; and further judges the stress of the frozen wall of different thicknesses in the stress field and the seepage stress field under the composite construction environment, so as to realize the optimization on the minimum thickness obtained by the first preliminary selection. Preferably, the total control unit 9 compares and selects the minimum thickness obtained by the first preliminary selection based on the above three-dimensional space structure model, so that the final minimum thickness obtained satisfies the water-rich layer construction characteristics. The comparison and selection result is that the obtained minimum thickness satisfies the reinforcement and water stopping requirements. Preferably, the total control unit 9 judges the required thickness of the frozen wall through the three-dimensional space structure model deformation monitoring point. Through the established three-dimensional space structure model, the deformation trend and mechanical change of the frozen wall under different soil layer construction environments are compared and judged, the minimum thickness of the first preliminary selection is calculated and further compared and selected, so as to save the construction period, construction cost and improve the construction efficiency. The present application considers the influence of the soil layer on the required cold quantity and the thickness of the frozen wall, realizes the detection of the temperature and the frozen wall of the working face 10 in the whole process of the freezing construction through the sensor unit 3, so as to increase the reference basis and the construction safety of the construction. Based on the general process of the existing technology for judging the thickness of the connecting passage, the present application proposes a three-step method, further considers the properties of the soil layer, especially the construction properties of the water-rich layer underground connecting passage, and creatively proposes a cold quantity automatic control system for the freezing construction of the connecting passage. Relying on the required cold quantity and the thickness of the frozen wall, the thickness of the frozen wall in the construction process satisfies the construction strength requirement and does not affect the excavation state of the working face 10, and the safety and economy of the construction are considered. The above-mentioned minimum thickness of the frozen wall refers to the minimum thickness of the frozen wall required under the premise of meeting the construction requirements of supporting the connecting passage without affecting the excavation state of the working face. The minimum thickness in the third optimization is further compared and selected from the multiple determined schemes in the first preliminary selection under the premise of considering the influence of the water-rich layer soil, and is the minimum thickness of the frozen wall meeting the construction standard. The above-mentioned first preliminary selection, second selection and third optimization reasonably and conveniently calculate the mechanical change of the frozen wall during construction, provide the basic parameters of the construction, fully exert the bearing capacity of the frozen wall, so that the thickness and the required cold quantity of the frozen wall designed by the above-mentioned method meet the engineering requirements, achieve the purpose of freezing the soil around the tunnel and not freezing the excavated soil, realize the reduction of the construction difficulty, the improvement of the construction efficiency, the shortening of the construction period and the energy-saving and environment-friendly technical effects.

[0042] Embodiment 2

[0043] The embodiment can be a further improvement and / or supplement to the foregoing embodiments, and repeated contents will not be described herein. The overall and / or part of the preferred embodiments of other embodiments can be supplemented as the embodiment without causing conflicts or contradictions.

[0044] The present application also relates to a cold automatic control method for the construction of a liaison passage freezing method. The method comprises at least the following steps:

[0045] S1: freezing pipes 2 are set on both sides of the liaison passage 1 and sensor units 3 are arranged, temperature measuring pipes 4 are set and sensor units 3 are arranged, and a salt water pipe 7 is connected with a freezing station 8 in the existing tunnel 6, the freezing station is controlled by a general control unit 9, and active freezing is carried out according to the calculation results.

[0046] S2: after the active freezing is completed, excavation is carried out, and temperature measuring points are arranged on the working face 10 during the excavation process, and each temperature measuring point is monitored during the excavation process.

[0047] S3: the monitoring data is uploaded to the general control unit 9 in real time, and the general control unit 9 automatically adjusts the cooling capacity of the freezing station according to the monitoring data, geological conditions, tunnel working conditions and other data after analysis and processing, so that the freezing wall 11 is in a thickness that meets the freezing conditions and does not affect the excavation state of the working face 10.

[0048] S4: repeat step S3 until the entire enclosure freezing stage construction is completed.

[0049] The step S1 comprises at least the following steps S101-S103:

[0050] S101: the freezing construction data obtained by the sensor unit 3, and the general control unit 9 calculates the required cooling capacity and the required freezing wall thickness based on the obtained freezing construction data for active freezing. The general control unit 9 at least divides the selection process of the freezing wall thickness and / or the required cooling capacity into a first initial selection, a second intermediate selection and a third preferred selection.

[0051] Preferably, S101: the general control unit 9 at least performs a first initial selection on the freezing wall thickness based on the freezing construction data obtained by the sensor unit 3. The general control unit 9 at least calculates the external load obtained based on the geological characteristics of the water-rich layer as the actual stress of the freezing wall, and performs a first initial selection on the liaison passage freezing wall thickness based on the calculated actual stress of the freezing wall.

[0052] Further preferably, wherein the specific steps of the freezing construction data obtained by the sensor unit are: the sensor unit 3 is at least arranged in the wedge-shaped area on both sides of the liaison passage to obtain the size of the force with stability of the liaison passage.

[0053] S102: The total control unit 9 plans the thickness of the freezing wall in the first preliminary selection based on the stress distribution of the freezing wall. After obtaining the external load, the total control unit 9 calculates the internal force of the structure of the cross section of the connecting passage based on structural mechanics. The total control unit 9 calculates the bending moment, shear force and axial force at the cross section of the freezing wall according to the superposition principle based on the elastic modulus of frozen soil, the flexibility coefficient, the sectional moment of inertia, the sectional radius and the height of the top arch-shaped angle, and further obtains the minimum thickness of the top arch shape and the bottom rectangle that meet the bending resistance, shear resistance and compression resistance.

[0054] S103: The total control unit 9 performs finite element analysis on the freezing wall based on at least the external load and the obtained thickness of the freezing wall to calibrate the minimum thickness. The finite element analysis uses the freezing construction data obtained by the sensor unit 3 to construct a model. The freezing construction data also includes soil parameters (elastic modulus of soil layer), average temperature of the freezing wall, frozen soil parameters (compression resistance, bending resistance and shear resistance parameters) and cross section geometric parameters. In the established finite element model, the total control unit 9 judges whether the thickness of the freezing wall meets the construction standard. In the case that the finite element model meets the construction standard, the minimum thickness obtained by the total control unit 9 is taken as the first preliminary selection. In the case that the finite element model does not meet the construction standard, the total control unit 9 controls the sensor unit 3 to calibrate the parameters and re-performs the first preliminary selection.

[0055] Wherein, the step S3 at least includes the following steps S301-S302:

[0056] S301: The total control unit 9 performs the second selection based on at least the temperature change detected by the sensor unit 3. The total control unit 9 calculates the cooling demand based on at least the freezing pipe parameters and the refrigeration pipe parameters. The total control unit 9 also adjusts the cooling demand based on the third preferred thickness of the freezing wall. The formula for calculating the cooling demand is:

[0057] Q = 1.25 x π x h1 x d1 x K + 1.3 x π x h2 x d2 x K

[0058] The total control unit 9 calculates the cooling demand based on the above formula, and controls the cooling supply based on the obtained cooling demand and the temperature change obtained by the sensor unit 3, so that the temperature of the freezing wall remains in the freezing condition.

[0059] S302: The total control unit 9 establishes a three-dimensional spatial structure of the connecting passage based on at least the freezing construction data obtained by the sensor unit 3, to truly reproduce the stress environment of the stratum; further, through the above three-dimensional spatial structure and material parameters, the thickness of the freezing wall in the connecting passage of the water-rich layer is simulated and analyzed; thereby realizing further optimization of the first preliminary selection.

[0060] More specifically about step S302, step S302 at least includes steps S3021-S3023.

[0061] S3021: The total control unit 9 performs the third optimization based on the freezing wall structure under the influence of the seepage stress field of the water-rich layer and the ground stress field. The total control unit 9 sets the extension direction of the communication passage as the first direction, sets the direction perpendicular to the first direction in the horizontal plane as the second direction, and sets the vertical direction as the third direction. The total control unit 9 takes the first direction, the second direction, and the third direction as the Y axis, the X axis, and the Z axis.

[0062] Preferably, S3021: The total control unit 9 selects the initial ground stress field as the pressure of the 5m overlying water body and generates it in a stepwise manner according to the gravity of the soil body. The total control unit 9 selects the initial seepage stress field as the fixed water head of the 5m upper surface and generates the hydrostatic pressure in a stepwise manner according to the gravity field of the water body. The total control unit 9 establishes a model based on the physical and mechanical parameters of the soil layer. The physical and mechanical parameters of the soil layer include bulk modulus, shear modulus, cohesion, and natural density, etc. The physical and mechanical parameters of the soil layer can be obtained by the sensor unit 3 or obtained by on-site geological exploration.

[0063] S3022: The total control unit 9 activates the freezing wall structure in the manner of assigning values to the established three-dimensional space structure model, and completes the construction simulation. The total control unit 9 performs the third optimization on the minimum thickness based on the results of the assignment simulation. The total control unit 9 at least judges the change process of the model arch top settlement, arch bottom heave, and arch waist convergence. The total control unit 9 obtains the construction characteristics of the water-rich layer by respectively comparing the internal forces of the freezing wall model of the same thickness in the ground stress field and the seepage stress field; and further judges the stress of the freezing wall of different thicknesses in the combined construction environment of the ground stress field and the seepage stress field, so as to realize the optimization of the minimum thickness obtained by the first preliminary selection.

[0064] S3023: The total control unit 9 compares and selects the minimum thickness obtained by the first preliminary selection based on the above-mentioned three-dimensional space structure model, so that the final minimum thickness obtained satisfies the construction characteristics of the water-rich layer. The comparison and selection result is that the obtained minimum thickness satisfies the requirements of reinforcement and water stop. The total control unit 9 judges the required thickness of the freezing wall through the deformation monitoring points of the above-mentioned three-dimensional space structure model.

[0065] The application realizes the minimum thickness checking of the first preliminary selection and further comparison and selection by comparing and judging the deformation trend and mechanical change of the frozen wall under different soil layer construction environments through the established three-dimensional space structure model, thereby saving the construction period and construction cost and improving the construction efficiency. The application aims at the problem that the existing required cold quantity and frozen wall thickness do not consider the influence of soil layers, leading to insufficient accuracy and practicability, realizes the detection of the temperature and frozen wall of the working face 10 in the whole frozen method construction process through the set sensor unit 3, so as to increase the reference basis and construction safety of the construction. The key point of the application is that the monitoring data on site are collected and uploaded to the general control unit 9 for data analysis and feedback regulation, the control system automatically controls the various frozen parameters of the frozen station, thereby adjusting the actual cooling capacity, the frozen wall thickness is adjusted in the way of combining data analysis with actual effect on site, so as to achieve the purpose of freezing only the stratum outside the tunnel and not freezing the working face 10.

[0066] Throughout the present specification, the features introduced by "preferably" are only optional ways, and should not be understood as necessarily provided, therefore the applicant reserves the right to abandon or delete the related preferred features at any time.

[0067] It should be noted that the above specific embodiments are exemplary, and those skilled in the art can think of various solutions under the inspiration of the disclosure of the present application, and these solutions also belong to the disclosed range of the present application and fall within the protection scope of the present application. Those skilled in the art should understand that the specification and drawings of the present application are illustrative and do not constitute a limitation on the claims. The protection scope of the present application is defined by the claims and their equivalents. The specification of the present application contains multiple inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally", which all indicate that the corresponding paragraph discloses an independent concept, and the applicant reserves the right to file a divisional application according to each inventive concept.

Claims

1. A cold energy automatic control system for construction of a contact tunnel freezing method, characterized by, At least comprising a total control unit (9) and a sensor unit (3), wherein, The sensor unit (3) is arranged at the freezing pipe (2) and the temperature measuring pipe (4) of the connecting passage to obtain freezing construction data, and the total control unit (9) calculates the required cooling capacity and the required freezing wall thickness based on the obtained freezing construction data to carry out active freezing, wherein, The total control unit (9) divides the selection process of the freezing wall thickness and / or the required cooling capacity into at least a first preliminary selection, a second intermediate selection and a third preferred selection which are sequentially executed, wherein, The total control unit (9) performs the first preliminary selection of the freezing wall thickness based on at least the freezing construction data obtained by the sensor unit (3); The total control unit (9) performs the second intermediate selection based on at least the temperature change detected by the sensor unit (3); The total control unit (9) performs the third preferred selection based on the structure of the freezing wall under the influence of the seepage stress field and the ground stress field of the water-rich layer.

2. The system of claim 1, wherein, The freezing construction data at least includes external load, temperature change and physical and mechanical parameters of the soil layer, wherein, The total control unit (9) calculates the actual stress of the freezing wall based on at least the geological characteristics of the water-rich layer and the obtained external load, and performs the first preliminary selection of the freezing wall thickness of the connecting passage based on the calculated actual stress of the freezing wall.

3. The system of claim 1, wherein, The total control unit (9) plans the freezing wall thickness in the first preliminary selection based on the stress distribution of the freezing wall. After obtaining the external load, the total control unit (9) performs structural internal force calculation on the cross section of the connecting passage based on structural mechanics. The total control unit (9) calculates the bending moment, shear force and axial force at the cross section of the freezing wall according to the superposition principle based on the elastic modulus of frozen soil, flexibility coefficient, cross section moment of inertia, cross section radius and height top arch angle, and further obtains the minimum thickness of the top arch and the bottom rectangle which meet the bending resistance, shear resistance and compression resistance.

4. The system of claim 1, wherein, The total control unit (9) performs finite element analysis on the freezing wall based on at least the external load and the obtained freezing wall thickness to calibrate the minimum thickness, wherein, In the established finite element model, the total control unit (9) judges whether the freezing wall thickness meets the construction standard. In the case that the finite element model meets the construction standard, the minimum thickness obtained by the total control unit (9) is taken as the first preliminary selection. In the case that the finite element model does not meet the construction standard, the total control unit (9) controls the sensor unit (3) to perform parameter calibration, and the first preliminary selection is performed again.

5. The system of claim 1, wherein, The total control unit (9) calculates the required cooling capacity based on at least the freezing pipe parameters and the cold freezing pipe parameters. The total control unit (9) further adjusts the required cooling capacity based on the third preferred freezing wall thickness. The calculation formula of the required cooling capacity is: Q = 1.25 x π x h1 x d1 x K + 1.3 x π x h2 x d2 x K Wherein, h1 is the length of the freezing pipe, d1 is the diameter of the freezing pipe, K is the heat dissipation coefficient of the freezing pipe, h2 is the length of the cold freezing pipe, and d2 is the diameter of the cold freezing pipe; The total control unit (9) calculates the required cooling capacity based on the formula, and controls the cooling capacity based on the obtained required cooling capacity and the temperature change obtained by the sensor unit (3), so that the temperature of the freezing wall remains in the freezing condition.

6. The system of claim 1, wherein, The total control unit (9) establishes a three-dimensional space structure of the communication passage based on the frozen construction data obtained by the sensor unit (3), to truly reproduce the stress environment of the stratum; the three-dimensional space structure and material parameters are used to simulate and analyze the thickness of the frozen wall in the communication passage in the water-rich layer; and the further optimization of the first initial selection is realized.

7. The system of claim 6, wherein, The total control unit (9) sets the extension direction of the communication passage as the first direction, sets the direction perpendicular to the first direction in the horizontal plane as the second direction, and sets the vertical direction as the third direction, and takes the first direction, the second direction and the third direction as the Y axis, the X axis and the Z axis; the total control unit (9) establishes a three-dimensional space structure model based on the physical and mechanical parameters of the stratum, the Y axis, the X axis and the Z axis.

8. The system according to any one of claims 1 to 7, characterized in that The total control unit (9) activates the frozen wall structure in the manner of assigning values to the established three-dimensional space structure model, and completes the construction simulation; the total control unit (9) performs a third optimization on the minimum thickness based on the results of the assignment simulation, wherein the total control unit (9) at least judges the change process of the model vault settlement, the vault bottom heave and the arch waist convergence, wherein, The total control unit (9) obtains the construction characteristics of the water-rich layer by comparing the internal forces of the frozen wall models with the same thickness in the geostress field and the seepage stress field respectively; judges the stress of the frozen wall with different thicknesses in the composite construction environment of the geostress field and the seepage stress field, to realize the third optimization of the minimum thickness obtained by the first initial selection.

9. A cold energy automatic control method for construction of a contact tunnel freezing method, characterized by, The method steps include: S1: freezing pipes (2) are set on both sides of the communication passage and sensor units (3) are arranged, temperature measuring pipes (4) are set and sensor units (3) are arranged, a salt water pipe (7) is connected with a freezing station (8) in the existing tunnel (6), and the freezing station (8) is actively frozen by a total control unit (9); S2: after active freezing is completed, excavation is carried out, and temperature measuring points are arranged on the working face (10) during the excavation process, and each temperature measuring point is monitored during the excavation process; S3: the monitoring data are uploaded to the total control unit (9) in real time, the total control unit (9) adjusts the cooling capacity of the freezing station (8) according to the monitoring data, so that the frozen wall is in a thickness that meets the freezing condition and does not affect the excavation state of the working face; S4: repeat step S3 until the entire enclosure freezing stage construction is completed.

10. The method of claim 9, wherein, The method steps further include: The total control unit (9) at least divides the selection process of the thickness of the frozen wall and / or the cooling capacity into a first initial selection, a second intermediate selection and a third optimization which are sequentially executed, wherein; The total control unit (9) at least calculates the actual stress of the frozen wall based on the geological characteristics of the water-rich layer, and performs a first initial selection on the thickness of the frozen wall of the communication passage based on the calculated actual stress of the frozen wall; The total control unit (9) at least performs a second intermediate selection based on the temperature change detected by the sensor unit (3); The total control unit (9) at least performs a third optimization based on the temperature change detected by the sensor unit (3). The total control unit (9) establishes the three-dimensional space structure of the contact channel based on the frozen construction data obtained by the sensor unit (3) to reproduce the stress environment of the stratum; judges the stress of the frozen wall with different thickness under the combined construction environment of the stress field and the seepage stress field to realize the third optimization of the minimum thickness obtained by the first preliminary selection.

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