Method for reinforcing freezing and monitoring of weak freezing area of shield butt joint

Abstract

The application provides an implementation method for reinforcing freezing and monitoring of a weak freezing area of shield butt joint, and relates to the technical field of shield butt joint engineering, and comprises the following steps: determining the thickness of a freezing wall, and determining the configuration parameters of a freezing hole according to the freezing development rate of a stratum in combination with the excavation constraint conditions of an excavation area and the configuration parameters of the freezing hole; arranging temperature measuring points in temperature measuring holes in a butt joint area based on the arrangement parameters of the temperature measuring holes; respectively arranging temperature measuring lines and ring-shaped temperature measuring points to respectively collect the temperature of the area between a slurry bin and a shield shell and the structural surface temperature of a shield machine; and monitoring and early warning are performed by using a preset monitoring system, and the monitoring and early warning results are interacted with a user end. The application is aimed at the salt water freezing reinforcement stratum condition of a shield butt joint engineering, and a partition real-time monitoring design is performed on a freezing curtain, especially a freezing reinforcement design and a monitoring design are performed on a weak freezing area, so that the safety of the freezing wall in a structure thermal disassembly process of a butt joint section is improved.

Description

Technical Field

[0001] This invention relates to the field of shield tunneling engineering technology, and more specifically, to a method for strengthening freezing and monitoring of the weak freezing zone during shield tunneling. Background Technology

[0002] When the shield tunneling docking position is located in a water-rich soft soil layer, the artificial freezing method becomes a safe and reliable construction method. That is, after the two shield tunnels have been excavated to the docking position, freezing pipes are laid by drilling at an angle on the shells of the two shield machines, and then the soil layer is frozen by circulating low temperature refrigerant.

[0003] Taking a specific shield tunneling machine docking project as an example, both shield machines have shells made of 8cm thick steel plates. Steel plates are excellent heat conductors, with a thermal conductivity approximately 30 times that of soil, providing a good heat transfer path. The following characteristics and problems exist during the freezing process:

[0004] First, during the freezing stage, insulation boards are usually laid inside the shield shell to reduce the impact of internal environmental changes on freezing. If the insulation boards are laid densely, the steel plate can act as a good low-temperature conduction medium after the freezing pipe comes into contact with the shield shell, which is conducive to freezing at the interface between the soil and the shield shell steel plate.

[0005] Secondly, during the excavation phase of the docking section, it is necessary to dismantle the steel plate structures such as the cutterhead inside the tunnel boring machine. This is often done using thermal cutting and welding methods such as cutting, welding, and carbon planing, which means prolonged exposure to high heat. As mentioned earlier, the steel plate becomes a good heat conduction path at this time, causing the frozen soil at the interface between the frozen soil and the steel plate to heat up rapidly until it melts. If this is not controlled, it can easily cause interface breakdown, resulting in safety hazards such as water leakage and instability of the frozen body.

[0006] Third, because the freezing pipes of the two tunnel boring machines are arranged at an angle, a triangular area is formed between the intersection of the freezing pipes and the machine shell. Since this area is located above the mud chamber and cutterhead, insulation work cannot be carried out in this location during freezing. Under the influence of ambient heat, the frozen soil is unlikely to meet design requirements, resulting in a low average temperature. At the same time, this area is located above the excavation zone and is most significantly affected by the heat from the hot cutting operation. During excavation, the soil in this part is very prone to deformation or even detachment due to melting, which adversely affects the overall stability of the frozen wall.

[0007] In summary, the interface between the frozen soil and the shield shell, as well as the triangular area above the excavation zone, are most significantly affected by heat input operations, and the temperature change rate is relatively rapid due to heat source input. The temperature development of the frozen soil directly affects the safety of construction during the excavation phase. On the one hand, it is necessary to strengthen the freezing of the aforementioned weakly frozen areas to ensure the safety and stability of the frozen body during construction; on the other hand, it is necessary to conduct real-time monitoring of key areas, and take corresponding measures on-site in a timely manner when the temperature exceeds the set warning value to control heat input and reduce the impact on the frozen body.

[0008] In existing implementation cases, two tunnel boring machines (TBMs) are often used to intersect and deploy freezing pipes, which extend obliquely into the soil through the shield body. Meanwhile, the dismantling of internal metal structures such as the cutterhead within the shield body frequently employs heat input methods such as flame cutting, carbon gouging, and welding. As mentioned earlier, the triangular area formed by the TBM shell and the shield shell steel plates are weak freezing areas. During construction, temperature monitoring is difficult, relying mainly on manual collection of temperature data from the exposed excavation face, making it impossible to directly detect temperature changes within the frozen soil. Furthermore, it is impossible to rapidly cool this area and dissipate heat based on the monitored temperature status.

[0009] For example, patent application number CN202111279322.0 discloses a freezing reinforcement device and its shield tunneling docking reinforcement method, aiming to solve the problems of low efficiency caused by the complexity of traditional freezing methods and the need to dismantle equipment and re-insert freezing pipes. By incorporating freezing pipes and optimizing the construction process, it achieves rapid freezing of the ground to form a frozen soil curtain, ensuring the safety of shield tunneling docking.

[0010] Specifically, it directly utilizes the inner wall of the tunnel boring machine (TBM) as a freezing plate, fixing the freezing pipes to the inner wall of the TBM using detachable anchor bolts and lifting rings. The thermal conductivity of the metal shield shell is used to transfer cold energy outwards, without driving freezing pipes into the soil. The patent also mentions laying temperature measuring pipes in the soil to assess whether docking can be initiated after reaching a preset threshold (e.g., -10℃). Furthermore, the freezing reinforcement device is mentioned as suitable for liquid nitrogen freezing.

[0011] The following technical defects exist in this freezing and reinforcement device:

[0012] (1) Liquid nitrogen freezing is more expensive and energy-intensive than brine freezing. It is suitable for short-term scenarios (such as emergency rescue and repair). The shield tunneling docking time is relatively long, so it is not the preferred refrigerant circulation medium in actual engineering.

[0013] (2) When using the inner wall of the tunnel boring machine as a freezing plate, combining it with liquid nitrogen freezing is safer and more reliable. This is because as the excavation cross-section size increases, the thickness of the freezing wall increases accordingly to meet the bearing capacity requirements. If brine freezing is used, more freezing time is required to cool the soil, which greatly increases the cost.

[0014] (3) The location, method and number of temperature measurement points were not designed in detail.

[0015] On the other hand, under current conditions of ground reinforcement using freezing methods, excavation operations mostly occur in tunnel connecting passage projects. The design of temperature measuring holes in these projects primarily considers the frozen wall interface where the spacing between freezing holes is relatively large, which has certain limitations compared to shield tunneling connection projects. These limitations are mainly manifested in:

[0016] First, both have weak interfaces at the permafrost-structure interface. However, in connecting tunnel projects, freezing holes are often placed on concrete segments, while in shield docking projects, freezing holes are placed on the shield shell (steel plate). The thermal conductivity of the steel plate is more than 20 times that of the reinforced concrete segments. This means that the risk of the weak interfaces at the permafrost-structure interface in the docking project melting and seeping water due to heat is significantly increased.

[0017] Secondly, the heat input during the excavation of the connecting passage is relatively small, while the demolition of the shield tunneling structure, which consists entirely of steel structures, requires thermal cutting operations, necessitating the monitoring and control of a large amount of heat input. However, the target monitoring system does not fully consider the correspondence between the excavation sequence and the corresponding monitoring hole locations, meaning there is a possibility that there are no monitoring points within the excavation area. For high-risk shield docking excavations, these blind spots make it impossible to effectively assess the impact of thermal cutting, posing significant risks during construction.

[0018] Finally, the target monitoring did not adequately consider temperature measurement inside the frozen wall. During shield tunneling, due to the angled placement of freezing holes and the structural properties, monitoring the frozen triangular weak freezing area is crucial. This triangular area is located directly above the excavation area, where the frozen soil is most affected by heat input during operations. If the frozen soil in this area thaws extensively, the effective thickness of the frozen wall will be significantly reduced, and the structural strength of the frozen soil will be greatly weakened. This could directly lead to the frozen soil being breached by water pressure, creating a significant safety hazard. Therefore, it is essential to focus on monitoring and reinforcing the freezing effect in this area to improve the overall safety and stability of the frozen solidified body.

[0019] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0020] In view of this, the present invention provides an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking, in order to solve the aforementioned problems.

[0021] To solve the above problems, the specific technical solution adopted by the present invention is as follows:

[0022] A method for strengthening freezing and monitoring of weak areas during shield tunneling connection includes the following steps:

[0023] S1. Obtain the dimensions of the shield excavation section and the stress state of the frozen body, determine the thickness of the frozen wall, and determine the configuration parameters of the freezing holes based on the freezing development rate of the strata.

[0024] S2. Obtain the diameter parameters of the tunnel boring machine, and determine the layout parameters of the temperature measuring holes in the docking area by combining the excavation constraints of the excavation area and the configuration parameters of the freezing holes.

[0025] S3. Based on the arrangement parameters of the temperature measuring holes in the docking area, arrange temperature measuring points in the temperature measuring holes in the docking area to collect the temperature of each monitoring point in the docking area.

[0026] S4. Based on the structural characteristics of the tunnel boring machine, temperature measuring lines and circumferential temperature measuring points are arranged to collect the temperature of the area between the mud chamber and the shield shell and the temperature of the structural surface of the tunnel boring machine.

[0027] S5. Based on the temperature of each monitoring point in the docking area, the temperature of the area between the mud chamber and the shield shell, and the structural surface temperature of the tunnel boring machine, use the preset monitoring system to conduct monitoring and early warning, and interact with the user terminal to exchange the monitoring and early warning results.

[0028] Preferably, the step of obtaining the diameter parameters of the tunnel boring machine and determining the arrangement parameters of the temperature measuring holes in the docking area, in conjunction with the excavation constraints of the excavation area and the configuration parameters of the freezing holes, includes:

[0029] S21. Collect the diameter parameters of the tunnel boring machine and determine the excavation height range of the target excavation layer and the outermost excavation layer in the excavation area;

[0030] S22. Using the excavation height range of the target excavation layer and the outermost excavation layer as excavation constraints, and combining the diameter parameters of the tunnel boring machine, construct an equation relating the number of excavation layers of the target excavation layer to the diameter parameters of the tunnel boring machine.

[0031] S23. Based on the equation relating the number of target excavation layers to the diameter parameter of the tunnel boring machine, determine the number of target excavation layers.

[0032] S24. Determine the total number of temperature measurement holes in the docking area based on the number of excavation layers in the target excavation layer and the characteristics of the outermost excavation layer.

[0033] S25. Determine the length and angle of the temperature measuring hole in the docking area according to the configuration parameters of the freezing hole.

[0034] Preferably, the expression for the equation relating the number of target excavation layers to the diameter parameter of the tunnel boring machine is:

[0035] D = nH1 + 2H2;

[0036] 1.8≤H1≤2.2;

[0037] 2.2≤H2≤2.6;

[0038] In the formula, D represents the diameter of the tunnel boring machine, H1 represents the excavation height of the target excavation layer, H2 represents the excavation height of the outermost excavation layer, and n represents the number of excavation layers of the target excavation layer.

[0039] Preferably, determining the total number of temperature measuring holes in the docking area based on the number of excavation layers in the target excavation layer and in combination with the characteristics of the outermost excavation layer includes:

[0040] S241. For the target excavation layer, the number of the target excavation layer is taken as the number of temperature measurement holes in the target excavation layer.

[0041] S242. For the outermost excavation layer, the temperature measuring holes of the outermost excavation layer are arranged in an equidistant manner, and the equation function of the temperature measuring holes of the outermost excavation layer is constructed using the excavation constraints and the diameter parameters of the tunnel boring machine.

[0042] S243. Solve the equation function for the temperature measuring holes in the outermost excavated layer to obtain the number of temperature measuring holes in the outermost excavated layer.

[0043] S244. Based on the configuration parameters of the freezing holes, randomly select a number of freezing holes at fixed intervals as soil internal temperature measurement holes to obtain the number of soil internal temperature measurement holes.

[0044] S245. Based on the excavation layer height of the target layer, determine and configure several soil temperature measuring holes above the excavation area to obtain the number of soil temperature measuring holes above the excavation area.

[0045] S246. Calculate the sum of the number of temperature measuring holes in the target excavation layer, the number of temperature measuring holes in the outermost excavation layer, the number of temperature measuring holes inside the soil, and the number of temperature measuring holes in the soil above the excavation area to determine the total number of temperature measuring holes in the docking area.

[0046] Preferably, the expression for the equation function of the temperature measuring holes in the outermost excavated layer is:

[0047] ;

[0048] ;

[0049] ;

[0050] In the formula, n ′ The number of temperature measuring holes in the outermost excavation layer is represented by α, D represents the diameter of the tunnel boring machine, H1 represents the excavation height of the target excavation layer, H2 represents the excavation height of the outermost excavation layer, α represents the angle between the temperature measuring hole of the outermost adjacent layer and the horizontal center line, β represents the angle between the temperature measuring holes of the two adjacent layers of the outermost layer and the horizontal center line, and θ represents the angle between the temperature measuring holes of the outermost excavation layer.

[0051] Preferably, based on the excavation layer height of the target layer, a number of soil temperature measuring holes above the excavation area are determined and configured, resulting in the following number of soil temperature measuring holes above the excavation area:

[0052] S2451. Based on the excavation layer height of the target layer, set a soil temperature measurement hole above the excavation area at the midpoint of the arc length of the excavation layer of the target layer.

[0053] S2452. Temperature measurement holes for the soil above the excavation area shall be set directly above the tunnel in the uppermost excavation layer of the outermost excavation layer and on both sides directly above the tunnel.

[0054] S2453. Determine the number of soil temperature measuring holes above the excavation area based on the set soil temperature measuring holes above the excavation area.

[0055] Preferably, the formula for calculating the setting angle of the soil temperature measuring holes above the excavation area on both sides directly above the tunnel is:

[0056] ;

[0057] In the formula, The angle at which temperature measuring holes for the soil above the excavation area are set on both sides directly above the tunnel, D represents the diameter of the tunnel boring machine, and H2 represents the excavation height of the outermost excavation layer.

[0058] Preferably, the step of arranging temperature measuring lines and circumferential temperature measuring points according to the structural characteristics of the tunnel boring machine to collect the temperature of the area between the mud chamber and the shield shell and the structural surface temperature of the tunnel boring machine includes:

[0059] Temperature measuring lines are laid inside the shield belt disc of the tunnel boring machine, and the number of measuring points on the temperature measuring lines is determined according to the size of the cutter box in order to collect the temperature of the area between the mud chamber and the shield shell.

[0060] The first circumferential temperature measuring point is set behind the rear partition of the bubble chamber, and the second circumferential temperature measuring point is set behind the front partition of the bubble chamber.

[0061] Preferably, before obtaining the cross-sectional dimensions of the shield tunnel excavation and the stress state of the frozen body, determining the thickness of the frozen wall, and determining the configuration parameters of the freezing holes based on the freezing development rate of the strata, the following steps are included:

[0062] During the manufacturing of the tunnel boring machine, freezing pipelines are laid to freeze the soil between the shield shells and ensure that the freezing rate of the soil in the cutterhead docking area meets the preset freezing requirements.

[0063] Preferably, the step of monitoring and issuing early warnings using a pre-set monitoring system based on the temperature of each monitoring point in the docking area, the temperature of the area between the mud chamber and the shield shell, and the structural surface temperature of the tunnel boring machine, and interacting with the user terminal to exchange the monitoring and early warning results includes:

[0064] S51. Use the acquisition module of the monitoring system to collect the temperature of each monitoring point in the docking area, the temperature of the area between the mud chamber and the shield shell, and the temperature of the structural surface of the tunnel boring machine to obtain temperature data.

[0065] S52. The acquisition module transmits the temperature data to the cloud processing platform of the monitoring system via a wireless network.

[0066] S53, the cloud processing platform reads temperature data and performs anomaly warning analysis on the temperature data to obtain anomaly warning analysis results;

[0067] S54. The temperature data is stored on the cloud platform of the monitoring system and a communication connection is established with the user terminal so that the user can browse the temperature data.

[0068] The beneficial effects of this invention are as follows:

[0069] 1. This invention addresses the salt water freezing and ground reinforcement conditions in shield tunnel docking projects by implementing a zoned real-time monitoring design for the freezing curtain, particularly focusing on freezing reinforcement and monitoring designs for weak freezing areas, thereby improving the safety of the frozen wall during the thermal dismantling process of the docking section structure.

[0070] 2. This invention utilizes a sloping freezing pipe within the soil as the primary freezing point, and uses a pre-reserved freezing pipe on the shield to circulate brine as a local auxiliary method to strengthen freezing in weak freezing areas. Simultaneously, a monitoring line is designed in this area to monitor temperature changes within the frozen soil and at the shield-soil interface in real time.

[0071] 3. This invention combines the excavation sequence of the docking section with a monitoring design for the outer side of the frozen wall (away from the shield shell), which can monitor the temperature change of the frozen wall at the excavation face in real time and reduce the excavation risk. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0073] Figure 1 This is a longitudinal schematic diagram of the arrangement of freezing holes and temperature measuring holes in an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking, according to an embodiment of the present invention.

[0074] Figure 2 This is a circumferential distribution diagram of the shield shell in an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield docking according to an embodiment of the present invention;

[0075] Figure 3 This is a schematic diagram of the cross-section of the XA-row temperature measuring tube, determined by the number of excavation layers and the layer height, in an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking according to an embodiment of the present invention.

[0076] Figure 4 This is a schematic diagram of the cross-section of the HA temperature measuring tube, determined by the number of excavation layers and the layer height, in an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking according to an embodiment of the present invention.

[0077] Figure 5 This is a schematic diagram of the cross-section of the HX freezing pipe, determined by the number of excavation layers and the layer height, in an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunneling according to an embodiment of the present invention.

[0078] Figure 6 This is a schematic diagram of the arrangement of XA, HA and JC measuring points in an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking according to an embodiment of the present invention.

[0079] Figure 7 This is a schematic diagram of the HX measuring point arrangement in an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking according to an embodiment of the present invention;

[0080] Figure 8 This is a schematic diagram of the reserved method and data transmission path for the circumferential temperature measurement lines XG, XH and HG in an implementation method for strengthening freezing and monitoring of the weak freezing area during shield tunnel docking according to an embodiment of the present invention.

[0081] Figure 9 This is a schematic diagram of the spacing between the freezing pipelines XF and HF in an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking, according to an embodiment of the present invention.

[0082] Figure 10 This is a flowchart of the intelligent monitoring organization in an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking, according to an embodiment of the present invention.

[0083] Figure 11 This is a flowchart of an implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunneling according to an embodiment of the present invention. Detailed Implementation

[0084] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0085] According to an embodiment of the present invention, a method for strengthening freezing and monitoring of the weak freezing zone during shield tunneling is provided.

[0086] Specifically, this invention addresses shield tunneling docking conditions by combining excavation sequence construction and freezing weak points with monitoring and enhanced freezing design. Monitoring data guides on-site construction, and timely control measures are taken to improve the safety of the frozen solidification during the active freezing process and excavation process.

[0087] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 11 As shown, the implementation method for strengthening freezing and monitoring of the weak freezing zone during shield tunneling docking according to an embodiment of the present invention includes the following steps:

[0088] S1. Obtain the dimensions of the shield excavation section and the stress state of the frozen body, determine the thickness of the frozen wall, and determine the configuration parameters of the freezing holes based on the freezing development rate of the strata.

[0089] As a preferred embodiment, the steps before obtaining the shield excavation cross-section dimensions and the stress state of the frozen body, determining the frozen wall thickness, and determining the configuration parameters of the freezing holes based on the ground freezing development rate include:

[0090] During the manufacturing of the tunnel boring machine, freezing pipelines are laid to freeze the soil between the freezing pipelines and the shield shell, and to ensure that the freezing rate of the soil in the cutterhead docking area meets the preset freezing requirements.

[0091] S2. Obtain the diameter parameters of the tunnel boring machine, and determine the layout parameters of the temperature measuring holes in the docking area by combining the excavation constraints of the excavation area and the configuration parameters of the freezing holes.

[0092] In a preferred embodiment, obtaining the diameter parameters of the tunnel boring machine and determining the arrangement parameters of the temperature measuring holes in the docking area, in conjunction with the excavation constraints of the excavation area and the configuration parameters of the freezing holes, includes:

[0093] S21. Collect the diameter parameters of the tunnel boring machine and determine the target excavation layer (the target excavation layer is the conventional excavation layer) and the excavation height range of the outermost excavation layer (the outermost excavation layer includes the uppermost excavation layer and the lowermost excavation layer) in the excavation area.

[0094] S22. Using the excavation height range of the target excavation layer and the outermost excavation layer as excavation constraints, and combining the diameter parameters of the tunnel boring machine, construct an equation relating the number of excavation layers of the target excavation layer to the diameter parameters of the tunnel boring machine.

[0095] S23. Based on the equation relating the number of target excavation layers to the diameter parameter of the tunnel boring machine, determine the number of target excavation layers.

[0096] In a preferred embodiment, the equation relating the number of target excavation layers to the diameter parameter of the tunnel boring machine is expressed as follows:

[0097] D = nH1 + 2H2;

[0098] 1.8≤H1≤2.2;

[0099] 2.2≤H2≤2.6;

[0100] In the formula, D represents the diameter of the tunnel boring machine, H1 represents the excavation height of the target excavation layer, H2 represents the excavation height of the outermost excavation layer, and n represents the number of excavation layers of the target excavation layer (n is an integer).

[0101] S24. Determine the total number of temperature measurement holes in the docking area based on the number of excavation layers in the target excavation layer and the characteristics of the outermost excavation layer.

[0102] In a preferred embodiment, determining the total number of temperature measuring holes in the docking area based on the number of excavation layers in the target excavation layer and in combination with the characteristics of the outermost excavation layer includes:

[0103] S241. For the target excavation layer, the number of the target excavation layer is taken as the number of temperature measurement holes in the target excavation layer.

[0104] S242. For the outermost excavation layer, the temperature measuring holes of the outermost excavation layer are arranged in an equidistant manner, and the equation function of the temperature measuring holes of the outermost excavation layer is constructed using the excavation constraints and the diameter parameters of the tunnel boring machine.

[0105] In a preferred embodiment, the expression for the equation function of the temperature measuring holes in the outermost excavated layer is:

[0106] ;

[0107] ;

[0108] ;

[0109] min(α,2β)≤θ≤max(α,2β);

[0110] In the formula, n ′ The number of temperature measuring holes in the outermost excavation layer is represented by α, D represents the diameter of the tunnel boring machine, H1 represents the excavation height of the target excavation layer, H2 represents the excavation height of the outermost excavation layer, α represents the angle between the temperature measuring hole of the outermost adjacent layer and the horizontal center line, β represents the angle between the temperature measuring holes of the two adjacent layers of the outermost layer and the horizontal center line, and θ represents the angle between the temperature measuring holes of the outermost excavation layer.

[0111] S243. Solve the equation function for the temperature measuring holes in the outermost excavated layer to obtain the number of temperature measuring holes in the outermost excavated layer.

[0112] S244. Based on the configuration parameters of the freezing holes, randomly select a number of freezing holes at fixed intervals as soil internal temperature measurement holes to obtain the number of soil internal temperature measurement holes.

[0113] S245. Based on the excavation layer height of the target layer, determine and configure several soil temperature measuring holes above the excavation area to obtain the number of soil temperature measuring holes above the excavation area.

[0114] In a preferred embodiment, based on the excavation layer height of the target layer, a number of soil temperature measuring holes above the excavation area are determined and configured, resulting in the following number of soil temperature measuring holes above the excavation area:

[0115] S2451. Based on the excavation layer height of the target layer, set a soil temperature measurement hole above the excavation area at the midpoint of the arc length of the excavation layer of the target layer.

[0116] S2452. Temperature measurement holes for the soil above the excavation area shall be set directly above the tunnel in the uppermost excavation layer of the outermost excavation layer and on both sides directly above the tunnel.

[0117] As a preferred embodiment, the formula for calculating the setting angle of the soil temperature measuring holes above the excavation area on both sides directly above the tunnel is:

[0118] ;

[0119] In the formula, The angle at which temperature measuring holes for the soil above the excavation area are set on both sides directly above the tunnel, D represents the diameter of the tunnel boring machine, and H2 represents the excavation height of the outermost excavation layer.

[0120] S2453. Determine the number of soil temperature measuring holes above the excavation area based on the set soil temperature measuring holes above the excavation area.

[0121] S246. Calculate the sum of the number of temperature measuring holes in the target excavation layer, the number of temperature measuring holes in the outermost excavation layer, the number of temperature measuring holes inside the soil, and the number of temperature measuring holes in the soil above the excavation area to determine the total number of temperature measuring holes in the docking area.

[0122] S25. Determine the length and angle of the temperature measuring hole in the docking area according to the configuration parameters of the freezing hole.

[0123] S3. Based on the arrangement parameters of the temperature measuring holes in the docking area, arrange temperature measuring points in the temperature measuring holes in the docking area to collect the temperature of each monitoring point in the docking area.

[0124] S4. Based on the structural characteristics of the tunnel boring machine, temperature measuring lines and circumferential temperature measuring points are arranged to collect the temperature of the area between the mud chamber and the shield shell and the temperature of the structural surface of the tunnel boring machine.

[0125] In a preferred embodiment, the step of arranging temperature measuring lines and circumferential temperature measuring points according to the structural characteristics of the tunnel boring machine to collect the temperature of the area between the mud chamber and the shield shell and the structural surface temperature of the tunnel boring machine includes:

[0126] Temperature measuring lines are laid inside the shield belt disc of the tunnel boring machine, and the number of measuring points on the temperature measuring lines is determined according to the size of the cutter box in order to collect the temperature of the area between the mud chamber and the shield shell.

[0127] The first circumferential temperature measuring point is set behind the rear partition of the bubble chamber, and the second circumferential temperature measuring point is set behind the front partition of the bubble chamber.

[0128] S5. Based on the temperature of each monitoring point in the docking area, the temperature of the area between the mud chamber and the shield shell, and the structural surface temperature of the tunnel boring machine, use the preset monitoring system to conduct monitoring and early warning, and interact with the user terminal to exchange the monitoring and early warning results.

[0129] In a preferred embodiment, the step of monitoring and issuing early warnings using a pre-set monitoring system based on the temperatures of various monitoring points in the docking area, the temperature of the area between the mud chamber and the shield shell, and the structural surface temperature of the tunnel boring machine, and interacting with the user terminal to exchange the monitoring and early warning results includes:

[0130] S51. Use the acquisition module of the monitoring system to collect the temperature of each monitoring point in the docking area, the temperature of the area between the mud chamber and the shield shell, and the temperature of the structural surface of the tunnel boring machine to obtain temperature data.

[0131] S52. The acquisition module transmits the temperature data to the cloud processing platform of the monitoring system via a wireless network.

[0132] S53, the cloud processing platform reads temperature data and performs anomaly warning analysis on the temperature data to obtain anomaly warning analysis results;

[0133] Specifically, the cloud processing platform reads temperature data and performs anomaly warning analysis on the temperature data, obtaining the following anomaly warning analysis results:

[0134] S531. The temperature data is preprocessed using the sliding window moving average method to smooth data fluctuations and initially eliminate random noise.

[0135] It should be noted that before using the sliding window moving average method to preprocess the temperature data, the window size N and the sliding step size S need to be determined based on the sampling frequency and noise characteristics of the shield tunnel freezing temperature data. The window size refers to the number of original data points included in each average calculation. If the temperature sampling interval is 5 minutes, N=3-5 sampling points are selected (corresponding to a 15~25 minute window). The target sliding step size is S=1 (that is, the window moves only 1 sampling point each time). If sampling is performed every 5 minutes, the window is updated every 5 minutes, which preserves complete time series information and avoids data loss.

[0136] Specifically, for temperature data, first, valid data is screened, and invalid values ​​are removed (such as null values ​​caused by sensor failure, abnormal high / low temperatures during shutdown, such as suddenly displaying 20℃ or -50℃). The previous valid data is used as a temporary substitute (only temporarily filled, and will be corrected in subsequent smoothing). Then, the smoothed value is calculated by right alignment or center alignment. After the smoothing calculation is completed, the "standard deviation of the deviation between the original valid data and the smoothed data" needs to be calculated. If the deviation drops from 0.8℃~1.2℃ (random noise range) before preprocessing to below 0.3℃, it means that the random noise has been effectively eliminated, and the smoothed data can be used for subsequent M-estimation robust regression. If the deviation is still greater than 0.5℃, the window size is dynamically adjusted in conjunction with the shield freezing stage (such as increasing N from 3 to 5 during the maintenance freezing period), and the above smoothing process is repeated until the noise elimination effect meets the requirements.

[0137] S532. A temperature data fitting model is established based on the M-estimation robust regression algorithm. The initial regression coefficients are solved by iterative weighted least squares method, the initial residuals are calculated and standardized by Hampel method to obtain the standardized residuals.

[0138] Specifically, a temperature data fitting model is established based on the M-estimation robust regression algorithm. The initial regression coefficients are solved by iterative weighted least squares method, and the initial residuals are calculated and standardized using the Hampel method to obtain the standardized residuals. The steps include:

[0139] S5321. Based on the characteristics of shield tunneling freezing projects, determine and configure the independent variables (factors affecting temperature, such as freezing time, brine flow rate, freezing pipe location, soil thermal conductivity, etc.) and dependent variables (temperature value) of the regression model, and establish a multiple linear regression model.

[0140] Specifically, the expression for the multiple linear regression model is:

[0141] T=β0+β1t+β2q+β3l+β4λ+ε;

[0142] In the formula, T is the temperature, t is the freezing time, q is the brine flow rate, l is the distance between the freezing pipes, λ is the thermal conductivity of the soil, β0, β1, β2, β3, and β4 are regression coefficients, and ε is the random error.

[0143] The matrix form is: Y = Xβ + ε; X represents the matrix of independent variables.

[0144] S5322. The initial regression coefficients are calculated using the least squares method (OLS) as the starting point for the iterative weighted least squares method.

[0145] It should be noted that when using Iterative Weighted Least Squares (IRLS) for robust regression, the initial regression coefficients must first be calculated using Ordinary Least Squares (OLS) as the starting point for iteration. The core principle is to minimize the sum of squared errors between the measured temperature value and the model-fitted value, i.e., by optimizing the objective function; S(β)=(Y-Xβ) T The optimal parameter estimate is sought using (Y-Xβ). In the specific derivation, the partial derivative of S(β) with respect to β is taken and set equal to zero to obtain the normal equation X. T Xβ=X T Y, and thus the initial regression coefficient formula is obtained:

[0146] ;

[0147] S5323. Calculate the residual vector based on the initial coefficients and estimate the residual scaling parameters; and calculate the weight of the current residual based on the Hampel weighting function.

[0148] Specifically, based on the obtained initial regression coefficients, the difference between the measured temperature value and the model fitted value is calculated point by point to form a residual vector (for example, if the measured temperature of a certain frozen wall measuring point is -13℃ and the fitted temperature is -12.5℃, then the residual is -0.5℃. A positive residual means that the measured temperature is higher than the fitted value, which may indicate insufficient freezing; a negative residual means that the measured temperature is lower than the fitted value, which may indicate overfreezing. The larger the absolute value of the residual, the more significant the deviation of the data from the model trend).

[0149] Then, the Hampel method is used to estimate the residual scaling parameters: First, the absolute values ​​of all residuals in the residual vector are taken, sorted from smallest to largest, and the median (i.e., the median of absolute deviation) is taken. Then, this median is divided by a constant 0.6745. Finally, the weights corresponding to each residual are calculated according to the Hampel weight function. This function suppresses outliers by adjusting the weights in stages. In engineering, the parameters a=1.7 and b=3.4 are usually taken. That is, when the absolute value of the standardized residual (residual divided by the scaling parameter) is ≤1.7, it is judged as normal data and the weight is set to 1; when the absolute value is between 1.7 and 3.4, the weight decreases linearly with the increase of the absolute value (e.g., when the standardized residual is 2.5, the weight is about 0.68); when the absolute value is >3.4, it is judged as an extreme outlier (e.g., the temperature rise caused by the breakage of the freezer tube reaches 5 after the residual is standardized), and the weight is set to 0 to completely eliminate its interference with subsequent model iterations and ensure the robustness of the regression coefficient calculation.

[0150] S5324. Substitute the calculated current residual weights into the weighted least squares formula to update the regression coefficients. If the maximum difference between the regression coefficients of two adjacent iterations is greater than a preset threshold (e.g., 0.0001), return to S5323. Recalculate the residuals, scale parameters, and weights based on the new coefficients to continue iterating. If the residuals are less than the threshold, stop iterating, determine the final regression coefficients, and complete the establishment of the temperature data fitting model. At the same time, the effectiveness of the standardized residuals can be further verified based on the final residuals and robust scale parameters.

[0151] Specifically, the current residual weights obtained from S5323 are used to construct a diagonal weight matrix, which is then substituted into the weighted least squares formula. The regression coefficients are updated through matrix operations. In this process, the contribution of abnormal data that were previously assigned small or zero weights (such as the temperature surge caused by the leakage of the freezing tube) to the coefficients is greatly weakened, making the new coefficients more consistent with the changing trend of normal temperature data (such as the law that the temperature steadily decreases as the freezing time increases).

[0152] Next, a preset threshold (e.g., 0.0001) is introduced to determine whether the iteration has converged: calculate the maximum value of the difference between corresponding elements in the regression coefficients of two adjacent iterations (k-th and k-1-th iterations). If the value is greater than 0.0001, it indicates that the coefficients are still fluctuating significantly and the model is not stable. It is necessary to return to S5323, recalculate the residuals (the difference between the measured temperature and the newly fitted temperature) based on the new coefficients, update the residual scaling parameters (because the residuals have changed, the robust scale needs to be re-estimated using the Hampel method) and weights (adjust the weights of each sample according to the new residuals).

[0153] Then, the final residuals can be calculated using the final regression coefficients, combined with the robust scaling parameters determined during the iteration process, through u i =e i / s(e i The standardized residual is obtained by taking the final residual (where s is the robust scaling parameter).

[0154] S534. Based on the determined final regression coefficients, and combined with the actual values ​​of the independent variables corresponding to each monitoring point, the values ​​are substituted into the multiple linear regression model point by point to generate a robust fitted temperature value for each monitoring point.

[0155] S534. Calculate the deviation between the measured temperature value and the robust fitted temperature value at each monitoring point, and calculate the mean standard deviation of the deviation. Use this as the basis for judging whether there is an anomaly in the temperature data. When the deviation exceeds a certain multiple (such as 3 times) of the mean, it is judged as an anomaly and an early warning is issued.

[0156] S54. The temperature data is stored on the cloud platform of the monitoring system and a communication connection is established with the user terminal so that the user can browse the temperature data.

[0157] To facilitate understanding of the above technical solutions of the present invention, the following further describes the above technical solutions of the present invention from the perspectives of architecture and principle, as follows:

[0158] like Figure 1 As shown, XA and HA are the outermost temperature measuring holes; Figure 2 The uppermost part corresponds to the XA temperature measuring hole, and the lowermost part corresponds to the HA temperature measuring hole arrangement. Figure 3 , 4 These are schematic diagrams of the cross-sections and excavation layers of the XA and HA temperature measuring holes, respectively.

[0159] To improve excavation safety and avoid exposing large areas of frozen body to air, a layered excavation method is often adopted. Due to the large amount of heat input during the operation, the thickness and average temperature of the frozen wall will be weakened. To monitor temperature changes on the outer side of the frozen wall, temperature measuring holes are installed at each excavation layer.

[0160] Here, assuming the shield diameter is D, the height of each layer should comprehensively consider the suitability for personnel excavation operations. The target layer excavation height H1 should be 1.8m-2.2m, divided into n layers (n is an integer). Due to the influence of the curved surface, the excavation height of the uppermost (lower) layer should be appropriately increased to ensure personnel operability. Therefore, the excavation height H2 of the uppermost (lower) layer should be 2.2m-2.6m. The overall structure is symmetrically distributed vertically and satisfies the following relationship:

[0161] D = nH1 + 2H2;

[0162] 1.8≤H1≤2.2;

[0163] 2.2≤H2≤2.6;

[0164] Due to the relatively long distance and minimal impact, to reduce the number of openings and improve economic efficiency, only one temperature measuring hole is installed on the outermost frozen wall of each target excavation layer, located at the midpoint of the arc surface. After the design of the temperature measuring holes for the target excavation layer is completed, considering the large arc lengths of the upper and lower excavation layers and the distance between the temperature measuring holes and adjacent layers, the upper (lower) temperature measuring holes are arranged at equal intervals to avoid monitoring blind spots and facilitate the analysis of temperature differences between adjacent freezing holes.

[0165] like Figure 1 In the diagram, XB, XC, and XD are the initial freezing points, while HB, HC, and HD are the subsequent freezing points. Their function is to install freezing pipes at these locations and circulate low-temperature refrigerant to lower the soil temperature. JC is an internal soil temperature measurement hole, located at the same cross-section as XC. Figure 2As can be seen, some freezing holes are selected at fixed intervals in row XC as temperature measuring holes. JC can be adjusted according to the actual construction requirements on site. It can be used for freezing operations in the early stage of freezing. When entering the maintenance freezing period, the freezing device can be replaced with a temperature measuring pipeline to monitor whether there are weak links inside the frozen wall. At the same time, it calculates and analyzes whether the average temperature of the internal soil meets the design requirements. After further analysis, excavation operations can be carried out.

[0166] like Figure 1 and Figure 2 The HX temperature measurement hole is located on the side of the rear tunnel boring machine (TBM), passing through the air chamber partition, extending at an angle into the soil and reaching above the shell of the preceding TBM. This temperature measurement hole can directly monitor the soil above the excavation area; therefore, to comprehensively understand the frozen soil condition, the number of measuring points inside the hole is increased. The intersection with the interior of the rear TBM shell serves as the monitoring starting point, and the bottom of the hole as the monitoring endpoint, providing comprehensive monitoring of temperature changes in the triangular area of ​​the docking excavation and at the interface between the frozen soil and the steel plate.

[0167] Figure 5 This is a schematic diagram of the cross-section of the HX freezing pipe, determined by the number and height of the excavation layers. As mentioned earlier, after the excavation layer height is determined, an HX temperature measuring hole is installed at the midpoint of the arc length of the target excavation layer. Unlike the XA and HA arrangements, temperature measuring holes are installed on both sides of each target excavation layer to enhance monitoring of vulnerable areas. For the uppermost excavation layer, one temperature measuring hole is designed directly above the tunnel, with one on each side, at an angle of 1 / 4 of the central angle corresponding to the upper (lower) excavation arc length.

[0168] The problem with setting up the temperature measuring holes in the lowest excavation layer (the temperature measuring holes in the dotted line in the figure) is that the bottom of the tunnel boring machine is the slag outlet, and it is impossible to reserve temperature measuring holes within a certain range. It is necessary to make targeted adjustments according to the size of the slag outlet of the tunnel boring machine. Therefore, this invention does not make specific designs for the temperature measuring holes in the lower part of HX. The arrangement of the temperature measuring holes in the lowest excavation layer in the figure is only for illustration.

[0169] In addition, a detailed design was carried out for the layout of internal measuring points in XA, HA, and JC. Figure 6 The diagram shows the layout of the XA, HA, and JC measuring points. The interface between the shield shell and the frozen soil, as well as the inner surface of the shield shell, are important monitoring points. Therefore, the measuring points in the above areas are densely arranged to ensure the freezing safety of the weak interface. The measuring points in the remaining soil are evenly distributed at equal intervals.

[0170] Specifically, firstly, the thickness of the frozen wall is designed based on the dimensions of the tunnel boring machine excavation section and the stress state of the frozen body. Secondly, the number, spacing, and length of freezing holes are determined based on the designed thickness of the frozen wall and the freezing development rate of the strata in the region. Thirdly, the angles and lengths of temperature measuring holes XA, HA, and JC are determined. The length of the temperature measuring holes should encompass the designed frozen wall area, and the angles should preferably be close to or include the outer contour line of the designed frozen wall. Since the thickness and contour of the frozen wall are determined based on geological conditions, the size of the excavation section, and other factors, this invention does not impose special design requirements on these aspects. However, the design principles for the temperature measuring holes are universally applicable and meet monitoring requirements.

[0171] As mentioned above, given that the lengths of XA, HA, and JC are L respectively X L H With L J Afterwards, the angles with the shield are Ω respectively. X Ω H With Ω J (The arrangement of freezing holes is existing technology and will not be elaborated upon here.) Because the spacing between the holes is the same, therefore... Figure 6 In this diagram, L represents the total length of the temperature measuring holes, Ω represents the angle, m represents the total number of measuring points, d represents the shield thickness, and λ represents the distance from the last measuring point to the previous measuring point. Specific design calculations can be performed using the following formula:

[0172] ;

[0173] ;

[0174] Figure 7 This is a schematic diagram of the HX measuring point layout. To comprehensively investigate the impact of heat input on the triangular weak area during the excavation stage, the center axis of the docking surface needs to be determined based on the tunnel boring machine's structural dimensions and docking position during the measuring point layout process. Monitoring points should be added in areas with directly exposed frozen soil without structural protection, and the vertical spacing should be adjusted from 2d to d accordingly. The overall design method for other measuring points is the same as above. Furthermore, the monitoring frequency of measuring points within the temperature measurement holes in the excavation area should be increased.

[0175] Based on the vertical distance d between the measuring points, and by recording the time t1 when a significant temperature rise (>1℃) occurs at the measuring point closest to the shield structure and the time t2 when a significant temperature rise (>1℃) occurs at the monitoring point closest to the shield structure, the temperature development rate under the heat input condition is estimated as v=d / (t2-t1).

[0176] Then, predict the impact range 1>vt under continuous heat input operation time t, and determine the maximum allowable melting range l of the frozen wall based on the actual working conditions. max Because the transfer of temperature into frozen soil is delayed, on-site construction should be carried out in accordance with l maxContinue to control the level at 0.5-0.7 times the normal level to ensure the impact area remains manageable. Simultaneously, further corresponding measures should be taken on-site, such as stopping heat input operations, cooling the excavation face environment, and increasing the flow rate and velocity of the brine in the freezing pipes.

[0177] For example, if the target monitoring frequency is 10 minutes / time, the monitoring frequency in the corresponding excavation area can be adjusted to 1 minute / time, or even shorter, to ensure that the monitoring is closer to the real-time dynamic effect. The shield shell thickness is 8 cm, i.e., d=8; the time when a significant temperature rise occurs at the measuring points closest to the shield structure surface is recorded. The time when significant temperature increases occurred at 10:00 and at nearby monitoring points. Given a time interval of 10:04, estimate the temperature development rate under the heat input condition, i.e., v = d / (t2 - t1) = 8 / 4 = 2 cm / min. Then, the maximum time for continued heat input is: t max =0.7l max / v=0.35l max .

[0178] in, Figure 1 XE and HE are the internal temperature measurement lines of the two shield cutterheads, respectively. This temperature measurement is limited to the atmospheric pressure cutterhead type. Digital sensors are arranged in a rectangular pattern on the inner edge of the cutterhead. Their function is to monitor the temperature in the area between the mud chamber and the shield shell during active freezing, and to determine the development of permafrost temperature in the docking area. The number of measuring points on the temperature measurement lines should be designed according to the cutterhead size. Since the cutterhead size varies for each shield machine, this invention does not specify a requirement for the number of measuring points. The arrangement is as follows: Figure 2 As shown.

[0179] Figure 1 In the design, XF and HF are reserved freezing pipelines. Utilizing the excellent thermal conductivity of the shield steel plate, they accelerate the freezing of the soil between XD / HD and the shield, ensuring rapid freezing of the soil in the cutterhead docking area and accelerating the overall freezing rate. More importantly, during the excavation phase when high heat input occurs, the area between the shield and the frozen soil becomes a weak point. The low-temperature refrigerant circulation of XF and HF enables rapid heat exchange, removing heat from the cutterhead docking area and ensuring safety during excavation.

[0180] The positions and arrangement of XF and HF are as follows: Figure 2 As shown. To enhance the above effects, the XF and HF freezing pipes were pre-embedded by welding during the tunnel boring machine manufacturing process. Simultaneously, eight sets of "serpentine" tightly fitted pipes were arranged circumferentially inside the shield shell. Each set of freezing pipes was individually connected to the liquid distribution ring, ensuring that the flow rate and velocity of each cryogenic medium could be individually controlled. This allowed for increased flow rate and velocity in the corresponding hot-cutting excavation area, accelerating heat exchange.

[0181] The starting point for the arrangement is located at the rear partition of the bubble chamber, and the endpoint can extend to the cut ring. Figure 8This diagram illustrates the reserved methods and data transmission paths for the circumferential temperature measurement lines XG, XH, and HG. The longitudinal length T is not specifically described here and will be adjusted in real-time according to the tunnel boring machine dimensions. The width W of each group can be calculated using the following formula:

[0182] W = πD / 36;

[0183] In addition, XG and XH are two preset circumferential temperature sensors. The sensors are DS18B20 digital temperature sensors, which can be connected to multiple sensors to facilitate multi-point monitoring of structural surface temperature. Figure 2 and Figure 9 The diagram illustrates the spacing between the XF and HF freezing pipes. The first sensor, XG, is positioned 5cm behind the rear partition of the bubble chamber, and the second sensor, XH, is positioned 5cm behind the front partition of the bubble chamber. Both XG and XH are arranged with 30mm diameter semi-circular holes pre-drilled in the shield steel plate to house DS18B20 digital temperature sensors. These holes are then sealed circumferentially with end plates. Both sensors have openings in their top end plates for wiring and external connections. Additionally, an extended pipe is pre-drilled on the top end plate of XH for connecting the XH sensor to the inside of the tunnel boring machine. Furthermore, the arrangement and position of HG are identical to XG.

[0184] like Figure 9 and Figure 10 Once all monitoring setups are complete, each monitoring port and its corresponding DS18B20 digital sensor will be integrated into a single cable and connected to a digital acquisition module. A specific acquisition cycle will be set according to site requirements, and data will be transmitted to a cloud processing platform via a wireless network (Wi-Fi signal). The monitoring data will be read, processed, and analyzed. The cloud platform will then store the data, which users can browse via their mobile phones. Thresholds can also be set for specific measuring points on the cloud platform. When the temperature exceeds the threshold, the cloud platform will issue an alarm and automatically send the information to each mobile phone, allowing for immediate handling of on-site issues and ensuring operational safety.

[0185] In summary, by utilizing the above-mentioned technical solutions of this invention, this invention addresses the ground conditions requiring brine freezing reinforcement in shield tunneling docking projects. It employs a zoned real-time monitoring design for the frozen curtain, particularly focusing on freezing reinforcement and monitoring in weak freezing areas, thereby improving the safety of the frozen wall during the thermal dismantling process of the docking section. This invention utilizes inclined freezing pipes within the soil as the primary freezing method, and uses pre-reserved freezing pipes on the shield shell to circulate brine for localized auxiliary freezing reinforcement in weak freezing areas. Simultaneously, a monitoring line is designed in this area to monitor temperature changes within the frozen soil and at the shield-soil interface in real time. Furthermore, this invention, combined with the excavation sequence of the docking section, incorporates a monitoring design for the outer side of the frozen wall (away from the shield shell), enabling real-time monitoring of temperature changes in the frozen wall at the excavation face, thus reducing excavation risks.

[0186] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, etc.) containing computer-usable program code.

[0187] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for strengthening freezing and monitoring in the weak freezing zone of a shield tunnel connection, characterized in that, Includes the following steps: S1. Obtain the dimensions of the shield excavation section and the stress state of the frozen body, determine the thickness of the frozen wall, and determine the configuration parameters of the freezing holes based on the freezing development rate of the strata. S2. Collect the diameter parameters of the tunnel boring machine (TBM) and determine the excavation height range of the target excavation layer and the outermost excavation layer in the excavation area; use the excavation height range of the target excavation layer and the outermost excavation layer as excavation constraints, and combine them with the diameter parameters of the TBM to construct an equation relating the number of excavation layers in the target excavation layer to the diameter parameters of the TBM; based on the equation relating the number of excavation layers in the target excavation layer to the diameter parameters of the TBM, solve for the number of excavation layers in the target excavation layer; based on the number of excavation layers in the target excavation layer and the characteristics of the outermost excavation layer, determine the total number of temperature measuring holes in the docking area; based on the configuration parameters of the freezing holes, determine the length and angle of the temperature measuring holes in the docking area. S3. Based on the arrangement parameters of the temperature measuring holes in the docking area, arrange temperature measuring points in the temperature measuring holes in the docking area to collect the temperature of each monitoring point in the docking area. S4. Based on the structural characteristics of the tunnel boring machine, temperature measuring lines and circumferential temperature measuring points are arranged to collect the temperature of the area between the mud chamber and the shield shell and the temperature of the structural surface of the tunnel boring machine. S5. Based on the temperature of each monitoring point in the docking area, the temperature of the area between the mud chamber and the shield shell, and the structural surface temperature of the tunnel boring machine, use the preset monitoring system to conduct monitoring and early warning, and interact with the user terminal to exchange the monitoring and early warning results.

2. The method for strengthening freezing and monitoring of weak areas in shield tunnel docking as described in claim 1, characterized in that, The equation relating the number of target excavation layers to the diameter parameter of the tunnel boring machine is expressed as follows: D = nH1 + 2H2; 1.8≤H1≤2.2； 2.2≤H2≤2.6； In the formula, D represents the diameter of the tunnel boring machine, H1 represents the excavation height of the target excavation layer, H2 represents the excavation height of the outermost excavation layer, and n represents the number of excavation layers of the target excavation layer.

3. The method for strengthening freezing and monitoring of weak areas in shield tunnel docking as described in claim 2, characterized in that, The determination of the total number of temperature measurement holes in the docking area based on the number of excavation layers in the target excavation layer and the characteristics of the outermost excavation layer includes: S241. For the target excavation layer, the number of the target excavation layer is taken as the number of temperature measurement holes in the target excavation layer. S242. For the outermost excavation layer, the temperature measuring holes of the outermost excavation layer are arranged in an equidistant manner, and the equation function of the temperature measuring holes of the outermost excavation layer is constructed using the excavation constraints and the diameter parameters of the tunnel boring machine. S243. Solve the equation function for the temperature measuring holes in the outermost excavated layer to obtain the number of temperature measuring holes in the outermost excavated layer. S244. Based on the configuration parameters of the freezing holes, randomly select a number of freezing holes at fixed intervals as soil internal temperature measurement holes to obtain the number of soil internal temperature measurement holes. S245. Based on the excavation layer height of the target layer, determine and configure several soil temperature measuring holes above the excavation area to obtain the number of soil temperature measuring holes above the excavation area. S246. Calculate the sum of the number of temperature measuring holes in the target excavation layer, the number of temperature measuring holes in the outermost excavation layer, the number of temperature measuring holes inside the soil, and the number of temperature measuring holes in the soil above the excavation area to determine the total number of temperature measuring holes in the docking area.

4. The method for strengthening freezing and monitoring of weak areas in shield tunnel docking as described in claim 3, characterized in that, The expression for the equation function of the temperature measuring holes in the outermost excavated layer is: ； ； ； In the formula, n ′ The number of temperature measuring holes in the outermost excavation layer is represented by α, D represents the diameter of the tunnel boring machine, H1 represents the excavation height of the target excavation layer, H2 represents the excavation height of the outermost excavation layer, α represents the angle between the temperature measuring hole of the outermost adjacent layer and the horizontal center line, β represents the angle between the temperature measuring holes of the two adjacent layers of the outermost layer and the horizontal center line, and θ represents the angle between the temperature measuring holes of the outermost excavation layer.

5. The method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking according to claim 3, characterized in that, Based on the excavation layer height of the target layer, a number of soil temperature measuring holes above the excavation area are determined and configured, resulting in the following number of soil temperature measuring holes above the excavation area: S2451. Based on the excavation layer height of the target layer, set a soil temperature measurement hole above the excavation area at the midpoint of the arc length of the excavation layer of the target layer. S2452. Temperature measurement holes for the soil above the excavation area shall be set directly above the tunnel in the uppermost excavation layer of the outermost excavation layer and on both sides directly above the tunnel. S2453. Determine the number of soil temperature measuring holes above the excavation area based on the set soil temperature measuring holes above the excavation area.

6. The method for strengthening freezing and monitoring of the weak freezing zone during shield tunneling as described in claim 5, characterized in that, The formula for calculating the angle of the soil temperature measuring holes located on both sides directly above the tunnel above the excavation area is as follows: ； In the formula, The angle at which temperature measuring holes for the soil above the excavation area are set on both sides directly above the tunnel, D represents the diameter of the tunnel boring machine, and H2 represents the excavation height of the outermost excavation layer.

7. The method for strengthening freezing and monitoring of the weak freezing zone during shield tunneling as described in claim 2, characterized in that, The step of arranging temperature measuring lines and circumferential temperature measuring points according to the structural characteristics of the tunnel boring machine (TBM) to collect the temperature of the area between the mud chamber and the shield shell, as well as the temperature of the structural surface of the TBM, includes: Temperature measuring lines are laid inside the shield belt disc of the tunnel boring machine, and the number of measuring points on the temperature measuring lines is determined according to the size of the cutter box in order to collect the temperature of the area between the mud chamber and the shield shell. The first circumferential temperature measuring point is set behind the rear partition of the bubble chamber, and the second circumferential temperature measuring point is set behind the front partition of the bubble chamber.

8. The method for strengthening freezing and monitoring of weak areas in shield tunnel docking as described in claim 7, characterized in that, Before obtaining the dimensions of the shield tunnel excavation section and the stress state of the frozen body, determining the thickness of the frozen wall, and determining the configuration parameters of the freezing holes based on the freezing development rate of the strata, the following steps are included: During the manufacturing of the tunnel boring machine, freezing pipelines are laid to freeze the soil between the freezing pipelines and the shield shell, and to ensure that the freezing rate of the soil in the cutterhead docking area meets the preset freezing requirements.

9. The method for strengthening freezing and monitoring of the weak freezing zone during shield tunnel docking according to claim 1, characterized in that, The process of monitoring and issuing early warnings using a pre-set monitoring system based on the temperatures at various monitoring points in the docking area, the temperature between the mud chamber and the shield shell, and the structural surface temperature of the tunnel boring machine, and interacting with the user terminal with the monitoring and early warning results includes: S51. Use the acquisition module of the monitoring system to collect the temperature of each monitoring point in the docking area, the temperature of the area between the mud chamber and the shield shell, and the temperature of the structural surface of the tunnel boring machine to obtain temperature data. S52. The acquisition module transmits the temperature data to the cloud processing platform of the monitoring system via a wireless network. S53, the cloud processing platform reads temperature data and performs anomaly warning analysis on the temperature data to obtain anomaly warning analysis results; S54. The temperature data is stored on the cloud platform of the monitoring system and a communication connection is established with the user terminal so that the user can browse the temperature data.

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