Tunnel shield construction simulation analysis system and analysis method for multi-karst-cave terrain

Abstract

The invention discloses a tunnel shield construction simulation analysis system and analysis method for a multi-karst-cave terrain, and the analysis method carries out the reinforcement treatment and shield tunnel analysis of karst caves at different positions relative to a tunnel through building a three-dimensional analysis model of a multi-karst-cave terrain tunnel, and comprises the following steps: L1, when the karst caves are located above the tunnel, the three-dimensional analysis model of the multi-karst-cave terrain tunnel is built, the three-dimensional analysis model of the multi-karst-cave terrain tunnel is built; the karst cave and the tunnel are reinforced; and L2, in the state that the karst cave is located on the side or below the tunnel, the construction process of the shield tunnel with the karst cave located in the working condition of the designated range of the tunnel is simulated, the structural stability rule of the tunnel is analyzed and obtained, meanwhile, the karst cave range influencing the tunnel stability is determined, and the optimal construction path is determined based on the karst cave range influencing the tunnel stability. The tunnel structure stability rule can be conveniently and comprehensively evaluated, so that the construction parameters and method are optimized, and high efficiency, safety and stability of tunnel construction are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of construction simulation analysis, and in particular to a tunnel shield construction simulation analysis system and analysis method for multi-cavern terrain. Background Art

[0002] Tunnel shield construction is an underground excavation technology widely used in urban subway, highway and railway construction. When shield excavation is carried out in areas with complex geological conditions, especially in areas with many karst caves or soil caves, these naturally formed cavity structures are often unpredictable, which poses great challenges to the project.

[0003] Traditionally, before encountering such special geological conditions, geological exploration methods such as drilling and geophysical exploration are used to grasp the distribution of underground rock and soil layers and the location of potential caves or earth caves as accurately as possible. However, even if detailed preliminary investigation measures are taken, it is difficult to completely avoid a series of construction risks caused by undiscovered or improper handling.

[0004] When faced with a stratum containing multiple caves or soil caves of unknown size and location, the existing technology usually adopts the method of first implementing pre-reinforcement treatment on known dangerous areas, such as grouting to fill the gaps to improve the overall stability and bearing capacity of the surrounding rock; at the same time, strengthen on-site monitoring and immediately activate the emergency plan once abnormal changes are detected. However, this method still has obvious shortcomings:

[0005] Low accuracy: It is difficult to accurately determine all small caves hidden deep inside using traditional geological exploration techniques;

[0006] High cost: Large-scale and indiscriminate preventive reinforcement of the entire working surface is not only costly, but may also result in a waste of resources;

[0007] Great safety hazard: Even if local reinforcement is carried out, if certain key points are missed, water gushing, mud bursting or even collapse accidents may still occur during the advancement of the shield machine, seriously threatening the safety of personnel and the integrity of equipment.

[0008] To this end, the present application specifically proposes a tunnel shield construction simulation analysis system and analysis method for multi-cavern terrain to solve the above-mentioned technical problems. Summary of the invention

[0009] The main purpose of the present invention is to provide a tunnel shield construction simulation analysis system and analysis method for multi-cavern terrain, simulate the influence of caves located on the side of the tunnel and at different spacings below the tunnel on the stability of the tunnel structure, obtain the optimal construction path, and apply it to the cave treatment before the urban shield tunnel passes through and the pre-reinforcement treatment of the surface, so as to solve the technical problems raised in the background technology.

[0010] The present invention adopts the following technical solutions to solve the above technical problems:

[0011] A tunnel shield construction simulation analysis system for multi-cavern terrain uses ANSYS to establish a three-dimensional analysis model of a tunnel in multi-cavern terrain, and uses the fast Lagrangian difference analysis program to simulate and analyze the tunnel excavation process, wherein:

[0012] For the three-dimensional analysis model, the left and right side boundaries and the lower boundary are determined according to the specified tunnel burial depth and diameter. The upper boundary of the model is established according to the actual terrain undulation and is set as a free boundary. The surrounding rock is adopted with hexahedron mesh elements;

[0013] During the simulation analysis process, the stratum rock and soil materials that have not been excavated are simulated using the Mohr-Coulomb model, and the existing buildings and lining materials on the stratum are simulated using the elastic model.

[0014] Preferably, in the three-dimensional analysis model, monitoring points are arranged at the crown, the invert, and the two side haunches at the specified position in the excavation direction for cross-section monitoring to analyze the stability of the tunnel structure.

[0015] Preferably, in the three-dimensional analysis model, the specified vertices of the simulated buildings are selected as monitoring points, and a specified excavation depth cross-section is set along the excavation direction as a monitoring line for monitoring the displacement of surface buildings.

[0016] Preferably, the specific simulation construction steps of the tunnel excavation process include:

[0017] S1. Under the initial stress field of the three-dimensional analysis model, the soil body to be excavated by the shield machine is deactivated. The deactivated soil body includes the core soil unit, the segment unit, and the grouting layer unit. The face thrust pressure is applied in the normal direction of the excavation face, and the shield shell unit of the shield machine is activated;

[0018] S2. After excavating the specified ring, the segment unit is activated at the same time, the thrust pressure is applied to the segment unit, the face tunneling pressure in step S1 is cancelled, and the shield shell unit is deactivated;

[0019] S3. Since the shield advances forward, voids are formed between the segments and the soil body. Therefore, the grouting layer unit is activated and the grouting pressure is applied to make the segments and the soil body closely combined and jointly support. At the same time, the segment thrust pressure in step S2 is cancelled;

[0020] S4. The grouting pressure in step S3 is cancelled, and steps S1 to S3 are repeated until the tunnel excavation is completed.

[0021] Preferably, a tunnel shield construction simulation analysis method for multi-cavern terrain uses the tunnel shield construction simulation analysis system described in any one of the above to reinforce the caverns at different positions relative to the tunnel and analyze the shield tunnel, including:

[0022] L1. When the karst cave is located above the tunnel, reinforce the karst cave and the tunnel.

[0023] L2. When the karst cave is located on the side or below the tunnel, simulate the construction process of the shield tunnel in the working condition where the karst cave is within the specified range of the tunnel, obtain and analyze the structural stability law of the tunnel, determine the range of the karst cave affecting the tunnel stability, and determine the optimal construction path based on the range of the karst cave affecting the tunnel stability.

[0024] Preferably, when the karst cave is located on the side or below the tunnel, the specific operation process for calculating and analyzing the structural stability law of the tunnel includes:

[0025] Under the initial stress field, conduct the simulated construction of the shield tunnel in the working condition where the karst cave is within the specified range of the tunnel, monitor the surface settlement of the model, input the preset data, and conduct surface settlement analysis, tunnel displacement analysis and segment stress field analysis based on the cross-section monitoring data and surface settlement monitoring data to obtain the influence law of the distance relationship between the karst cave and the tunnel on the structural stability of the tunnel when the karst cave is located on the side or below the tunnel.

[0026] Preferably, the surface settlement analysis includes:

[0027] When the karst cave has the same diameter and different distances from the tunnel, obtain the maximum settlement change curve of the surface along the line;

[0028] According to the maximum settlement change curve, obtain the surface settlement law at this time: under the condition of the same cave diameter, as the distance between the tunnel and the karst cave increases, the maximum surface settlement decreases;

[0029] When the karst cave is located on the side of the tunnel, preset the allowable value of the maximum surface settlement, and confirm the distance range that needs to be filled and reinforced when the karst cave is located on the side of the tunnel according to the allowable value of the maximum settlement at this time;

[0030] When the karst cave is located below the tunnel, preset the settlement allowable value without the karst cave, and confirm the distance range that needs to be filled and reinforced when the karst cave is located below the tunnel according to the settlement allowable value without the karst cave at this time.

[0031] Preferably, the tunnel displacement analysis includes:

[0032] When the karst cave is at different distances from the tunnel, obtain the settlement change curve of the tunnel vault and the heave change curve of the tunnel invert;

[0033] According to the settlement change curve and the heave change curve, obtain the displacement influence law at this time: the vertical displacement of the tunnel vault, the heave value of the vault, and the horizontal convergence of the tunnel all decrease as the distance between the karst cave and the tunnel increases.

[0034] Preferably, the segment stress field analysis includes:

[0035] When the karst cave is at different distances from the tunnel, obtain the curve of the maximum stress value received by the lining segment.

[0036] According to the curve of the maximum stress value, obtain the stress law of the segment at this time: the maximum stress value received by the lining segment increases as the distance between the karst cave and the tunnel increases.

[0037] Preferably, the method for determining the range of the karst cave affecting the tunnel stability in the L2 state includes:

[0038] Through surface settlement analysis, tunnel displacement analysis and segment stress field analysis, obtain the maximum surface settlement change amount a, the maximum segment stress value b, the tunnel crown settlement change amount c and the invert heave change amount d at different distances between the karst cave and the tunnel when the karst cave is located on the side and below the tunnel.

[0039] Preset the stability weights of the maximum surface settlement change amount a, the maximum segment stress value b, the tunnel crown settlement change amount c and the invert heave change amount d as α, β, γ and δ respectively, then there is a stability determination value E for the same distance between the karst cave and the tunnel:

[0040]

[0041] Preset a determination threshold K. If the stability determination value E = K, then the distance between the karst cave and the tunnel at this time is the specific karst cave range value affecting the tunnel stability.

[0042] On the other hand, the present invention also discloses a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the processor is made to execute the steps of the above method.

[0043] On yet another aspect, the present invention also discloses a computer device including a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, the processor is made to execute the steps of the above method.

[0044] As can be seen from the above technical solutions, the present invention provides a tunnel shield construction simulation analysis system and analysis method for a multi-karst cave terrain. Compared with the prior art, the present invention has the following advantages:

[0045] 1. By setting up a simulation analysis system, the present invention can identify potential geological risks in advance, conduct risk assessment and classification, provide data support for construction, and at the same time, by simulating and predicting potential risks, a safer construction plan can be designed, the accident rate can be reduced, and workers and the surrounding environment can be protected.

[0046] 2. By setting up a simulation analysis system, the present invention can determine the optimal shield machine propulsion path according to the actual terrain and geological conditions, avoid directly crossing large karst cave areas, reduce risks during construction, and thus reduce unnecessary downtime, thereby shortening the entire tunnel construction cycle.

[0047] 3. By setting up a simulation analysis system, the present invention can monitor the propulsion state of the shield machine and the deformation of the surrounding soil layer in real time, adjust construction parameters in a timely manner, control the deformation of the ground and surrounding buildings, thereby improving the working efficiency of the shield machine and achieving a higher propulsion speed.

[0048] 4. By setting up a simulation analysis system, the present invention can simulate the influence of different distances between karst caves on the side and below the tunnel on the tunnel structure stability, obtain the optimal construction path, and apply it to the treatment of karst caves before the urban shield tunnel passes through and the pre-reinforcement treatment of the ground surface.

[0049] 5. By conducting simulated construction of a karst cave shield tunnel under the initial stress field and analyzing the surface settlement, tunnel displacement, and segment stress field based on the monitoring data, the present invention can conveniently and comprehensively evaluate the law of tunnel structure stability, thereby optimizing construction parameters and methods to ensure the high efficiency, safety, and stability of tunnel construction.

[0050] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Of course, any product implementing the present invention does not necessarily need to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0052] Figure 1 It is a schematic simulation diagram of the calculation model of the simulation analysis system of the present invention;

[0053] Figure 2 It is a schematic plan view of the excavation section showing the layout of the tunnel structure monitoring points of the present invention;

[0054] Figure 3 It is a schematic top plan view showing the layout of the ground surface monitoring points of the present invention;

[0055] Figure 4 It is a schematic broken line diagram showing the influence of different distances between karst caves and the tunnel on the ground surface settlement of the present invention;

[0056] Figure 5Schematic diagram of the settlement change curve of the tunnel vault of the present invention;

[0057] Figure 6 Schematic diagram of the heave change curve of the tunnel invert of the present invention;

[0058] Figure 7 Schematic diagram of the horizontal convergence change curve of the tunnel of the present invention;

[0059] Figure 8 Contour map of the maximum principal stress of the segment in the state without karst cave of the present invention;

[0060] Figure 9 Contour map of the maximum principal stress of the segment in the state where the distance between the karst cave and the tunnel is 2 m of the present invention;

[0061] Figure 10 Contour map of the maximum principal stress of the segment in the state where the distance between the karst cave and the tunnel is 3 m of the present invention;

[0062] Figure 11 Contour map of the maximum principal stress of the segment in the state where the distance between the karst cave and the tunnel is 4 m of the present invention;

[0063] Figure 12 Schematic diagram of the broken line of the maximum principal stress change of the segment under different distances of the present invention;

[0064] Figure 13 Schematic diagram of the broken line of the influence of the change of the distance between the karst cave and the tunnel on the ground settlement of the present invention;

[0065] Figure 14 Schematic diagram of the settlement change curve of the tunnel vault above the karst cave of the present invention;

[0066] Figure 15 Schematic diagram of the heave change curve of the tunnel invert above the karst cave of the present invention;

[0067] Figure 16 Schematic diagram of the horizontal convergence change curve of the tunnel above the karst cave of the present invention;

[0068] Figure 17 Schematic diagram of the broken line of the maximum stress change of the segment above the karst cave of the present invention;

[0069] Figure 18 Schematic diagram of the overall operation process of the method of the present invention. Detailed implementation mode

[0070] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0071] In the embodiments, refer in detail to Figures 1 to 18 .

[0072] A tunnel shield construction simulation analysis system for a multi-cavern terrain proposed in the embodiments of the present invention uses ANSYS to establish a three-dimensional analysis model of a tunnel in a multi-cavern terrain, and uses the fast Lagrangian difference analysis program FLAC3D software to simulate and analyze the tunnel excavation process. During the simulation analysis and calculation process, the soil and rock materials of the unexcavated stratum are simulated using the Mohr-Coulomb model, and the existing buildings and lining materials on the stratum are simulated using the elastic model.

[0073] At this time, through the simulation analysis system, potential geological risks can be identified in advance, risk assessment and classification can be carried out, providing data support for construction. At the same time, by simulating and predicting potential risks, a safer construction plan can be designed, reducing the accident rate and protecting workers and the surrounding environment.

[0074] Specifically, referring to Figure 1 , the system establishment method includes:

[0075] During the tunnel excavation process, the soil will be disturbed. In order to reduce the influence of boundary conditions in numerical simulation, the three-dimensional analysis model determines the left and right side boundaries and the lower boundary according to the specified tunnel burial depth and hole diameter. The upper boundary of the model is established according to the actual terrain undulation and set as a free boundary. The surrounding rock uses hexahedral mesh elements;

[0076] At the same time, in order to minimize the influence of boundary conditions and the like on the calculation results, as Figure 2 shown, when selecting the monitoring section, monitoring points are arranged at the crown, invert and two side waists of the specified position in the excavation direction in the three-dimensional analysis model for section monitoring, for analyzing the stability of the tunnel structure;

[0077] In addition, as Figure 3 shown, the specified vertices of the simulated buildings can also be selected as monitoring points in the three-dimensional analysis model, and a specified excavation depth section is set as the monitoring line along the excavation direction for surface building displacement monitoring.

[0078] In a specific implementation process, the left and right side boundaries of the model are selected at a distance of 3 to 5 times the tunnel diameter from the tunnel centerline, the lower boundary is taken at a distance of 3 to 5 times the tunnel diameter from the tunnel bottom, the tunnel burial depth is taken as 24.5 m, the excavation direction is taken as 50 m, and the final calculation model size is x×y×z = 76 m×50 m×62 m, where the Y direction is the tunnel excavation direction and the z direction represents the soil burial depth thickness;

[0079] And the upper boundary is established according to the actual terrain undulation and is set as a free boundary without constraints. The surrounding rock uses hexahedron mesh elements. The model is divided into a total of 80,682 nodes and 73,200 elements. The established three-dimensional calculation model is as Figure 1 shown;

[0080] When selecting the monitoring section, select the 20th position in the excavation direction.

[0081] Furthermore, the specific simulation construction steps in the tunnel excavation process include:

[0082] S1. Under the initial stress field of the three-dimensional analysis model, passivate the soil body that the shield machine is about to excavate. The passivated soil body includes the core soil unit, the segment unit, and the grouting layer unit. Apply the face thrust pressure in the normal direction of the excavation face, and activate the shield shell unit of the shield machine;

[0083] S2. After excavating the specified ring, activate the segment unit at the same time, apply the thrust pressure to the segment unit, cancel the face tunneling pressure in step S1, and passivate the shield shell unit;

[0084] S3. Since the shield advances forward, voids are formed between the segments and the soil body. Therefore, activate the grouting layer unit and apply the grouting pressure to make the segments and the soil body closely combined and jointly support. At the same time, cancel the segment thrust pressure in step S2;

[0085] S4. Cancel the grouting pressure in step S3, and repeat steps S1 to S3 until the tunnel excavation is completed.

[0086] At this time, by setting up the simulation analysis system, the propulsion state of the shield machine and the deformation of the surrounding soil layer can be monitored in real time, the construction parameters can be adjusted in time, and the deformation of the ground and surrounding buildings can be controlled, so as to improve the working efficiency of the shield machine and achieve a higher propulsion speed.

[0087] On the other hand, the present invention also discloses a tunnel shield construction simulation and analysis method for multi-cavern terrain. Using the above-mentioned tunnel shield construction simulation and analysis system for multi-cavern terrain, the caves at different positions relative to the tunnel are reinforced and the shield tunnel is analyzed. It can simulate the influence of caves located at different distances on the side of the tunnel and below the tunnel on the stability of the tunnel structure. It is used to analyze and obtain the optimal parameters in the tunnel shield construction process in multi-cavern terrain, thereby obtaining the optimal construction path, and is applied to the cave treatment before the urban shield tunnel passes through and the pre-reinforcement treatment of the surface.

[0088] Since karst caves at different locations may be encountered during the construction of subway tunnels in karst-developed areas, shield tunnel analysis is conducted on karst caves at different locations, such as Figure 18 As shown, including:

[0089] L1. When the karst cave is located above the tunnel, the tunnel excavation process will cause a certain disturbance to the soil layer. When the structure of the soil or rock layer is unstable, the karst cave will be in danger of collapse, affecting the tunnel construction and hindering the excavation process. More seriously, it may cause the collapse of the surface above the tunnel and the collapse of existing buildings on the surface. Therefore, in order to ensure the smooth progress and construction safety of the construction process, when a karst cave is found above the tunnel during the exploration process, the karst cave and the tunnel need to be reinforced;

[0090] L2. When the karst cave is located at the side or below the tunnel, simulate the construction process of the shield tunnel with the karst cave located within the specified range of the tunnel, analyze and obtain the structural stability law of the tunnel, and at the same time determine the range of the karst cave that affects the stability of the tunnel, and determine the optimal construction path based on the range of the karst cave that affects the stability of the tunnel. The specific operation process for analyzing and obtaining the structural stability law of the tunnel includes: under the initial stress field, simulate the construction of the shield tunnel with the karst cave located within the specified range of the tunnel, monitor the surface settlement of the model, and input preset data, and perform surface settlement analysis, tunnel displacement analysis and segment stress field analysis based on the cross-section monitoring data and surface settlement monitoring data to obtain the influence of the distance relationship between the karst cave and the tunnel on the structural stability of the tunnel when the karst cave is located at the side or below the tunnel. Among them:

[0091] (1) Surface subsidence analysis includes:

[0092] a1. When the distance between the same diameter cave and the tunnel is different, obtain the maximum settlement change curve of the surface on the line;

[0093] a2. According to the maximum settlement change curve, the surface settlement law at this time is obtained: under the condition of the same tunnel diameter, as the distance between the tunnel and the cave increases, the maximum surface settlement decreases;

[0094] When the karst cave is located on the side of the tunnel, preset the allowable maximum settlement value of the ground surface. According to the allowable maximum settlement value at this time, confirm the distance range that needs to be filled and reinforced when the karst cave is located on the side of the tunnel.

[0095] a3. When the karst cave is located below the tunnel, preset the settlement allowable value without the karst cave. According to the settlement allowable value without the karst cave at this time, confirm the distance range that needs to be filled and reinforced when the karst cave is located below the tunnel.

[0096] (2) Tunnel displacement analysis includes:

[0097] b1. When the karst cave is at different distances from the tunnel, obtain the settlement change curve of the tunnel crown and the heave change curve of the tunnel invert.

[0098] b2. According to the settlement change curve and the heave change curve, obtain the displacement influence law at this time: the vertical displacement of the tunnel crown, the crown heave value, and the horizontal convergence of the tunnel all decrease as the distance between the karst cave and the tunnel increases.

[0099] (3) Segment stress field analysis includes:

[0100] c1. When the karst cave is at different distances from the tunnel, obtain the change curve of the maximum stress value borne by the lining segment.

[0101] c2. According to the change curve of the maximum stress value, obtain the segment stress law at this time: the maximum stress value borne by the lining segment increases as the distance between the karst cave and the tunnel increases.

[0102] In addition, based on the above analysis, the method for determining the karst cave range affecting the tunnel stability in the L2 state includes:

[0103] d1. Through surface settlement analysis, tunnel displacement analysis, and segment stress field analysis, obtain the maximum surface settlement change amount a, the maximum segment stress value b, the tunnel crown settlement change amount c, and the tunnel invert heave change amount d for different distances between the karst cave and the tunnel when the karst cave is located on the side and below the tunnel.

[0104] d2. Preset the stability weights of the maximum surface settlement change amount a, the maximum segment stress value b, the tunnel crown settlement change amount c, and the tunnel invert heave change amount d as α, β, γ, and δ respectively. Then, for the same distance between the karst cave and the tunnel, there is a stability judgment value E:

[0105]

[0106] Preset a judgment threshold K. If the stability judgment value E = K, then the distance between the karst cave and the tunnel at this time is the specific karst cave range value affecting the tunnel stability.

[0107] In a specific implementation process, when there are karst caves on the left / right side of the tunnel, the karst caves will affect the lateral stress of the tunnel, causing the tunnel to be in a state of uneven pressure. In the absence of special circumstances, the existence of karst caves will not have a particularly serious impact on the tunnel structure. However, since the operation period of the tunnel is relatively long, excessive displacement may occur in the tunnel structure during use, affecting the safety of the tunnel.

[0108] To avoid this situation, it is necessary to deal with the karst caves within the range that affects the stability of the tunnel structure. Therefore, it is necessary to first determine the range of karst caves that affect the stability of the tunnel. The following three working conditions are established, namely: (1) The karst cave is within 2 m to the left of the tunnel; (2) The karst cave is within 3 m to the left of the tunnel; (3) The karst cave is within 4 m of the tunnel. By simulating these three working conditions and analyzing the structural stability of the tunnel based on the calculation results, the range of karst caves that affect the structural stability of the tunnel is finally determined.

[0109] Models with karst caves located 2 m, 3 m, and 4 m to the left of the tunnel are established within the system. The construction process of the shield tunnel is simulated using the FLAC3D software. The construction is simulated under the initial stress field. The stability of the tunnel structure, the displacement change law of the existing surface buildings, and the surface settlement analysis, tunnel displacement analysis, and segment stress field analysis are carried out by inputting preset values to obtain the influence law of the distance relationship between the karst cave and the tunnel on the structural stability of the tunnel when there is a karst cave on the side of the tunnel, as follows:

[0110] (1) Surface settlement analysis

[0111] The variation curves of surface settlement when karst caves with the same diameter are at different distances on the side of the tunnel are as Figure 4 shown. Therefore, it can be seen that when the diameter of the karst cave is the same, the greater the distance between the karst cave and the tunnel, the smaller the maximum surface settlement. This shows that during tunnel construction, the karst cave has an impact on surface settlement, and karst caves within a certain range need to be filled and reinforced. It can be seen that when the distance between the karst cave and the tunnel is within 3 m, the maximum surface settlement exceeds the allowable value. Therefore, it is preliminarily determined that karst caves within 3 m to the side of the tunnel need to be subject to certain pre-reinforcement treatment;

[0112] (2) Tunnel displacement analysis

[0113] The displacement change law of the tunnel structure caused during construction at different distances between the karst caves is as Figure 5 、 Figure 6 and Figure 7 shown. When there is a karst cave on the side of the tunnel, the stability of the tunnel structure will be affected;

[0114] It can be seen from the settlement change curve of the tunnel vault that the greater the distance between the karst cave and the tunnel, the smaller the vault settlement. Within the range of 3m between the karst cave and the tunnel, the maximum settlement values of the tunnel vault are not much different and are within the safe range, and finally tend to be stable. When the distance between the karst cave and the tunnel is 4m, the settlement value of the vault is much larger than that within 3m, and the change range is relatively large;

[0115] It can be seen from the heave change curve of the tunnel invert that at the beginning of construction, the distance between the karst cave and the tunnel has little influence on the heave of the tunnel invert. In the middle and late stages of excavation, the size of the tunnel invert heave decreases with the increase of the distance between the karst cave and the tunnel;

[0116] (3) Segment stress field analysis

[0117] According to Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 and Figure 12 stress analysis, when there is a karst cave on the side of the tunnel, the maximum principal stress of the segment will increase significantly compared with the case without a karst cave. When the diameter of the karst cave is the same, the closer the karst cave is to the tunnel, the greater the maximum principal stress of the lining segment. As the spacing increases, the stress gradually approaches the value without a karst cave.

[0118] To sum up, when the diameter of the karst cave is the same and there is a karst cave on the side of the tunnel, the influence law of the distance relationship between the karst cave and the tunnel on the stability of the tunnel structure is as follows: the vertical displacement of the tunnel vault, the vault heave value, and the horizontal convergence of the tunnel will all decrease with the increase of the distance between the karst cave and the tunnel; the maximum stress value received by the lining segment increases with the increase of the distance between the karst cave and the tunnel.

[0119] In another specific implementation process, similarly, when there is a karst cave under the tunnel, the construction will affect the stability of the surrounding rock of the tunnel. In case of serious instability, it may lead to the overall collapse of the tunnel or the sudden fall of the shield machine during the construction. Therefore, models with the karst cave located within 5m, 10m, and 15m below the tunnel are established, and the construction process of the shield tunnel is simulated by FLAC3D software. The stability of the tunnel structure and the displacement change law of the existing surface buildings are analyzed from the calculation results. Under the initial stress field, the simulated construction is carried out, and the preset values are input for surface settlement analysis, tunnel displacement analysis, and segment stress field analysis to obtain the influence law of the distance relationship between the karst cave and the tunnel on the stability of the tunnel structure when there is a karst cave on the side of the tunnel, as follows:

[0120] (1) Surface settlement analysis

[0121] When there is a karst cave under the tunnel, for karst caves with the same diameter, the influence law of the change of the distance between the karst cave and the tunnel on the surface settlement displacement is as Figure 13As shown by the maximum settlement change curve of the ground surface on the monitoring line, when there is a karst cave under the tunnel, the maximum settlement of the ground surface will increase significantly compared with the situation without a karst cave (the distance between the tunnel and the karst cave is 0). However, as the distance between the tunnel and the karst cave increases, the ground settlement gradually decreases. When the tunnel-karst cave distance is 10m, it gradually approaches the settlement value without a karst cave. Therefore, it is preliminarily judged that the karst caves within 10m below the tunnel need to be reinforced before excavation.

[0122] (2) Tunnel displacement analysis

[0123] The displacement change law of the tunnel structure caused during construction at different karst cave distances is as Figure 14 、 Figure 15 and Figure 16 shown. When there is a karst cave under the tunnel, it will affect the settlement of the tunnel crown. When the diameter of the karst cave is certain, the final settlement values of the tunnel crown at cave distances of 5m, 10m, and 15m are 32.53mm, 23.86mm, and 14.98mm respectively. It can be seen that the settlement value of the tunnel crown will gradually decrease as the distance between the karst cave and the tunnel increases, and finally tends to a stable state as shown by the curve in the figure;

[0124] The uplift values of the tunnel invert at cave distances of 5m, 10m, and 15m are 21.20mm, 18.56mm, and 13.45mm respectively. Similarly, the closer the karst cave is to the tunnel, the greater the uplift value of the tunnel invert;

[0125] From the horizontal convergence of the tunnel, it can be seen that the horizontal displacement of the tunnel will also be affected by the distance between the karst cave and the tunnel;

[0126] (3) Segment stress field analysis

[0127] According to Figure 17 it can be known that when the karst cave is under the tunnel, the stress on the segments is greater than that without a karst cave, and the closer the karst cave is to the tunnel, the greater the stress on the segments. When the distance between the tunnel and the karst cave is greater than 10m, the stress value on the segments gradually approaches that without a karst cave;

[0128] To sum up, when there is a karst cave under the shield tunnel, the stability of the internal structure of the tunnel will be affected to a certain extent. From the law of in-tunnel displacement: when the diameter of the karst cave is certain, the crown settlement and the uplift value of the tunnel invert will decrease as the distance between the karst cave and the tunnel increases. When the distance is greater than 10m, the displacement value is relatively close to that without a karst cave; from the aspect of the stress on the segments: the maximum principal stress decreases as the distance between the karst cave and the tunnel increases, and gradually approaches the stress without a karst cave. Therefore, it is recommended that during construction, the karst caves within 10m below the tunnel be pre-reinforced.

[0129] According to multiple data collections, when the above-mentioned karst caves are located at different positions in the tunnel, substituting the range data of the pre-reinforcement treatment into the stability determination value formula can fit and determine the stability weights of the maximum surface settlement change a, the maximum segment stress value b, the tunnel crown settlement change c, and the invert heave change d, so as to conveniently and accurately determine the specific karst cave range value affecting the tunnel stability.

[0130] In addition, using the simulation system can also determine the optimal shield machine propulsion path according to the actual terrain and geological conditions, avoid directly passing through large karst cave areas, reduce the risks during construction; the optimized construction path and effective risk control can reduce unnecessary downtime, thereby shortening the entire tunnel construction period.

[0131] In summary, by simulating the construction of a karst cave shield tunnel under the initial stress field and conducting surface settlement analysis, tunnel displacement analysis, and segment stress field analysis based on the monitoring data, it is possible to conveniently and comprehensively evaluate the stability law of the tunnel structure, thereby optimizing the construction parameters and methods to ensure the high efficiency, safety, and stability of the tunnel construction.

[0132] On the other hand, the present invention also discloses a computer-readable storage medium storing a computer program, which when executed by a processor causes the processor to execute the steps of the above method.

[0133] On yet another aspect, the present invention also discloses a computer device including a memory and a processor, where the memory stores a computer program, and when the computer program is executed by the processor, it causes the processor to execute the steps of the above method.

[0134] In yet another embodiment provided by the present application, there is also provided a computer program product containing instructions, which when run on a computer causes the computer to execute the corresponding analysis method of the tunnel shield construction simulation analysis system for any multi-karst cave terrain in the above embodiments.

[0135] It can be understood that the system provided by the embodiments of the present invention corresponds to the method provided by the embodiments of the present invention, and the explanations, examples, and beneficial effects of the relevant content can refer to the corresponding parts in the above method.

[0136] The embodiments of the present application also provide an electronic device including a processor, a communication interface, a memory, and a communication bus. Among them, the processor, the communication interface, and the memory complete communication with each other through the communication bus.

[0137] The memory is used to store a computer program.

[0138] The processor is used to execute the program stored on the memory to implement the corresponding analysis method executed by the above tunnel shield construction simulation analysis system for multi-karst cave terrain.

[0139] The communication bus mentioned in the above electronic device can be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into an address bus, a data bus, a control bus, etc.

[0140] The communication interface is used for communication between the above electronic device and other devices.

[0141] The memory can include a Random Access Memory (RAM), and can also include a Non-Volatile Memory (NVM), such as at least one disk memory. Optionally, the memory can also be at least one storage device located far from the aforementioned processor.

[0142] The above-mentioned processor can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0143] It should also be noted that the electronic device also includes a terminal device, which can also be called a terminal, a user equipment, a mobile station, a mobile terminal, etc. The terminal device can be a mobile phone, a smart TV, a wearable device, a tablet computer, a computer with wireless transceiver function, a virtual reality terminal device, an augmented reality terminal device, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in remote surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The embodiments of the present application do not limit the specific technologies and specific device forms adopted by the terminal device.

[0144] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, digital subscriber line) or a wireless manner (such as infrared, wireless, microwave). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium, or a semiconductor medium (such as a solid-state drive), etc.

[0145] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0146] In addition, it should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0147] In addition, if there are descriptions such as "first", "second", etc. involved in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and / or" appearing throughout the text includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, in the embodiments of the present invention, "a plurality" means two or more. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

Claims

1. A tunnel shield construction simulation analysis method for multi-cavern terrain, characterized in that: By establishing a three-dimensional analysis model of a tunnel with multiple karst caves, the karst caves at different locations relative to the tunnel are reinforced and the shield tunnel is analyzed, including: L1. When the cave is located above the tunnel, the cave and the tunnel are reinforced; L2. When the karst cave is located on the side or below the tunnel, simulate the construction process of the shield tunnel with the karst cave within the specified range of the tunnel, analyze and obtain the structural stability law of the tunnel, and at the same time determine the range of the karst cave that affects the stability of the tunnel, and determine the optimal construction path based on the range of the karst cave that affects the stability of the tunnel.

2. The tunnel shield construction simulation analysis method for multi-cavern terrain according to claim 1, characterized in that: When the cave is located on the side or below the tunnel, the specific operation process for analyzing and obtaining the structural stability law of the tunnel includes: Under the initial stress field, simulated shield tunnel construction is carried out with the karst cave located within the specified range of the tunnel. The surface settlement of the model is monitored and preset data is input. Surface settlement analysis, tunnel displacement analysis and segment stress field analysis are carried out based on the cross-section monitoring data and surface settlement monitoring data to obtain the influence of the distance relationship between the karst cave and the tunnel on the stability of the tunnel structure when the karst cave is located on the side or below the tunnel.

3. The tunnel shield construction simulation analysis method for multi-cavern terrain according to claim 2 is characterized in that: The surface subsidence analysis includes: When the distance between the same diameter cave and the tunnel is different, the maximum settlement change curve of the surface on the line is obtained; According to the maximum settlement change curve, the surface settlement law at this time is obtained: under the condition of the same tunnel diameter, as the distance between the tunnel and the cave increases, the maximum surface settlement decreases; When the cave is located on the side of the tunnel, the maximum allowable settlement value of the surface is preset, and the distance range that needs to be filled and reinforced when the cave is located on the side of the tunnel is determined based on the maximum allowable settlement value at this time; When a cave is located under the tunnel, an allowable settlement value when there is no cave is preset, and the distance range that requires filling and reinforcement treatment when the cave is located under the tunnel is determined based on the allowable settlement value when there is no cave at this time.

4. The tunnel shield construction simulation analysis method for multi-cavern terrain according to claim 2, characterized in that: The tunnel displacement analysis includes: When the distance between the cave and the tunnel is different, the settlement change curve of the tunnel vault and the uplift change curve of the vault bottom are obtained; According to the settlement change curve and the uplift change curve, the displacement influence law at this time is obtained: the vertical displacement of the tunnel vault, the vault uplift value and the horizontal convergence of the tunnel all decrease as the distance between the cave and the tunnel increases.

5. The tunnel shield construction simulation analysis method for multi-cavern terrain according to claim 2, characterized in that: The segment stress field analysis includes: Obtain the maximum stress variation curve of the lining segment at different distances between the cave and the tunnel; According to the maximum stress value variation curve, the stress law of the segment at this time is obtained: the maximum stress value of the lining segment increases with the increase of the distance between the cave and the tunnel.

6. The tunnel shield construction simulation analysis method for multi-cavern terrain according to claim 2, characterized in that: The method for determining the scope of the caves that affect the stability of the tunnel in the L2 state includes: Through surface settlement analysis, tunnel displacement analysis and segment stress field analysis, we can obtain the maximum surface settlement change a, segment maximum stress value b, tunnel vault settlement change c and vault bottom uplift change d at different distances between the cave and the tunnel when the cave is located on the side and below the tunnel. The stability weights of the maximum surface settlement change a, the maximum segment stress value b, the tunnel vault settlement change c, and the vault bottom uplift change d are preset as α, β, γ, and δ, respectively. For the same distance between the cave and the tunnel, there is a stability judgment value E: A judgment threshold K is preset. If the stability judgment value E=K, then the distance between the cave and the tunnel is the specific cave range value that affects the stability of the tunnel.

7. A tunnel shield construction simulation analysis system for multi-cavern terrain, applied to the tunnel shield construction simulation analysis method for multi-cavern terrain as described in any one of claims 1 to 6, characterized in that: ANSYS was used to establish a three-dimensional analysis model of the tunnel in multi-cavern terrain, and the fast Lagrangian difference analysis program was used to simulate the tunnel excavation process, including: The 3D analysis model determines the left and right side boundaries and the lower boundary according to the specified tunnel burial depth and hole diameter. The upper boundary of the model is established according to the actual terrain undulations and set as a free boundary. The surrounding rock adopts hexahedral grid units. During the simulation analysis, the unexcavated stratum rock and soil materials were simulated using the Moore-Coulomb model, and the existing buildings and lining materials on the stratum were simulated using the elastic model.

8. The tunnel shield construction simulation analysis system for multi-cavern terrain according to claim 7, characterized in that: In the three-dimensional analysis model, monitoring points are arranged on the arch top, arch bottom and arch waists on both sides at designated positions in the excavation direction for cross-section monitoring, so as to analyze the stability of the tunnel structure.

9. The tunnel shield construction simulation analysis system for multi-cavern terrain according to claim 7, characterized in that: In the three-dimensional analysis model, designated vertices of the simulated building are selected as monitoring points, and designated excavation depth sections are set along the excavation direction as monitoring lines for monitoring the displacement of the surface building.

10. The tunnel shield construction simulation analysis system for multi-cavern terrain according to claim 7, characterized in that: The specific simulation construction steps of the tunnel excavation process include: S1. Under the initial stress field of the three-dimensional analysis model, the soil to be excavated by the shield machine is passivated. The passivated soil includes core soil units, segment units and grouting layer units. The top thrust pressure of the tunnel face is applied in the normal direction of the excavation face, and the shield shell unit of the shield machine is activated. S2. After the designated ring is excavated, the segment units are activated at the same time, and a top thrust pressure is applied to the segment units, the tunneling pressure of the tunnel face in step S1 is canceled, and the shield units are passivated; S3. As the shield advances forward, a gap is formed between the segment and the soil, so the grouting layer unit is activated and grouting pressure is applied to make the segment and the soil tightly combined and supported together, and at the same time, the segment jacking pressure in step S2 is cancelled; S4. Cancel the grouting pressure in step S3, and repeat steps S1 to S3 until the tunnel excavation is completed.

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