Overall construction method for complex tunnel group structure based on settlement control

Abstract

The present application relates to a kind of complex tunnel group structure overall construction method based on settlement control, comprising the following steps: (1) determining the overall control standard of stratum settlement of complex tunnel group structure;(2) stratum structure reinforcement is carried out in the upper center position of the construction area of the complex tunnel group structure;(3) stratum structure is layered from top to bottom, and the excavation area is excavated, and when it is excavated to the top elevation position of complex tunnel group structure, horizontal strengthening water plugging pile construction is carried out;(4) backfilling the excavation area and supplementing reinforcement;(5) the construction of complex tunnel group structure is carried out;(6) the complex tunnel group structure is reinforced.The method of the present application can effectively stop water, isolate stratum settlement deformation by stratum reinforcement and excavation construction control, is convenient for construction, high safety, and the social and economic benefits are very obvious.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering construction technology, specifically to a general construction method for complex tunnel group structures based on settlement control. Background Technology

[0002] With the rapid development of my country's transportation engineering construction, many parallel tunnel projects have emerged. Due to time constraints, it is often not possible to complete the construction and backfilling of one tunnel before starting construction on the next. As a result, multiple tunnels are often constructed simultaneously. In such cases, due to location and cost limitations, some tunnels become unusable due to excessive settlement, which has a significant impact on the entire construction process.

[0003] Furthermore, with the continuous construction of urban underground engineering and the increasing development of rail transit, situations requiring the construction of complex tunnel complexes arise to meet application demands. The construction of such complex tunnel complexes is highly susceptible to risks such as sandblasting, water inrush, excessive ground settlement, and even localized collapses. Traditional construction methods struggle to meet settlement and deformation control requirements, and construction can severely impact the topography or the structural safety and normal functionality of related structures. Compared to the construction of single tunnels, the construction of multiple tunnels places higher demands on tunnel construction methods, tunnel lining structures, initial support structure models, and support parameters. Corresponding improvements to construction methods are necessary to enhance the safety, reliability, and economy of the project.

[0004] Therefore, it is necessary to study a safe and reliable construction method to address the above problems. Summary of the Invention

[0005] To overcome the aforementioned deficiencies in existing technologies, this invention provides a general construction method for complex tunnel group structures based on settlement control. This method, through ground reinforcement and excavation control of complex tunnel group structures, effectively achieves water stoppage and isolation of ground settlement deformation. It is convenient to construct, highly safe, and yields significant social and economic benefits.

[0006] To achieve the above objectives, this invention provides a general construction method for complex tunnel group structures based on settlement control, comprising the following steps:

[0007] (1) Obtain the stratigraphic pattern and construction method of the unfavorable geology in the construction area of ​​the complex tunnel group structure, conduct cross-sectional monitoring of the complex tunnel group structure, generate the relationship curve between the stratum settlement index and time, and make corresponding control adjustments, and finally determine the overall control standard for stratum settlement of the complex tunnel group structure.

[0008] (2) Reinforce the ground structure at the center of the construction area above the complex tunnel group structure; construct excavation areas on both sides of the ground structure reinforcement area, construct reinforced protective structures on both sides of the excavation area, and simultaneously construct reinforcement piles for the ground structure around the excavation area along the radial direction of the tunnel cross section.

[0009] (3) When the excavation of the excavation area is carried out in layers from top to bottom of the stratum structure, and the top elevation of the complex tunnel group structure is reached, horizontal reinforcement water-blocking piles are constructed; one end of the horizontal reinforcement water-blocking pile extends into the area of ​​the stratum structure reinforcement, and the other end can be intersected with the reinforcement pile;

[0010] (4) Backfill the excavated area and reinforce the backfilled excavated area;

[0011] (5) Carry out the construction of complex tunnel group structure; take the area of ​​the ground structure reinforcement as the center, carry out the tunnel excavation construction at the center position below it, and carry out the excavation construction of other tunnels in a symmetrical order from the center to both sides.

[0012] (6) Reinforcement treatment of the complex tunnel group structure, including initial support construction, secondary lining construction and invert arch construction.

[0013] Preferably, the two sides are the directions that are transverse to the travel direction of the complex tunnel group structure.

[0014] In any of the above schemes, it is preferred that, in step (2), the reinforcing piles are arranged in multiple rows evenly along the direction of travel of the complex tunnel group structure.

[0015] In any of the above schemes, it is preferred that, in step (3), the excavation area serves as the construction space and outlet for the horizontal reinforced water-blocking piles; the length of the horizontal reinforced water-blocking piles extending into the area of ​​the ground structure reinforcement and intersecting with the reinforcement piles is 1.5-2m, so as to ensure the water-blocking effect.

[0016] In any of the above schemes, preferably, in step (5), when the complex tunnel group structure has an odd number of tunnels, the tunnel excavation is carried out below the area where the geological structure is reinforced, with the area as the center; when the complex tunnel group structure has an even number of tunnels, the excavation is carried out below the area where the geological structure is reinforced, with the area as the center, with the adjacent half of the two adjacent tunnels at the center being excavated, and then the excavation is carried out with the two adjacent tunnels at the far half being excavated; after the tunnel at the center is excavated in the above two cases, the excavation of other tunnels at symmetrical positions is carried out simultaneously in the order of moving to the left and right sides.

[0017] In any of the above schemes, it is preferred that, in step (5), when the complex tunnel group structure consists of an even number of tunnels, the excavation and construction of the two adjacent tunnels at the center position is as follows:

[0018] First, excavate the upper 1 / 3 of the height of the adjacent half of the tunnel; when it has been excavated to 10m, excavate the middle 1 / 3 of the height of the adjacent half of the tunnel; when it has been excavated to 8m, excavate the lower 1 / 3 of the height of the adjacent half of the tunnel.

[0019] Next, when the lower 1 / 3 of the height of the adjacent half of the tunnel has been excavated to 8m, the upper 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated at the same time; when it has been excavated to 10m, the middle 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated; when it has been excavated to 8m, the lower 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated.

[0020] Finally, the cross-sections of the two adjacent tunnels in the center were excavated simultaneously.

[0021] In any of the above schemes, it is preferred that, in step (5), when the complex tunnel group structure has an odd number of tunnels, the tunnel excavation at the center is carried out as follows:

[0022] First, excavate the upper third of the right half of the tunnel height; when it has been excavated for 10m, excavate the upper third of the left half of the tunnel height; when it has been excavated for 8m, excavate the middle third of the right half of the tunnel height; when it has been excavated for 5m, excavate the middle third of the left half of the tunnel height; when it has been excavated for 5m, simultaneously excavate the lower third of the left and right half of the tunnel height; finally, the tunnel cross-section is excavated simultaneously.

[0023] In any of the above schemes, it is preferred that, in step (5), the excavation and construction of other tunnels in non-central locations are the same as the excavation and construction of the central tunnel when the complex tunnel group structure has an odd number of tunnels.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. The method of the present invention achieves effective water stoppage and isolation of ground settlement and deformation by strengthening the strata and controlling the excavation construction of complex tunnel group structures. It is convenient to construct, highly safe, and has significant social and economic benefits.

[0026] 2. This invention comprehensively considers the geological conditions and structural characteristics of tunnel groups, and formulates corresponding control standards and methods, which effectively control the ground settlement of complex tunnel group structures and ensure construction safety; at the same time, it can avoid the waste of support and reinforcement costs, and improve the scientificity, reliability, stability and control efficiency of the construction plan for complex tunnel group structures.

[0027] 3. This invention enables the orderly and rational excavation arrangement of complex tunnel group structures, with simultaneous construction and support; it saves construction time, fully solves the problems of difficult simultaneous construction and uneven stress in complex tunnel group structures, effectively reduces the risk of ground settlement and tunnel collapse, and ensures the safety, speed and economy of the construction process. Detailed Implementation

[0028] The technical solution of this application will be described in detail below with reference to specific embodiments of this application. However, the following embodiments are only used to understand the present invention. The embodiments and features in the embodiments of this application can be combined with each other. This application can be implemented in a variety of different ways as defined and covered by the claims.

[0029] Example 1

[0030] A general construction method for complex tunnel group structures based on settlement control includes the following steps:

[0031] (1) Obtain the stratigraphic pattern and construction method of the unfavorable geology in the construction area of ​​the complex tunnel group structure, conduct cross-sectional monitoring of the complex tunnel group structure, generate the relationship curve between the stratum settlement index and time, and make corresponding control adjustments, and finally determine the overall control standard for stratum settlement of the complex tunnel group structure.

[0032] (2) Reinforce the ground structure at the center of the construction area above the complex tunnel group structure; construct excavation areas on both sides of the ground structure reinforcement area, construct reinforced protective structures on both sides of the excavation area, and simultaneously construct reinforcement piles for the ground structure around the excavation area along the radial direction of the tunnel cross section.

[0033] (3) When the excavation of the excavation area is carried out in layers from top to bottom of the stratum structure, and the top elevation of the complex tunnel group structure is reached, horizontal reinforcement water-blocking piles are constructed; one end of the horizontal reinforcement water-blocking pile extends into the area of ​​the stratum structure reinforcement, and the other end can be intersected with the reinforcement pile;

[0034] (4) Backfill the excavated area and reinforce the backfilled excavated area;

[0035] (5) Carry out the construction of complex tunnel group structure; take the area of ​​the ground structure reinforcement as the center, carry out the tunnel excavation construction at the center position below it, and carry out the excavation construction of other tunnels in a symmetrical order from the center to both sides.

[0036] (6) Reinforcement treatment of the complex tunnel group structure, including initial support construction, secondary lining construction and invert arch construction.

[0037] The two sides refer to the directions that are transverse to the travel direction of the complex tunnel group structure.

[0038] In step (2), the reinforcing piles are arranged in multiple rows evenly along the direction of travel of the complex tunnel group structure.

[0039] In step (3), the excavation area serves as the construction space and outlet for the horizontal reinforced water-blocking piles; the length of the horizontal reinforced water-blocking piles extending into the area of ​​the ground structure reinforcement and intersecting with the reinforcement piles is 1.5-2m to ensure the water-blocking effect.

[0040] In step (5), when the complex tunnel group structure has an odd number of tunnels, the tunnel excavation is carried out below the area where the geological structure is reinforced, with the area as the center; when the complex tunnel group structure has an even number of tunnels, the excavation is carried out below the area where the geological structure is reinforced, with the area as the center, with the adjacent half of the two adjacent tunnels at the center being excavated, and then the excavation is carried out with the two adjacent tunnels at the far half being excavated; after the tunnel at the center is excavated in the above two cases, the excavation of other tunnels at symmetrical positions is carried out simultaneously in the order of moving to the left and right.

[0041] In step (5), when the complex tunnel group structure consists of an even number of tunnels, the excavation and construction of the two adjacent tunnels at the center are as follows:

[0042] First, excavate the upper 1 / 3 of the height of the adjacent half of the tunnel; when it has been excavated to 10m, excavate the middle 1 / 3 of the height of the adjacent half of the tunnel; when it has been excavated to 8m, excavate the lower 1 / 3 of the height of the adjacent half of the tunnel.

[0043] Next, when the lower 1 / 3 of the height of the adjacent half of the tunnel has been excavated to 8m, the upper 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated at the same time; when it has been excavated to 10m, the middle 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated; when it has been excavated to 8m, the lower 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated.

[0044] Finally, the cross-sections of the two adjacent tunnels in the center were excavated simultaneously.

[0045] In step (5), when the complex tunnel group structure consists of an odd number of tunnels, the excavation and construction of the tunnel at the center is as follows:

[0046] First, excavate the upper third of the right half of the tunnel height; when it has been excavated for 10m, excavate the upper third of the left half of the tunnel height; when it has been excavated for 8m, excavate the middle third of the right half of the tunnel height; when it has been excavated for 5m, excavate the middle third of the left half of the tunnel height; when it has been excavated for 5m, simultaneously excavate the lower third of the left and right half of the tunnel height; finally, the tunnel cross-section is excavated simultaneously.

[0047] In step (5), the excavation of other tunnels in non-central locations is the same as the excavation of the central tunnel when the complex tunnel group structure has an odd number of tunnels.

[0048] Example 2

[0049] A general construction method for complex tunnel group structures based on settlement control includes the following steps:

[0050] (1) Obtain the stratigraphic pattern and construction method of the unfavorable geology in the construction area of ​​the complex tunnel group structure, conduct cross-sectional monitoring of the complex tunnel group structure, generate the relationship curve between the stratum settlement index and time, and make corresponding control adjustments, and finally determine the overall control standard for stratum settlement of the complex tunnel group structure.

[0051] (2) Reinforce the ground structure at the center of the construction area above the complex tunnel group structure; construct excavation areas on both sides of the ground structure reinforcement area, construct reinforced protective structures on both sides of the excavation area, and simultaneously construct reinforcement piles for the ground structure around the excavation area along the radial direction of the tunnel cross section.

[0052] (3) When the excavation of the excavation area is carried out in layers from top to bottom of the stratum structure, and the top elevation of the complex tunnel group structure is reached, horizontal reinforcement water-blocking piles are constructed; one end of the horizontal reinforcement water-blocking pile extends into the area of ​​the stratum structure reinforcement, and the other end can be intersected with the reinforcement pile;

[0053] (4) Backfill the excavated area and reinforce the backfilled excavated area;

[0054] (5) Carry out the construction of complex tunnel group structure; take the area of ​​the ground structure reinforcement as the center, carry out the tunnel excavation construction at the center position below it, and carry out the excavation construction of other tunnels in a symmetrical order from the center to both sides.

[0055] (6) Reinforcement treatment of the complex tunnel group structure, including initial support construction, secondary lining construction and invert arch construction.

[0056] The two sides refer to the directions that are transverse to the travel direction of the complex tunnel group structure.

[0057] In step (2), the reinforcing piles are arranged in multiple rows evenly along the direction of travel of the complex tunnel group structure.

[0058] In step (3), the excavation area serves as the construction space and outlet for the horizontal reinforced water-blocking piles; the length of the horizontal reinforced water-blocking piles extending into the area of ​​the ground structure reinforcement and intersecting with the reinforcement piles is 1.5-2m to ensure the water-blocking effect.

[0059] In step (5), when the complex tunnel group structure has an odd number of tunnels, the tunnel excavation is carried out below the area where the geological structure is reinforced, with the area as the center; when the complex tunnel group structure has an even number of tunnels, the excavation is carried out below the area where the geological structure is reinforced, with the area as the center, with the adjacent half of the two adjacent tunnels at the center being excavated, and then the excavation is carried out with the two adjacent tunnels at the far half being excavated; after the tunnel at the center is excavated in the above two cases, the excavation of other tunnels at symmetrical positions is carried out simultaneously in the order of moving to the left and right.

[0060] In step (5), when the complex tunnel group structure consists of an even number of tunnels, the excavation and construction of the two adjacent tunnels at the center are as follows:

[0061] First, excavate the upper 1 / 3 of the height of the adjacent half of the tunnel; when it has been excavated to 10m, excavate the middle 1 / 3 of the height of the adjacent half of the tunnel; when it has been excavated to 8m, excavate the lower 1 / 3 of the height of the adjacent half of the tunnel.

[0062] Next, when the lower 1 / 3 of the height of the adjacent half of the tunnel has been excavated to 8m, the upper 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated at the same time; when it has been excavated to 10m, the middle 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated; when it has been excavated to 8m, the lower 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated.

[0063] Finally, the cross-sections of the two adjacent tunnels in the center were excavated simultaneously.

[0064] In step (5), when the complex tunnel group structure consists of an odd number of tunnels, the excavation and construction of the tunnel at the center is as follows:

[0065] First, excavate the upper third of the right half of the tunnel height; when it has been excavated for 10m, excavate the upper third of the left half of the tunnel height; when it has been excavated for 8m, excavate the middle third of the right half of the tunnel height; when it has been excavated for 5m, excavate the middle third of the left half of the tunnel height; when it has been excavated for 5m, simultaneously excavate the lower third of the left and right half of the tunnel height; finally, the tunnel cross-section is excavated simultaneously.

[0066] In step (5), the excavation of other tunnels in non-central locations is the same as the excavation of the central tunnel when the complex tunnel group structure has an odd number of tunnels.

[0067] To further improve the technical effect of the present invention, in this embodiment, determining the overall control standard for ground settlement of complex tunnel group structures includes the following steps:

[0068] a. Regularly monitor the ground settlement of the complex tunnel group structure to obtain data values ​​at multiple time points, and then connect the above data values ​​to obtain time variation curves, including the curve of the top settlement of the complex tunnel group structure over time and the curve of ground settlement over time.

[0069] b. Based on the curves of the top settlement of the complex tunnel group structure and the curves of the ground settlement over time, the average curve of the ground settlement of the complex tunnel group structure over time is obtained, which is located at the center of the curves of the top settlement of the complex tunnel group structure and the curves of the ground settlement over time.

[0070] c. After a period of settlement fluctuation, the average change curve of the stratum settlement over time of the complex tunnel group structure tends to stabilize, and the final settlement value after the stratum settlement stabilizes is obtained. The ratio of this settlement value to the initial settlement value of the average change curve of the stratum settlement over time of the complex tunnel group structure is used as the first stability factor w.

[0071] d. Based on the preliminary design of the stratum settlement control scheme and considering the influence of formation water, a stratum settlement data analysis model is established. That is, the lateral deformation coefficient is set as a fixed value, and the settlement deformation equation, which is the ratio of stress to strain in the direction of stress under uniaxial stress in the stratum, is as follows:

[0072] λ=((1+x) / 2)*λ 初 (1)

[0073] Where, λ 初 Let x be the initial value of the ratio, and let x be the settlement deformation parameter, which is:

[0074] x=(λ 初 (Δψ1φ1+Δψ2φ2)) / 2(λ 初 (Δψ1φ1-Δψ2φ2)+(φ1-φ2) 2 )

[0075] φ1 and φ2 are the first effective stress and the second effective stress, respectively; Δψ1 and Δψ2 are the first effective strain and the second effective strain, respectively.

[0076] e. Extract the settlement value corresponding to the location where the formation settlement begins to produce cracks in the formation settlement data analysis model, and use the ratio of this settlement value to the initial settlement value at that location as the second stability factor w';

[0077] f. Determine the adjustment factor δ = w' / w;

[0078] g. Determine the deformation amount when the initial support structure of the complex tunnel group fails, and calculate the settlement amount of the stratum during the construction of the initial support. Take 2 / 3 of the sum of the deformation amount and the settlement amount as the overall control standard for the settlement of the stratum of the complex tunnel group structure. The settlement amount of the stratum during the construction of the initial support is calculated based on the stratum settlement data analysis model.

[0079] The above-described method establishes the overall control standard for ground settlement in complex tunnel complex structures, achieving the goal of overall control and enabling refined control of construction safety. This approach is highly operable and yields better practical control results. By assessing tunnel construction safety based on real-time measurable ground settlement during construction, safety control is achieved, reducing blind following and bias in stability control of complex tunnel complex structures and ensuring construction safety. Numerical simulation and appropriate adjustments using determined adjustment factors enable settlement control during the tunnel construction phase, improving the scientific rigor and reliability of the tunnel construction plan.

[0080] Example 3

[0081] A general construction method for complex tunnel group structures based on settlement control includes the following steps:

[0082] (1) Obtain the stratigraphic pattern and construction method of the unfavorable geology in the construction area of ​​the complex tunnel group structure, conduct cross-sectional monitoring of the complex tunnel group structure, generate the relationship curve between the stratum settlement index and time, and make corresponding control adjustments, and finally determine the overall control standard for stratum settlement of the complex tunnel group structure.

[0083] (2) Reinforce the ground structure at the center of the construction area above the complex tunnel group structure; construct excavation areas on both sides of the ground structure reinforcement area, construct reinforced protective structures on both sides of the excavation area, and simultaneously construct reinforcement piles for the ground structure around the excavation area along the radial direction of the tunnel cross section.

[0084] (3) When the excavation of the excavation area is carried out in layers from top to bottom of the stratum structure, and the top elevation of the complex tunnel group structure is reached, horizontal reinforcement water-blocking piles are constructed; one end of the horizontal reinforcement water-blocking pile extends into the area of ​​the stratum structure reinforcement, and the other end can be intersected with the reinforcement pile;

[0085] (4) Backfill the excavated area and reinforce the backfilled excavated area;

[0086] (5) Carry out the construction of complex tunnel group structure; take the area of ​​the ground structure reinforcement as the center, carry out the tunnel excavation construction at the center position below it, and carry out the excavation construction of other tunnels in a symmetrical order from the center to both sides.

[0087] (6) Reinforcement treatment of the complex tunnel group structure, including initial support construction, secondary lining construction and invert arch construction.

[0088] The two sides refer to the directions that are transverse to the travel direction of the complex tunnel group structure.

[0089] In step (2), the reinforcing piles are arranged in multiple rows evenly along the direction of travel of the complex tunnel group structure.

[0090] In step (3), the excavation area serves as the construction space and outlet for the horizontal reinforced water-blocking piles; the length of the horizontal reinforced water-blocking piles extending into the area of ​​the ground structure reinforcement and intersecting with the reinforcement piles is 1.5-2m to ensure the water-blocking effect.

[0091] In step (5), when the complex tunnel group structure has an odd number of tunnels, the tunnel excavation is carried out below the area where the geological structure is reinforced, with the area as the center; when the complex tunnel group structure has an even number of tunnels, the excavation is carried out below the area where the geological structure is reinforced, with the area as the center, with the adjacent half of the two adjacent tunnels at the center being excavated, and then the excavation is carried out with the two adjacent tunnels at the far half being excavated; after the tunnel at the center is excavated in the above two cases, the excavation of other tunnels at symmetrical positions is carried out simultaneously in the order of moving to the left and right.

[0092] In step (5), when the complex tunnel group structure consists of an even number of tunnels, the excavation and construction of the two adjacent tunnels at the center are as follows:

[0093] First, excavate the upper 1 / 3 of the height of the adjacent half of the tunnel; when it has been excavated to 10m, excavate the middle 1 / 3 of the height of the adjacent half of the tunnel; when it has been excavated to 8m, excavate the lower 1 / 3 of the height of the adjacent half of the tunnel.

[0094] Next, when the lower 1 / 3 of the height of the adjacent half of the tunnel has been excavated to 8m, the upper 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated at the same time; when it has been excavated to 10m, the middle 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated; when it has been excavated to 8m, the lower 1 / 3 of the height of the tunnel far from each other's half of the tunnel is excavated.

[0095] Finally, the cross-sections of the two adjacent tunnels in the center were excavated simultaneously.

[0096] In step (5), when the complex tunnel group structure consists of an odd number of tunnels, the excavation and construction of the tunnel at the center is as follows:

[0097] First, excavate the upper third of the right half of the tunnel height; when it has been excavated for 10m, excavate the upper third of the left half of the tunnel height; when it has been excavated for 8m, excavate the middle third of the right half of the tunnel height; when it has been excavated for 5m, excavate the middle third of the left half of the tunnel height; when it has been excavated for 5m, simultaneously excavate the lower third of the left and right half of the tunnel height; finally, the tunnel cross-section is excavated simultaneously.

[0098] In step (5), the excavation of other tunnels in non-central locations is the same as the excavation of the central tunnel when the complex tunnel group structure has an odd number of tunnels.

[0099] In order to further improve the technical effect of the present invention, in this embodiment, in step (4), three layers of backfill structure are backfilled from top to bottom, namely C20 concrete block, C25 concrete block and C35 concrete block; the three layers of backfill structure are evenly spaced and connected vertically by multiple supplementary reinforcement components, the supplementary reinforcement components are steel pipe concrete structures, and cement stabilized crushed stone is filled between the three layers of backfill structure.

[0100] This invention solves the problem of non-compaction in the backfill area by using different materials for layered backfilling, ensuring that the backfill of the entire excavation area meets the settlement standards, and further guaranteeing the settlement control effect.

[0101] In step (5), the ground settlement at the excavation face is controlled. The overall settlement is set at 5-6 mm during the excavation process. A movable support structure matching the tunnel cross-section is set up during the excavation process to resist the ground settlement. Simultaneous grouting is carried out during the excavation process to control the ground settlement of the tunnel. The construction method is dynamically adjusted in real time according to the automatic monitoring results.

[0102] The movable support structure includes a support plate and support columns. The support plate contacts the circumferential surface of the excavated tunnel and is supported by the support columns. Synchronous grouting involves injecting grout between the support plate and the circumferential surface of the tunnel. Stress detection devices are installed on the support columns to monitor changes or degrees of stress applied to each column in real time, allowing for prediction of the safety and controllability of the applied support force. The support plate is also equipped with a deformation detection device to monitor the degree of deformation in real time, thereby predicting the safety and controllability of each support plate. This movable support structure can significantly improve the quality and safety of complex tunnel structures, accurately predict potential ground settlement during tunnel excavation, and allow for immediate implementation of necessary measures. Furthermore, it can reduce construction costs by improving workability.

[0103] The material ratio for synchronous grouting is per 1m 3Grouting should consist of 150-180 kg of cement, 80-120 kg of water glass, 1000-1100 kg of lightweight sand, 200-280 kg of fly ash, 120-130 kg of bentonite, and 350-380 kg of water. The grouting pressure and volume should be controlled simultaneously, with the grouting pressure maintained at 0.18-0.22 MPa.

[0104] The automatic real-time monitoring system includes sensing devices, data collection and transmission devices, control units, and communication units; it performs automatic real-time monitoring by using the three-dimensional coordinates of control points. The above method employs techniques such as movable support structures, automatic monitoring, and synchronous grouting reinforcement, optimizing the settlement control effect of complex tunnel structures, and achieving significant practical construction results.

[0105] As can be seen from the above embodiments, the method of the present invention achieves the effects of effective water stoppage and isolation of ground settlement and deformation by strengthening the strata and controlling the excavation construction of complex tunnel group structures. It is convenient to construct, has high safety, and has significant social and economic benefits.

[0106] This invention comprehensively considers geological conditions and the structural characteristics of tunnel groups, and formulates corresponding control standards and methods to effectively control the ground settlement of complex tunnel group structures and ensure construction safety. At the same time, it can avoid the waste of support and reinforcement costs and improve the scientificity, reliability, stability and control efficiency of the construction plan for complex tunnel group structures.

[0107] This invention enables sequential excavation, synchronous construction, and synchronous support of complex tunnel group structures; it saves construction time, solves the problems of difficult synchronous construction and uneven stress in complex tunnel group structures, effectively reduces the risk of ground settlement and tunnel collapse, and ensures the safety, speed, and economy of the construction process.

[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A general construction method for complex tunnel group structures based on settlement control, characterized in that, Includes the following steps: (1) Obtain the stratigraphic pattern and construction method of the unfavorable geology in the construction area of ​​the complex tunnel group structure, conduct cross-sectional monitoring, generate the relationship curve between the stratum settlement index and time, and make corresponding control adjustments to finally determine the overall control standard for stratum settlement of the complex tunnel group structure. (2) Reinforce the ground structure above the center of the construction area of ​​the complex tunnel group structure; construct the excavation area on both sides of the ground structure reinforcement area, construct the reinforced protective structure on both sides of the excavation area, and simultaneously construct the reinforcement piles of the ground structure around the excavation area along the radial direction of the tunnel section. (3) When the excavation of the excavation area is carried out in layers from top to bottom of the stratum structure, and the top elevation of the complex tunnel group structure is reached, the horizontal reinforcement water-blocking piles are constructed. One end of the horizontal reinforcement water-blocking pile extends into the area of ​​the stratum structure reinforcement, and the other end can be set up to intersect with the reinforcement pile. (4) Backfill the excavated area and reinforce the excavated area after backfilling; (5) Carry out the construction of complex tunnel group structure; take the area of ​​the ground structure reinforcement as the center, carry out the tunnel excavation construction at the center position below it, and carry out the excavation construction of other tunnels in a symmetrical order from the center to both sides. When there are an even number of tunnels, the excavation is carried out on the adjacent half of the two tunnels at the center, centered on the area where the geological structure has been reinforced. Then, the excavation of the two adjacent tunnels at the far side is carried out. After the central tunnel is excavated, the other tunnels at symmetrical locations are excavated simultaneously, moving to the left and right sides. Specifically, the upper 1 / 3 of the height of the adjacent half of the tunnel is excavated first; when it has been excavated to 10m, the adjacent half of the tunnel is then excavated. The middle third of the tunnel height is excavated; when it has been excavated to 8m, the lower third of the height of the adjacent half of the tunnel is excavated; then, when the lower third of the height of the adjacent half of the tunnel has been excavated to 8m, the upper third of the height of the half of the tunnel furthest from each other is excavated; when it has been excavated to 10m, the middle third of the height of the half of the tunnel furthest from each other is excavated; when it has been excavated to 8m, the lower third of the height of the half of the tunnel furthest from each other is excavated; finally, the cross-sections of the two adjacent tunnels at the center are excavated simultaneously. During the excavation process, the overall settlement is set at 5-6mm. A movable support structure that matches the tunnel cross-section is set up as an auxiliary structure during the excavation process. Grouting is carried out simultaneously during the excavation process, and the construction method is dynamically adjusted in real time based on the automatic monitoring results. The movable support structure includes a support plate and support columns. The support plate contacts the circumferential surface of the excavated tunnel and is supported by the support columns. Synchronous grouting involves injecting grout between the support plate and the circumferential surface of the tunnel; stress detection devices are installed on the support columns, and deformation detection devices are installed on the support plates. (6) Reinforce the complex tunnel group structure, including the initial support construction, secondary lining construction and invert arch construction.

2. The overall construction method for complex tunnel group structures based on settlement control according to claim 1, characterized in that, The two sides refer to the directions that are transverse to the travel direction of the complex tunnel group structure.

3. The overall construction method for complex tunnel group structures based on settlement control according to claim 2, characterized in that, In step (2), the reinforcing piles are arranged in multiple rows evenly along the direction of travel of the complex tunnel group structure.

4. The overall construction method for complex tunnel group structures based on settlement control according to claim 3, characterized in that, In step (3), the excavation area serves as the construction space and outlet for the horizontal reinforced water-blocking piles; the length of the horizontal reinforced water-blocking piles extending into the area of ​​the ground structure reinforcement and intersecting with the reinforcement piles is 1.5-2m to ensure the water-blocking effect.

5. The overall construction method for complex tunnel group structures based on settlement control according to claim 4, characterized in that, In step (5), when the complex tunnel group structure has an odd number of tunnels, the tunnel excavation is carried out below the area where the geological structure is reinforced, with the central position as the center; after the central position tunnel is excavated, the other tunnels at symmetrical positions are excavated simultaneously in the order of moving to the left and right sides.

6. The overall construction method for complex tunnel group structures based on settlement control according to claim 5, characterized in that, In step (5), when the complex tunnel group structure consists of an odd number of tunnels, the excavation of the central tunnel is carried out as follows: first, the upper 1 / 3 of the height of the right half of the tunnel is excavated; after it has been excavated for 10m, the upper 1 / 3 of the height of the left half of the tunnel is excavated; after it has been excavated for 8m, the middle 1 / 3 of the height of the right half of the tunnel is excavated; after it has been excavated for 5m, the middle 1 / 3 of the height of the left half of the tunnel is excavated; after it has been excavated for 5m, the lower 1 / 3 of the height of both the left and right half of the tunnel is excavated simultaneously; finally, the cross-section of the tunnel is excavated simultaneously.

7. The overall construction method for complex tunnel group structures based on settlement control according to claim 6, characterized in that, In step (5), the excavation of other tunnels in non-central locations is the same as the excavation of the central tunnel when the complex tunnel group structure has an odd number of tunnels.