Dynamic real-time optimization construction method for super-large deep foundation pit with asymmetric excavation and zero distance to existing underground structure

Abstract

This invention relates to a dynamic real-time optimization construction method for ultra-large deep foundation pits with zero-distance proximity to existing underground structures through asymmetric excavation, comprising the following steps: S10, dividing the foundation pit into a central area and a peripheral area on both sides of the existing underground structure; S20, constructing the foundation pit according to a first construction plan, while simultaneously monitoring the stress and deformation of the existing underground structure in real time; S30, constructing a numerical model and performing numerical simulation and inversion analysis on the first construction plan to verify the accuracy of the model; S40, constructing multiple sets of second construction plans; S50, determining the vertical construction plan for the foundation pit; S60, constructing multiple sets of third construction plans; S70, determining the horizontal construction plan for the foundation pit; S80, determining the three-dimensional compartmentalization sequence based on the vertical and horizontal construction plans, and constructing the two central area compartments and six peripheral area compartments using an asymmetric staggered compartmentalization mode. This invention fills the technical gap in zero-distance proximity construction under conditions of depth differences on both sides, providing design parameters and construction method selection for similar projects.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering and underground engineering construction technology, and in particular to the close-proximity excavation construction of ultra-large deep foundation pits in densely populated urban areas. Specifically, it relates to a dynamic real-time optimization construction method for ultra-large deep foundation pits with zero-distance proximity to existing underground structures through asymmetric excavation. Background Technology

[0002] With rapid economic development and continuous urbanization, integrated transportation hubs have become core facilities for first-tier cities to enhance their functional carrying capacity. These hubs integrate various modes of transportation, such as rail transit and surface public transport, while simultaneously incorporating diverse business formats like offices, residences, and commerce, forming a highly efficient and interconnected "transportation + urban function" complex. This not only meets the travel needs of citizens but also promotes the intensive use of urban space. However, this inevitably involves construction near existing buildings. How to address the impact of adjacent foundation pits on existing operating stations is crucial for the construction of urban rail transit. In the development of the Lize Airport Terminal Integrated Transportation Hub, foundation pit construction was involved on the east and west sides of the existing Lize Business District Station on Line 16. During construction, the excavation of the foundation pits caused soil unloading and uneven disturbance to the surrounding soil layers, thus disrupting the original stress balance. This disruption of balance can trigger stress redistribution in the soil layers, potentially leading to chain reactions such as deformation of the retaining structure and settlement of the surrounding soil, ultimately causing uplift deformation of the existing Lize Business District Station on Line 16, affecting its stability and safety. During the construction of the Lize Business District Integrated Transportation Hub, the existing Line 16 needs to maintain normal operation. According to the specifications, its deformation range must be strictly controlled within the range of ±2mm to -3mm. This stringent standard not only requires real-time capture of structural responses through dynamic monitoring to avoid risks, but also requires optimizing the construction sequence based on the characteristics of the project. By precisely controlling key aspects such as the excavation pace and the timing of support erection, the safety of the operating line and the progress of construction can be coordinated.

[0003] Current research on foundation pit construction near existing buildings mainly defines "near" as a distance range of 3-5m, and related results are mainly focused on this range. However, existing research has not yet addressed the extreme case of the foundation pit being "zero distance" from the existing building, and there are still gaps in related construction technologies and theoretical support.

[0004] In addition, current research on foundation pit construction near existing buildings mainly focuses on the single case of single-sided proximity, and the relevant technical paths and theoretical analyses are relatively mature. However, for complex scenarios where existing buildings are simultaneously approached from both sides, and for construction responses when there are differences in the excavation depth of the foundation pits on both sides, the existing research coverage is low, and the stress mechanism and deformation control methods are still lacking systematic discussion. The depth and breadth of research need to be expanded.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the main purpose of this invention is to propose a dynamic real-time optimization construction method for ultra-large deep foundation pits with zero-distance proximity to existing underground structures through asymmetric excavation, so as to solve the current problem of excavation construction with zero-distance proximity to existing underground structures at different excavation depths on both sides of ultra-large deep foundation pits.

[0007] The technical solution of the present invention is as follows:

[0008] A dynamic real-time optimization construction method for ultra-large deep foundation pits with asymmetric excavation and zero-distance proximity to existing underground structures includes the following steps:

[0009] S10. Based on the characteristics of the ultra-large deep foundation pit with zero distance proximity to the existing underground structure during asymmetric excavation, the foundation pit is divided into a central area and a peripheral area on both sides of the existing underground structure.

[0010] S20. Carry out the foundation pit construction according to the first construction plan. The first construction plan is to construct the foundation pit vertically in symmetrical layers, while monitoring the stress and deformation of the existing underground structure in real time.

[0011] S30. Construct a numerical model and perform numerical simulation and inversion analysis on the first construction scheme. Verify the accuracy of the model based on the existing underground structure deformation simulation results and monitoring results.

[0012] S40. Based on the first construction scheme and combined with the geological characteristics and engineering experience, construct multiple sets of second construction schemes. The multiple sets of second construction schemes are to simultaneously excavate multiple predetermined steps in the central area of ​​the foundation pit in the forward direction and the surrounding area in the reverse direction.

[0013] S50. Numerical simulation is performed on multiple sets of the second construction scheme to determine the vertical construction scheme of the foundation pit. The vertical construction scheme is to excavate the central area of ​​the foundation pit in the forward direction and the surrounding area in the reverse direction simultaneously at predetermined step distances.

[0014] S60. Based on the second construction scheme and combined with the geological characteristics and engineering experience, construct multiple sets of third construction schemes. The multiple sets of third construction schemes are block construction of the central area of ​​the foundation pit in the forward direction and the surrounding area in the reverse direction.

[0015] S70. Numerical simulation is performed on multiple sets of the third construction scheme to determine the transverse construction scheme of the foundation pit. The transverse construction scheme is to construct the foundation pit in a block manner with the central area working in the forward direction and the surrounding area working in the reverse direction. The foundation pit is divided into two central area blocks and six surrounding area blocks on the plane.

[0016] S80. Based on the determined vertical and horizontal construction plans, determine the three-dimensional compartmentalization sequence, and carry out construction on the two central compartments and the six peripheral compartments using an asymmetrical staggered compartmentalization mode.

[0017] Preferably, in S20, the first construction plan is an initial design construction plan or a preliminary construction plan determined based on engineering experience.

[0018] Preferably, in S40, multiple sets of the second construction scheme include:

[0019] The central area of ​​the foundation pit is excavated in a forward direction while the surrounding area is excavated in a reverse direction, with each excavation being 1m in length.

[0020] The central area of ​​the foundation pit is excavated in a forward direction while the surrounding area is excavated in a reverse direction, with each excavation being 2m in length.

[0021] The central area of ​​the foundation pit is excavated in a forward direction while the surrounding area is excavated in a reverse direction, with each excavation being 3 meters deep.

[0022] Preferably, in S50, the vertical construction scheme involves simultaneous layered excavation of the central area of ​​the foundation pit in a forward direction and the surrounding area in a reverse direction, with each excavation being 2m.

[0023] Preferably, in S60, the multiple sets of the third construction schemes include:

[0024] (1) The asynchronous excavation process is adopted, with the two central blocks constructed in sequence first, and the six peripheral blocks constructed in reverse.

[0025] (2) The asynchronous excavation process is adopted, with the six peripheral blocks constructed in reverse and the two central blocks constructed in sequence.

[0026] (3) The asynchronous excavation process is adopted, and the "segmented excavation" sequence is adopted. First, the construction of two central area blocks is started, and then the six peripheral area blocks are excavated in the "interval excavation" sequence: the first batch of blocks P1, P3 and P5 are excavated, and then blocks P2, P4 and P6 are excavated.

[0027] (4) The asynchronous excavation process is adopted, and the "segmented excavation" sequence is adopted. First, the construction of two central area blocks is started, and then the six peripheral area blocks are excavated in the "interval excavation" sequence: the first batch of blocks P2, P4 and P6 are excavated, and then blocks P1, P3 and P5 are excavated.

[0028] Preferably, in S80, the three-dimensional compartmentalization sequence is determined, and an asymmetrical staggered compartmentalization pattern is used for the construction of the two central compartments and the six peripheral compartments, including:

[0029] The six surrounding area blocks were divided into the first group of surrounding area blocks to be excavated in the first batch and the second group of surrounding area blocks to be excavated in the subsequent batch, according to the "skip-block mode".

[0030] The first group of surrounding warehouse blocks and the second group of surrounding warehouse blocks are designed with a "1 / 3 warehouse length offset" in the plane;

[0031] The construction joints between the surrounding storage blocks and the central storage blocks are vertically staggered.

[0032] Preferably, in S80, each of the central area blocks is divided into independent three-dimensional sub-blocks called "bottom plate sub-blocks", "side wall sub-blocks", and "floor slab sub-blocks" according to the difference in stiffness of the vertical components;

[0033] Each of the surrounding blocks is divided into independent three-dimensional sub-blocks, namely "bottom slab sub-block", "side wall sub-block", and "floor slab sub-block", according to the difference in the stiffness of the vertical components, so as to achieve vertical coordination of "excavation-support-structural construction".

[0034] Preferably, the central area storage blocks are constructed "from bottom to top", first excavating the bottom slab storage blocks and pouring the foundation, then excavating the side wall storage blocks in layers and simultaneously constructing the horizontal supports, and finally constructing the floor slab storage blocks.

[0035] The surrounding area storage blocks are constructed "from top to bottom". After excavating to the design elevation of the pit bottom, the floor slab storage blocks, side wall storage blocks, and bottom slab storage blocks are constructed "from top to bottom".

[0036] Preferably, after the bottom slab of the central area slab is poured, multiple stress relief joints are reserved on its surface and the joint width is monitored. After the joint width stabilizes, the side wall slabs are poured in layers.

[0037] Preferably, after all sub-blocks are constructed, the connecting parts of each sub-block are poured a second time to enhance the interface rigidity of the bottom slab sub-blocks, side wall sub-blocks, and floor slab sub-blocks, forming a closed three-dimensional integral structure.

[0038] The advantages of this invention over the prior art are: This invention proposes a dynamic real-time optimization construction method for ultra-large deep foundation pits with asymmetric excavation and zero-distance proximity to existing underground structures, which can be better understood from one or more of the following aspects:

[0039] (1) In view of the special situation that there are no relevant engineering cases for reference in the case of asymmetric excavation of ultra-large deep foundation pits with zero distance to existing underground structures, the present invention provides an effective construction method. By dynamically optimizing in real time during the construction process, the construction plan can be ensured to meet the control requirements of the stress and deformation of the underground structure, and the safety of the existing underground structure during the zero-distance excavation process on both sides can be guaranteed.

[0040] (2) The present invention first preliminarily formulates a first construction plan and carries out construction according to the first construction plan. Then, it adopts a combination of numerical simulation and on-site monitoring to verify the accuracy of the numerical model, so as to ensure that the subsequent numerical simulation conforms to the actual construction.

[0041] (3) This invention continues to construct multiple sets of second construction schemes based on the first construction scheme, and construct multiple sets of third construction schemes based on the second construction schemes as comparative construction schemes. Numerical simulations are performed on the multiple sets of comparative construction schemes to determine the vertical construction scheme and the horizontal construction scheme based on the simulation results. The comparative construction schemes constructed based on the first construction scheme of actual construction will be more realistic, closer to the actual project, and more conducive to optimizing the actual construction scheme.

[0042] (4) The present invention optimizes the first construction scheme of actual construction. On the one hand, the foundation pit adopts a symmetrical layered excavation process in the vertical direction, and the excavation operation is carried out simultaneously on both sides of the existing underground structure. On the other hand, the foundation pit is divided into a central area block and a peripheral area block in the plane, and the block is constructed in a coordinated manner to optimize the stress state. On this basis, the central area block is constructed "from bottom to top" in combination with the three-dimensional block division sequence and the forward construction method, and the peripheral area block is constructed "from top to bottom" in combination with the three-dimensional block division sequence and the reverse construction method. The forward construction in the center improves the construction efficiency and quickly forms the core support, while the reverse construction in the periphery controls the structural deformation and reduces environmental disturbance.

[0043] (5) The present invention adopts a three-dimensional compartmentalization sequence and uses an “asymmetric staggered compartmentalization mode” for the compartmentalization of the central area and the compartmentalization of the surrounding area, so as to achieve full coordination of “three-dimensional compartmentalization”, “staggered compartmentalization” and “combined forward and reverse construction”.

[0044] (6) The research results of this invention can improve the database of zero-distance close-contact construction in asymmetric excavation, fill the technical gap of zero-distance close-contact construction under the condition of different depths on both sides, and provide design parameters and construction method selection for similar projects (such as scenarios where the depth ratio of the foundation pits on both sides is >1).

[0045] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of the present invention, nor is it intended to restrict the scope of the invention. Other features of the invention will become readily apparent from the following description. Furthermore, implementation of any embodiment of the present invention does not imply the simultaneous possession or achievement of multiple or all of the aforementioned beneficial effects. Attached Figure Description

[0046] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0047] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0048] Figure 1 This is a schematic diagram of the overall process of the dynamic real-time optimization construction method according to an embodiment of the present invention;

[0049] Figure 2 This is a schematic diagram of the foundation pit engineering plan according to an embodiment of the present invention;

[0050] Figure 3 This is a schematic diagram of the existing underground structure of the foundation pit project according to an embodiment of the present invention;

[0051] Figure 4 This is a schematic elevation view of the foundation pit excavation design according to an embodiment of the present invention;

[0052] Figure 5 This is a schematic diagram illustrating the dynamic real-time optimization of construction content according to an embodiment of the present invention;

[0053] Figure 6 This is a schematic diagram of the foundation pit divided into sections on a plane according to an embodiment of the present invention;

[0054] Figure 7 This is a schematic diagram of structural deformation monitoring and numerical simulation according to an embodiment of the present invention;

[0055] Figure 8 This is a schematic diagram of the deformation simulation of the second construction scheme according to an embodiment of the present invention;

[0056] Figure 9 This is a schematic diagram of the excavation of the foundation pit in sections on a plane, according to an embodiment of the present invention.

[0057] Figure 10 This is a schematic diagram illustrating the retention of 1 / 3 of the warehouse length misalignment in an embodiment of the present invention;

[0058] Figure 11 This is a schematic diagram of the next construction step for a 1 / 3 warehouse length according to an embodiment of the present invention;

[0059] Figure 12 This is a schematic diagram of a modified foundation pit construction scheme according to an embodiment of the present invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0061] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] It should be understood that the terms "comprising / including," "consisting of," or any other variations are intended to cover non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements includes not only those elements but may also include, where necessary, other elements not expressly listed, or elements inherent to such a product, apparatus, process, or method. Without further limitation, an element defined by the phrases "comprising / including," "consisting of," does not exclude the presence of additional identical elements in the product, apparatus, process, or method that includes said element.

[0063] It should also be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of the present invention.

[0064] To achieve the objectives of this invention, given the insufficient research on zero-distance proximity construction for asymmetric excavation, this study mainly focuses on the following aspects:

[0065] 1. The specific characteristics of the research scenario

[0066] In close proximity to the work site, asymmetric excavation, i.e., the difference in excavation depth between the two sides of the foundation pit, will lead to asymmetric unloading, causing additional bending moment and shear deformation in the existing building foundation. Research on such complex stress scenarios is currently in the exploratory stage, and the relevant mechanical mechanisms and control methods have not yet been systematically developed.

[0067] 2. Key Research Dimensions

[0068] Focusing on the impact of depth differences (different excavation depths on the east and west sides of the foundation pit) on construction disturbance: Analyzing the asymmetry of soil stress redistribution and its load transfer path to existing building foundations when foundation pits of different depths are excavated simultaneously; exploring the tensile and compressive effects of the deformation difference of the retaining structure caused by depth differences on the walls of existing buildings; quantifying the differences in the effects of different excavation sequences (deep first then shallow / shallow first then deep) on disturbance control.

[0069] 3. Data Output and Technical Goals

[0070] Through on-site monitoring and numerical simulation, key data under the working conditions of depth difference are obtained, including the settlement curve of existing buildings, the axial force change of the foundation pit retaining structure, and the lateral displacement distribution of the soil. A quantitative relationship model of "depth difference-stress asymmetry-building response" is established to clarify the depth difference limit and collaborative excavation parameters for safe construction.

[0071] 4. Application and Expansion of the Research

[0072] The research findings can improve the database of zero-distance close-contact construction, fill the technical gap in zero-distance close-contact construction under conditions of depth difference, and provide design parameters and construction method selection for similar projects (such as scenarios where the depth ratio of the two foundation pits is greater than 1).

[0073] The implementation of the present invention will be described in detail below with reference to preferred embodiments.

[0074] First see Figure 1The flowchart shown illustrates a dynamic real-time optimization construction method for ultra-large deep foundation pits with asymmetric excavation and zero-distance proximity to existing underground structures. The method includes the following steps: S10, Based on the characteristics of ultra-large deep foundation pits with asymmetric excavation and zero-distance proximity to existing underground structures, the foundation pit is divided into a central area and a peripheral area on both sides of the existing underground structure; S20, Foundation pit construction is carried out according to the first construction scheme, which involves vertically symmetrical layered construction of the foundation pit, while simultaneously monitoring the stress and deformation of the existing underground structure in real time; S30, A numerical model is constructed, and numerical simulation and inversion analysis are performed on the first construction scheme. The accuracy of the model is verified based on the simulation results of the deformation of the existing underground structure and the monitoring results; S40, Based on the first construction scheme and combined with geological characteristics and engineering experience, multiple sets of second construction schemes are constructed. These multiple sets of second construction schemes involve simultaneous layered excavation with forward excavation in the central area and reverse excavation in the peripheral area. S50. Perform numerical simulation on multiple sets of second construction schemes to determine the vertical construction scheme of the foundation pit. The vertical construction scheme is to excavate the foundation pit in the center area in a forward direction and the surrounding area in a reverse direction simultaneously at predetermined step distances. S60. Based on the second construction scheme and combined with the geological characteristics and engineering experience, construct multiple sets of third construction schemes. The multiple sets of third construction schemes are to construct the foundation pit in the center area in a forward direction and the surrounding area in a reverse direction in block construction. S70. Perform numerical simulation on multiple sets of third construction schemes to determine the horizontal construction scheme of the foundation pit. The horizontal construction scheme is to construct the foundation pit in the center area in a forward direction and the surrounding area in a reverse direction in block construction. The foundation pit is divided into two central area blocks and six surrounding area blocks in the plane. S80. According to the determined vertical construction scheme and horizontal construction scheme, determine the three-dimensional block division sequence, and carry out construction on the two central area blocks and the six surrounding area blocks using an asymmetrical staggered block jumping mode.

[0075] This invention quantifies the variation patterns of displacement field (settlement, tilt) and stress field (foundation reaction force, wall strain) of existing underground structures under different construction steps by changing the construction sequence and using a combination of numerical simulation and on-site monitoring. It compares and analyzes the disturbance control effects of multiple schemes, identifies the optimal construction procedure, and obtains the construction method that minimizes the deformation and stress of the existing underground structure, so as to ensure the safety and normal operation of the station structure.

[0076] The following analysis, based on the Beijing Lize Business District Integrated Transportation Hub Terminal Project, systematically examines its complex soil and water environment, foundation pit support system, and the combination of forward and reverse construction, and elaborates on the implementation of each stage.

[0077] like Figure 2As shown, the Lize Business District Station of Metro (Lines 14, 16, Airport Line, Line 11, Lijin Line and Terminal) project is located under plots 64# and 65# and surrounding roads. The above-ground building area is no more than 270,000 square meters, and the underground building area is about 302,500 square meters. The foundation pit is designed to be 427m long × 154m wide × 38m deep. Currently, Lines 14 and 16 have been completed and opened to traffic, the station of Daxing Airport Line is under construction, and the main structure of the stations of Line 11 and Lijin Line is reserved at this station.

[0078] like Figure 3 , Figure 4 As shown, the development of the Lize City Terminal Integrated Transportation Hub requires the excavation of foundation pits on both sides of the existing Line 16 and the construction of underground structures. This invention mainly optimizes the construction sequence of the foundation pits on both sides of the existing Line 16 structure to reduce the impact on the deformation of the existing Line 16.

[0079] The Lize Business District site primarily consists of pebble strata. The particle size distribution curve of these strata exhibits a continuous distribution, indicating excellent gradation. This results in strong interlocking between particles, forming a dense natural framework structure with a low porosity. Mechanically, this exhibits low compressibility and high bearing capacity, providing favorable natural bearing conditions for foundation engineering. However, this stratum also possesses high permeability, making it prone to seepage deformation such as piping and soil erosion under groundwater conditions. This places stringent requirements on the design of the cutoff wall for foundation pit excavation. Furthermore, the high strength and heterogeneity of the pebble layer can lead to drilling difficulties and excessive borehole inclination during pile foundation construction. Additionally, the dense structure may cause loosening of the particle framework under vibration loads, inducing additional settlement.

[0080] Given the complex characteristics of the pebble strata, multiple comparative schemes need to be developed for different construction steps. Numerical simulations should be used to quantify structural stress, ground deformation, and other indicators under different schemes. A comprehensive comparison should be made, considering both technical feasibility and economic rationality, to ultimately determine the optimal construction scheme that balances safety risks and project benefits. The overall approach is as follows: Figure 5 As shown.

[0081] S10. Based on the characteristics of the ultra-large deep foundation pit with zero distance proximity to the existing underground structure during asymmetric excavation, the foundation pit is divided into a central area and a peripheral area on both sides of the existing underground structure.

[0082] like Figure 6 As shown, the existing Line 16 structure crosses the design area of ​​the foundation pit. Based on the characteristics of the foundation pit, the foundation pit is divided into a central area and a peripheral area on both sides of the existing underground structure. Each side of the existing underground structure is divided into a central area and a peripheral area surrounding the central area on three sides. The other side of the central area is the existing underground structure, namely the existing Line 16 structure, which is in close proximity to it.

[0083] S20. Carry out the foundation pit construction according to the first construction plan. The first construction plan is to construct the foundation pit vertically in symmetrical layers, while monitoring the stress and deformation of the existing underground structure in real time.

[0084] In this embodiment, the first construction plan can be initially selected as the initial design construction plan, or a preliminary construction plan can be determined based on engineering experience and site environment for actual construction.

[0085] The stress-deformation analysis of the existing underground structure in this embodiment includes:

[0086] (1) Stress and Deformation Analysis of Steel Pipe Columns

[0087] As the core vertical load-bearing component of the entire subway station, the steel pipe column bears the loads of the superstructure, earth pressure, water pressure, and train dynamic loads. Its stress is primarily axial pressure, while it must also resist bending moments and shear forces caused by horizontal forces. The steel pipe and the core concrete work together; the confinement effect of the steel pipe on the concrete improves the component's load-bearing capacity and ductility, while the core concrete enhances the steel pipe's buckling resistance. Therefore, during construction near the subway station, it is crucial to pay close attention to the stress and deformation of the steel pipe columns. The following key stages will be analyzed regarding the stress and deformation of the steel pipe columns: 1) The different soil excavation methods used on both sides of the foundation pit affect the stress and deformation of the steel pipe columns due to stress transfer caused by soil unloading; 2) During the construction of the horizontal support on the east side of the foundation pit, the gradual redistribution of stress after the horizontal support is completed significantly impacts the stress and deformation of the subway station's steel pipe columns; 3) After the terminal building construction is completed, the overall stress tends to stabilize, and the stress and deformation of the steel pipe columns also tend to stabilize. Figure 7 As shown.

[0088] (2) Deformation analysis of side piles

[0089] As the core retaining structure of the entire subway station, the side piles resist lateral earth pressure, water pressure, and construction loads during the excavation phase, maintaining soil stability; they control lateral displacement deformation of the station, forming a closed load-bearing structure to bear the lateral loads during the station's operation. Therefore, during construction near the subway station, it is crucial to pay close attention to the lateral deformation of the side piles. The following key stages will be analyzed for the lateral deformation of the side piles: 1) The use of different soil excavation methods on both sides of the excavation pit, resulting in stress transfer due to soil unloading, affecting the lateral deformation of the side piles; 2) During the construction of the transverse supports on the east side of the excavation pit, the gradual redistribution of stress as the supports bear the horizontal loads after construction significantly impacts the lateral deformation of the subway station's side piles; 3) After the terminal building construction is completed, the overall stress tends to stabilize, and the lateral deformation of the side piles also tends to stabilize.

[0090] (3) Deformation analysis of top plate, middle plate and bottom plate

[0091] The roof slab, middle slab, and bottom slab of a subway station are the core load-bearing components, together forming a vertical load-bearing system: the roof slab directly bears the self-weight of the superstructure, ground surcharge, and construction loads, transmitting vertical forces through stiffness diffusion; the middle slab, as a horizontal dividing structure, bears the reaction force of the tunnel boring machine and lateral constraint loads, coordinating the stress on the upper and lower structures; the bottom slab sits directly on the bearing layer of the foundation, resisting the base reaction force and groundwater buoyancy, and controlling the overall settlement of the structure. Therefore, when constructing near the subway station, it is crucial to monitor the vertical deformation and planar displacement of the slabs. The following key stages of slab deformation characteristics are analyzed: When differentiated excavation techniques are used on both sides of the foundation pit, the vertical stress gradient caused by the difference in soil unloading rate and range will lead to uneven settlement of the top, middle, and bottom slabs; During the construction stage of the horizontal support of the foundation pit on the east side, as the axial force of the support is gradually applied, the horizontal constraint load is transferred to the slab through the retaining structure, causing a redistribution of internal forces in the structure, which may cause local flexural deformation of the slab; After the construction of the terminal building is completed, the structural system forms overall stiffness, and the deformation of the top, middle, and bottom slabs is controlled by the combined effect of the upper dead load and live load, and the deformation rate tends to be gradual and eventually stabilizes.

[0092] Based on the above deformation monitoring, the deformation patterns of existing underground structures are analyzed.

[0093] S30. Construct a numerical model, perform numerical simulation and inversion analysis on the first construction scheme, and verify the accuracy of the model based on the existing underground structure deformation simulation results and monitoring results.

[0094] Field measurements and numerical simulations, such as Figure 7 As shown, the numerical model constructed in this invention is suitable and can be used for subsequent simulation of comparative construction schemes.

[0095] It should be noted that the numerical model and inversion analysis method constructed here are not the focus of this invention and will not be elaborated in detail. It is sufficient that the simulation can be performed and the results are reasonable.

[0096] S40. Based on the first construction scheme and combined with the geological characteristics and engineering experience, construct multiple sets of second construction schemes. The multiple sets of second construction schemes involve simultaneous layered excavation of multiple predetermined steps in the central area of ​​the foundation pit and the surrounding area in the reverse direction.

[0097] In this embodiment, based on the geological characteristics of the foundation pit location and combined with engineering experience, the central area of ​​the foundation pit on both the east and west sides of the existing station is excavated in a forward direction while the surrounding area is excavated in a reverse direction, with each excavation step distance set to 1m, 2m, and 3m respectively. Details are as follows:

[0098] (1) The foundation pits on the east and west sides and around the existing Line 16 station are constructed symmetrically in layers, with each layer being 1m long;

[0099] See also Figure 4The existing foundation pit project of the Lize Business District Station of Line 16 adopts a symmetrical layered excavation process. Earthwork excavation is carried out simultaneously on the east and west sides and surrounding areas via reverse excavation. The depth of each excavation is strictly controlled to 1 meter, and disturbance to the retaining structure and surrounding environment is reduced through step-by-step unloading. The specific construction process is as follows: When the earthwork excavation of the right-side foundation pit reaches the B4M (intermediate level of the fourth underground level) elevation, the first horizontal support is immediately constructed to form an initial stress balance system. Subsequently, the reverse construction method is used to construct the two horizontal supports corresponding to the bottom and top slabs of the B3 level sequentially. After the support system is completed, a stiffness test is conducted to ensure that the design stiffness requirements are met. After the three support systems pass the acceptance test and meet the strength requirements, excavation continues downward to the B4 level bottom slab elevation, and the fourth support is constructed simultaneously. Finally, the excavation work from the pit to the bottom is completed under the coordinated force of the four supports. During the main structure construction phase, the terminal building's foundation slab and steel pipe columns were poured first, and then the main structure of the terminal building was constructed layer by layer upwards in a reverse construction manner. The completed structural layers were used as a temporary support system to achieve the integration of "structural construction and load bearing" and effectively control the structural deformation and foundation pit stability during the construction process.

[0100] (2) Symmetrical layered construction of the foundation pits on the east and west sides of the existing Line 16 station and around the perimeter, 2m each time;

[0101] The existing foundation pit project of the Lize Business District Station on Line 16 adopts a symmetrical layered excavation process. Earthwork excavation is carried out simultaneously on the east and west sides and surrounding areas via reverse construction. The depth of each excavation is strictly controlled to 2 meters. Step-by-step unloading minimizes disturbance to the retaining structure and surrounding environment. The specific construction process is as follows: When the earthwork excavation of the right-side foundation pit reaches the B4M elevation, the first layer of lateral supports is immediately constructed to form an initial stress balance system. Subsequently, the reverse construction method is used to construct the two corresponding horizontal supports for the B3 layer bottom slab and top slab. After the support system is completed, a stiffness test is conducted to ensure that the design stiffness requirements are met. After the three support systems pass the acceptance test and meet the strength requirements, excavation continues downward to the B4 layer bottom slab elevation, and the fourth support is constructed simultaneously. Finally, the excavation from the foundation pit to the bottom is completed under the coordinated force of the four supports. During the main structure construction phase, the terminal building's foundation slab and steel pipe columns were poured first, and then the main structure of the terminal building was constructed layer by layer upwards in a reverse construction manner. The completed structural layers were used as a temporary support system to achieve the integration of "structural construction and load bearing" and effectively control the structural deformation and foundation pit stability during the construction process.

[0102] (3) The foundation pits on the east and west sides and around the existing Line 16 station are constructed symmetrically in layers, with each layer being 3m.

[0103] The existing foundation pit project of the Lize Business District Station on Line 16 adopts a symmetrical layered excavation process. Earthwork excavation is carried out simultaneously on the east and west sides and surrounding areas via reverse construction. The depth of each excavation is strictly controlled to 3 meters. Step-by-step unloading minimizes disturbance to the retaining structure and surrounding environment. The specific construction process is as follows: When the earthwork excavation of the right-side foundation pit reaches the B4M elevation, the first horizontal support is immediately constructed to form an initial stress balance system. Subsequently, the reverse construction method is used to construct the two horizontal supports corresponding to the B3 floor slab and top slab. After the support system is completed, a stiffness test is conducted to ensure that the design stiffness requirements are met. After the three support systems pass the acceptance test and meet the strength requirements, excavation continues downward to the B4 floor slab elevation, and the fourth support is constructed simultaneously. Finally, the excavation from the foundation pit to the bottom is completed under the coordinated force of the four supports. During the main structure construction phase, the terminal building's foundation slab and steel pipe columns were poured first, and then the main structure of the terminal building was constructed layer by layer upwards in a reverse construction manner. The completed structural layers were used as a temporary support system to achieve the integration of "structural construction and load bearing" and effectively control the structural deformation and foundation pit stability during the construction process.

[0104] The deformation values ​​simulated by the above three sets of excavation step distances of 1m, 2m, and 3m are as follows: Figure 8 As shown.

[0105] S50. Numerical simulations were performed on multiple sets of second construction schemes to determine the vertical construction scheme of the foundation pit, and the predetermined step distance was set for the simultaneous layered excavation of the central area of ​​the foundation pit in the forward direction and the surrounding area in the reverse direction.

[0106] In this embodiment, the evaluation factors are combined with a two-dimensional weighted approach of "economy-safety". Figure 8 Based on the deformation curve and economic comparison shown, the scheme (2) was determined for construction. That is, the existing Line 16 Lize Business District Station foundation pit project adopts the symmetrical layered excavation process, and the earthwork excavation operation is carried out simultaneously on the east and west sides and the surrounding reverse foundation pits. The single excavation depth is strictly controlled to 2m. The disturbance to the retaining structure and the surrounding environment is reduced by step unloading.

[0107] S60. Based on the second construction scheme and combined with the geological characteristics and engineering experience, construct multiple sets of third construction schemes. The multiple sets of third construction schemes are divided into block constructions: the central area of ​​the foundation pit is constructed in the forward direction and the surrounding area is constructed in the reverse direction.

[0108] In this embodiment, based on the characteristics of the foundation pit and the symmetrical layered construction with a single excavation depth of 2m, the foundation pit is divided into two central area blocks and six peripheral area blocks on the plane. Multiple third construction schemes include:

[0109] (1) The asynchronous excavation process is adopted, with the two central blocks constructed in sequence first, and the six peripheral blocks constructed in reverse.

[0110] The existing foundation pit project for the Lize Business District Station of Line 16 adopts a zoned asynchronous excavation process, proceeding in the order of "first constructing the two central sections in a forward-moving manner, then constructing the six surrounding sections in a reverse-moving manner." The specific construction steps are as follows: First, construction begins on the two central sections, with layered excavation. The depth of each excavation is strictly controlled to 2 meters, and lateral supports are simultaneously installed to ensure the structural balance of the retaining structure. After the support system passes inspection, the forward-moving method is used to construct the structure of this area, i.e., pouring foundations, walls, floor slabs, and other components sequentially from bottom to top, providing internal stability support for the surrounding areas. Once the structural construction of the two central sections is completed and reaches the design strength, earthwork excavation for the six surrounding sections begins simultaneously, with the depth of each excavation also strictly controlled to 2 meters. The entire process follows the principle of "layered excavation and time-limited support" to minimize the time the foundation pit is exposed without support and reduce the risk of deformation. After the earthwork excavation of the six surrounding sections reaches the design elevation at the bottom of the pit, reverse-moving construction immediately commences. The floor slabs, walls, and vertical components are poured layer by layer from top to bottom. The completed central structure and the surrounding temporary support system together form a load-bearing frame, further stabilizing the overall shape of the foundation pit. Ultimately, the entire foundation pit and structure are closed. By following the construction sequence from the inside out, the deformation resistance of the central structure is fully utilized, ensuring the safety of the project and the surrounding environment.

[0111] (2) The asynchronous excavation process is adopted, with the six peripheral blocks constructed in reverse and the two central blocks constructed in sequence.

[0112] The existing Line 16 Lize Business District Station foundation pit project adopts a zoned asynchronous excavation process, proceeding sequentially with "first constructing the six surrounding reverse-construction areas, then constructing the two central forward-construction areas." The specific construction steps are as follows: First, earthwork excavation of the six surrounding areas is carried out simultaneously, with each excavation depth strictly controlled at 2 meters. The entire process adheres to the principle of "layered excavation and time-limited support" to minimize the unsupported exposure time of the foundation pit and reduce the risk of deformation. After the earthwork excavation of the six surrounding areas reaches the design elevation at the bottom of the pit, the construction of the terminal building structure in reverse construction immediately begins. Floor slabs, walls, and vertical components are poured layer by layer from top to bottom, utilizing the completed structure as a temporary load-bearing system to further stabilize the foundation pit shape and lay a safe foundation for subsequent construction. After the construction of the terminal building structure in all six surrounding areas is completed and reaches the design strength, construction of the two central areas commences. In the central area, the earthwork was first excavated in layers, with the depth of each excavation controlled at 2 meters. Lateral supports were installed concurrently with the excavation to ensure the structural balance of the retaining structure. After the support system passed inspection, the terminal building structure in this area was constructed using the sequential construction method, that is, the foundation, walls, floors, and other components were poured in order from bottom to top, ultimately achieving the overall closure of the entire foundation pit and terminal building structure.

[0113] (3) The asynchronous excavation process is adopted, and the "segmented excavation" sequence is adopted. First, the construction of two central area blocks is started, and then the six peripheral area blocks are excavated in the "interval excavation" sequence: the first batch of blocks P1, P3 and P5 are excavated, and then blocks P2, P4 and P6 are excavated.

[0114] The existing foundation pit project for the Lize Business District Station of Line 16 adopts a zoned asynchronous excavation process, implemented in a "segmented, skip-excavation" sequence. The specific construction steps are as follows: First, construction begins on the two central area blocks, with layered excavation of the earthwork. The depth of each excavation is strictly controlled to 2 meters. Lateral supports are simultaneously constructed as the excavation progresses to ensure the structural balance of the retaining structure. After the support system passes inspection, the structure in this area is constructed using a sequential construction method, that is, foundations, walls, floor slabs, and other components are poured in a "bottom-up" order to provide internal stability support for the surrounding construction areas. After the structural construction of the two central blocks is completed and reaches the design strength, the surrounding area will be divided into six independent blocks (numbered P1-P6). Work will proceed in a staggered, "intermittent excavation" sequence: Blocks P1, P3, and P5 will be excavated first, following the principle of "layered excavation and time-limited support." Temporary support will be immediately implemented after each 2m excavation. After excavating to the design elevation at the bottom of the pit, reverse construction will commence, with floor slabs, walls, and vertical components poured layer by layer "from top to bottom," utilizing the central structure and the already constructed structure of this block to form a locally stable system. Blocks P2, P4, and P6 will be excavated at intervals of at least 10 days, with simultaneous support and reverse construction. Construction joints will be precisely aligned with the central area and adjacent blocks. After the reverse construction of all surrounding blocks is completed, secondary pouring will be carried out at the connection points of each block to form a closed structural system.

[0115] (4) The asynchronous excavation process is adopted, and the "segmented excavation" sequence is adopted. First, the construction of two central area blocks is started, and then the six peripheral area blocks are excavated in the "interval excavation" sequence: the first batch of blocks P2, P4 and P6 are excavated, and then blocks P1, P3 and P5 are excavated.

[0116] The existing foundation pit project for the Lize Business District Station of Line 16 adopts a zoned asynchronous excavation process, implemented in a "segmented, skip-excavation" sequence. The specific construction steps are as follows: First, construction begins on the two central area blocks, with layered excavation of the earthwork. The depth of each excavation is strictly controlled to 2 meters. Lateral supports are simultaneously constructed as the excavation progresses to ensure the structural balance of the retaining structure. After the support system passes inspection, the structure in this area is constructed using a sequential construction method, that is, foundations, walls, floor slabs, and other components are poured in a "bottom-up" order to provide internal stability support for the surrounding construction areas. After the structural construction of the two central blocks is completed and reaches the design strength, the surrounding area will be divided into six independent blocks (numbered P1-P6). Work will proceed in a staggered, "intermittent excavation" sequence: Blocks P2, P4, and P6 will be excavated first, following the principle of "layered excavation and time-limited support." Temporary support will be immediately implemented after each 2m excavation. Once the design elevation at the bottom of the pit is reached, reverse construction will commence, with floor slabs, walls, and vertical components poured layer by layer "from top to bottom," utilizing the central structure and the already constructed structure of this block to form a locally stable system. At intervals of more than 10 days, blocks P1, P3, and P5 will be excavated, with simultaneous support and reverse construction. Construction joints will be precisely aligned with the central area and adjacent blocks. After the reverse construction of all surrounding blocks is completed, secondary pouring will be carried out at the connection points of each block to form a closed structural system.

[0117] S70. Numerical simulations were performed on multiple sets of third construction schemes to determine the transverse construction scheme of the foundation pit. The transverse construction scheme is to construct the foundation pit in a block manner with the central area working in the forward direction and the surrounding area working in the reverse direction. The foundation pit is divided into two central area blocks and six surrounding area blocks on the plane.

[0118] In this embodiment, combining the three-dimensional quantitative decision-making factors of "geology-structure-environment," and based on the characteristic of the asymmetric excavation of the ultra-large deep foundation pit being in close proximity to the existing underground structure, the central area is divided into two central area blocks on both sides of the existing underground structure, and the surrounding area is divided into six peripheral area blocks around the central area. Figure 9 As shown, the surrounding area blocks are P1-P6.

[0119] It is easy to understand that the central area block is the central area of ​​the foundation pit. In this invention, due to the existence of the existing underground structure, and the existing underground structure dividing the foundation pit, the central area is divided into two central area blocks at different depths on both sides for construction on both sides. The peripheral area is divided into six peripheral area blocks.

[0120] The central storage area was constructed from the bottom up using a three-dimensional storage sequence combined with a sequential construction method, while the surrounding storage areas were constructed from the top down using a three-dimensional storage sequence combined with a reverse construction method. Figure 9 The diagram shows reverse construction P1, P2, P3, P4, P5, and P6. The central forward construction improves construction efficiency, quickly forming core support, while the surrounding reverse construction controls structural deformation and reduces environmental disturbance.

[0121] S80. Based on the determined vertical and horizontal construction plans for the foundation pit, determine the three-dimensional compartmentalization sequence, and carry out construction of the two central compartments and six peripheral compartments using an asymmetrical staggered compartmentalization mode.

[0122] In this embodiment, see continue to refer to Figure 9 According to the "skip-warehouse mode", the surrounding warehouse blocks are divided into a group of P1, P3, P5 and a group of P2, P4, P6. The P1, P3, P5 warehouse blocks are excavated first, and the P2, P4, P6 warehouse blocks are excavated later (the excavation order can be interchanged).

[0123] Furthermore, the P1, P3, and P5 blocks are designed with a "1 / 3 block length offset" from the P2, P4, and P6 blocks in the plane, such as... Figure 10 , Figure 11 As shown, P1 is constructed along the entire length, P3 retains 1 / 3 of the seam length for the next construction step, P5 is constructed along the entire length, P2 is constructed along the entire length, P4 retains 1 / 3 of the seam length for the next construction step, and P6 is constructed along the entire length.

[0124] Meanwhile, the construction joints between the surrounding storage blocks and the central storage blocks are vertically staggered to avoid forming a continuous stress transfer path.

[0125] Furthermore, based on the differences in stiffness of the vertical components of the underground structure to be constructed, each central area block is divided into independent three-dimensional sub-blocks: "bottom slab sub-block," "side wall sub-block," and "floor slab sub-block." The bottom slab, due to its large thickness and high equivalent stiffness, is separately classified as the bottom core block. The side walls and floor slabs have similar thicknesses, but due to differences in stiffness, they are classified as side wall blocks and floor slab blocks.

[0126] Similarly, each surrounding area block is divided into independent three-dimensional sub-blocks, namely "bottom slab sub-block", "side wall sub-block", and "floor slab sub-block", according to the difference in the stiffness of the vertical components. This ensures that the layered excavation and support are matched with the stiffness requirements of the corresponding vertical blocks, and achieves vertical coordination of "excavation-support-structural construction".

[0127] Furthermore, the central area storage blocks are constructed "from bottom to top." First, the bottom slab storage blocks are excavated and the foundation is poured. Then, the side wall storage blocks are excavated layer by layer and the horizontal supports are constructed simultaneously. Finally, the floor slab storage blocks are constructed. The scheme of "pre-casting of the bottom slab storage blocks combined with phased construction of vertical components" is adopted. After the bottom slab is poured, three stress relief joints with a width of 20mm are reserved on its surface. The joint width is monitored after 7 days. After the joint width stabilizes, the side wall storage blocks and floor slab storage blocks are poured in layers. By optimizing the traditional sequential construction method, the vertical shrinkage stress is released, and stress concentration between components with different stiffnesses is avoided.

[0128] The surrounding area storage blocks are constructed "from top to bottom". After excavating to the design elevation of the pit bottom, the floor slab storage blocks, side wall storage blocks, and bottom slab storage blocks are constructed "from top to bottom". During the construction process, the central rigidity core and the existing structure of this storage block are used to form a local stable system.

[0129] After all sub-compartment blocks are constructed, secondary pouring is carried out at the connection points of each sub-compartment block to enhance the interface rigidity of the bottom slab sub-compartment block, side wall sub-compartment block, and floor slab sub-compartment block, ultimately forming a closed three-dimensional integral structure, realizing the full coordination of "three-dimensional compartmenting", "staggered compartmenting" and "combined forward and reverse construction".

[0130] In summary, this invention addresses the challenges of asymmetric excavation involving extremely large and deep foundation pits adjacent to existing underground structures. Due to the extreme working conditions and significant risks associated with such excavations, there is a lack of practical engineering cases and systematic research, resulting in a lack of mature theoretical support and data references for construction scheme design in this scenario. Therefore, targeted research is urgently needed to fill this theoretical gap. This invention focuses on analyzing the disturbance mechanisms of key steps in different construction schemes on existing buildings; and the differential settlement characteristics of existing building foundations caused by the superposition of superimposed loads during the construction phase of the terminal building structure.

[0131] In terms of research methods and technical approaches, this invention employs a combination of numerical simulation and on-site monitoring to quantify the variation patterns of the displacement field (settlement, tilt) of existing buildings under different construction steps, such as... Figure 7 As shown, the numerical simulation results are in good agreement with the field measurement results; by comparing and analyzing the disturbance control effects of multiple schemes, the optimal construction procedure was obtained, such as... Figure 12 As shown, the deformation value of the existing underground structure was significantly reduced during the construction of the optimal scheme.

[0132] The research results of this invention can form a disturbance control technology guideline for asymmetric excavation and close-proximity construction, clarify the safety threshold (such as the settlement rate of existing buildings ≤0.5mm / d) and dynamic adjustment strategy for each construction step, and provide replicable construction experience and technical support for similar projects.

[0133] It will be readily understood by those skilled in the art that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0134] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dynamic real-time optimization construction method for an asymmetrically excavated super-large deep foundation pit close to existing underground structures, characterized in that, Includes the following steps: S10. Based on the characteristics of the ultra-large deep foundation pit with zero distance proximity to the existing underground structure during asymmetric excavation, the foundation pit is divided into a central area and a peripheral area on both sides of the existing underground structure. S20. Carry out the foundation pit construction according to the first construction plan. The first construction plan is to construct the foundation pit vertically in symmetrical layers, while monitoring the stress and deformation of the existing underground structure in real time. S30. Construct a numerical model and perform numerical simulation and inversion analysis on the first construction scheme. Verify the accuracy of the model based on the existing underground structure deformation simulation results and monitoring results. S40. Based on the first construction scheme and combined with the geological characteristics and engineering experience, construct multiple sets of second construction schemes. The multiple sets of second construction schemes are to simultaneously excavate multiple predetermined steps in the central area of ​​the foundation pit in the forward direction and the surrounding area in the reverse direction. S50. Numerical simulation is performed on multiple sets of the second construction scheme to determine the vertical construction scheme of the foundation pit. The vertical construction scheme is to excavate the central area of ​​the foundation pit in the forward direction and the surrounding area in the reverse direction simultaneously at predetermined step distances. S60. Based on the second construction scheme and combined with the geological characteristics and engineering experience, construct multiple sets of third construction schemes. The multiple sets of third construction schemes are block construction of the central area of ​​the foundation pit in the forward direction and the surrounding area in the reverse direction. S70. Numerical simulation is performed on multiple sets of the third construction scheme to determine the transverse construction scheme of the foundation pit. The transverse construction scheme is to construct the foundation pit in a block manner with the central area working in the forward direction and the surrounding area working in the reverse direction. The foundation pit is divided into two central area blocks and six surrounding area blocks on the plane. S80. Based on the determined vertical and horizontal construction plans for the foundation pit, determine the three-dimensional compartmentalization sequence, and construct the two central compartments and six peripheral compartments using an asymmetrical staggered compartmentalization pattern; specifically including: The six surrounding area blocks were divided into the first group of surrounding area blocks to be excavated in the first batch and the second group of surrounding area blocks to be excavated in the subsequent batch, according to the "skip-block mode". The first group of surrounding warehouse blocks and the second group of surrounding warehouse blocks are designed with "1 / 3 warehouse length offset" in the plane; The construction joints between the peripheral storage area and the central storage area are vertically staggered; and Each central area block is divided into independent three-dimensional sub-blocks, namely "bottom slab sub-block", "side wall sub-block", and "floor slab sub-block", according to the difference in the stiffness of the vertical components; Each of the surrounding blocks is divided into independent three-dimensional sub-blocks—"bottom slab sub-blocks," "side wall sub-blocks," and "floor slab sub-blocks"—based on differences in the stiffness of vertical components, achieving vertical coordination between excavation, support, and structural construction; and The central area storage blocks are constructed "from bottom to top". First, the bottom slab storage blocks are excavated and the foundation is poured. Then, the side wall storage blocks are excavated layer by layer and the horizontal supports are constructed simultaneously. Finally, the floor slab storage blocks are constructed. The surrounding area storage blocks are constructed "from top to bottom". After excavating to the design elevation of the pit bottom, the floor slab storage blocks, side wall storage blocks, and bottom slab storage blocks are constructed "from top to bottom".

2. The construction method according to claim 1, characterized in that, In S20, the first construction plan is the initial design construction plan or the preliminary construction plan determined based on engineering experience.

3. The construction method according to claim 1, characterized in that, In S40, multiple sets of the second construction schemes include: The central area of ​​the foundation pit is excavated in a forward direction while the surrounding area is excavated in a reverse direction, with each excavation being 1m in length. The central area of ​​the foundation pit is excavated in a forward direction while the surrounding area is excavated in a reverse direction, with each excavation being 2m in length. The central area of ​​the foundation pit is excavated in a forward direction while the surrounding area is excavated in a reverse direction, with each excavation being 3 meters deep.

4. The construction method according to claim 3, characterized in that, In S50, the vertical construction scheme is to excavate the central area of ​​the foundation pit in a forward direction and the surrounding area in a reverse direction simultaneously in layers, with each excavation being 2m.

5. The construction method according to claim 1, characterized in that, In S60, the multiple sets of the third construction schemes include: (1) The asynchronous excavation process is adopted, with the two central blocks constructed in sequence first, and the six peripheral blocks constructed in reverse. (2) The asynchronous excavation process is adopted, with the six peripheral blocks constructed in reverse and the two central blocks constructed in sequence. (3) The asynchronous excavation process is adopted, and the "segmented excavation" sequence is adopted. First, the construction of two central area blocks is started, and then the six peripheral area blocks are excavated in the "interval excavation" sequence: the first batch of blocks P1, P3 and P5 are excavated, and then blocks P2, P4 and P6 are excavated. (4) Adopt the partitioned asynchronous excavation process and adopt the "segmented skipping" sequence. First, start the construction of two central area blocks, and then adopt the "interval excavation" skipping sequence to excavate six peripheral area blocks: the first batch of blocks P2, P4 and P6 are excavated, and then blocks P1, P3 and P5 are excavated.

6. The construction method according to claim 1, characterized in that, After the bottom slab of the central area slab is poured, multiple stress relief joints are reserved on its surface and the joint width is monitored. After the joint width stabilizes, the side wall slabs are poured in layers.

7. The construction method according to claim 6, characterized in that, After all sub-blocks are constructed, secondary pouring is carried out at the connection points of each sub-block to enhance the interface rigidity of the bottom slab sub-blocks, side wall sub-blocks, and floor slab sub-blocks, forming a closed three-dimensional integral structure.

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