Evaluation method for surrounding building wall structure deformation caused by foundation pit excavation

Abstract

The invention discloses a method for evaluating surrounding building wall structure deformation caused by foundation pit excavation, which comprises the following steps of: determining foundation pit excavation process parameters and stratum soil mechanical parameters, and determining the size of a foundation pit and the distance between the edge of the foundation pit and a surrounding building; monitoring points are arranged, the deformation condition of wall structures of surrounding buildings is monitored in the foundation pit excavation process, and monitoring data are collected and statistically analyzed; the method comprises the following steps: performing simulation analysis on underground soil deformation caused in the excavation process of a foundation pit by adopting Plaxis finite element calculation software, simulating deformation of a wall structure of a building around the foundation pit due to excavation of the foundation pit, and generating simulation deformation data of a corresponding monitoring point; generating predicted deformation data of the next time or process node through Plaxis finite element calculation software on the basis of the actually measured deformation data of the current time or process node; and predicting and evaluating the deformation degree of the building wall structure according to the predicted deformation data. According to the method, the influence of foundation pit excavation on surrounding buildings is effectively evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of building safety monitoring, and particularly relates to an evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation. Background Art

[0002] At present, foundation pit excavation, as an important link in urban construction, its safety is directly related to the project quality and the stability of the surrounding environment. With the progress of new foundation pit excavation construction, the deformation problems of surrounding buildings have become increasingly prominent, and accurate prediction of the deformation of surrounding buildings has become crucial. Therefore, effective evaluation and monitoring of the deformation of surrounding buildings caused by foundation pit excavation are of great significance, not only for project quality monitoring, but also for ensuring the safety of buildings.

[0003] With the continuous upgrading of urban infrastructure and the construction of new buildings, the construction frequency of underground and ground projects in urban spaces has gradually increased, and excavation activities may affect surrounding buildings and public facilities. Surrounding buildings may deform and be damaged due to ground movement, resulting in problems such as the destruction of historical heritage, third-party impacts, construction delays, and increased project costs. Therefore, for the wall deformation problems of surrounding buildings caused by foundation pit excavation, it is necessary to evaluate and control them in a timely and effective manner to ensure the safety and stability of surrounding buildings. Summary of the Invention

[0004] The present invention provides an evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation to solve the technical problems existing in the known technology.

[0005] The technical solution adopted by the present invention to solve the technical problems existing in the known technology is as follows:

[0006] An evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation includes the following method steps:

[0007] Determine the foundation pit excavation process parameters and the soil mechanics parameters of the excavation stratum, and determine the size of the excavation foundation pit and the distance between the foundation pit edge and the surrounding buildings;

[0008] Set monitoring points, monitor the deformation of the wall structure of the surrounding buildings during the foundation pit excavation process, and collect and statistically analyze the monitoring data;

[0009] Use the Plaxis finite element calculation software to simulate and analyze the deformation of the underground soil body caused by the foundation pit excavation process, simulate the deformation of the wall structure of the surrounding buildings caused by the foundation pit excavation, and generate the simulated deformation data corresponding to the monitoring points;

[0010] The measured deformation data collected by the monitoring points are compared with the simulated deformation data generated for the corresponding monitoring points to obtain the prediction error and prediction accuracy. Based on the measured deformation data at the current time node or process node, the predicted deformation data for the next time node or process node are generated through the Plaxis finite element calculation software. The deformation degree of the surrounding building wall structure is predicted and evaluated according to the predicted deformation data.

[0011] Further, the predicted deformation data includes the slope deformation, inclination deformation, angular deformation, and lateral strain of the wall.

[0012] Further, according to the prediction and evaluation results of the deformation degree of the surrounding building wall structure, the deformation degree of the surrounding building wall structure is classified, and corresponding protection measures are taken according to the deformation degree level. The protection measures include controlling the construction sequence, timely supporting the internal bracing of the foundation pit, extending the grouting time, extending the foundation pit excavation time, increasing the bracing stiffness during the foundation pit support process, improving the hardening of the ground around the external buildings of the foundation pit, and strengthening the foundation of the surrounding buildings of the foundation pit by adding support piles and pouring concrete.

[0013] Further, the method for generating the simulated deformation data for the corresponding monitoring points includes the following method steps:

[0014] Using the Plaxis finite element calculation software, a three-dimensional finite element simulation of the foundation pit excavation and the working conditions of the surrounding buildings is carried out. The formation parameters, construction steps during the foundation pit excavation process, materials and specifications of the surrounding buildings of the foundation pit are input, and the settlement deformation data of the building wall structure of the corresponding monitoring points are output. The deformation data of the building wall structure includes the horizontal displacement, vertical deformation, and crack size of the wall.

[0015] Further, each building around the foundation pit is divided into multiple compartment units. By measuring the vertical displacement and horizontal displacement at the four corners of each compartment unit, the following deformations of each compartment unit are calculated: slope deformation, inclination deformation, angular deformation, and lateral strain. Among them:

[0016] The inclination deformation refers to the angular change of a building or a part of it relative to its original vertical position.

[0017] The slope refers to the angular change between a building or a part of it and the horizontal plane.

[0018] The angular deformation is the change in the angle formed between two adjacent components in a building. The angular deformation is also called three-dimensional shear deformation.

[0019] The lateral strain refers to the deformation or displacement that occurs in a building in the horizontal direction.

[0020] Further, each building around the foundation pit is divided into three compartment units.

[0021] Furthermore, monitoring points are set on the exterior wall of the building, load-bearing columns, and both sides of the deformation joints near the foundation pit of each compartment unit; each compartment unit is regarded as a cube, and monitoring points are set on the four sides of the compartment unit near the foundation pit, among which monitoring points are set at the four corner points of the compartment unit, and the number of monitoring points set on each side of the compartment unit is greater than 3.

[0022] Furthermore, let: the cross-section of the foundation pit be rectangular, and a certain building around the foundation pit is located on the long side of the cross-section of the foundation pit; the building around the foundation pit is divided into multiple compartment units; the eight corner points of any compartment unit are respectively named: A, B, C, D, E, F, G, H, where the plane formed by the four corner points A, B, C, and D is the front, which is perpendicular to the long side of the cross-section of the foundation pit; the plane formed by the four corner points C, D, H, and G is the top surface; the plane formed by the four corner points A, D, H, and E is the left surface; S is the slope of the compartment unit; T is the inclination of the compartment unit; β 3d is the three-dimensional shear deformation of the wall structure of the compartment unit;

[0023] Calculate S and T according to the following formula:

[0024]

[0025] Calculate β of the damage caused to the compartment unit during the excavation of the foundation pit according to the following formula 3d :

[0026]

[0027] In the formula:

[0028] A v is the vertical displacement value of the corner point A of the compartment unit;

[0029] B v is the vertical displacement value of the corner point B of the compartment unit;

[0030] E v is the vertical displacement value of the corner point E of the compartment unit;

[0031] F v is the vertical displacement value of the corner point F of the compartment unit;

[0032] A l is the horizontal displacement value of the corner point A of the compartment unit;

[0033] B l is the horizontal displacement value of the corner point B of the compartment unit;

[0034] C l is the horizontal displacement value of the corner point C of the compartment unit;

[0035] D lThe horizontal displacement value of point D, which is the corner point of the compartment unit;

[0036] E l The horizontal displacement value of point E, which is the corner point of the compartment unit;

[0037] F l The horizontal displacement value of point F, which is the corner point of the compartment unit;

[0038] G l The horizontal displacement value of point G, which is the corner point of the compartment unit;

[0039] H l The horizontal displacement value of point H, which is the corner point of the compartment unit;

[0040] L is the distance between the front and the back of the compartment unit;

[0041] d is the distance between the left and the right of the compartment unit;

[0042] h is the distance between the top and the bottom of the compartment unit.

[0043] Furthermore, the measuring device for monitoring the deformation of the wall structure of the buildings around the foundation pit during the foundation pit excavation process includes a level, a total station, and a caliper;

[0044] The total station is used to monitor the slope deformation, inclination deformation, angular deformation, and lateral strain of the wall of the buildings around the foundation pit;

[0045] The level is used to monitor the vertical displacement of the wall of the buildings around the foundation pit;

[0046] The caliper is used to measure the cracks of the building.

[0047] Furthermore, the monitoring points are set according to the technical specifications for the monitoring of building foundation pit engineering.

[0048] The advantages and positive effects of the present invention are:

[0049] The present invention aims to provide a comprehensive evaluation method for establishing guidelines for controlling building damage. By developing an evaluation method for the deformation of the wall structure of the surrounding buildings caused by the foundation pit excavation, modeling is carried out in combination with the cracks and deformations of the structure, and verification is carried out through the on-site data and the test data of the physical model. This method can not only effectively evaluate the impact of the foundation pit excavation on the surrounding buildings, but also provide a scientific basis for engineering monitoring and safety control, and ensure the safety and stability of the buildings and the surrounding environment.

[0050] The present invention provides a systematic and scientific evaluation method, which can effectively monitor and control the deformation of the wall structure of the buildings affected by the adjacent excavated foundation pit, and provides important technical support for the safety and sustainable development of urban construction. Description of the Drawings

[0051] Figure 1 It is the flowchart of the evaluation method for the deformation of the wall structure of the surrounding buildings caused by the foundation pit excavation in the present invention.

[0052] Figure 2 It is the schematic diagram of the three-section method evaluation and monitoring point positions of the wall of the building surrounding the foundation pit in the present invention.

[0053] Figure 3 It is the schematic diagram of the monitoring point positions setting of a compartment unit in the present invention.

[0054] In the figure: A, B, C, D, E, F, G, H are the eight corner point numbers of the compartment unit;

[0055] L is the distance between the front and the back of the compartment unit;

[0056] d is the distance between the left and the right of the compartment unit;

[0057] h is the distance between the top and the bottom of the compartment unit. Specific implementation manners

[0058] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0059] In the description of the present invention, the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component; it can also be an electrical connection or a signal transmission; for those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific situations.

[0060] Please refer to Figures 1 to 3 , an evaluation method for the deformation of the wall structure of the surrounding buildings caused by the foundation pit excavation, including the following method steps:

[0061] Determine the foundation pit excavation process parameters and the soil mechanics parameters of the excavated strata, and determine the size of the excavated foundation pit and the distance between the foundation pit edge and the surrounding buildings;

[0062] Set monitoring points, monitor the deformation of the wall structure of the surrounding buildings during the foundation pit excavation process, and collect and statistically analyze the monitoring data;

[0063] Using the Plaxis finite element calculation software, the deformation of the underground soil mass caused by the foundation pit excavation process is simulated and analyzed, the deformation of the wall structure of the surrounding buildings of the foundation pit generated by the foundation pit excavation is simulated, and the simulated deformation data of the corresponding monitoring points are generated;

[0064] The measured deformation data collected by the monitoring points are compared with the simulated deformation data generated by the corresponding monitoring points to obtain the prediction error and prediction accuracy; based on the measured deformation data at the current time node or process node, the predicted deformation data at the next time node or process node are generated through the Plaxis finite element calculation software; the deformation degree of the wall structure of the surrounding buildings is predicted and evaluated according to the predicted deformation data.

[0065] Preferably, the predicted deformation data may include the slope deformation, inclination deformation, angular deformation and lateral strain of the wall.

[0066] Preferably, according to the prediction and evaluation results of the deformation degree of the wall structure of the surrounding buildings, the deformation degree of the wall structure of the surrounding buildings can be classified, and corresponding protection measures can be taken according to the deformation degree level; the protection measures may include controlling the construction sequence, timely supporting the internal support of the foundation pit, extending the grouting time, extending the foundation pit excavation time, increasing the support stiffness during the foundation pit support process, improving the hardening of the ground around the external buildings of the foundation pit; strengthening the foundation of the surrounding buildings of the foundation pit by adding support piles and pouring concrete.

[0067] According to the prediction and evaluation results of the deformation degree of the building wall structure, the deformation degree of the wall structure of the surrounding buildings can be divided into three levels. Among them, the first-level deformation is small cracks that are easy to handle during normal decoration, slight damage: the cracks can be repaired through simple decoration, and the typical crack width is 0.1mm - 5mm. The damage is generally limited to the interior wall finish. Some cracks may be found outside the masonry upon careful inspection. The typical crack width can reach 1mm. The second-level deformation is slight damage: the cracks can be repaired through simple decoration, and the typical crack width is 0.1mm - 5mm. The cracks are easy to repair and may require secondary repair. The cracks that develop secondarily can be covered with a suitable lining. The typical crack width can reach 5mm. The third-level deformation is severe damage: the building needs major repairs or even reconstruction, the function is damaged, and the typical crack width is greater than 5mm. The building needs major repairs or even reconstruction, the doors and windows are severely deformed, the floor is significantly tilted, the load-bearing capacity of the beam decreases, and the pipes are broken. The typical crack width can reach more than 15mm.

[0068] Preferably, the method for generating the simulated deformation data of the corresponding monitoring points may include the following method steps:

[0069] The Plaxis finite element calculation software can be used to perform three-dimensional finite element simulations on the working conditions of foundation pit excavation and surrounding buildings. Input the formation parameters, construction steps during the foundation pit excavation process, materials and specifications of the surrounding buildings of the foundation pit, and output the settlement deformation data of the building wall structure at the corresponding monitoring points; the deformation data of the building wall structure includes the horizontal displacement, vertical deformation, and crack size of the wall.

[0070] The Plaxis finite element calculation software is a general geotechnical finite element calculation software launched by the Dutch company PLAXIS B.V. It is widely used in the finite element analysis of various complex geotechnical engineering projects, such as: the mutual influence between large foundation pits and the surrounding environment, the interaction between shield tunnel construction and existing surrounding buildings, the mutual influence between large pile raft foundations (bridge pile foundations) and adjacent foundation pits, the stress deformation analysis of sheet pile wharves, the influence of sudden rise and fall of reservoir water levels on dam stability, the consolidation and drainage analysis of soft soil foundations, the seepage analysis of foundation pit dewatering and full fluid-solid coupling analysis, the dynamic analysis of buildings under free vibration and seismic loads, the stability analysis of slopes after excavation and reinforcement, etc.

[0071] Preferably, each building around the foundation pit can be divided into multiple compartment units. By measuring the vertical and horizontal displacements at the four corners of each compartment unit, calculate the following deformations of each compartment unit: slope deformation, inclination deformation, angular deformation, and lateral strain; where:

[0072] The inclination deformation refers to the angular change of a building or a part of it relative to its original vertical position.

[0073] The slope refers to the angular change between a building or a part of it and the horizontal plane.

[0074] The angular deformation is the change in the angle formed between two adjacent components in a building; the angular deformation is also called three-dimensional shear deformation.

[0075] The lateral strain refers to the deformation or displacement that occurs in the horizontal direction of a building.

[0076] Preferably, each building around the foundation pit can be divided into three compartment units.

[0077] Preferably, monitoring points can be set on the exterior wall of the building, load-bearing columns, and both sides of the deformation joints on the side of each compartment unit close to the foundation pit; each compartment unit can be regarded as a cube, and monitoring points can be set on the four sides of the compartment unit on the side close to the foundation pit, where monitoring points are set at the four corner points of the compartment unit, and the number of monitoring points set on each side of the compartment unit is greater than 3.

[0078] Preferably, it can be set that: the cross-section of the foundation pit is rectangular, and a building around the foundation pit is located on one side of the long side of the cross-section of the foundation pit; the building around the foundation pit is divided into multiple compartment units; the eight corner points of any compartment unit are respectively named: A, B, C, D, E, F, G, H, where the plane formed by the four corner points A, B, C, and D is the front, which is perpendicular to the long side of the cross-section of the foundation pit; the plane formed by the four corner points E, F, G, and H is the back; the plane formed by the four corner points C, D, H, and G is the top surface; the plane formed by the four corner points A, B, F, and E is the bottom surface, the plane formed by the four corner points A, D, H, and E is the left surface; the plane formed by the four corner points B, C, G, and F is the right surface; S is the slope of the compartment unit; T is the inclination of the compartment unit; β 3d is the three-dimensional shear deformation of the wall structure of the compartment unit;

[0079] S and T can be calculated according to the following formula:

[0080]

[0081] β of the damage caused to the compartment unit during the foundation pit excavation process can be calculated according to the following formula 3d :

[0082]

[0083] In the formula:

[0084] A v is the vertical displacement value of the corner point A of the compartment unit;

[0085] B v is the vertical displacement value of the corner point B of the compartment unit;

[0086] E v is the vertical displacement value of the corner point E of the compartment unit;

[0087] F v is the vertical displacement value of the corner point F of the compartment unit;

[0088] A l is the horizontal displacement value of the corner point A of the compartment unit;

[0089] B l is the horizontal displacement value of the corner point B of the compartment unit;

[0090] C l is the horizontal displacement value of the corner point C of the compartment unit;

[0091] D l is the horizontal displacement value of the corner point D of the compartment unit;

[0092] E l is the horizontal displacement value of the corner point E of the compartment unit;

[0093] F l is the horizontal displacement value of the F point, which is the corner point of the compartment unit;

[0094] G l is the horizontal displacement value of the G point, which is the corner point of the compartment unit;

[0095] H l is the horizontal displacement value of the H point, which is the corner point of the compartment unit;

[0096] L is the distance between the front and the back of the compartment unit;

[0097] d is the distance between the left and the right of the compartment unit;

[0098] h is the distance between the top and the bottom of the compartment unit.

[0099] Preferably, the measuring device for monitoring the deformation of the wall structure of the building around the foundation pit during the foundation pit excavation process includes a level, a total station, and a caliper;

[0100] The total station is used to monitor the slope deformation, inclination deformation, angular deformation, and lateral strain of the wall of the building around the foundation pit;

[0101] The level is used to monitor the vertical displacement of the wall of the building around the foundation pit;

[0102] The caliper is used to measure the building cracks.

[0103] Preferably, the monitoring points are set according to the Technical Specification for Monitoring of Building Foundation Pit Engineering.

[0104] The following further illustrates the working process and working principle of the present invention with a preferred embodiment of the present invention:

[0105] An evaluation method for the deformation of the wall structure of the surrounding building caused by the foundation pit excavation includes the following steps:

[0106] Step 1: Determine the key parameters and observations. It is necessary to determine the foundation pit excavation process parameters and the soil mechanics parameters of the excavation stratum, as well as the distance and scope between the excavation foundation pit and the buildings around the foundation pit. At the same time, observe and record the crack deformation of the wall structure of the buildings around the foundation pit. Through the settlement values and deformation value data obtained by monitoring, conduct detailed analysis and statistics to understand the influence degree of the foundation pit excavation on the surrounding buildings.

[0107] First, after determining the foundation pit excavation area range, construction steps, and soil physics indexes, it is necessary to detect in detail the engineering status of the adjacent buildings before the foundation pit excavation. This includes obtaining information such as the load situation, crack deformation situation, and structural stability of the buildings around the foundation pit. Comprehensively understand the condition and damage situation of the buildings around the foundation pit.

[0108] Secondly, a number of monitoring points are set between the foundation pit support structure during excavation and the building wall around the foundation pit. These monitoring points should be arranged at the key corner points of the building wall to ensure the comprehensiveness and accuracy of monitoring. A settlement monitoring device and a horizontal deformation monitoring device are arranged at each monitoring point to monitor the deformation of the building wall in real time. By collecting the damage conditions of the building wall, its settlement and deformation data are obtained, and the deformation values of different monitoring points are statistically analyzed, which also provides important support for subsequent engineering monitoring and safety control.

[0109] Step 2: Analysis by Plaxis numerical simulation technology. Combining with Plaxis numerical simulation technology, the underground soil deformation that may be caused during the foundation pit excavation process is simulated and analyzed. Through numerical simulation, the influence degree of the foundation pit excavation on the building wall structure around can be predicted, and a quantitative basis can be provided. This step can help engineers more accurately evaluate the potential impact of the foundation pit excavation on the buildings around the foundation pit and provide a scientific basis for the formulation of subsequent control measures.

[0110] Using the Plaxis finite element calculation software, a three-dimensional model is established to calculate the ground settlement, and the underground soil deformation that may be caused during the foundation pit excavation process is accurately simulated and analyzed. Through modeling with the numerical simulation software, the influence degree of the foundation pit excavation on the building wall structure around is predicted, including the horizontal displacement, vertical deformation of the wall and the possible crack conditions; based on the numerical simulation results, a quantitative basis is provided to evaluate the safety and stability of the wall structure during the foundation pit excavation process.

[0111] According to the actual measurement data and numerical simulation results, combined with the structural characteristics of the building wall and the mechanical parameters of the underground soil, the influence of the foundation pit excavation on the wall structure is systematically analyzed. Specifically, it includes: a detailed analysis of the stress and deformation of the underground soil caused by the foundation pit excavation, especially its application in the water-rich soft stratum; according to the results of the Plaxis numerical simulation, quantitatively evaluate the deformation of the wall structure during the foundation pit excavation process and predict the possible maximum displacement and deformation amount;

[0112] Combined with the measured and simulated data, a comprehensive evaluation report on the deformation of the building wall structure is provided to provide a scientific basis for the construction supervision to take control measures in a timely manner.

[0113] Step 3: Three-section method evaluation of the building wall around the foundation pit. Based on the measured data and numerical simulation results, a three-section method evaluation of the building wall around the foundation pit is carried out.

[0114] The specific steps of the three-section method evaluation of the building wall are as follows:

[0115] The building structure around the foundation pit is divided into three compartment units, namely the first compartment unit, the second compartment unit, and the third compartment unit. The aim is to accurately calculate the deformation of each compartment unit, including important parameters such as slope deformation, inclination deformation, angular deformation, and lateral strain.

[0116] When conducting deformation monitoring, first set monitoring points on the retaining wall structure of the building around the foundation pit, and set monitoring equipment at the monitoring points to measure the vertical displacement (v) and horizontal displacement (l) of the four corners of each compartment unit. Please refer to Figure 2 、 Figure 3 , Figure 3 The compartment unit shown is Figure 2 the third compartment unit in the building around the foundation pit shown.

[0117] Taking the third compartment unit as an example, the eight corner points of the third compartment unit are respectively named A, B, C, D, E, F, G, H; among them, the plane formed by the four corner points A, B, C, D is the front, which is perpendicular to the long side of the cross-section of the foundation pit; the plane formed by the four corner points E, F, G, H is the back; the plane formed by the four corner points C, D, H, G is the top surface; the plane formed by the four corner points A, B, F, E is the bottom surface, the plane formed by the four corner points A, D, H, E is the left surface; the plane formed by the four corner points B, C, G, F is the right surface;

[0118] The monitoring points on the retaining wall are arranged at the parts where the stress and deformation are large and representative during the construction process. Monitoring points can be set at the eight corner points A, B, C, D, E, F, G, H of the third compartment unit respectively, and more than 3 monitoring points can be evenly distributed on each side of the retaining wall of the third compartment unit, and monitoring points are also set at the middle part of the retaining wall.

[0119] For example: Set 3 monitoring points on the sides AB and CD of the retaining wall of the three-compartment unit, set 4 monitoring points evenly on the sides BC and DA, let the midpoint of side AB be P and the midpoint of side CD be Q, and set 4 monitoring points evenly on the line connecting P and Q.

[0120] Let S be the slope of the compartment unit; T be the inclination of the compartment unit; β 3d be the three-dimensional shear deformation of the compartment unit wall structure;

[0121] S and T can be calculated according to the following formula:

[0122]

[0123] β that causes damage to the compartment unit during the foundation pit excavation process can be calculated according to the following formula 3d :

[0124]

[0125] A v is the vertical displacement value of corner point A of the compartment unit;

[0126] B v is the vertical displacement value of corner point B of the compartment unit;

[0127] E v is the vertical displacement value of corner point E of the compartment unit;

[0128] F v is the vertical displacement value of corner point F of the compartment unit;

[0129] A l is the horizontal displacement value of point A of corner point of the compartment unit;

[0130] B l is the horizontal displacement value of point B of corner point of the compartment unit;

[0131] C l is the horizontal displacement value of point C of corner point of the compartment unit;

[0132] D l is the horizontal displacement value of point D of corner point of the compartment unit;

[0133] E l is the horizontal displacement value of point E of corner point of the compartment unit;

[0134] F l is the horizontal displacement value of point F of corner point of the compartment unit;

[0135] G l is the horizontal displacement value of point G of corner point of the compartment unit;

[0136] H l is the horizontal displacement value of point H of corner point of the compartment unit;

[0137] L is the distance between the front and the back of the compartment unit;

[0138] d is the distance between the left and the right of the compartment unit;

[0139] h is the distance between the top and the bottom of the compartment unit.

[0140] In order to effectively determine the deformation of the structure during the foundation pit excavation, and at the same time, to comprehensively evaluate the influence of the foundation pit excavation on the buildings around the foundation pit, a set of identical measuring points are arranged along the direction of the foundation pit edge for systematic three-dimensional monitoring.

[0141] Calculate S and T that affect the structure of the buildings around the foundation pit, and obtain the three-dimensional shear deformation of the influence and damage of the foundation pit excavation on the buildings around the foundation pit.

[0142] The inclination deformation is the rigid body rotation of the cross-section of the compartment unit; the slope deformation is the change in the distance between the front and the back of the compartment unit; the angular deformation (β 3d ) is the shear deformation of the cross-section of the compartment unit; the top lateral strain is the change in the horizontal displacement of the top of the compartment unit, that is, the change in the side lengths of side DH and side CG; the bottom lateral strain is the change in the horizontal displacement of the bottom of the compartment unit, that is, the change in the side lengths of side BF and side AE.

[0143] Based on the damage criterion of the strain state theory, the average strain state of the building unit is evaluated. The average strain state of the wall structure of the building unit can be evaluated. The ground motion is applied to the foundation of the building unit structure, generating lateral strain and angular deformation or shear strain. The building unit structure includes the connecting wall structure between two building units, the support columns within the building unit, and the enclosure wall; the ground motion is applied to two different building geometries or stiffnesses, or two different ground displacement gradients, also generating lateral strain and angular deformation or shear strain. Since the ground motion is applied to the bottom of the structure, the lateral strain generated by the applied horizontal displacement is the largest near the bottom of the structure.

[0144] By analyzing the deformation data of each compartment unit, a three-dimensional impact analysis of the excavation of the foundation pit on the surrounding buildings can be obtained. This includes a comprehensive understanding of the deformation degree and change trend of the buildings in different directions, thus providing a scientific basis for subsequent engineering decisions. In addition, the monitored data can also be used to evaluate the impact of the foundation pit excavation on the building safety, ensuring the smooth progress of the project.

[0145] By comprehensively evaluating the deformation of the wall structure, including angular deformation, lateral strain, etc., potential problems can be discovered in a timely manner and corresponding control measures can be taken to ensure the safety and stability of the building structure. This step provides an important basis for engineering monitoring and safety control, ensuring that the surrounding buildings are not damaged during the foundation pit excavation process.

[0146] To obtain the actual measured deformation data of the buildings around the foundation pit, the following measuring devices are used: level, total station, caliper.

[0147] According to the technical specification for building foundation pit engineering monitoring, the monitoring points can be set according to the following method steps:

[0148] The monitoring points of the buildings around the foundation pit are set on the retaining wall, with no less than 3 points on each side of the building. Measuring points need to be set at the midpoints of the short sides of the square foundation pit and at the external corners of the foundation pit. For the settlement and inclination monitoring of the buildings around the foundation pit, no less than 3 measuring points should be set on each side at the four corners of the buildings around the foundation pit, every 10 - 15 m along the retaining wall or on every 2 - 3 column bases; at the boundaries of different foundations or bases, structures; on both sides of the deformation joints, seismic joints or severely cracked areas; on both sides at the junctions of new and old buildings or high and low buildings; at the symmetric parts of the foundation axes of high-rise structures, with no less than 6 points for each structure. The horizontal displacement monitoring of the buildings should be arranged on the external walls, load-bearing columns, both sides of the deformation joints and other representative parts of the buildings on the side adjacent to the foundation pit or tunnel. And it can be arranged at the same position as the vertical displacement monitoring points of the buildings. For the monitoring of the building cracks, calipers should be used and representative cracks should be selected for arrangement. When the original cracks increase or new cracks appear, additional monitoring points should be set in time. No less than 2 monitoring points should be set for each crack, and they should preferably be set at the widest part and the ends of the cracks. By processing the monitoring data, the data is statistically analyzed and reports are generated.

[0149] Combined with the measured deformation data collected by the monitoring points and the corresponding simulated deformation data, the three-dimensional shear deformation data of each compartment unit is calculated, and based on the calculated data, the deformation degree of the wall structure of the entire building is predicted and evaluated.

[0150] Calculate the three-dimensional shear deformation data of each compartment unit, and based on the calculated data, predict and evaluate the deformation degree of the wall structure of the entire building.

[0151] The above-mentioned level, total station, and caliper can adopt applicable devices and equipment in the existing technology.

[0152] The above-described embodiments are only used to illustrate the technical ideas and characteristics of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The patent scope of the present invention cannot be limited only by these embodiments, that is, all equivalent changes or modifications made in accordance with the spirit disclosed by the present invention still fall within the patent scope of the present invention.

Claims

1. An evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation, characterized in that, The method steps include the following: Determine the excavation process parameters of the foundation pit and the soil mechanics parameters of the excavated strata, and determine the size of the excavated foundation pit and the distance between the foundation pit edge and the surrounding buildings. Set up monitoring points, monitor the deformation of the wall structure of the surrounding buildings during the foundation pit excavation process, and collect and statistically analyze the monitoring data. Use the Plaxis finite element calculation software to simulate and analyze the deformation of the underground soil caused during the foundation pit excavation process, simulate the deformation of the wall structure of the surrounding buildings due to the foundation pit excavation, and generate the simulated deformation data corresponding to the monitoring points. Compare the measured deformation data collected by the monitoring points with the simulated deformation data generated for the corresponding monitoring points to obtain the prediction error and prediction accuracy; based on the measured deformation data at the current time node or process node, generate the predicted deformation data for the next time node or process node through the Plaxis finite element calculation software; predict and evaluate the deformation degree of the wall structure of the surrounding buildings according to the predicted deformation data.

2. The assessment method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation according to claim 1, characterized in that, The predicted deformation data includes slope deformation, inclination deformation, angular deformation, and lateral strain of the wall.

3. The evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation according to claim 1, characterized in that According to the prediction and evaluation results of the deformation degree of the wall structure of the surrounding buildings, classify the deformation degree of the wall structure of the surrounding buildings, and take corresponding protection measures according to the deformation degree level; the protection measures include controlling the construction sequence, timely supporting the internal support of the foundation pit, extending the grouting time, extending the foundation pit excavation time, increasing the support stiffness during the foundation pit support process, improving and hardening the ground around the external buildings of the foundation pit; strengthening the foundation of the surrounding buildings of the foundation pit by adding support piles and pouring concrete.

4. The evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation according to claim 1, characterized in that, The method for generating the simulated deformation data corresponding to the monitoring points includes the following method steps: Use the Plaxis finite element calculation software to perform three-dimensional finite element simulation on the working conditions of the foundation pit excavation and the surrounding buildings, input the formation parameters, construction steps during the foundation pit excavation process, materials and specifications of the surrounding buildings of the foundation pit, and output the settlement deformation data of the wall structure of the buildings corresponding to the monitoring points; the deformation data of the wall structure of the buildings includes the horizontal displacement, vertical deformation, and crack size of the wall.

5. The evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation according to claim 1, characterized in that, Divide each building around the foundation pit into multiple compartment units, and calculate the following deformations of each compartment unit by measuring the vertical and horizontal displacements at the four corners of each compartment unit: slope deformation, inclination deformation, angular deformation, and lateral strain; where: Inclination deformation refers to the angular change of a building or a part of it relative to its original vertical position. Slope refers to the angular change between a building or a part of it and the horizontal plane. Angular deformation is the change in the angle formed between two adjacent components in a building; angular deformation is also called three-dimensional shear deformation. Lateral strain refers to the deformation or displacement that occurs in the horizontal direction of a building.

6. The evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation according to claim 5, wherein, Divide each building around the foundation pit into three compartment units.

7. The evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation according to claim 6, characterized in that, Set up monitoring points on the external wall of the building, load-bearing columns, and both sides of the deformation joints on the side of each compartment unit close to the foundation pit; regard each compartment unit as a cube, and set up monitoring points on the four sides of the compartment unit on the side close to the foundation pit, where monitoring points are set at the four corner points of the compartment unit, and the number of monitoring points set on each side of the compartment unit is greater than 3.

8. The evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation according to claim 5, characterized in that: The cross-section of the foundation pit is rectangular, and some buildings around the foundation pit are located on one side of the long side of the cross-section of the foundation pit; the buildings around the foundation pit are divided into multiple compartment units; the eight corner points of any compartment unit are respectively named as: A, B, C, D, E, F, G, H, where the plane formed by the four corner points A, B, C, and D is the front, which is perpendicular to the long side of the cross-section of the foundation pit; the plane formed by the four corner points C, D, H, and G is the top surface; the plane formed by the four corner points A, D, H, and E is the left surface; S is the slope of the compartment unit; T is the inclination of the compartment unit; β 3d is the three-dimensional shear deformation of the wall structure of the compartment unit; Calculate S and T according to the following formula: or Calculate β which represents the damage to the compartment unit during the foundation pit excavation process according to the following formula 3d :[[]]END]] In the formula: A v is the vertical displacement value of the corner point A of the compartment unit; B v is the vertical displacement value of the corner point B of the compartment unit; E v is the vertical displacement value of the corner point E of the compartment unit; F v is the vertical displacement value of the corner point F of the compartment unit; A l The horizontal displacement value of corner point A of the compartment unit; B l The horizontal displacement value of corner point B of the compartment unit; C l is the horizontal displacement value of the corner point C of the compartment unit; D l The horizontal displacement value of the corner point D of the compartment unit; E l is the horizontal displacement value of the corner point E of the compartment unit; F l is the horizontal displacement value of the F point, which is the corner point of the compartment unit; G l is the horizontal displacement value of the G point, which is the corner point of the compartment unit; H l The horizontal displacement value of the corner point H of the compartment unit; L is the distance between the front and the back of the compartment unit; d is the distance between the left and the right of the compartment unit; h is the distance between the top and the bottom of the compartment unit.

9. The evaluation method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation according to claim 1, wherein The measuring device for monitoring the deformation of the wall structure of the buildings around the foundation pit during the foundation pit excavation process includes a level, a total station, and a caliper; The total station is used to monitor the slope deformation, inclination deformation, angular deformation, and lateral strain of the wall of the buildings around the foundation pit; The level is used to monitor the vertical displacement of the wall of the buildings around the foundation pit; The caliper is used to measure the building cracks.

10. The assessment method for the deformation of the wall structure of surrounding buildings caused by foundation pit excavation according to claim 1, characterized in that Monitoring points are set according to the Technical Code for Monitoring of Building Foundation Pit Engineering.

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