A safety analysis method for deep foundation pits

Abstract

The present invention discloses a method for safety analysis of deep foundation pits, which relates to the technical field of safety analysis of deep foundation pits and includes the following analysis steps: outputting the comprehensive stress state value, risk level assessment value, and safety level of the deep foundation pit through a calculation and analysis module. The present invention comprehensively considers multiple factors such as the normal stress and shear stress of the deep foundation pit in the x and y directions and the current elastic modulus of the supporting material, realizing a comprehensive and accurate assessment of the comprehensive stress state of the deep foundation pit. And based on the comprehensive stress state value of the foundation pit, the geological condition score, and the strength of the supporting structure, a comprehensive and systematic assessment of the risk level of the deep foundation pit is realized. In addition, by comprehensively considering multiple risk thresholds, an accurate determination and early warning of the safety level of the deep foundation pit are realized. When the stress state or risk level of the deep foundation pit exceeds the risk threshold, the system can automatically send out an early warning signal to remind the construction personnel to take measures in time for intervention and adjustment, making the overall safety analysis of the deep foundation pit more intelligent and timely.

Description

Technical Field

[0001] The present invention relates to the technical field of deep foundation pit safety analysis, and specifically provides a deep foundation pit safety analysis method. Background Art

[0002] In the process of urbanization, as an important part of large-scale construction projects, the safety of deep foundation pit projects is directly related to the quality of the entire project and the safety of personnel. However, the construction environment of deep foundation pits is complex and changeable, with various factors such as geological conditions, groundwater levels, and construction techniques intertwined, making the safety assessment of deep foundation pits face huge challenges.

[0003] Currently, existing deep foundation pit safety analysis methods may rely on a single normal stress or shear stress index for the comprehensive stress state assessment of deep foundation pits, ignoring the complexity and multi-dimensionality of the stress state. As a result, the assessment results may not be accurate enough, making it difficult to comprehensively reflect the stress state of deep foundation pits. In addition, for the risk assessment of deep foundation pits, only single factors such as geological conditions or the strength of the support structure may be considered, ignoring other possible influencing factors such as groundwater and construction techniques. This leads to incomplete assessment results and makes it difficult to accurately reflect the risk level of deep foundation pits. Moreover, in the existing technology, the determination of the safety level of deep foundation pits often relies on empirical judgment and simple threshold comparison, lacking scientificity and accuracy. As a result, the determination results of the safety level may not be reliable enough, making it difficult to effectively guide the safety management of deep foundation pit construction. Summary of the Invention

[0004] The purpose of the present invention is to provide a deep foundation pit safety analysis method to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A deep foundation pit safety analysis method includes the following analysis steps:

[0006] Step I: Collect the stress values, geological condition information, and support structure strength inside the deep foundation pit through a data acquisition module, and input the collected data into a data processing module;

[0007] Step II: Organize and clean the stress values, geological condition information, and support structure strength inside the deep foundation pit through the data processing module, and output the normal stress SVA in the x direction of the deep foundation pit, the normal stress SVB in the y direction of the deep foundation pit, the shear stress Sxy in the x and y directions of the deep foundation pit, and the strength DDA of the support structure;

[0008] Step III: Input the normal stress SVA in the x direction of the deep foundation pit, the normal stress SVB in the y direction of the deep foundation pit, the shear stress Sxy in the x and y directions of the deep foundation pit, and the strength DDA of the support structure into a calculation and analysis module, and output the comprehensive stress state value SVOP, the risk level assessment value ROPF, and the safety level of the deep foundation pit;

[0009] Step Ⅳ: Input the comprehensive stress state value SVOP, risk level assessment value ROPF, and safety level of the deep foundation pit into the safety measure module. The safety measure module implements safety measures based on the safety level. Then, after taking the safety measures, continue to monitor the deep foundation pit, and adjust the safety measures in a timely manner according to the monitoring results and changes in the safety level.

[0010] Optionally, the calculation and analysis module includes: a stress state comprehensive sub-module, a risk assessment sub-module, and a foundation pit safety level sub-module.

[0011] Optionally, the calculation formula of the stress state comprehensive sub-module is as follows:

[0012] ;

[0013] Where:

[0014] SVOP refers to the comprehensive stress state value of the deep foundation pit;

[0015] SVA refers to the normal stress of the deep foundation pit in the x direction, SVAA refers to the stress reference value, SVM refers to the ideal maximum normal stress, representing the maximum normal stress that the foundation pit bears under the most unfavorable conditions, SVB refers to the normal stress of the deep foundation pit in the y direction, Sxy refers to the shear stress of the deep foundation pit in the x and y directions, SP refers to the ideal maximum shear stress, representing the maximum shear stress that the foundation pit bears under the most unfavorable conditions, A1 refers to the influence constant related to the properties of the foundation pit support material, E refers to the current elastic modulus of the foundation pit support material, representing the stiffness of the material, that is, the ability of the material to resist deformation in the elastic deformation stage, EA refers to the reference elastic modulus, and SVA - SVAA refers to the deviation degree of the stress received by the deep foundation pit in the x direction relative to the reference value;

[0016] The processing process of the stress state comprehensive sub-module is as follows: Input the normal stress SVA of the deep foundation pit in the x direction, the normal stress SVB of the deep foundation pit in the y direction, and the shear stress Sxy of the deep foundation pit in the x and y directions into the stress state comprehensive sub-module, and output the comprehensive stress state value SVOP of the deep foundation pit based on the stress reference value SVAA and the ideal maximum normal stress SVM.

[0017] Optionally, the calculation formula of the risk assessment sub-module is as follows:

[0018] ;

[0019] Where:

[0020] ROPF refers to the risk level assessment value;

[0021] RA refers to the weight coefficient of SVOP, RB refers to the weight coefficient of GGA, GGA refers to the geological condition score, GGAM refers to the maximum value of the geological condition score, RC refers to the weight coefficient of DDA, DDA refers to the strength of the support structure, DP refers to the reference value of the support structure strength, and GGA / GGAM refers to the ratio of the geological condition score to the maximum score;

[0022] The processing process of the risk assessment sub-module is as follows: Input the comprehensive stress state value SVOP of the deep foundation pit and the strength DDA of the support structure into the risk assessment sub-module, and output the risk level assessment value ROPF based on the geological condition score GGA and the reference value DP of the support structure strength.

[0023] Optionally, the calculation formula of the foundation pit safety level sub-module is as follows:

[0024] Safety level ;

[0025] Where:

[0026] ROAA refers to the first risk threshold with a value of 0.4, indicating that the critical value of a lower risk level is considered that the safety risk is controllable if it is lower than this value;

[0027] ROBB refers to the second risk threshold with a value of 0.75;

[0028] SVBB refers to the comprehensive stress state critical threshold with a value of 0.65, indicating that when the comprehensive stress state exceeds

[0029] this value, special attention needs to be paid to the stability of the deep foundation pit;

[0030] The processing process of the foundation pit safety level sub-module is as follows: Input the comprehensive stress state value SVOP of the deep foundation pit and the risk level assessment value ROPF into the foundation pit safety level sub-module, and output Safety Level 1, Safety Level 2, and Safety Level 3 based on the first risk threshold ROAA, the second risk threshold ROBB, and the comprehensive stress state critical threshold SVBB.

[0031] Optionally, the safety measure module is specifically:

[0032] When it is in Safety Level 1, the deep foundation pit is in a low-risk state;

[0033] Treatment measures: Continue according to the normal construction plan, but regular monitoring and inspection of the stability of the deep foundation pit need to be maintained;

[0034] When it is in Safety Level 2, the deep foundation pit is in a medium-risk state;

[0035] Treatment measures: Take additional monitoring and preventive measures, that is, increase the number of monitoring points to improve the monitoring frequency, strengthen the inspection and maintenance of the support structure, and at the same time adjust the construction plan to reduce the impact on the stability of the deep foundation pit;

[0036] When the safety level is 3, the deep foundation pit is in a high-risk state;

[0037] Treatment measures: Immediately stop the construction activities and conduct a comprehensive safety assessment, take emergency support measures, that is, increase the temporary support structure or reinforce the existing support structure, organize an expert team to conduct a consultation to formulate a detailed safety treatment plan, and ensure that all construction personnel understand and abide by the relevant safety regulations.

[0038] Optionally, the data acquisition module uses stress sensors, geological exploration equipment, and support structure strength testing equipment;

[0039] The geological exploration equipment is specifically a ground penetrating radar and drilling equipment, which is used to analyze the geological conditions to evaluate the geological condition score;

[0040] The support structure strength testing equipment is specifically a pressure sensor and a tensile testing machine, which is used to measure the support structure to output the strength DDA of the support structure.

[0041] Optionally, the stress sensors are installed on the side wall and bottom of the deep foundation pit, and the normal stress and shear stress in the x and y directions of the deep foundation pit are measured through the stress sensors.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] First, the present invention outputs the comprehensive stress state value of the deep foundation pit through the comprehensive stress state sub-module. This sub-module comprehensively considers the normal stress, shear stress, maximum normal stress, and maximum shear stress in the x and y directions of the deep foundation pit, and combines the ratio of the current elastic modulus to the reference elastic modulus to evaluate the comprehensive stress state of the deep foundation pit. This sub-module can comprehensively reflect the stress state of the deep foundation pit, and considering the change of the elastic modulus makes the evaluation result more accurate. The calculation of the comprehensive stress state value of the deep foundation pit provides intuitive data on the stress state of the deep foundation pit, which helps to judge whether it is within the safe range. The change trend of SVOP can predict the change of the stress state of the deep foundation pit, providing a basis for subsequent preventive measures.

[0044] II. The risk assessment sub-module of the present invention outputs a risk level assessment value. This sub-module quantitatively assesses the risk level of the deep foundation pit by combining the comprehensive stress state, geological conditions, support structure strength, and other influencing factors. This sub-module covers multiple influencing factors, making the assessment results more comprehensive. Quantitatively assessing the risk level of the deep foundation pit provides a clear risk reminder for decision-makers. Potential safety hazards can be detected in a timely manner through the change of the risk level assessment value to avoid accidents, and more reasonable risk management measures can be formulated by combining historical data and experience.

[0045] III. The present invention outputs three safety levels through the foundation pit safety level sub-module. The foundation pit safety level sub-module and the safety measure module cooperate with each other to determine the safety level of the deep foundation pit and make early warning measures in a timely manner based on the comprehensive stress state value and the risk level assessment value of the deep foundation pit. This method can intuitively reflect the safety status of the deep foundation pit and provide clear guidance for decision-makers. When the safety level is low, measures such as strengthening support and adjusting the construction plan are taken to improve safety. When the safety level is high, it is necessary to closely monitor the changes in the deep foundation pit and take timely measures to prevent accidents.

[0046] IV. The present invention iterates the stress reference value in the comprehensive stress state sub-module through the risk level assessment value, enabling continuous cyclic iteration and optimization of the comprehensive stress state value and the risk level assessment value of the deep foundation pit. By iterating and adjusting the stress reference value through the risk level assessment value, a dynamic adjustment and feedback mechanism is established. As the construction of the deep foundation pit progresses and the geological conditions change, the risk level will be updated in real time and the value of the stress reference value will be adjusted accordingly to ensure the accuracy and timeliness of the safety assessment. This iterative form updates the risk level assessment value in real time and adjusts the value of the stress reference value accordingly, which can detect potential safety hazards in a timely manner and take corresponding early warning and prevention and control measures to avoid accidents. The iterative analysis results provide an important basis for construction decision-making, such as determining a reasonable excavation sequence, support timing, and monitoring frequency, etc., to ensure the smooth progress of the construction process. Compared with the existing methods, this iterative method not only considers the stress state of the deep foundation pit. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is the step flow chart of this deep foundation pit safety analysis method;

[0048] Figure 2 is the overall structure schematic diagram of this deep foundation pit safety analysis method;

[0049] Figure 3 is the structure schematic diagram of the calculation and analysis module of this deep foundation pit safety analysis method. DETAILED DESCRIPTION OF THE INVENTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] Regarding this deep foundation pit safety analysis method, it is different from the existing deep foundation pit safety analysis methods. In the existing safety analysis methods, the comprehensive stress state assessment of deep foundation pits often relies on a single normal stress or shear stress index, ignoring the complexity and multi-dimensionality of the stress state. This results in inaccurate assessment results and it is difficult to comprehensively reflect the stress state of deep foundation pits. Moreover, for the risk assessment of deep foundation pits, only single factors such as geological conditions may be considered, ignoring other possible influencing factors. This leads to incomplete assessment results and it is difficult to accurately reflect the risk level of deep foundation pits. Additionally, the determination of the safety level of deep foundation pits often relies on empirical judgment or simple threshold comparison, lacking scientificity and accuracy. This causes the safety level determination results to be unreliable and it is difficult to effectively guide the safety management of deep foundation pit construction.

[0052] However, the modules of this deep foundation pit safety analysis system method comprehensively consider multiple factors such as the normal stress, shear stress, maximum normal stress, maximum shear stress, and current elastic modulus of the deep foundation pit in the x and y directions, achieving a comprehensive assessment of the comprehensive stress state of the deep foundation pit. And this method comprehensively considers factors such as the comprehensive stress state, geological condition score, and support structure strength, achieving a comprehensive assessment of the risk level of the deep foundation pit. This method comprehensively considers the risk level and comprehensive stress state, as well as multiple thresholds and warning function values, achieving an accurate determination and warning of the safety level of the deep foundation pit.

[0053] Embodiment 1, please refer to Figures 1 to 3 , this embodiment provides a deep foundation pit safety analysis method, including the following analysis steps:

[0054] Step I: Collect the stress values, geological condition information, and support structure strength inside the deep foundation pit through the data acquisition module, and input the collected data into the data processing module;

[0055] Step II: Organize and clean the stress values, geological condition information, and support structure strength inside the deep foundation pit through the data processing module, and output the normal stress SVA of the deep foundation pit in the x direction, the normal stress SVB of the deep foundation pit in the y direction, the shear stress Sxy of the deep foundation pit in the x and y directions, and the strength DDA of the support structure.

[0056] Step Ⅲ: Through the calculation and analysis module, the normal stress SVA of the deep foundation pit in the x-direction, the normal stress SVB of the deep foundation pit in the y-direction, the shear stress Sxy of the deep foundation pit in the x and y directions, and the strength DDA of the supporting structure are used to output the comprehensive stress state value SVOP of the deep foundation pit, the risk level assessment value ROPF, and the safety level.

[0057] Step Ⅳ: The comprehensive stress state value SVOP, the risk level assessment value ROPF, and the safety level of the deep foundation pit are input into the safety measure module. The safety measure module implements safety measures corresponding to the safety level. Then, after taking the safety measures, the deep foundation pit is continuously monitored, and the safety measures are adjusted in a timely manner according to the monitoring results and the changes in the safety level.

[0058] The calculation and analysis module includes: a stress state comprehensive sub-module, a risk assessment sub-module, and a foundation pit safety level sub-module.

[0059] In this embodiment: Multiple sub-modules in this calculation and analysis module are interrelated and complementary in the safety analysis of the deep foundation pit. The comprehensive stress state SVOP obtained by the operation of the stress state comprehensive sub-module is one of the inputs of the risk assessment sub-module. The risk level ROPF calculated by the risk assessment sub-module and the SVOP calculated by the stress state comprehensive sub-module are jointly used as the inputs of the foundation pit safety level sub-module to finally determine the safety level of the deep foundation pit or issue a warning. Computer-aided analysis can integrate and manage the input data required by the three groups of sub-modules to ensure the accuracy and consistency of the data. By real-time monitoring and recording various data of the deep foundation pit, reliable data support is provided for the calculation of multiple sub-modules. Computer-aided analysis can achieve visual display of the data, making the evaluation results more intuitive and easy to understand, facilitating decision-makers to make quick judgments. Combining the calculation results of multiple sub-modules and the actual situation, scientific decision-making support is provided for decision-makers to ensure the safe construction of the deep foundation pit. Multiple groups of sub-modules comprehensively consider the stress state, geological conditions, supporting structure strength, and other influencing factors of the deep foundation pit, making the evaluation results more comprehensive and accurate. By setting multiple risk thresholds, the three groups of sub-modules can achieve refined evaluation of the safety status of the deep foundation pit, improving the accuracy and timeliness of early warning. With the help of computer-aided analysis, rapid calculation and data visual display of the three groups of sub-modules can be achieved, improving the evaluation efficiency and accuracy, and reducing the cost of manual calculation and data processing. The three groups of sub-modules have high flexibility and adaptability and can be adjusted and optimized according to the actual situation to meet the safety analysis needs of different deep foundation pits.

[0060] Please refer to Figures 1 to 3 , the processing process of the stress state comprehensive sub-module is as follows:

[0061] ;

[0062] Among them:

[0063] SVOP refers to the comprehensive stress state value of the deep foundation pit;

[0064] SVA refers to the normal stress in the x - direction of the deep foundation pit, SVAA refers to the stress reference value, SVM refers to the ideal maximum normal stress, representing the maximum normal stress that the foundation pit bears under the most unfavorable conditions, SVB refers to the normal stress in the y - direction of the deep foundation pit, Sxy refers to the shear stress in the x and y directions of the deep foundation pit, SP refers to the ideal maximum shear stress, representing the maximum shear stress that the foundation pit bears under the most unfavorable conditions, A1 refers to the influence constant related to the properties of the foundation pit support material, E refers to the current elastic modulus of the foundation pit support material, representing the stiffness of the material, that is, the ability of the material to resist deformation in the elastic deformation stage, EA refers to the reference elastic modulus, and SVA - SVAA refers to the deviation degree of the stress in the x - direction of the deep foundation pit relative to the reference value;

[0065] The processing process of the stress state comprehensive sub - module is as follows: Input the normal stress SVA in the x - direction of the deep foundation pit, the normal stress SVB in the y - direction of the deep foundation pit, and the shear stress Sxy in the x and y directions of the deep foundation pit into the stress state comprehensive sub - module, and output the comprehensive stress state value SVOP of the deep foundation pit based on the stress reference value SVAA and the ideal maximum normal stress SVM.

[0066] In this embodiment: The support structure of the deep foundation pit is usually composed of multiple materials. Steel: Used to make support beams, sheet piles and other support structures, with an elastic modulus of 200 - 210 GPa; Concrete: Used to make diaphragm walls, internal supports, etc., with an elastic modulus of 20 - 30 GPa; Soil: Natural soil or backfill soil around the deep foundation pit;

[0067] This sub - module evaluates the comprehensive stress state of the deep foundation pit by comprehensively considering the normal stress, shear stress in the x and y directions of the deep foundation pit, as well as the reference stress value, maximum normal stress and maximum shear stress, and combining the ratio of the current elastic modulus to the reference elastic modulus. This sub - module comprehensively reflects the stress state of the deep foundation pit, and takes into account the change of the elastic modulus, making the evaluation result more accurate. The calculation of SVOP provides intuitive data on the stress state of the deep foundation pit, which helps to judge whether it is within the safe range. Through the change trend of SVOP, the stress state change of the deep foundation pit can be predicted, providing a basis for taking preventive measures.

[0068] Please refer to Figures 1 to 3 , the processing process of the risk assessment sub - module is as follows:

[0069] ;

[0070] Among them:

[0071] ROPF refers to the risk level assessment value;

[0072] RA refers to the weight coefficient of SVOP, RB refers to the weight coefficient of GGA, GGA refers to the geological condition score, GGAM refers to the maximum value of the geological condition score, RC refers to the weight coefficient of DDA, DDA refers to the strength of the support structure, DP refers to the reference value of the support structure strength, and GGA / GGAM refers to the ratio of the geological condition score to the maximum score;

[0073] The processing process of the risk assessment sub-module is as follows: Input the comprehensive stress state value SVOP of the deep foundation pit and the strength DDA of the support structure into the risk assessment sub-module, and output the risk level assessment value ROPF based on the geological condition score GGA and the reference value DP of the support structure strength.

[0074] In this embodiment: For the geological condition score GGA, this score is a comprehensive evaluation index used to quantify the impact of the geological conditions in the area of the deep foundation pit on construction safety. The scoring criteria can be set based on multiple geological factors, such as soil layer stability, rock layer distribution, groundwater level, and adverse geological phenomena, etc. The specific analysis is as follows:

[0075] Soil layer stability: Evaluate the stability of the soil layer according to parameters such as the type, thickness, unit weight, internal friction angle, and cohesion of the soil layer. The higher the stability, the higher the score, and the scoring range is 0 - 20 points;

[0076] Rock layer distribution: Evaluate the type, hardness, integrity of the rock layer, and the interaction between the rock layer and the soil layer. The harder and more complete the rock layer, the higher the score, and the scoring range is 0 - 30 points;

[0077] Groundwater level: Evaluate the depth, change range of the groundwater level, and its impact on construction. The lower the groundwater level and the smaller the change, the higher the score, and the scoring range is 0 - 20 points;

[0078] Adverse geological phenomena: Evaluate whether there are adverse geological phenomena such as landslides, mudslides, karst caves, etc., and the potential threats of these phenomena to construction safety. The absence of adverse geological phenomena or smaller threats results in a higher score, and the scoring range is 0 - 30 points;

[0079] In summary, the geological condition score GGA is the sum of the scores of each factor, that is:

[0080] GGA = soil layer stability score + rock layer distribution score + groundwater level score + adverse geological phenomenon score;

[0081] This sub-module quantifies the risk level of deep foundation pits by combining the comprehensive stress state, geological conditions, support structure strength, and other influencing factors. This sub-module covers a variety of influencing factors, making the evaluation results more comprehensive, quantifying the risk level of deep foundation pit evaluation, providing clear risk warnings for decision-makers. Through the change of ROPF, potential safety hazards can be detected in a timely manner to avoid accidents. Moreover, by combining historical data and experience, more reasonable risk management measures can be formulated;

[0082] It should be noted that based on the risk level evaluation value ROPF, the stress reference value SVAA in the comprehensive stress state sub-module is iterated, so that the comprehensive stress state value SVOP and the risk level evaluation value ROPF of the deep foundation pit are continuously cycled and iterated for optimization, thereby improving the accuracy of the overall calculation and analysis. The processing process is as follows:

[0083] First: ;

[0084] Secondly: Set the iteration termination conditions:

[0085] Termination condition 1: The number of iterations is 100 times;

[0086] Termination condition 2: |SVAA new -SVAA old |<0.001;

[0087] Among them:

[0088] SVAAnew refers to the updated stress reference value;

[0089] SVAAold refers to the stress reference value before update, α refers to the learning rate, refers to the partial derivative of ROPF with respect to SVAA, indicating the rate of change of ROPF with respect to SVAA;

[0090] In this embodiment: By using ROPF to iterate SVAA, a dynamic adjustment and feedback mechanism is established. This means that as the deep foundation pit construction progresses and the geological conditions change, the risk level ROPF will be updated in real time, and the value of SVAA will be adjusted accordingly, thus ensuring the accuracy and timeliness of safety assessment. The iterative process can gradually approach the optimal solution, that is, find the value of SVAA that minimizes the risk level ROPF, which greatly improves the accuracy of safety assessment, helps to more accurately predict and prevent potential safety risks. This iterative method can adapt to the safety analysis of deep foundation pits under different geological conditions, construction methods and safety requirements. By adjusting the iterative parameters and convergence conditions, it can flexibly cope with various complex situations. Through iterative analysis, the optimal support structure parameters, such as the diameter, spacing and embedment depth of the support piles, can be found, thus optimizing the support design and improving the stability of the deep foundation pit. This iterative form updates the risk level ROPF in real time and adjusts the value of SVAA accordingly, which can timely detect potential safety hazards and take corresponding early warning and prevention and control measures to avoid accidents. The results of iterative analysis can provide important basis for construction decisions, such as determining a reasonable excavation sequence, support timing and monitoring frequency, etc., to ensure the smooth progress of the construction process. Compared with traditional methods, this iterative method not only considers the stress state of the deep foundation pit, but also comprehensively considers the influence of various factors such as geological conditions and construction methods on safety, thus improving the comprehensiveness and accuracy of the analysis. Through the iterative algorithm, the value of SVAA that minimizes the risk level can be efficiently solved, avoiding the cumbersome trial calculation and optimization process in traditional methods. This iterative method is easy to combine with automated monitoring systems and intelligent decision-making systems to realize the automation and intelligence of deep foundation pit safety analysis, improving the analysis efficiency and accuracy. ROPF is an important index for the safety assessment of deep foundation pits, which comprehensively reflects the influence of various factors such as the stress state, geological conditions and construction methods of deep foundation pits on safety. As a key parameter in the comprehensive stress state sub-module, SVAA directly affects the calculation results of the comprehensive stress state SVOP, and further affects the size of the risk level ROPF. Therefore, by continuously adjusting the value of SVAA, the safety state of the deep foundation pit is optimized. This iterative process reflects the close correlation and mutual influence between ROPF and SVAA.

[0091] Please refer to Figures 1 to 3 , the processing process of the foundation pit safety level sub-module is as follows:

[0092] Safety level ;

[0093] Among them:

[0094] ROAA refers to the first risk threshold with a value of 0.4, indicating that the critical value of a lower risk level is considered that the safety risk is controllable below this value;

[0095] ROBB refers to the risk threshold II with a value of 0.75;

[0096] SVBB refers to the critical threshold of the comprehensive stress state with a value of 0.65, indicating that special attention should be paid to the stability of the deep foundation pit when the comprehensive stress state exceeds this value;

[0097] When it exceeds this value, special attention should be paid to the stability of the deep foundation pit;

[0098] The processing procedure of the foundation pit safety level sub-module is as follows: Input the comprehensive stress state value SVOP and the risk level assessment value ROPF of the deep foundation pit into the foundation pit safety level sub-module, and based on the risk threshold I ROAA, the risk threshold II ROBB, and the critical threshold of the comprehensive stress state SVBB, output safety level 1, safety level 2, and safety level 3;

[0099] The safety measure module is specifically as follows:

[0100] When in safety level 1, the deep foundation pit is in a low-risk state;

[0101] Processing measures: Continue according to the normal construction plan, but regular monitoring and inspection of the stability of the deep foundation pit need to be maintained;

[0102] When in safety level 2, the deep foundation pit is in a medium-risk state;

[0103] Processing measures: Take additional monitoring and preventive measures, that is, increase the number of monitoring points to improve the monitoring frequency, and strengthen the inspection and maintenance of the support structure. At the same time, adjust the construction plan to reduce the impact on the stability of the deep foundation pit;

[0104] When in safety level 3, the deep foundation pit is in a high-risk state;

[0105] Processing measures: Immediately stop construction activities and conduct a comprehensive safety assessment, take emergency support measures, that is, increase temporary support structures or reinforce existing support structures. At the same time, organize an expert team to conduct consultations to formulate a detailed safety treatment plan, and ensure that all construction personnel understand and comply with relevant safety regulations.

[0106] In this embodiment: With the mutual cooperation of the foundation pit safety level sub-module and the safety measure module, based on the comprehensive stress state value SVOP and the risk level assessment value ROPF of the deep foundation pit, the safety level of the deep foundation pit can be determined and early warning measures can be taken in a timely manner. This method can intuitively reflect the safety status of the deep foundation pit, provide clear guidance for decision-makers. When the safety level is relatively low, measures such as strengthening the support and adjusting the construction plan can be taken to improve safety. When the safety level is relatively high, it is necessary to closely monitor the changes in the deep foundation pit and take timely measures to prevent accidents from occurring.

[0107] In the specific implementation process, a deep foundation pit safety analysis system is constructed using multiple sub-modules in this method. By inputting the normal stress SVA of the deep foundation pit in the x-direction, the normal stress SVB of the deep foundation pit in the y-direction, and the shear stress Sxy of the deep foundation pit in the x and y directions into the stress state comprehensive sub-module, the comprehensive stress state value SVOP of the deep foundation pit is output. This sub-module evaluates the comprehensive stress state of the deep foundation pit by comprehensively considering the normal stress and shear stress in the x and y directions of the deep foundation pit, as well as the maximum normal stress and maximum shear stress, and combining the ratio of the current elastic modulus to the reference elastic modulus. This sub-module can comprehensively reflect the stress state of the deep foundation pit and make the evaluation result more accurate by considering the change of the elastic modulus. The calculation of SVOP provides intuitive data on the stress state of the deep foundation pit, which helps to judge whether it is within the safe range. The change trend of SVOP can predict the change of the stress state of the deep foundation pit and provide a basis for taking preventive measures.

[0108] Input the comprehensive stress state value SVOP of the deep foundation pit and the strength DDA of the support structure into the risk assessment sub-module, and output the risk level assessment value ROPF. This sub-module quantitatively evaluates the risk level of the deep foundation pit by combining the comprehensive stress state, geological conditions, support structure strength, and other influencing factors. This sub-module covers various influencing factors to make the evaluation result more comprehensive, quantifies the risk level of the deep foundation pit, provides a clear risk prompt for decision-makers, can timely discover potential safety hazards through the change of ROPF to avoid accidents, and can formulate more reasonable risk management measures by combining historical data and experience.

[0109] Input the comprehensive stress state value SVOP of the deep foundation pit and the risk level assessment value ROPF into the foundation pit safety level sub-module, and output safety level 1, safety level 2, and safety level 3. Under the mutual cooperation of this foundation pit safety level sub-module and the safety measure module, based on the comprehensive stress state value SVOP of the deep foundation pit and the risk level assessment value ROPF, the safety level of the deep foundation pit is determined and early warning measures are taken in a timely manner. This method can intuitively reflect the safety status of the deep foundation pit and provide clear guidance for decision-makers. When the safety level is low, measures such as strengthening the support and adjusting the construction plan can be taken to improve safety. When the safety level is high, the change of the deep foundation pit needs to be closely monitored and measures should be taken in a timely manner to prevent accidents.

[0110] Based on the risk level assessment value ROPF, the stress reference value SVAA in the stress state comprehensive submodule is iterated, so that the comprehensive stress state value SVOP of the deep foundation pit and the risk level assessment value ROPF are continuously iterated and optimized. By iterating SVAA through ROPF, a dynamic adjustment and feedback mechanism is established, which means that with the progress of deep foundation pit construction and changes in geological conditions, the risk level ROPF will be updated in real time and the value of SVAA will be adjusted accordingly to ensure the accuracy and timeliness of the safety assessment. This iterative form updates the risk level ROPF in real time and adjusts the value of SVAA accordingly, which can timely discover potential safety hazards and take corresponding early warning and prevention and control measures to avoid accidents. The iterative analysis results can provide important basis for construction decisions, such as determining a reasonable excavation sequence, support timing and monitoring frequency, etc., to ensure the smooth progress of the construction process. Compared with traditional methods, this iterative method not only considers the stress state of the deep foundation pit.

[0111] In summary, this method enables multiple sub-modules to cooperate with each other in calculation, and can also perform overall cycles and iterations, so that the overall system has the effect of automatic optimization and updating, and thus has better adaptability.

[0112] Example 2: Please refer to Figure 1 , Figure 2 and Figure 3 ,The data acquisition module uses stress sensors, geological exploration equipment, and support structure strength testing equipment;

[0113] Stress sensors are installed on the side walls and bottom of the deep foundation pit, and the normal stress and shear stress of the deep foundation pit in the x and y directions are measured by the stress sensors;

[0114] Geological exploration equipment specifically includes geological radar and drilling equipment, which are used to analyze geological conditions to assess geological condition scores;

[0115] The support structure strength testing equipment is specifically a pressure sensor and a tensile testing machine, which are used to measure the support structure to output the strength DDA of the support structure.

[0116] In this embodiment: geological exploration equipment should be installed around and at the bottom of the deep foundation pit for exploration to obtain geological condition information. The support structure strength test should be carried out on key parts of the support structure, such as support piles and anchor cables. The various sensors and detection equipment used by the data acquisition module can monitor and upload the safety and stability status of the deep foundation pit in real time, and calculate and analyze the safety performance of the deep foundation pit in a timely and real-time manner, so as to achieve the purpose of dynamic and real-time monitoring of the safety of the deep foundation pit through timely updated data.

[0117] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A deep foundation pit safety analysis method, characterized by: The analysis steps include: Step I: collect stress values, geological condition information and support structure strength in the deep foundation pit through the data acquisition module, and input the collected data into the data processing module; Step II: The stress values, geological condition information and support structure strength in the deep foundation pit are sorted and cleaned through the data processing module, and the normal stress SVA of the deep foundation pit in the x direction, the normal stress SVB of the deep foundation pit in the y direction, the shear stress Sxy of the deep foundation pit in the x and y directions and the strength DDA of the support structure are output; Step III: The normal stress SVA of the deep foundation pit in the x direction, the normal stress SVB of the deep foundation pit in the y direction, the shear stress Sxy of the deep foundation pit in the x and y directions and the strength DDA of the supporting structure are calculated and analyzed by the module, and the comprehensive stress state value SVOP of the deep foundation pit, the risk level assessment value ROPF and the safety level are output; Step IV: Input the comprehensive stress state value SVOP, risk level assessment value ROPF and safety level of the deep foundation pit into the safety measures module. The safety measures module implements safety measures based on the safety level. After taking the safety measures, the deep foundation pit is continuously monitored. According to the monitoring results and the changes in the safety level, the safety measures are adjusted in time. The calculation and analysis module includes: a stress state comprehensive submodule, a risk assessment submodule and a foundation pit safety level submodule; The calculation formula of the stress state comprehensive submodule is as follows: ； in: SVOP refers to the value of comprehensive stress state of deep foundation pit; SVA refers to the normal stress of the deep foundation pit in the x direction, SVAA refers to the stress reference value, SVM refers to the ideal maximum normal stress, which indicates the maximum normal stress that the foundation pit bears under the most unfavorable conditions, SVB refers to the normal stress of the deep foundation pit in the y direction, Sxy refers to the shear stress of the deep foundation pit in the x and y directions, SP refers to the ideal maximum shear stress, which indicates the maximum shear stress that the foundation pit bears under the most unfavorable conditions, A1 refers to the influence constant related to the properties of the foundation pit support material, E refers to the current elastic modulus of the foundation pit support material, which indicates the stiffness of the material, that is, the ability of the material to resist deformation in the elastic deformation stage, EA refers to the reference elastic modulus, and SVA-SVAA refers to the degree of deviation of the stress in the x direction of the deep foundation pit from the reference value; The processing process of the stress state comprehensive submodule is as follows: the normal stress SVA of the deep foundation pit in the x direction, the normal stress SVB of the deep foundation pit in the y direction, and the shear stress Sxy of the deep foundation pit in the x and y directions are input into the stress state comprehensive submodule, and the comprehensive stress state value SVOP of the deep foundation pit is output based on the stress reference value SVAA and the ideal maximum normal stress SVM; The calculation formula of the risk assessment submodule is as follows: ； in: ROPF refers to the risk level assessment value; RA refers to the weight coefficient of SVOP, RB refers to the weight coefficient of GGA, GGA refers to the geological condition score, GGAM refers to the maximum value of the geological condition score, RC refers to the weight coefficient of DDA, DDA refers to the strength of the support structure, DP refers to the reference value of the strength of the support structure, GGA / GGAM refers to the ratio of the geological condition score to the maximum score; The processing process of the risk assessment submodule is as follows: the comprehensive stress state value SVOP of the deep foundation pit and the strength DDA of the support structure are input into the risk assessment submodule, and the risk level assessment value ROPF is output based on the geological condition score GGA and the reference value DP of the support structure strength; The calculation formula of the foundation pit safety level submodule is as follows: ； in: ROAA refers to the risk threshold value one with a value of 0.4, which means the critical value of the lower risk level. Below this value, the security risk is considered controllable; ROBB refers to the risk threshold value 2, which is 0.75; SVBB refers to the critical threshold of the comprehensive stress state, which is 0.65, indicating that the comprehensive stress state exceeds When this value is exceeded, special attention should be paid to the stability of the deep foundation pit; The processing process of the foundation pit safety level submodule is as follows: the comprehensive stress state value SVOP and the risk level assessment value ROPF of the deep foundation pit are input into the foundation pit safety level submodule, and based on the risk threshold 1 ROAA, the risk threshold 2 ROBB and the comprehensive stress state critical threshold SVBB, the safety level 1, safety level 2 and safety level 3 are output.

2. The deep foundation pit safety analysis method according to claim 1, characterized in that: The safety measures module is specifically: At safety level 1, the deep foundation pit is in a low-risk state; Treatment measures: Continue to proceed according to the normal construction plan, but maintain regular monitoring and inspection of the stability of the deep foundation pit; At safety level 2, the deep foundation pit is at medium risk; Treatment measures: Take additional monitoring and preventive measures, that is, increase the number of monitoring points to improve the monitoring frequency, strengthen the inspection and maintenance of the support structure, and adjust the construction plan to reduce the impact on the stability of the deep foundation pit; At safety level 3, the deep foundation pit is at high risk; Treatment measures: Immediately stop construction activities and conduct a comprehensive safety assessment, take emergency support measures, that is, add temporary support structures or reinforce existing support structures, and organize an expert team to discuss and formulate a detailed safety treatment plan, and ensure that all construction personnel understand and comply with relevant safety regulations.

3. The deep foundation pit safety analysis method according to claim 1, characterized in that: The data acquisition module uses stress sensors, geological exploration equipment and support structure strength testing equipment; The geological exploration equipment is specifically a geological radar and a drilling equipment, which is used to analyze geological conditions to evaluate the geological condition score; The support structure strength testing equipment is specifically a pressure sensor and a tensile testing machine, which are used to measure the support structure to output the strength DDA of the support structure.

4. The deep foundation pit safety analysis method according to claim 3 is characterized in that: The stress sensors are installed on the side walls and the bottom of the deep foundation pit, and the normal stress (SVA, SVB) and the shear stress (Sxy) of the deep foundation pit in the x and y directions are measured by the stress sensors.

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