Bucket foundation construction process stability evaluation system and method
The stability assessment system for the construction process of the bucket foundation, generated by finite element modeling and random interface generation, solves the problem of uncertainty in the sinking depth of the bucket under the bucket structure, and realizes accurate risk assessment and safety guidance in the construction process.
Patent Information
- Application Number
- CN202511662714.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-13
- Publication Date
- 2026-02-27
AI Technical Summary
Existing technologies cannot effectively address the uncertainty in the sinking depth of the lower barrel in the construction of barrel foundations, resulting in an inability to accurately assess construction risks and potential engineering accidents.
A stability assessment system for the construction process of bucket foundations was established by using finite element modeling units, parameter correction units, random interface generation units, and safety factor calculation units, combined with on-site monitoring data. The system simulates the uncertainty of sinking depth by generating random interfaces and calculates the safety factor to guide construction.
It enables accurate and reliable assessment of the bucket foundation construction process, effectively guiding on-site construction, reducing risks, and preventing engineering accidents.
Smart Images
Figure CN121580705A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of bucket foundation construction, in particular to a bucket foundation construction process stability evaluation system and method. BACKGROUND
[0002] In engineering construction, the combined structure of sand pile composite foundation and bucket foundation is widely used to meet the increasing requirements of foundation bearing and stability. In the actual construction of this structure, due to the variability of spatial distribution of soil layers and construction errors and other factors, it is difficult for the bucket body structure of the bucket foundation to sink to the designed sand pile elevation. Moreover, the top surface elevation of the sand pile itself is also uneven, and these two factors together cause the actual depth of the bucket body structure of the bucket foundation sinking into the sand pile composite foundation to be uncertain.
[0003] At present, the traditional specification formula method or deterministic finite element method is usually used in engineering to evaluate stability, but these methods cannot effectively deal with the uncertainty of the sinking depth, and it is difficult to truly reflect the actual risk state in construction, so they cannot provide accurate and reliable safety guidance for site construction, and there is a risk of accidents caused by inaccurate stability evaluation. SUMMARY
[0004] In view of the deficiencies of the prior art, the present application provides a bucket foundation construction process stability evaluation system and method, which solves the problems mentioned in the background.
[0005] The present application provides the following technical scheme: a bucket foundation construction process stability evaluation system and method, comprising a finite element modeling unit, a parameter correction unit, a random interface generation unit, a safety factor calculation unit and a construction control unit; The finite element modeling unit is used to establish a calculation section model; The parameter correction unit is used to perform inverse analysis and correction on the finite element model parameters based on the field monitoring data; The random interface generation unit is used to generate a random interface between the bucket body structure of the bucket and the sand pile composite foundation to simulate the uncertainty of the sinking depth of the bucket body structure; The safety factor calculation unit is used to calculate the safety factor of each construction stage; The construction control unit is used to guide the site construction based on the safety factor evaluation results.
[0006] Preferably, when the finite element modeling unit calculates the strength index of the sand pile composite foundation, the natural soil layer parameters are valued according to the data in the geological exploration report, the strength index of the sand pile composite foundation is calculated using the comprehensive physical and mechanical performance index, and the internal friction angle and cohesion are calculated according to the following formula: ; ; ; wherein, is the internal friction angle of the composite soil layer, m is the area replacement rate, is the stress concentration coefficient, is the internal friction angle of the pile body material, is the internal friction angle of the soil between piles, is the cohesion of the composite soil layer, is the cohesion of the soil between piles, n is the stress ratio of the pile soil; When the finite element modeling unit calculates the compression modulus of the sand pile composite foundation, the following formula is used: ; wherein, is the compression modulus of the i-th layer of the pile body, is the compression modulus of the i-th layer of the soil between piles.
[0007] Preferably, the real-time acquisition of the field monitoring data by the parameter correction unit includes the inclination of the barrel structure, the earth pressure at the bottom of the barrel structure, the settlement values on both sides of the barrel structure, and the layered settlement values of the soil body. The parameter correction unit sets a calculation working condition corresponding to the actual working condition in the finite element model, and the initial stress field is generated using a lateral pressure coefficient consolidation mode.
[0008] Preferably, the random interface generation unit generates a plurality of random points in the horizontal direction at equal intervals in the lower barrel compartment of the barrel structure, the horizontal coordinates of each point are fixed, and the vertical coordinates are randomly generated within a predetermined height range upward from the bottom of the barrel structure. The interface between the lower barrel of the barrel structure and the sand pile composite foundation is formed by connecting these points. The random interface generation unit generates the vertical coordinates of the random points by calling a random number generation function, and imports the coordinate information into the finite element model.
[0009] Preferably, the safety factor calculation unit increases a safety calculation step after each construction step, and defines the safety factor by accumulating the incremental multiplication coefficient; The safety factor calculation unit generates multiple groups of random interfaces, calculates multiple groups of safety factors, and performs stationarity test on the safety factor data. If the data is stationary, the average value or the minimum value is taken as the safety factor of the calculation section; The safety factor calculation unit analyzes the barrel-soil failure interface, takes the maximum displacement mutation as the failure surface judgment standard, and draws the barrel-soil interface failure surface.
[0010] A barrel foundation construction process stability evaluation method, comprising the following steps: Step S1, establishing a finite element model of a calculation section; Step S2: Based on the on-site monitoring data, the parameters of the finite element model are corrected through inversion analysis; Step S3: Generate a random interface between the lower bucket of the barrel structure and the sand pile composite foundation to simulate the uncertainty of the sinking depth of the lower bucket of the barrel structure, and calculate the safety factor based on this. Step S4: Based on the safety factor assessment results, control the on-site construction process.
[0011] Preferably, in step S1, the strength index of the sand pile composite foundation is calculated using comprehensive physical and mechanical performance indicators, including: The internal friction angle is calculated using the following formula: ; Cohesion is calculated using the following formula: ; in: ; The internal friction angle of the composite soil layer is denoted by m, and the area replacement ratio is denoted by m. The stress concentration factor is... The internal friction angle of the pile material. The internal friction angle between the piles and the soil. For the cohesion of composite soil layers, is the soil cohesion between piles, and n is the pile-soil stress ratio; In step S1, the compression modulus of the sand pile composite foundation is calculated using the following formula: ; in, Let be the compression modulus of the i-th pile layer. Let be the compression modulus of the soil between piles in the i-th layer.
[0012] Preferably, step S2 includes: Step S201: Real-time collection of monitoring data during on-site construction. The monitoring data includes the inclination of the bucket structure, the soil pressure at the bottom of the lower bucket of the bucket structure, the settlement values on both sides of the bucket structure, and the stratified settlement values of the soil. Step S202: Set the calculation conditions corresponding to the actual working conditions in the finite element model, and generate the initial stress field using the lateral pressure coefficient consolidation mode. Step S203: Compare the calculated data of the finite element model with the field monitoring data, and adjust the physical and mechanical parameters of the soil and the boundary drainage conditions through inversion analysis so that the difference between the calculated data and the monitoring data is within the acceptable range for the project.
[0013] Preferably, step S3 includes: Step S301: Based on the on-site sand pile monitoring data and the design bottom elevation of the bucket foundation, determine the range of variation in the depth of the lower bucket of the bucket structure sinking into the composite foundation; Step S302: Create the interface between the lower barrel of the barrel structure and the sand pile composite foundation. Generate multiple random points at equal intervals in the horizontal direction within the lower barrel compartment of the barrel structure. The horizontal coordinate of each point is fixed, and the vertical coordinate is randomly generated within the depth variation range. Connect these points to form the interface. Step S303: After each construction step, a safety calculation step is added to obtain the safety factor for each construction stage by accumulating the incremental multiplication factor. Step S304: Repeat steps S302 and S303 to generate multiple sets of random interfaces and calculate multiple sets of safety factors; Step S305: Perform a stationarity test on multiple sets of safety factor data. If the test results are stationary, take the average or minimum value as the safety factor of the calculated section. Step S306: Perform the bucket-soil failure interface analysis, using the maximum displacement abrupt change as the failure surface criterion, and draw the bucket-soil interface failure surface.
[0014] Preferably, step S4 includes: Step S401: When the calculated safety factor is greater than or equal to the design safety factor, the on-site construction shall continue according to the original construction plan. Step S402: When the calculated safety factor is less than the design safety factor, corrective measures are taken on site, and steps S2 and S3 are repeated for stability assessment. The corrective measures include one or more of the following: reducing the loading rate, installing plastic drainage boards, stopping landside backfilling, and grouting to reinforce and optimize the damaged surface.
[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention establishes a calculation model that considers the comprehensive mechanical indicators of sand pile composite foundation, and dynamically inversely corrects the model parameters based on field monitoring data. Under the condition that the depth of the lower bucket of the bucket structure sinking into the sand pile composite foundation is uncertain, it can achieve an accurate and reliable assessment of the stability of the overall structure construction process, and effectively guide on-site construction and risk control based on the assessment results.
[0016] 2. This invention, by setting up a random generation method for the interface between the bucket and the soil, simulates the uncertainty of the depth of the lower bucket sinking into the composite foundation of the sand pile in the bucket structure, and performs a large number of random sampling calculations, which solves the technical problem that the traditional standard formula method and finite element method cannot evaluate the structural stability under uncertain sinking depth conditions, and realizes a more realistic and conservative assessment of construction safety risks. Attached Figure Description
[0017] Figure 1This is a diagram of the system architecture for evaluating the stability of the bucket foundation construction process according to the present invention. Figure 2 This is a flowchart of the stability assessment method for the construction process of the bucket foundation according to the present invention; Figure 3 This is a comparison diagram of the marine sedimentation fitting of the barrel structure of the present invention; Figure 4 This is a comparison diagram of the horizontal displacement fitting of the barrel structure of the present invention; Figure 5 This is a schematic diagram of the interface structure between the lower bucket and the sand pile composite foundation of the present invention. Figure 6 This is a table showing the unit root test results of the present invention; Figure 7 This is a statistical curve of the safety factor of the present invention; Figure 8 This is a schematic diagram of the soil failure surface structure under different sand pile replacement rates according to the present invention. Detailed Implementation
[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] Please see Figures 1-8 A stability assessment system for the construction process of a bucket foundation includes a finite element modeling unit, a parameter correction unit, a random interface generation unit, a safety factor calculation unit, and a construction control unit. Finite element modeling units are used to establish computational cross-sectional models; The parameter correction unit is used to perform inversion analysis and correction of finite element model parameters based on field monitoring data; The random interface generation unit is used to generate random interfaces between the lower bucket of the barrel structure and the sand pile composite foundation to simulate the uncertainty of the sinking depth of the lower bucket of the barrel structure. The safety factor calculation unit is used to calculate the safety factor for each construction stage; The construction control unit is used to guide on-site construction based on the results of safety factor assessments.
[0020] When calculating the strength index of the sand pile composite foundation using the finite element modeling unit, the natural soil layer parameters are taken from the data in the geological survey report, and the strength index of the sand pile composite foundation is calculated using comprehensive physical and mechanical performance indicators. The internal friction angle and cohesion are calculated using the following formulas: ; ; ; in, The internal friction angle of the composite soil layer is denoted by m, and the area replacement ratio is denoted by m. The stress concentration factor is... The internal friction angle of the pile material. The internal friction angle between the piles and the soil. For the cohesion of composite soil layers, is the soil cohesion between piles, and n is the pile-soil stress ratio; When calculating the compression modulus of sand pile composite foundation using finite element modeling units, the following formula is used: ; in, Let be the compression modulus of the i-th pile layer. Let be the compression modulus of the soil between piles in the i-th layer.
[0021] The on-site monitoring data collected in real time by the parameter correction unit includes: the inclination of the barrel structure, the soil pressure at the bottom of the lower barrel of the barrel structure, the settlement values on both sides of the barrel structure, and the stratified settlement values of the soil. The parameter correction unit sets the calculation conditions in the finite element model to correspond to the actual working conditions, and the initial stress field is generated using the lateral pressure coefficient consolidation mode.
[0022] The random interface generation unit generates multiple random points at equal intervals in the horizontal direction within the lower chamber of the barrel structure. The horizontal coordinate of each point is fixed, while the vertical coordinate is randomly generated within a predetermined height range from the bottom of the lower chamber of the barrel structure upwards. Connecting these points forms the interface between the lower chamber of the barrel structure and the sand pile composite foundation. The random interface generation unit generates the ordinate of the random point by calling a random number generation function, and then imports the coordinate information into the finite element model. The random interface generation unit uses the random.uniform() function in Python to generate random ordinates, and then imports the coordinate information into the PLAXIS finite element model.
[0023] The safety factor calculation unit adds a safety calculation step after each construction step, and defines the safety factor through a cumulative incremental multiplication factor. The safety factor calculation unit adds a safety calculation step after each construction step, where the incremental multiplication factor Msf is 0.05, the number of calculation steps is set to 100 or 1000, and the safety factor is defined by the cumulative incremental multiplication factor. The safety factor calculation unit generates multiple sets of random interfaces, calculates multiple sets of safety factors, and performs a stationarity test on the safety factor data. If the data is stationary, the average or minimum value is taken as the safety factor of the calculated section. The safety factor calculation unit performs a failure interface analysis of the soil-bucket interface, using the maximum displacement abrupt change as the criterion for determining the failure surface, and plots the failure surface of the soil-bucket interface.
[0024] A method for stability assessment during the construction process of a bucket foundation includes the following steps: Step S1: Establish the finite element model of the calculation section; Step S2: Based on the on-site monitoring data, the parameters of the finite element model are corrected through inversion analysis; Step S3: Generate a random interface between the lower bucket of the barrel structure and the sand pile composite foundation to simulate the uncertainty of the sinking depth of the lower bucket of the barrel structure, and calculate the safety factor based on this. Step S4: Based on the safety factor assessment results, control the on-site construction process.
[0025] In step S1, the strength index of the sand pile composite foundation is calculated using comprehensive physical and mechanical performance indicators, including: The internal friction angle is calculated using the following formula: ; Cohesion is calculated using the following formula: ; in: ; The internal friction angle of the composite soil layer is denoted by m, and the area replacement ratio is denoted by m. The stress concentration factor is... The internal friction angle of the pile material. The internal friction angle between the piles and the soil. For the cohesion of composite soil layers, is the soil cohesion between piles, and n is the pile-soil stress ratio; In step S1, the compression modulus of the sand pile composite foundation is calculated using the following formula: ; in, Let be the compression modulus of the i-th pile layer. Let be the compression modulus of the soil between piles in the i-th layer.
[0026] Step S2 includes: Step S201: Real-time collection of monitoring data during on-site construction. The monitoring data includes the inclination of the bucket structure, the soil pressure at the bottom of the lower bucket of the bucket structure, the settlement values on both sides of the bucket structure, and the stratified settlement values of the soil. Step S202: Set the calculation conditions corresponding to the actual working conditions in the finite element model, and generate the initial stress field using the lateral pressure coefficient consolidation mode. Step S203: Compare the calculated data of the finite element model with the field monitoring data, and adjust the physical and mechanical parameters of the soil and the boundary drainage conditions through inversion analysis so that the difference between the calculated data and the monitoring data is within the acceptable range for the project.
[0027] Step S3 includes: Step S301: Based on the on-site sand pile monitoring data and the design bottom elevation of the bucket foundation, determine the range of variation in the depth of the lower bucket of the bucket structure sinking into the composite foundation; Step S302: Create the interface between the lower barrel of the barrel structure and the sand pile composite foundation. Generate multiple random points at equal intervals in the horizontal direction within the lower barrel compartment of the barrel structure. The horizontal coordinate of each point is fixed, and the vertical coordinate is randomly generated within the depth variation range. Connect these points to form the interface. Step S303: After each construction step, a safety calculation step is added to obtain the safety factor for each construction stage by accumulating the incremental multiplication factor. Step S304: Repeat steps S302 and S303 to generate multiple sets of random interfaces and calculate multiple sets of safety factors; Step S305: Perform a stationarity test on multiple sets of safety factor data. If the test results are stationary, take the average or minimum value as the safety factor of the calculated section. Step S306: Perform the bucket-soil failure interface analysis, using the maximum displacement abrupt change as the failure surface criterion, and draw the bucket-soil interface failure surface.
[0028] Step S4 includes: Step S401: When the calculated safety factor is greater than or equal to the design safety factor, the on-site construction shall continue according to the original construction plan. Step S402: When the calculated safety factor is less than the design safety factor, corrective measures are taken on site, and steps S2 and S3 are repeated for stability assessment. The corrective measures include one or more of the following: reducing the loading rate, installing plastic drainage boards, stopping landside backfilling, and grouting to reinforce and optimize the damaged surface.
[0029] During implementation, preliminary preparations and data collection include collecting engineering geological survey reports, design drawings and parameters of bucket foundations and sand pile composite foundations, and deploying monitoring systems at the construction site, including inclinometers, earth pressure cells, settlement gauges and stratified settlement meters, to ensure that data on bucket tilt, base earth pressure, bucket side settlement and stratified soil settlement can be obtained in real time.
[0030] Model establishment and calibration: Finite element software, such as PLAXIS 2D, was used to create an initial calculation section model. Natural soil layer parameters were assigned based on the geological survey report. The sand pile composite foundation was considered a homogeneous material, and its comprehensive strength index and internal friction angle were considered. Cohesion and compressive modulus The calculation is performed according to the formula. The monitoring data collected on site is input into the system. Through inversion analysis, the parameters such as the elastic modulus of the soil, cohesion, and internal friction angle in the model are adjusted until the displacement, stress, etc. calculated by the model are basically consistent with the on-site monitoring data in terms of magnitude and variation. In this way, a calibration model that can truly reflect the on-site working conditions is obtained.
[0031] Stochastic stability analysis, based on the calibrated model, uses a random number generation algorithm, such as the random.uniform() function in Python, to generate multiple random points with ordinates in the lower compartment of each barrel structure at the interface between the barrel and the sand pile. Connecting these points forms a randomly undulating interface to simulate the uncertainty of the sinking depth in the range of 0 to 1 meter. Repeat this process to generate a sufficient number, such as 100 sets of random interface models.
[0032] Statistical analysis is performed on the large number of safety factors obtained from the calculation. For example, the unit root test is used to determine the stationarity of the data. Finally, the average or minimum value is taken as the overall safety factor for this construction stage.
[0033] Construction decision-making and feedback control involve comparing the calculated safety factor with the design safety factor required by the specifications, which is usually 1.3.
[0034] If the calculated safety factor is ≥1.3, the system outputs a "safe" signal, indicating that construction can continue as planned on site.
[0035] If the calculated safety factor is less than 1.3, the system outputs an "early warning" signal and activates the corrective decision library, suggesting measures such as reducing the loading rate, installing plastic drainage boards, suspending backfilling, or carrying out grouting reinforcement.
[0036] After implementing corrective measures, the system re-collects monitoring data, repeats steps S2 and 3, and conducts a new round of stability assessment, forming a closed-loop control of "assessment-decision-feedback-reassessment" until the risk is eliminated.
[0037] like Figures 3-5 In the specific implementation process: Step S1: Establish the finite element model of the calculation section. Using PLAXIS 2D finite element software, establish the calculation section model. The parameters of the natural soil layer are taken from the data in the geological survey report. The strength index of the sand pile composite foundation can be adopted using the comprehensive physical and mechanical performance index. The finite element model parameters are then corrected.
[0038] Step S201: Collect multiple key monitoring data in real time during the on-site construction process. The data includes at least: the inclination of the barrel structure, the soil pressure at the bottom of the lower barrel of the barrel structure, the settlement values on both sides of the barrel structure, and the stratified settlement values of the soil, so as to provide a data basis for the subsequent inversion analysis of the finite element model.
[0039] Step S202: Based on the actual working conditions at the construction site, set the corresponding calculation conditions in the finite element model to generate the initial model. The initial stress field is generated using the consolidation mode, i.e., the lateral pressure coefficient mode, to accurately simulate the initial stress state of the soil at the site.
[0040] In step S203, while ensuring that the geometric dimensions of the model remain unchanged, the calculated data of the finite element model, such as displacement and stress, are compared with the field monitoring data collected in step S201. Through inversion analysis, the key physical and mechanical parameters of the soil, such as elastic modulus, cohesion, internal friction angle, permeability coefficient, and boundary drainage conditions, are systematically adjusted so that the differences between the calculated data and the monitoring data in terms of magnitude and variation are controlled within a reasonable range acceptable to the engineering, thereby achieving the calibration of the finite element model.
[0041] Step S3 aims to simulate the uncertainty of the depth of the lower bucket of the bucket structure sinking into the sand pile composite foundation during actual construction by introducing a random generation method for the bucket-soil interface, thereby more realistically and conservatively assessing the stability of the structure.
[0042] Step S301: Based on the on-site sand pile monitoring data and the design bottom elevation of the bucket foundation, determine the range of variation in the depth of the lower bucket of the bucket structure sinking into the composite foundation. It is usually within the range of 0 to 1 meter, in order to quantify the possible elevation deviation and foundation inhomogeneity during construction.
[0043] Step S302: Create the interface between the lower barrel of the barrel structure and the sand pile composite foundation. This embodiment illustrates the case within a 0-1 meter range. Random points are generated at equal horizontal intervals within the lower barrel compartment of the barrel structure. The x-coordinate of each point is fixed, while the y-coordinate is randomly generated within a 0-1 meter range above the bottom of the lower barrel. In this case, nine random points A1, A2, A3, A4, A5, A6, A7, A8, and A9 are set. Connecting A1 to A9 sequentially forms the interface between the lower barrel of the barrel structure and the sand pile composite foundation. See [link to example]. Figure 3 As shown. Nine random points were assigned equal x-coordinates, and the `random.uniform()` function in Python was used to randomly generate y-coordinates ranging from 0 to 1 meter. These coordinates were then imported into the PLAXIS finite element model. The modeling process for different engineering projects should be adjusted according to the size and accuracy requirements of the barrel structure, ensuring at least one point within each compartment.
[0044] Step S303: For each model group, perform a safety calculation step and increment the multiplication factor. A safety factor of 0.05 is used, and the strength reduction method is used to calculate the safety factor. Displacement contour maps at failure are recorded to determine the failure surface of the soil in the bucket. The calculation step is set to 100 steps; if failure is not reached after 100 steps, the number of steps is increased to 1000. Through these safety calculation steps, the safety factor for each construction stage is calculated, including the cumulative increment multiplier. The relationship with soil parameters is shown in the following formula: ; , It is the reduction strength parameter that just maintains the model balance, and it is controlled by the incremental multiplication factor. It continues to increase until destruction occurs; at this point, the cumulative increment multiplier... Defined as the safety factor.
[0045] Step S304, as Figure 6 Due to the uncertainty of the interface between the bucket and the soil, it is necessary to generate 100 sets of random interfaces according to the method in step S302, and calculate the safety factor of 100 sets of different bucket-soil interfaces. Since the number of sets is large and the amount of calculation is large, in order to improve the calculation efficiency, the following method is used.
[0046] 1. Create a new txt file and copy the command language of the nine points A1-A9 of the bucket-soil interface in the PLAXIS model into the txt file.
[0047] 2. Use the random.uniform() function in Python to generate the ordinates of nine points A1-A9. Similarly, the x-coordinates of each point remain unchanged, while the ordinates are randomly generated within a range of 0 to 1 meter above the bottom of the barrel structure.
[0048] 3. Input the generated command into the PLAXIS software and run the command to generate a set of bucket-soil interface.
[0049] 4. Repeat steps S302 and 303 to obtain 100 sets of calculation models with different interfaces. Put the files into the same folder and perform batch calculations.
[0050] 5. Connect to the Python interpreter included with the PLAXIS software, input the command language, and obtain the cumulative increment multiplier for each calculation condition. 100 safety factors were calculated, and the `adfuller` function from the Python Stats models library was used to perform a unit root test on the 100 data sets to determine whether the data was stationary. The results of this unit root test are shown in Table 1. The p-value of 0.0087 is less than the 5% critical value of -2.891, indicating that the null hypothesis is rejected at the 5% significance level, meaning the series is considered stationary. If the test results show no stationarity, the number of data sets needs to be increased and the test repeated. 6. After the data unit root test results are stable, obtain the output random model set, and take the average value as the safety factor of the calculated section. In conservative design, the minimum value can be taken as the safety factor of the calculated section.
[0051] Step S305: Analysis of the failure interface of the bucket soil. Using the maximum displacement change as the criterion for the failure surface, output the safety factor and the failure surface. Select the analysis condition, open the incremental displacement cloud map in the software, and draw the maximum incremental displacement boundary with a curve to obtain the failure surface of the bucket soil interface.
[0052] Step S4: On-site construction process control and adjustment.
[0053] Step S401: Compare the design safety factor with the calculated safety factor. Usually, the design safety factor can be taken as 1.3 according to the specifications. When the calculated safety factor is greater than or equal to the design safety factor, the on-site loading and landside backfilling can continue according to the original construction plan.
[0054] Step S402: When the calculated safety factor is less than the design safety factor, measures including but not limited to: reducing the loading rate, installing plastic drainage boards, stopping landside backfilling, and grouting to reinforce and optimize the damaged surface should be taken on site. Continuous monitoring data should be observed, and steps S2 and S3 should be repeated to conduct a stability assessment and avoid the risk of instability of the barrel revetment.
[0055] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A stability assessment system for the construction process of a bucket foundation, characterized in that, It includes finite element modeling units, parameter correction units, random interface generation units, safety factor calculation units, and construction control units; Finite element modeling units are used to establish computational cross-sectional models; The parameter correction unit is used to perform inversion analysis and correction of finite element model parameters based on field monitoring data; The random interface generation unit is used to generate random interfaces between the lower bucket of the barrel structure and the sand pile composite foundation to simulate the uncertainty of the sinking depth of the lower bucket of the barrel structure. The safety factor calculation unit is used to calculate the safety factor for each construction stage; The construction control unit is used to guide on-site construction based on the results of safety factor assessments.
2. The stability assessment system for the construction process of a bucket foundation according to claim 1, characterized in that, When calculating the strength index of the sand pile composite foundation using the finite element modeling unit, the natural soil layer parameters are taken from the data in the geological survey report, and the strength index of the sand pile composite foundation is calculated using comprehensive physical and mechanical performance indicators. The internal friction angle and cohesion are calculated using the following formulas: ； ； ； in, The internal friction angle of the composite soil layer is denoted by m, and the area replacement ratio is denoted by m. The stress concentration factor is... The internal friction angle of the pile material. The internal friction angle between the piles and the soil. For the cohesion of composite soil layers, is the soil cohesion between piles, and n is the pile-soil stress ratio; When calculating the compression modulus of sand pile composite foundation using finite element modeling units, the following formula is used: ； in, Let be the compression modulus of the i-th pile layer. Let be the compression modulus of the soil between piles in the i-th layer.
3. The stability assessment system for the construction process of a bucket foundation according to claim 1, characterized in that, The on-site monitoring data collected in real time by the parameter correction unit includes: the inclination of the barrel structure, the soil pressure at the bottom of the lower barrel of the barrel structure, the settlement values on both sides of the barrel structure, and the stratified settlement values of the soil. The parameter correction unit sets the calculation conditions in the finite element model to correspond to the actual working conditions, and the initial stress field is generated using the lateral pressure coefficient consolidation mode.
4. The stability assessment system for the construction process of a bucket foundation according to claim 1, characterized in that, The random interface generation unit generates multiple random points at equal intervals in the horizontal direction within the lower chamber of the barrel structure. The horizontal coordinate of each point is fixed, while the vertical coordinate is randomly generated within a predetermined height range from the bottom of the lower chamber of the barrel structure upwards. Connecting these points forms the interface between the lower chamber of the barrel structure and the sand pile composite foundation. The random interface generation unit generates the ordinate of the random point by calling a random number generation function and imports the coordinate information into the finite element model.
5. The stability assessment system for the construction process of a bucket foundation according to claim 1, characterized in that, The safety factor calculation unit adds a safety calculation step after each construction step, and defines the safety factor by the cumulative incremental multiplication factor. The safety factor calculation unit generates multiple sets of random interfaces, calculates multiple sets of safety factors, and performs a stationarity test on the safety factor data. If the data is stationary, the average or minimum value is taken as the safety factor of the calculated section. The safety factor calculation unit performs a failure interface analysis of the soil-bucket interface, using the maximum displacement abrupt change as the criterion for determining the failure surface, and plots the failure surface of the soil-bucket interface.
6. A method for evaluating the stability of a bucket foundation during construction, characterized in that, Includes the following steps: Step S1: Establish the finite element model of the calculation section; Step S2: Based on the on-site monitoring data, the parameters of the finite element model are corrected through inversion analysis; Step S3: Generate a random interface between the lower bucket of the barrel structure and the sand pile composite foundation to simulate the uncertainty of the sinking depth of the lower bucket of the barrel structure, and calculate the safety factor based on this. Step S4: Based on the safety factor assessment results, control the on-site construction process.
7. The method for stability assessment during the construction process of a bucket foundation according to claim 6, characterized in that, In step S1, the strength index of the sand pile composite foundation is calculated using comprehensive physical and mechanical performance indicators, including: The internal friction angle is calculated using the following formula: ； Cohesion is calculated using the following formula: ； in: ； The internal friction angle of the composite soil layer is denoted by m, and the area replacement ratio is denoted by m. The stress concentration factor is... The internal friction angle of the pile material. The internal friction angle between the piles and the soil. For the cohesion of composite soil layers, is the soil cohesion between piles, and n is the pile-soil stress ratio; In step S1, the compression modulus of the sand pile composite foundation is calculated using the following formula: ； in, Let be the compression modulus of the i-th pile layer. Let be the compression modulus of the soil between piles in the i-th layer.
8. The method for stability assessment during the construction process of a bucket foundation according to claim 7, characterized in that, Step S2 includes: Step S201: Real-time collection of monitoring data during on-site construction. The monitoring data includes the inclination of the bucket structure, the soil pressure at the bottom of the lower bucket of the bucket structure, the settlement values on both sides of the bucket structure, and the stratified settlement values of the soil. Step S202: Set the calculation conditions corresponding to the actual working conditions in the finite element model, and generate the initial stress field using the lateral pressure coefficient consolidation mode. Step S203: Compare the calculated data of the finite element model with the field monitoring data, and adjust the physical and mechanical parameters of the soil and the boundary drainage conditions through inversion analysis so that the difference between the calculated data and the monitoring data is within the acceptable range for the project.
9. The method for stability assessment during the construction process of a bucket foundation according to claim 8, characterized in that, Step S3 includes: Step S301: Based on the on-site sand pile monitoring data and the design bottom elevation of the bucket foundation, determine the range of variation in the depth of the lower bucket of the bucket structure sinking into the composite foundation; Step S302: Create the interface between the lower barrel of the barrel structure and the sand pile composite foundation. Generate multiple random points at equal intervals in the horizontal direction within the lower barrel compartment of the barrel structure. The horizontal coordinate of each point is fixed, and the vertical coordinate is randomly generated within the depth variation range. Connect these points to form the interface. Step S303: After each construction step, a safety calculation step is added to obtain the safety factor for each construction stage by accumulating the incremental multiplication factor. Step S304: Repeat steps S302 and S303 to generate multiple sets of random interfaces and calculate multiple sets of safety factors; Step S305: Perform a stationarity test on multiple sets of safety factor data. If the test results are stationary, take the average or minimum value as the safety factor of the calculated section. Step S306: Perform the bucket-soil failure interface analysis, using the maximum displacement abrupt change as the failure surface criterion, and draw the bucket-soil interface failure surface.
10. The method for stability assessment during the construction process of a bucket foundation according to claim 9, characterized in that, Step S4 includes: Step S401: When the calculated safety factor is greater than or equal to the design safety factor, the on-site construction shall continue according to the original construction plan. Step S402: When the calculated safety factor is less than the design safety factor, corrective measures are taken on site, and steps S2 and S3 are repeated for stability assessment. The corrective measures include one or more of the following: reducing the loading rate, installing plastic drainage boards, stopping landside backfilling, and grouting to reinforce and optimize the damaged surface.