Method and system for calculating end resistance of steel pipe pile and storage medium

Abstract

The application provides a steel pipe pile end resistance calculation method, system and storage medium, relates to the pile end resistance calculation technical field, and the specific steps comprise: calculating pile end stiffness and pile side stiffness, determining the initial load bearing ratio and the value range of the pile end bearing ratio; gradually applying load through the static load test, recording the pile top settlement under each level of load, drawing the load-settlement curve, and extracting the settlement measured value of each level of load; calculating the theoretical value of the pile top settlement according to the initial load bearing ratio, in combination with the pile end stiffness and the pile side stiffness; comparing the theoretical value and the measured value of the settlement, iteratively optimizing the load bearing ratio through the genetic algorithm, and obtaining the optimal value of the load bearing ratio; and calculating the pile end resistance. The application corrects the pile end resistance in combination with the static load test data, dynamically optimizes the load distribution ratio, accurately reflects the evolution characteristics of the pile end and pile side resistance in the load loading process, and effectively improves the calculation precision of the pile end resistance under the limit load state.

Description

Technical Field

[0001] This invention relates to the field of pile end resistance calculation technology, specifically to a method, system, and storage medium for calculating the end resistance of steel pipe piles. Background Technology

[0002] Pile foundations are a widely used type of foundation in building engineering. Their bearing capacity primarily derives from the combined effect of pile end resistance and pile side friction. In practical engineering, the calculation of pile foundation bearing capacity directly affects the safety and economy of pile foundation design; therefore, accurate prediction of pile foundation bearing capacity is of great significance. Pile end resistance reflects the reaction force of the soil at the pile bottom, and its magnitude is mainly related to the physical and mechanical properties of the soil at the pile end and the effective stress distribution of the soil below the pile end. Pile side friction, on the other hand, is the frictional force of the soil surrounding the pile, and is related to the shear strength of the surrounding soil and the roughness of the pile surface. Under uniform soil conditions, the distribution of loads at the pile end and pile side is relatively simple. However, as the load gradually increases until the ultimate state, the distribution ratio between pile end resistance and pile side friction exhibits a certain non-linear trend.

[0003] Currently, the methods for calculating pile end resistance mainly rely on theoretical models combined with soil parameters for estimation. However, traditional pile end resistance calculations typically assume a linear distribution of the stiffness of the soil at the pile end and the friction of the soil along the pile side, which makes it difficult to accurately reflect the complex dynamic relationship between the load distribution at the pile end and along the pile side during actual pile foundation bearing. This, to some extent, limits the accuracy of pile foundation bearing capacity calculations.

[0004] For example, in the prior art, patent CN118747398A provides a method, system, storage medium, and device for calculating the end resistance of a pipe pile. Its main steps are as follows: First, the end resistance is initially estimated based on the physical and mechanical properties of the soil at the pile tip (such as soil properties and the pressure of the overlying soil); then, based on the end resistance, the pile side friction and soil column weight are calculated layer by layer, and the effective stress of each soil layer is analyzed; according to the calculation results, the sum of the friction and soil column weight of all soil layers is compared with the current end resistance. If the difference in the comparison results does not meet the preset conditions, the end resistance is adjusted and recalculated until the deviation requirement is met, finally yielding the end resistance of the pipe pile.

[0005] However, the following shortcomings still exist. As can be seen from the above statement, the existing technology does not adequately consider the dynamic evolution law of pile tip and pile side loads, and is still based on fixed theoretical assumptions for calculation, failing to dynamically reflect the distribution changes as the load increases; at the same time, it lacks the correction of measured data and relies entirely on theoretical models, resulting in a large deviation between the calculation results and actual values ​​under complex geological conditions, making it difficult to accurately reflect the pile tip resistance.

[0006] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a method, system, and storage medium for calculating the end resistance of steel pipe piles, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for calculating the end resistance of steel pipe piles, comprising the following steps:

[0010] S1. Under uniform soil conditions, collect the geometric parameters, pile top load and soil mechanical parameters of the steel pipe pile, calculate the pile end stiffness and pile side stiffness based on the geometric parameters and soil mechanical parameters, set the initial load bearing ratio of the pile end and pile side according to the stiffness ratio of the two, and determine the value range of the pile end bearing ratio in combination with the geometric parameters and stiffness ratio.

[0011] S2. Apply loads step by step through static load tests, record the settlement of the pile top under each load level, plot the load-settlement curve, and extract the measured values ​​of the pile top settlement under each load level and the load under the ultimate load state.

[0012] S3. Calculate the load borne by the pile tip and the load borne by the pile side according to the initial load bearing ratio. Combine the pile tip stiffness and the pile side stiffness to calculate the pile tip settlement and the pile side slip, and obtain the theoretical value of the pile top settlement corresponding to each grade of load.

[0013] S4. Compare the theoretical value of the settlement at the top of the pile with the measured value step by step, calculate the error corresponding to each grade of load, and take minimizing the total error of all grade loads as the optimization objective. Within the range of the load bearing ratio between the pile tip and the pile side, iteratively optimize the load bearing ratio through a genetic algorithm. During the iterative optimization process, the total error between the theoretical value and the measured value of the settlement is calculated repeatedly until the total error is less than the set threshold. The optimal value of the load bearing ratio between the pile tip and the pile side is then extracted.

[0014] S5. Based on the load under the ultimate load state and the optimal value of the load-bearing ratio between the pile tip and the pile side, calculate the load borne by the pile tip under the ultimate load state and output it as the pile tip resistance.

[0015] Furthermore, the geometric parameters of the steel pipe pile include the effective length of the steel pipe pile inserted into the soil, the outer diameter and inner diameter of the steel pipe pile, and the Young's modulus of the steel pipe pile; the soil mechanical parameters are the soil shear modulus.

[0016] Furthermore, the formulas used to obtain the pile tip stiffness and pile side stiffness are as follows:

[0017] ;

[0018] in, For pile tip stiffness, For pile side stiffness, The Young's modulus of the steel pipe pile. The outer diameter of the steel pipe pile. The inner diameter of the steel pipe pile. For soil shear modulus, This refers to the effective length of the steel pipe pile inserted into the soil.

[0019] Furthermore, based on the pile tip stiffness and pile side stiffness, the logic for setting the initial load-bearing ratio between the pile tip and pile side is as follows:

[0020] The initial load-bearing ratio is defined as the ratio of the load borne at the pile tip to the load borne on the pile side. According to the principles of mechanics, the ratio of the load borne at the pile tip to the load borne on the pile side is equal to the ratio of the pile tip stiffness to the pile side stiffness, that is:

[0021] ;

[0022] in, The load borne by the pile tip. The load borne by the pile side;

[0023] Based on the pile top load and the load balance formula, we obtain:

[0024] ;

[0025] in, This is the load at the top of the pile, which is the cumulative value of the loads in all loading stages;

[0026] The ratio of load borne by the pile tip and pile side:

[0027] ;

[0028] in, This represents the proportion of the load borne by the pile tip. This represents the proportion of the load borne by the pile side;

[0029] The initial load distribution ratio between the pile tip and the pile side is: : ;

[0030] The logic for determining the range of values ​​for the pile end bearing ratio by combining the effective length-to-outer-diameter ratio and the stiffness ratio is as follows:

[0031] If the ratio of effective length to outer diameter is less than a threshold, and the stiffness ratio is greater than a threshold, then set... ;

[0032] If the ratio of effective length to outer diameter is not less than a threshold, or the stiffness ratio is not greater than a threshold, then set... .

[0033] Furthermore, the loads borne at the pile tip and along the pile side are calculated. Combined with the pile tip stiffness and pile side stiffness, the pile tip settlement and pile side slip are calculated using the following formulas:

[0034] The elastic and plastic stages of soil deformation are a continuous process. In the elastic stage, the pile tip stiffness and pile side stiffness remain constant; while in the plastic stage, the pile tip stiffness and pile side stiffness gradually change with increasing load. During the gradual loading process, the load on the pile top changes according to... Apply in a manner where, For graded load indexing, , The total number of stages of the graded load is [number]. When the graded load reaches the [number]th [stage], [the number of stages is determined]. At level 1, both the soil at the pile tip and along the pile side reach their ultimate limit state. This is the ultimate load of the pile foundation;

[0035] 1) In the elastic stage, the deformation of the soil is linearly related to the load;

[0036] The load borne at the pile tip and the load borne on the pile side:

[0037] ;

[0038] ;

[0039] in, For the first A graded load, For the first load borne by the pile end A graded load, The first load borne by the pile side One graded load;

[0040] Pile tip settlement and pile side slip:

[0041] ;

[0042] in, For the first Pile tip settlement under graded loads For the first Pile side slip under graded loads;

[0043] Calculate the theoretical values ​​of pile top settlement corresponding to each load level:

[0044] ;

[0045] in, For the first Theoretical values ​​of pile top settlement under graded loads;

[0046] 2) During the plastic stage, calculate the loads borne by the pile tip and the pile sides:

[0047] ;

[0048] in, For the first Pile end stiffness under graded loads For the first Pile side stiffness under graded loads;

[0049] Calculate the theoretical values ​​of pile top settlement corresponding to each load level:

[0050] ;

[0051] in, For the first The theoretical value of pile top settlement under graded loads.

[0052] Furthermore, the theoretical value of the settlement at the pile top is compared with the measured value step by step to calculate the error corresponding to each load level. The formula used is as follows:

[0053] For each load class, calculate the error between the theoretical and measured values:

[0054] ;

[0055] in, For the first The error between the theoretical and measured values ​​of settlement under each graded load. For the first Measured values ​​of pile top settlement under graded loads;

[0056] The formula used to calculate the total error of all graded loads is as follows:

[0057] ;

[0058] in, This represents the total error across all graded loads.

[0059] Furthermore, the logic for iteratively optimizing the load-bearing ratio using a genetic algorithm is as follows:

[0060] Constructing the initial population Initial population ,in, The first in the initial population Individual, This is the index of an individual in the initial population, and , The initial population size. ,in, The first The proportion of load borne by the pile tip and the proportion of load borne by the pile side for each individual pile.

[0061] With total error Minimize the initial population as the optimization objective. Perform iterative optimization, that is, optimize the initial population. Individuals in the population undergo selection, crossover, and mutation operations. During iterative optimization, the initial population is adjusted within the range of the pile tip bearing ratio. Iterative optimization involves selecting individuals with the highest total error as parents, exchanging and combining the genes of the parents through crossover operations to generate new individuals, and then performing mutation operations on the genes of the pile tip bearing ratio and pile side bearing ratio in the newly generated individuals. This process of selection, crossover, and mutation is repeated until the total error is less than the set threshold.

[0062] In the initial population After iterative optimization, the optimal individual is labeled as The optimal values ​​for the load-bearing ratio between the pile tip and the pile side are respectively the pile tip bearing ratio. and pile side bearing ratio ;

[0063] Furthermore, the formula used to calculate the load borne by the pile tip under the ultimate load state is as follows:

[0064] ;

[0065] in, This refers to the load borne by the pile tip under ultimate load conditions, i.e., the pile tip resistance.

[0066] To achieve the above objectives, the present invention also provides the following technical solution:

[0067] A system for calculating the end resistance of a steel pipe pile, the system being used to execute any of the above-described methods for calculating the end resistance of a steel pipe pile, comprising:

[0068] The ratio setting module is used to collect the geometric parameters, pile top load and soil mechanical parameters of steel pipe piles under uniform soil conditions, calculate the pile end stiffness and pile side stiffness based on the geometric parameters and soil mechanical parameters, set the initial load bearing ratio of pile end and pile side according to the stiffness ratio of the two, and determine the value range of the pile end bearing ratio in combination with the geometric parameters and stiffness ratio.

[0069] The test module is used to apply loads step by step through static load tests, record the settlement of the pile top under each load level, plot the load-settlement curve, and extract the measured values ​​of the pile top settlement under each load level as well as the load under the ultimate load state.

[0070] The calculation module is used to calculate the load borne by the pile tip and the load borne by the pile side according to the initial load bearing ratio. Combined with the pile tip stiffness and the pile side stiffness, it calculates the pile tip settlement and the pile side slip, and thus obtains the theoretical value of the pile top settlement corresponding to each grade of load.

[0071] The iterative optimization module compares the theoretical and measured values ​​of the settlement at the pile top step by step, calculates the error corresponding to each grade of load, and takes minimizing the total error of all grade loads as the optimization objective. Within the range of the load bearing ratio between the pile tip and the pile side, the module uses a genetic algorithm to iteratively optimize the load bearing ratio. During the iterative optimization process, the total error between the theoretical and measured values ​​of the settlement is calculated repeatedly until the total error is less than the set threshold, and the optimal value of the load bearing ratio between the pile tip and the pile side is extracted.

[0072] The output module is used to calculate the load borne by the pile end under the ultimate load state based on the load under the ultimate load state and the optimal value of the load bearing ratio between the pile end and the pile side, and output it as the pile end resistance.

[0073] A storage medium for storing a computer program, which, when executed by a processor, implements any of the above-described methods for calculating the end resistance of a steel pipe pile.

[0074] Compared with the prior art, the beneficial effects of the present invention are:

[0075] This invention introduces static load test data, extracts the load-settlement curve and the measured settlement values ​​of each load level, and combines theoretical calculations to correct the pile end resistance. This effectively makes up for the shortcomings of existing technologies that rely entirely on theoretical models, thus making the calculation results closer to the actual engineering situation. As the load gradually increases to the ultimate state, by dynamically optimizing the distribution ratio of the pile end and pile side loads, it more accurately simulates the dynamic evolution characteristics of pile side friction and pile end resistance when the load is gradually loaded, and can accurately reflect the distribution characteristics of pile end resistance under the ultimate working condition, significantly improving the calculation accuracy of pile end resistance under the ultimate load state.

[0076] Furthermore, this invention combines static load test data with the dynamic distribution relationship of graded loads, and optimizes the load distribution ratio between pile tip and pile side by introducing a genetic algorithm, avoiding human adjustment errors and further improving calculation accuracy and applicability. Attached Figure Description

[0077] Figure 1This is a schematic diagram of the overall method flow of the present invention;

[0078] Figure 2 This is a block diagram of the module composition of the present invention. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0080] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0081] Example:

[0082] Please see Figures 1-2 The present invention provides a technical solution:

[0083] A method for calculating the end resistance of steel pipe piles, comprising the following steps:

[0084] S1. Under uniform soil conditions, collect the geometric parameters, pile top load and soil mechanical parameters of the steel pipe pile, calculate the pile end stiffness and pile side stiffness based on the geometric parameters and soil mechanical parameters, set the initial load bearing ratio of the pile end and pile side according to the stiffness ratio of the two, and determine the value range of the pile end bearing ratio in combination with the geometric parameters and stiffness ratio.

[0085] Based on the above embodiments, the geometric parameters of the steel pipe pile include the effective length of the steel pipe pile inserted into the soil, the outer diameter and inner diameter of the steel pipe pile, and the Young's modulus of the steel pipe pile; the soil mechanical parameter is the soil shear modulus.

[0086] Based on the above embodiments, the methods for collecting the effective length of the steel pipe pile inserted into the soil, the outer and inner diameters of the steel pipe pile, the Young's modulus of the steel pipe pile, and the shear modulus of the soil are as follows:

[0087] The effective length of the steel pipe pile inserted into the soil was measured on site using a steel ruler. The outer and inner diameters of the steel pipe pile were measured on site using a vernier caliper. The elastic modulus of the steel pipe pile was determined by laboratory mechanical testing using a tensile testing machine. The shear modulus of the soil was obtained using a triaxial shear tester.

[0088] Based on the above embodiments, pile tip stiffness reflects the rigidity of the pile tip (pile end) when the pile is subjected to axial force, characterizing the pile tip's ability to resist compressive or tensile deformation. A steel pipe pile can essentially be considered as an elastic member with a certain cross-sectional area and length; its axial stiffness reflects its ability to resist axial deformation. For a steel pipe pile, the cross-sectional area is the area of ​​the annular cross-section formed by its outer diameter and inner diameter. Therefore, when calculating pile tip stiffness, according to elasticity theory, the pile tip stiffness of a steel pipe pile can be estimated using the expression for the axial stiffness of the aforementioned member.

[0089] Based on the above embodiments, the pile end stiffness is calculated using the principle of axial stiffness calculation for members in elasticity mechanics, and the formula used is as follows:

[0090] ;

[0091] in, For pile tip stiffness, The Young's modulus of the steel pipe pile. The outer diameter of the steel pipe pile. The inner diameter of the steel pipe pile. This refers to the effective length of the steel pipe pile inserted into the soil.

[0092] Based on the above embodiments, the pile side stiffness reflects the shear resistance stiffness of the soil to the pile side when the pile side interacts with the surrounding soil. It is a stiffness measure of the pile side friction and reflects the resistance to the force generated by the relative displacement at the pile-soil interface.

[0093] Soil shear modulus is a basic physical parameter that describes the soil's ability to resist shear deformation and characterizes the stiffness of the soil under shear stress. Pile side friction is essentially the shear behavior of the soil on the pile side. Therefore, soil shear modulus is a key indicator for evaluating pile side stiffness.

[0094] As a cylindrical rigid body, the contact area between the pile side and the soil of a steel pipe pile is mainly determined by the pile perimeter and the pile length. The pile perimeter reflects the boundary length of the contact between the pile and the soil per unit length and is an important geometric parameter that affects the distribution of pile side friction.

[0095] Describing pile side stiffness as the product of soil shear modulus and pile perimeter is a simplified and practical linear model. It assumes that pile side stiffness is proportional to pile perimeter and directly related to soil shear stiffness. This assumption is applicable to working conditions where the soil and pile interface are uniformly rigid and within the elastic range.

[0096] Based on the above embodiments, the pile side stiffness is calculated based on the linear assumption of soil shear modulus and pile perimeter, using the following formula:

[0097] ;

[0098] in, For pile side stiffness, The outer diameter of the steel pipe pile. This is the soil shear modulus.

[0099] Based on the above embodiments, the logic for setting the initial load-bearing ratio between the pile tip and pile side based on the pile tip stiffness and pile side stiffness is as follows:

[0100] Steel pipe piles can bear axial loads from the soil through two methods: end bearing and side friction. The end bearing and side bearing together bear the total load applied at the pile top. Treating the end bearing and side bearing as two elastic elements bearing the same total load, their deformations are equal. According to the principles of elasticity:

[0101] ;

[0102] in, This is the amount of deformation. The load borne by the pile tip. This refers to the load borne by the pile side.

[0103] Based on the above formula, we can obtain:

[0104]

[0105] The ratio of the load borne at the pile tip to the load borne on the pile side is equal to the ratio of the pile tip stiffness to the pile side stiffness.

[0106] Based on the pile top load and the load balance formula, we obtain:

[0107] ;

[0108] in, This is the load at the top of the pile, which is the cumulative value of the loads in all loading stages;

[0109] The initial load distribution ratio between the pile tip and the pile side is:

[0110] ;

[0111] in, This represents the proportion of the load borne by the pile tip. This represents the proportion of the load borne by the pile side;

[0112] Based on the above formula, we can solve for:

[0113] ;

[0114] Based on the above embodiments, the logic for determining the range of values ​​for the pile end bearing ratio by combining the effective length-to-outer diameter ratio and the stiffness ratio is as follows:

[0115] The effective length refers to the actual length of the pile body that participates in bearing the force (the effective length of the steel pipe pile inserted into the soil), and the outer diameter is the outer diameter dimension of the steel pipe pile. The ratio of the two reflects the shape characteristics of the pile and indirectly reflects the range of the pile side friction.

[0116] When the ratio of effective length to outer diameter is less than the threshold, the total force of pile side friction is limited, and the pile end bearing is relatively dominant.

[0117] When the ratio of effective length to outer diameter is not less than the threshold, the pile side friction area is large, the pile side friction bearing capacity is enhanced, the pile side bearing ratio increases, and the pile end bearing ratio decreases.

[0118] Three to five test piles with different length-to-diameter ratios were selected for vertical static load tests. Strain gauges were attached to different depths of the pile to test the axial force distribution. The side friction of each section of the pile was calculated by the difference in axial force, and the pile tip bearing ratio was obtained. The curves of pile tip bearing ratio, effective length and outer diameter ratio were plotted. The inflection point where the pile tip bearing ratio changed from a rapid decrease to a gradual decrease was found. The corresponding effective length and outer diameter ratio is the threshold.

[0119] The stiffness ratio characterizes the magnitude of the pile tip stiffness relative to the pile side stiffness;

[0120] If the stiffness ratio is greater than the threshold, it indicates that the pile tip stiffness is greater, the pile tip can withstand greater loads, and the pile tip load ratio is larger.

[0121] If the stiffness ratio is not greater than the threshold, it indicates that the pile side stiffness is dominant, the proportion of pile side bearing increases, and the proportion of pile end bearing is relatively small.

[0122] Based on the characteristics of the pile foundation structure and the material properties, the stiffness ratio threshold is generally set at [value missing]. Nearby indicates the critical point when the pile tip stiffness is equal to the pile side stiffness.

[0123] In conclusion, we can conclude that:

[0124] If the ratio of effective length to outer diameter is less than a threshold, and the stiffness ratio is greater than a threshold, then set... ;

[0125] If the ratio of effective length to outer diameter is not less than a threshold, or the stiffness ratio is not greater than a threshold, then set... .

[0126] S2. Through static load tests, loads are gradually increased according to preset load levels. After each load level is applied, the load is kept constant, and the settlement is allowed to stabilize (without significant change). Then, the settlement at the top of the pile is recorded under each load level using a laser rangefinder. The settlement under each load level is measured multiple times, and the average value is taken. The load is plotted on the x-axis and the settlement at the top of the pile is plotted on the y-axis. The measured values ​​of the settlement at the top of the pile under each load level and the load under the ultimate load state are extracted. The ultimate load point is identified from the load-settlement curve, which usually corresponds to the point of sudden increase in settlement or the specified critical value of settlement.

[0127] S3. Calculate the load borne by the pile tip and the load borne by the pile side according to the initial load bearing ratio. Combine the pile tip stiffness and the pile side stiffness to calculate the pile tip settlement and the pile side slip, and obtain the theoretical value of the pile top settlement corresponding to each level of load.

[0128] Based on the above embodiments, the load borne by the pile tip and the load borne by the pile side are calculated. Combining the pile tip stiffness and the pile side stiffness, the pile tip settlement and the pile side slip are calculated using the following formulas:

[0129] The elastic and plastic stages of soil deformation are a continuous process. In the elastic stage, the pile tip stiffness and pile side stiffness remain constant; while in the plastic stage, the pile tip stiffness and pile side stiffness gradually change with increasing load. During the gradual loading process, the load on the pile top changes according to... Apply in a manner where, For graded load indexing, , The total number of stages of the graded load is [number]. When the graded load reaches the [number]th [stage], [the number of stages is determined]. At level 1, both the soil at the pile tip and along the pile side reach their ultimate limit state. This is the ultimate load of the pile foundation;

[0130] 1) In the elastic stage, the deformation of the soil is linearly related to the load;

[0131] The load borne at the pile tip and the load borne on the pile side:

[0132] ;

[0133] ;

[0134] in, For the first A graded load, For the first load borne by the pile end A graded load, The first load borne by the pile side One graded load;

[0135] Pile tip settlement and pile side slip:

[0136] ;

[0137] in, For the first Pile tip settlement under graded loads For the first Pile side slip under graded loads;

[0138] Calculate the theoretical values ​​of pile top settlement corresponding to each load level:

[0139] ;

[0140] in, For the first Theoretical values ​​of pile top settlement under graded loads;

[0141] Based on this, it should be noted that:

[0142] Since the deformation in the elastic stage is sequential, the total vertical displacement at the pile top is equal to the sum of the pile tip settlement and the pile side slip. At this point, the pile tip stiffness... and pile side stiffness It is a constant value, the load is distributed according to a fixed load ratio, the deformation is linear, and the superposition conforms to the linear superposition principle of elasticity. Therefore, the pile top settlement is the superposition of the pile end settlement and the pile side slip.

[0143] 2) During the plastic stage, calculate the loads borne by the pile tip and the pile sides:

[0144] ;

[0145] in, For the first Pile end stiffness under graded loads For the first Pile side stiffness under graded loads;

[0146] Compare and The results showed and Equal, meaning the pile top displacement of the pile tip and the soil sidewalls are the same;

[0147] The theoretical values ​​of pile top settlement corresponding to each load level are obtained:

[0148] ;

[0149] in, For the first The theoretical value of pile top settlement under graded loads.

[0150] Based on this, it should be noted that:

[0151] During the plastic stage, plastic deformation occurs in the soil at the pile tip and along the pile sides, resulting in lower and uneven stiffness, i.e., pile tip stiffness... and pile side stiffness As the load increases, the load-bearing capacity of the pile tip and pile side is no longer in a fixed ratio, but is dynamically distributed according to the current stiffness ratio.

[0152] The overall vertical deformation (pile top settlement) of the pile foundation is borne by the pile tip and pile side stiffness in parallel, resulting in the same displacement;

[0153] Because the pile body is an integral structure, the settlement at the pile top is a unified vertical displacement. The settlement at the pile tip and the slippage on the pile side are no longer two independent displacement sources, but rather manifest as the same displacement. In other words, the deformation at the pile tip and the pile side occurs synchronously, and their deformation amounts are equal. The settlement at the pile top is equal to the settlement at the pile tip or the slippage on the pile side.

[0154] In addition, theoretical calculations combined with the initial load bearing ratio yielded theoretical settlement under each load level, demonstrating both the linear superposition law of the elastic stage and the nonlinear characteristics of stiffness degradation in the plastic stage. This comprehensively simulated the dynamic evolution of pile end resistance and pile side friction, achieving effective integration of theoretical models and measured data, and significantly improving the accuracy of settlement prediction.

[0155] In addition, it should be noted that:

[0156] During the plastic stage, the stiffness of the pile tip and pile side and As the load increases, the dynamic changes occur, and its evolution depends on the initial load-bearing ratio. And the nonlinear characteristics of the soil, although not explicitly included in the theoretical formula for calculating pile top settlement. ,but It is related to the loads at the pile tip and along the pile sides, and the loads at the pile tip and along the pile sides are in turn related to... There is a connection. The evolution of stiffness indirectly determines the pile top settlement under various load levels, which is then optimized through iterative optimization using a genetic algorithm. At that time, based on the candidates Calculate the corresponding stiffness evolution curve and theoretical settlement value, compare the error with the measured value, and gradually adjust accordingly. The goal is to minimize the total error of each load level, thereby achieving dynamic optimization of the load-bearing ratio.

[0157] S4. Compare the theoretical value of the settlement at the top of the pile with the measured value step by step, calculate the error corresponding to each load level, and take minimizing the total error of all load levels as the optimization objective. Within the range of the load bearing ratio between the pile tip and the pile side, iteratively optimize the load bearing ratio through a genetic algorithm. During the iterative optimization process, the total error between the theoretical value and the measured value of the settlement is calculated iteratively until the total error is less than the set threshold, and the optimal value of the load bearing ratio between the pile tip and the pile side is extracted.

[0158] Based on the above embodiments, the theoretical value of the settlement at the pile top is compared with the measured value step by step, and the error corresponding to each load level is calculated. The formula used is as follows:

[0159] For each load level, calculate the error between the theoretical and measured values:

[0160] ;

[0161] in, For the first The error between the theoretical and measured values ​​of settlement under each graded load. For the first Measured values ​​of pile top settlement under graded loads;

[0162] The formula used to calculate the total error of all graded loads is as follows:

[0163] ;

[0164] in, This represents the total error across all graded loads.

[0165] Based on the above embodiments, the logic for iteratively optimizing the load-bearing ratio using a genetic algorithm is as follows:

[0166] Constructing the initial population Initial population ,in, The first in the initial population Individual, This is the index of an individual in the initial population, and , The initial population size. ,in, The first The proportion of load borne by the pile tip and the proportion of load borne by the pile side for each individual pile.

[0167] With total error Minimize the initial population as the optimization objective. Perform iterative optimization, that is, optimize the initial population. Individuals in the population undergo selection, crossover, and mutation operations. During iterative optimization, the initial population is adjusted within the range of the pile tip bearing ratio. Iterative optimization involves selecting individuals with the highest total error as parents, where the highest refers to individuals in the top 50% of the total error. Through crossover operations, the genes of the parent individuals are exchanged and combined to generate new individuals. Then, the genes for the pile tip bearing ratio and pile side bearing ratio in the newly generated individuals are mutated. The selection, crossover, and mutation operations are repeated until the total error is less than the set threshold.

[0168] In the initial population After iterative optimization, the optimal individual is labeled as The optimal values ​​for the load-bearing ratio between the pile tip and the pile side are respectively the pile tip bearing ratio. and pile side bearing ratio .

[0169] Based on the above, it should be noted that:

[0170] By combining static load test data with the dynamic distribution relationship of graded loads, a genetic algorithm is used to iteratively optimize the load bearing ratio. By utilizing the principle of minimizing multi-stage settlement error, the automatic optimization and adjustment of the load distribution ratio between the pile tip and pile side is realized. This avoids the blindness and manual intervention of traditional empirical parameter adjustment. It accurately simulates the dynamic evolution characteristics of pile side friction and pile tip resistance when the load is gradually applied, and can accurately reflect the distribution characteristics of pile tip resistance under extreme working conditions, significantly improving the calculation accuracy of pile tip resistance under extreme load conditions.

[0171] S5. Based on the load under the ultimate load state and the optimal value of the load-bearing ratio between the pile tip and the pile side, calculate the load borne by the pile tip under the ultimate load state and output it as the pile tip resistance.

[0172] Based on the above embodiments, the formula used to calculate the load borne by the pile tip under the ultimate load state is as follows:

[0173] ;

[0174] in, This refers to the load borne by the pile tip under ultimate load conditions.

[0175] Pile end resistance refers to the ultimate bearing capacity contribution of the soil per unit area at the pile tip to the pile foundation. The sum of these contributions equals the ultimate load borne by the pile tip, i.e., the pile end resistance is... .

[0176] Based on the above, it should be noted that:

[0177] Based on the optimized pile end load ratio and ultimate load state, the pile end resistance under ultimate load is accurately calculated, providing a reliable method for evaluating pile end resistance and solving the problem of inaccurate pile end resistance calculation in existing methods.

[0178] Please see Figure 2 The present invention also provides a technical solution:

[0179] A system for calculating the end resistance of a steel pipe pile, the system being used to execute any of the above-described methods for calculating the end resistance of a steel pipe pile, comprising:

[0180] The ratio setting module is used to collect the geometric parameters, pile top load and soil mechanical parameters of steel pipe piles under uniform soil conditions, calculate the pile end stiffness and pile side stiffness based on the geometric parameters and soil mechanical parameters, set the initial load bearing ratio of pile end and pile side according to the stiffness ratio of the two, and determine the value range of the pile end bearing ratio in combination with the geometric parameters and stiffness ratio.

[0181] The test module is used to apply loads step by step through static load tests, record the settlement of the pile top under each load level, plot the load-settlement curve, and extract the measured values ​​of the pile top settlement under each load level as well as the load under the ultimate load state.

[0182] The calculation module is used to calculate the load borne at the pile tip and the load borne on the pile side based on the initial load bearing ratio. Combined with the pile tip stiffness and the pile side stiffness, it calculates the pile tip settlement and the pile side slip, and thus obtains the theoretical value of the pile top settlement corresponding to each level of load.

[0183] The iterative optimization module compares the theoretical and measured values ​​of the settlement at the pile top level by level, calculates the error corresponding to each load level, and minimizes the total error of all load levels as the optimization objective. Within the range of the load bearing ratio between the pile tip and the pile side, the module uses a genetic algorithm to iteratively optimize the load bearing ratio. During the iterative optimization process, the total error between the theoretical and measured values ​​of the settlement is calculated repeatedly until the total error is less than the set threshold, and the optimal value of the load bearing ratio between the pile tip and the pile side is extracted.

[0184] The output module is used to calculate the load borne by the pile end under the ultimate load state based on the load under the ultimate load state and the optimal value of the load bearing ratio between the pile end and the pile side, and output it as the pile end resistance.

[0185] A storage medium for storing a computer program, which, when executed by a processor, implements any of the above-described methods for calculating the end resistance of a steel pipe pile.

[0186] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0187] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by software, electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0188] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0189] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for calculating the end resistance of steel pipe piles, characterized in that, The specific steps include: S1. Under uniform soil conditions, collect the geometric parameters, pile top load and soil mechanical parameters of the steel pipe pile, calculate the pile end stiffness and pile side stiffness based on the geometric parameters and soil mechanical parameters, set the initial load bearing ratio of the pile end and pile side according to the stiffness ratio of the two, and determine the value range of the pile end bearing ratio in combination with the geometric parameters and stiffness ratio. S2. Apply loads step by step through static load tests, record the settlement of the pile top under each load level, plot the load-settlement curve, and extract the measured values ​​of the pile top settlement under each load level and the load under the ultimate load state. S3. Calculate the load borne by the pile tip and the load borne by the pile side according to the initial load bearing ratio. Combine the pile tip stiffness and the pile side stiffness to calculate the pile tip settlement and the pile side slip, and obtain the theoretical value of the pile top settlement corresponding to each grade of load. S4. Compare the theoretical value of the settlement at the top of the pile with the measured value step by step, calculate the error corresponding to each grade of load, and take minimizing the total error of all grade loads as the optimization objective. Within the range of the load bearing ratio between the pile tip and the pile side, iteratively optimize the load bearing ratio through a genetic algorithm. During the iterative optimization process, the total error between the theoretical value and the measured value of the settlement is calculated repeatedly until the total error is less than the set threshold. The optimal value of the load bearing ratio between the pile tip and the pile side is then extracted. S5. Based on the load under the ultimate load state and the optimal value of the load-bearing ratio between the pile tip and the pile side, calculate the load borne by the pile tip under the ultimate load state and output it as the pile tip resistance.

2. The method for calculating the end resistance of steel pipe piles according to claim 1, characterized in that, The geometric parameters of the steel pipe pile include the effective length of the steel pipe pile inserted into the soil, the outer and inner diameters of the steel pipe pile, and the Young's modulus of the steel pipe pile; the soil mechanical parameters are the soil shear modulus.

3. The method for calculating the end resistance of steel pipe piles according to claim 2, characterized in that, The formulas used to obtain the pile tip stiffness and pile side stiffness are as follows: ； in, For pile tip stiffness, For pile side stiffness, The Young's modulus of the steel pipe pile. The outer diameter of the steel pipe pile. The inner diameter of the steel pipe pile. For soil shear modulus, This refers to the effective length of the steel pipe pile inserted into the soil.

4. The method for calculating the end resistance of steel pipe piles according to claim 3, characterized in that, Based on the pile tip stiffness and pile side stiffness, the logic for setting the initial load bearing ratio between the pile tip and pile side is as follows: The initial load-bearing ratio is defined as the ratio of the load borne at the pile tip to the load borne on the pile side. According to the principles of mechanics, the ratio of the load borne at the pile tip to the load borne on the pile side is equal to the ratio of the pile tip stiffness to the pile side stiffness, that is: ； in, The load borne by the pile tip. The load borne by the pile side; Based on the pile top load and the load balance formula, we obtain: ； in, This is the load at the top of the pile, which is the cumulative value of the loads in all loading stages; The ratio of load borne by the pile tip and the pile side: ； in, This represents the proportion of the load borne by the pile tip. This represents the proportion of the load borne by the pile side; The initial load distribution ratio between the pile tip and the pile side is: : ; The logic for determining the range of values ​​for the pile end bearing ratio by combining the effective length-to-outer-diameter ratio and the stiffness ratio is as follows: If the ratio of effective length to outer diameter is less than a threshold, and the stiffness ratio is greater than a threshold, then set... ; If the ratio of effective length to outer diameter is not less than a threshold, or the stiffness ratio is not greater than a threshold, then set... .

5. The method for calculating the end resistance of steel pipe piles according to claim 4, characterized in that, The calculation of pile tip load and pile side load, combined with pile tip stiffness and pile side stiffness, is used to calculate pile tip settlement and pile side slip, based on the following formulas: The elastic and plastic stages of soil deformation are a continuous process. In the elastic stage, the pile tip stiffness and pile side stiffness remain constant; while in the plastic stage, the pile tip stiffness and pile side stiffness gradually change with increasing load. During the gradual loading process, the load on the pile top changes according to... Apply in a manner where, For graded load indexing, , The total number of stages of the graded load is [number]. When the graded load reaches the [number]th [stage], [the number of stages is determined]. At level 1, both the soil at the pile tip and along the pile side reach their ultimate limit state. This is the ultimate load of the pile foundation; 1) In the elastic stage, the deformation of the soil is linearly related to the load; The load borne at the pile tip and the load borne on the pile side: ； ； in, For the first A graded load, For the first load borne by the pile end A graded load, The first load borne by the pile side One graded load; Pile tip settlement and pile side slip: ； in, For the first Pile tip settlement under graded loads For the first Pile side slip under graded loads; Calculate the theoretical values ​​of pile top settlement corresponding to each load level: ； in, For the first Theoretical values ​​of pile top settlement under graded loads; 2) During the plastic stage, calculate the loads borne by the pile tip and the pile sides: ； in, For the first Pile end stiffness under graded loads For the first Pile side stiffness under graded loads; Calculate the theoretical values ​​of pile top settlement corresponding to each load level: ； in, For the first The theoretical value of pile top settlement under graded loads.

6. The method for calculating the end resistance of steel pipe piles according to claim 5, characterized in that, The theoretical value of the settlement at the top of the pile is compared with the measured value step by step to calculate the error corresponding to each load level. The formula used is as follows: For each load class, calculate the error between the theoretical and measured values: ； in, For the first The error between the theoretical and measured values ​​of settlement under each graded load. For the first Measured values ​​of pile top settlement under graded loads; The formula used to calculate the total error of all graded loads is as follows: ； in, This represents the total error across all graded loads.

7. The method for calculating the end resistance of steel pipe piles according to claim 6, characterized in that, The logic of iteratively optimizing the load-bearing ratio using a genetic algorithm is as follows: Constructing the initial population Initial population ,in, The first in the initial population Individual, This is the index of an individual in the initial population, and , The initial population size. ,in, The first The proportion of load borne by the pile tip and the proportion of load borne by the pile side for each individual pile. With total error Minimize the initial population as the optimization objective. Perform iterative optimization, that is, optimize the initial population. Individuals in the population undergo selection, crossover, and mutation operations. During iterative optimization, the initial population is adjusted within the range of the pile tip bearing ratio. Iterative optimization involves selecting individuals with the highest total error as parents, exchanging and combining the genes of the parents through crossover operations to generate new individuals, and then performing mutation operations on the genes of the pile tip bearing ratio and pile side bearing ratio in the newly generated individuals. This process of selection, crossover, and mutation is repeated until the total error is less than the set threshold. In the initial population After iterative optimization, the optimal individual is labeled as The optimal values ​​for the load-bearing ratio between the pile tip and the pile side are respectively the pile tip bearing ratio. and pile side bearing ratio .

8. The method for calculating the end resistance of steel pipe piles according to claim 7, characterized in that, The formula used to calculate the load borne by the pile tip under the ultimate load state is as follows: ； in, This refers to the load borne by the pile tip under ultimate load conditions, i.e., the pile tip resistance.

9. A system for calculating the end resistance of a steel pipe pile, the system being used to execute the method for calculating the end resistance of a steel pipe pile as described in any one of claims 1-8, characterized in that, include: The ratio setting module is used to collect the geometric parameters, pile top load and soil mechanical parameters of steel pipe piles under uniform soil conditions, calculate the pile end stiffness and pile side stiffness based on the geometric parameters and soil mechanical parameters, set the initial load bearing ratio of pile end and pile side according to the stiffness ratio of the two, and determine the value range of the pile end bearing ratio in combination with the geometric parameters and stiffness ratio. The test module is used to apply loads step by step through static load tests, record the settlement of the pile top under each load level, plot the load-settlement curve, and extract the measured values ​​of the pile top settlement under each load level as well as the load under the ultimate load state. The calculation module is used to calculate the load borne by the pile tip and the load borne by the pile side according to the initial load bearing ratio. Combined with the pile tip stiffness and the pile side stiffness, it calculates the pile tip settlement and the pile side slip, and thus obtains the theoretical value of the pile top settlement corresponding to each grade of load. The iterative optimization module compares the theoretical and measured values ​​of the settlement at the pile top step by step, calculates the error corresponding to each grade of load, and takes minimizing the total error of all grade loads as the optimization objective. Within the range of the load bearing ratio between the pile tip and the pile side, the module uses a genetic algorithm to iteratively optimize the load bearing ratio. During the iterative optimization process, the total error between the theoretical and measured values ​​of the settlement is calculated repeatedly until the total error is less than the set threshold, and the optimal value of the load bearing ratio between the pile tip and the pile side is extracted. The output module is used to calculate the load borne by the pile end under the ultimate load state based on the load under the ultimate load state and the optimal value of the load bearing ratio between the pile end and the pile side, and output it as the pile end resistance.

10. A storage medium, characterized in that, Used to store a computer program, which, when executed by a processor, implements a method for calculating the end resistance of a steel pipe pile as described in any one of claims 1-8.

Images