River levee flood control pile foundation construction method based on BIM technology

Abstract

The invention provides a BIM (Building Information Modeling) technology-based river levee flood control pile foundation construction method, and relates to the technical field of building construction.The BIM technology-based river levee flood control pile foundation construction method comprises the following steps: constructing a three-dimensional geological model of a river levee region on the basis of a BIM technology, and generating hydrological data of continuous underwater depth through a Kriging interpolation method; secondly, under the construction parameter combination, the dynamic water pressure and the static bearing capacity of the pile body are calculated in a segmented mode, and the dynamic bearing capacity is generated; then, an overturning moment and an anti-overturning moment are calculated, and an anti-overturning safety coefficient is generated; material cost and construction cost are calculated based on the pile body volume and the construction parameters, and total cost is generated; and finally, taking maximization of the dynamic bearing capacity, maximization of the anti-overturning safety coefficient and minimization of the total cost as optimization objectives, calculating fitness values of particles, optimizing construction parameters by using a particle swarm algorithm, and outputting optimal construction parameters.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building construction, in particular to a river embankment flood prevention pile foundation construction method based on BIM technology. BACKGROUND

[0002] The traditional river embankment flood prevention pile foundation construction method mainly relies on experience design and static calculation, which is difficult to fully consider complex geological conditions, dynamic hydrological load and real-time changes in the construction process, resulting in conservative or insufficient pile foundation design, affecting the safety and economy of the project. In the prior art, the combination of geological models and construction parameters is not close enough, and there is a lack of accurate quantitative analysis of dynamic loads, which limits the construction optimization. In addition, the adjustment of construction parameters mainly relies on manual trial and error, which is low in efficiency and difficult to achieve multi-objective collaborative optimization. These problems restrict the precision and adaptability of the flood prevention pile foundation construction, causing deviations between the construction effect and the design expectation, affecting the safety and economy of the river embankment flood control project. Therefore, an integrated geological modeling, dynamic load analysis and intelligent optimization method is urgently needed to solve the shortcomings of existing solutions.

[0003] In the prior art, the construction method of pile foundation engineering based on BIM technology disclosed in publication CN115563675A establishes a three-dimensional simulation model in the early stage of pile foundation engineering through BIM technology, simulates the whole process of pile foundation engineering as much as possible according to the actual situation, plans well, and avoids phenomena such as personnel and machinery nesting in the construction process and material waste; and collects and integrates related information such as site progress, quality and safety in the construction process through BIM technology, optimizes the project schedule, quality and safety management process.

[0004] The main problem of the above-mentioned scheme is that it mainly relies on static geological exploration reports and design drawings, does not involve real-time calculation and optimization of dynamic loads, and cannot adapt to the complex hydrogeological changes in river embankment flood control projects; directly generates a geological model based on geological exploration, which cannot fully reflect the continuity and local variation of geological parameters, thereby affecting the accuracy of pile foundation design.

[0005] The above information disclosed in the background section is only used to strengthen the understanding of the background of the present disclosure, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present application is to provide a river embankment flood prevention pile foundation construction method based on BIM technology to solve the problems raised in the background.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions: A river embankment flood prevention pile foundation construction method based on BIM technology, the specific steps comprising: Step 1: Construct a three-dimensional geological model of the river embankment area based on BIM technology, determine the installation location of the flood control pile foundation in the three-dimensional geological model, set multiple sampling points at different underwater depths at the installation location, collect hydrological data at each sampling point, generate continuous underwater depth hydrological data by Kriging interpolation method, determine the actual construction parameter range based on expert evaluation, and set different construction parameter combinations within the construction parameter range; Step 2: For each construction parameter combination, the pile body is segmented at equal intervals, the hydrodynamic pressure at the location of each segment of the pile body is calculated based on the hydrological data of the pile body at different depths and the angle between the pile body and the horizontal plane, and then the unit length pile body hydrodynamic pressure is generated, the static bearing capacity of the pile body is calculated based on the soil parameters at the installation location, and the dynamic bearing capacity is generated based on the static bearing capacity of the pile body and the unit length pile body hydrodynamic pressure; Step 3: Calculate the overturning moment generated by the hydrodynamic pressure on the pile body based on the hydrodynamic pressure at the location of each segment of the pile body, calculate the anti-overturning moment of the soil on the pile foundation based on the pile foundation depth and the soil resistance, and generate the anti-overturning safety factor based on the overturning moment and the anti-overturning moment; Step 4: Generate material cost based on the volume of the pile body and the unit volume material price, generate construction cost based on the construction parameters of the pile foundation, and generate total cost based on the material cost and the construction cost; Step 5: Maximize the dynamic bearing capacity, maximize the anti-overturning safety factor, and minimize the total cost as the optimization goal, calculate the fitness value of each particle, optimize the construction parameters based on the particle swarm algorithm, record the optimal position of each particle and the optimal position of all particles at each iteration, adjust the particle velocity of the next iteration based on the fitness value and the particle velocity of the current iteration, and output the historical optimal position of all particles as the optimal construction parameters when the maximum iteration number is reached.

[0008] Further, the construction parameters include pile foundation depth, pile foundation and horizontal plane angle, pile body diameter, and pile body length; The flood control pile body represents the entire flood control pile, which is composed of a pile body and a pile foundation, the pile foundation represents the part of the pile body that is underground, and the part of the pile body that is not the pile foundation is the pile body; The hydrological data includes water flow velocity and water flow acceleration.

[0009] Further, the formula for generating continuous depth hydrological data is: Take the horizontal plane as the XOY plane, and the Z axis vertically upward from the XOY plane to establish a coordinate system; Use the variogram to reflect the difference of hydrological data with distance, and the formula is: ; Wherein, The distance between adjacent sampling points is Indicates distance as The degree of difference between the two sampling points, Indicates distance as Number of sampling points Indicates distance as The set of sampling point pairs Indicates distance as sampling point pairs, Indicates the index of the sampling point. Indicates the relationship with the first The distance between each sampling point is The index of the sampling points, Indicates the first The coordinates of each sampling point Indicates the first The coordinates of each sampling point Representing coordinates Hydrological data at the location, Representing coordinates Hydrological data at the location; For any unknown point, its hydrological data is the weighted sum of the hydrological data from all sampling points. The unknown point refers to all points on the pile body other than the sampling points. The formula upon which the Kriging equation is based is: ; in, To represent an unknown point, express Hydrological data at the location, Indicates the number of sampling points. Indicates the first Each sampling point pair The contribution weight.

[0010] Furthermore, the principle underlying the generation of dynamic bearing capacity is as follows: The formula used to calculate the dynamic water pressure of each pile segment is as follows: ; ; ; in, Indicates the first The dynamic water pressure at the location of the pile segment, Indicates the index of the pile segment, and , Indicates the number of segments in the pile body, and , This indicates that the calculation result is rounded up. Indicates the length of the pile body. Indicates the length of each segment of the pile body. Indicates the first inertia component of a segment of pile body, denotes the inertia coefficient, denotes the water density, denotes the cross-sectional area of a segment of pile body, denotes the water flow acceleration at the position of the segment of pile body, denotes the component of the water flow acceleration at the position of the segment of pile body perpendicular to the pile body, denotes the water flow acceleration at the position of the segment of pile body, denotes the water flow acceleration at the position of the segment of pile body, denotes the resistance component of a segment of pile body, denotes the resistance coefficient, denotes the pile diameter, denotes the water flow velocity at the position of the segment of pile body, denotes the component of the water flow velocity at the position of the segment of pile body perpendicular to the pile body, denotes the water flow velocity at the position of the segment of pile body, denotes the water flow velocity at the position of the segment of pile body, denotes the angle between the pile axis and the horizontal plane; The formula for generating the dynamic water pressure per unit length of pile body is: ; wherein, denotes the dynamic water pressure per unit length of pile body; The formula for calculating the static bearing capacity is: ; ; ; ; ; ; wherein, denotes the static bearing capacity, denotes the pile tip resistance, denotes the pile side friction, denotes the pile cross-sectional area, denotes the soil cohesion, denotes the soil overburden pressure at the pile tip, denotes the soil bulk density, denotes the pile diameter, denotes the bearing capacity coefficient of the soil cohesion, the soil overburden pressure at the pile tip and the soil bulk density, respectively, denotes the soil internal friction angle, denotes the pile side friction, denotes the pile length, denotes the undrained shear strength of the soil, denotes the cohesion coefficient, and​ ; The formula for calculating the dynamic bearing capacity is: ; Wherein, represents the dynamic bearing capacity.

[0011] Further, the principle for generating the overturning safety factor is: The formula for calculating the overturning moment is: ; Wherein, represents the overturning moment, represents the distance from the midpoint of the pile body to the bottom of the pile foundation; The formula for calculating the anti-overturning moment is: ; ; Wherein, represents the anti-overturning moment, represents the earth pressure coefficient, represents the effective unit weight of the soil, represents the depth of the pile foundation, represents the self-weight of the pile body, represents the distance from the overturning rotation point to the bottom of the pile foundation; The formula for generating the anti-overturning safety factor is: ; Wherein, represents the anti-overturning safety factor. Further, the principle for generating the total cost is:

[0012] The formula for calculating the material cost is: ; Wherein, represents the material cost, represents the length of the pile body, represents the density of the pile body material, represents the unit price of the pile body material; The formula for calculating the construction cost is: ; Wherein, represents the construction cost, respectively represents the influence coefficient of the drilling size and the inclination angle on the construction; The formula for generating the total cost is: ; Wherein, in, This represents the total cost.

[0013] Furthermore, the principle underlying the optimization of construction parameters based on the particle swarm optimization algorithm is as follows: The formula for calculating fitness value is: ; in, Represents the fitness value. These represent the weighting coefficients for dynamic bearing capacity, overturning safety factor, and total cost, respectively. and ; Each particle corresponds to a group ,in, Indicates particle index, Indicates the first The pile depth corresponding to each particle Indicates the first The angle between the pile foundation and the horizontal plane corresponding to each particle Indicates the first The diameter of the pile corresponding to each particle Indicates the first The length of the pile corresponding to each particle; A group of particles is randomly selected and their velocities are randomly initialized. The fitness values ​​of the particles are calculated, and dynamic weights are generated based on these fitness values ​​using the following formula: ; ; in, Indicates the first The dynamic weight of each particle Indicates the initial weights, and , Indicates the current iteration number. Indicates the maximum number of iterations. Indicates the first Normalization bias of individual particles Indicates the first The fitness value of each particle. This represents the minimum fitness value in the current iteration. This represents the maximum fitness value in the current iteration; The formula used to adjust particle velocity based on dynamic weights is: ; in, Indicates the first The velocity of a particle in the (t+1)th iteration Indicates the first Velocity of the i-th particle at the t-th iteration, Indicates an individual learning factor, Indicates a social learning factor, and , Random number to avoid the algorithm falling into local optimum, and , Indicates the position of the i-th particle in the historical iteration, Indicates the position of the i-th particle in the historical iteration, Indicates the position of the i-th particle in the historical iteration, Indicates the position of the i-th particle in the historical iteration, Indicates the position of the i-th particle at the t-th iteration, Indicates the position of the i-th particle at the t-th iteration, Indicates the Euclidean distance between and And Indicates the Euclidean distance between and Indicates the Euclidean distance between and And Indicates the Euclidean distance between and

[0014] Compared with the prior art, the beneficial effects of the present application are: The present application collects hydrological data at different depths, quantifies the spatial correlation of the hydrological data through a variation function, generates continuous depth hydrological parameters through weighted interpolation, makes up for the deficiency of discrete sampling data, and improves data continuity; based on the soil body parameter calculation of the three-dimensional geological model, the static bearing capacity is generated, and then the dynamic bearing capacity is generated by superimposing the influence of dynamic water pressure, so that the pile foundation design is more in line with the actual working condition, and through segmented calculation of the pile body dynamic water pressure, combined with hydrological data and pile body inclination, the unit length dynamic water pressure is generated, which solves the defect that the traditional static empirical formula cannot reflect the dynamic hydrological change, and avoids the overturning risk caused by underestimating the dynamic water pressure in the traditional design.

[0015] The present application also calculates the overturning moment and the anti-overturning moment, generates the anti-overturning safety factor, and calculates the dynamic water pressure in segments and superimposes the overturning moment, so that the load is more in line with the actual hydrological conditions, compared with the traditional method considering a single load, the present application combines flow velocity, acceleration, soil body parameters, pile foundation geometric size and other factors, improves the calculation accuracy and improves the stability of the pile foundation. Based on the particle swarm algorithm, the construction parameters are optimized in multiple targets, the normalized deviation and iteration attenuation mechanism are introduced, the algorithm focuses on global search in the early stage and local optimization in the later stage, and the convergence speed and accuracy are improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] Fig. 1 It is the method flowchart of the embodiment of the present application; Fig. 2 It is the schematic diagram of the dynamic water pressure change at different depths of the embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to specific embodiments.

[0018] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the common meanings understood by those with ordinary skills in the art to which the present application belongs. The terms "first", "second" and similar terms used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, without excluding other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like only represent relative positional relationships, which can change accordingly when the absolute positions of the described objects change.

[0019] Embodiment: Please refer to Figs. 1-2 The present application provides a technical solution: A river embankment flood prevention pile foundation construction method based on BIM technology, the specific steps comprising: Step 1: Construct a three-dimensional geological model of the river embankment area based on BIM technology, and determine the installation position of the flood prevention pile foundation in the three-dimensional geological model. Set multiple sampling points with different underwater depths at the installation position, collect hydrological data of each sampling point, and generate continuous underwater depth hydrological data through Kriging interpolation method. Determine the actual construction parameter range based on expert evaluation, and set different construction parameter combinations within the construction parameter range. In this embodiment, the principle for constructing a three-dimensional geological model of the river embankment area based on BIM technology is: Collect topographic data, geological data and environmental data of the river embankment area. The topographic data includes ground elevation, terrain undulation and riverbed morphology. The geological data includes soil layer distribution, rock layer thickness, geological structure and groundwater level distribution. The environmental data includes the distribution of buildings, vegetation and underground pipelines around the river embankment. A laser radar is carried by a drone to collect topographic data and environmental data of the river embankment area, and a total station is used to supplement the measurement of areas that cannot be covered by the drone. Drill holes in the river embankment area to obtain soil samples and rock samples at different depths, and analyze the physical and mechanical properties of the soil layer in the laboratory, including density, water content and shear strength.

[0020] The construction parameters include pile foundation depth, pile foundation and horizontal plane angle, pile diameter and pile length. The term "flood control pile body" refers to the entire flood control pile, which consists of the pile body and the pile foundation. The pile foundation refers to the underground part of the pile body, while the part of the pile body other than the pile foundation is the pile body. Hydrological data includes water flow velocity and water flow acceleration.

[0021] In this embodiment, the principle underlying the generation of continuous underwater depth hydrological data is as follows: A coordinate system is established with the plane where the flood control piles are installed as the XOY plane and the Z-axis passing through the flood control pile installation location and perpendicular to the XOY plane upwards. The variogram is used to reflect the differences in hydrological data with distance, and the formula used is as follows: ; in, Indicates the distance between adjacent sampling points. Indicates distance as The degree of difference between the two sampling points, Indicates distance as Number of sampling points Indicates distance as The set of sampling point pairs Indicates distance as sampling point pairs, Indicates the index of the sampling point. Indicates the relationship with the first The distance between each sampling point is The index of the sampling points, Indicates the first The coordinates of each sampling point Indicates the first The coordinates of each sampling point Representing coordinates Hydrological data at the location, Representing coordinates Hydrological data at the location; The variogram reflects hydrological parameters, including the spatial dependence of water flow velocity and acceleration, and the distance between adjacent sampling points, by statistically analyzing the differences in data at different distances. The smaller the value, the higher the variability function. The smaller the value, the higher the data similarity; conversely, the larger the value, the greater the data difference. Follow When the value increases and approaches a stable value, it indicates that the hydrological data has continuous non-uniform characteristics in space.

[0022] For any unknown point, its hydrological data is the weighted sum of the hydrological data from all sampling points. The unknown point refers to all points on the pile body other than the sampling points. The formula upon which the Kriging equation is based is: ; wherein, unknown point, hydrological data at, hydrological data at, number of sampling points, contribution weight of the th sampling point to.

[0023] The purpose of the Kriging equation is to interpolate according to the data of discrete sampling points, fit the continuous spatial distribution of hydrological parameters, so as to obtain the hydrological data of the corresponding position at any known underwater depth. For unknown point , the prediction value is the weighted sum of the hydrological data of all known sampling points, weight of the th sampling point, used to reflect the contribution of the th sampling point to the unknown point, The greater the , the stronger the influence on , which is manifested as close distance or close hydrological data value, The smaller the , the weaker the influence on .

[0024] Step 2: For each construction parameter combination, the pile body is equally segmented, the hydrodynamic pressure of the position of each segment of the pile body is calculated based on the hydrological data of the pile body at different depths and the angle between the pile body and the horizontal plane, and then the unit length pile body hydrodynamic pressure is generated. The static bearing capacity of the pile body is calculated based on the soil parameters of the installation position, and the dynamic bearing capacity is generated based on the static bearing capacity of the pile body and the unit length pile body hydrodynamic pressure. In this embodiment, the principle for generating the dynamic bearing capacity is: The formula for calculating the hydrodynamic pressure of each segment of the pile body is: ; ; ; wherein, hydrodynamic pressure of the position of the th segment of the pile body, index of the segmentation of the pile body, and , number of pile body segmentation, and , means rounding up the calculation result, length of the pile body, length of the segmentation of the pile body, th segment of the pile body, ​inertia component of the segment pile body, inertia coefficient, water density, cross-sectional area of the segment pile body, the first component of the water flow acceleration at the position of the segment pile body perpendicular to the pile body, the first water flow acceleration at the position of the segment pile body, the first resistance component of the segment pile body, resistance coefficient, pile diameter, the first component of the water flow velocity at the position of the segment pile body perpendicular to the pile body, the first water flow velocity at the position of the segment pile body, inclination angle between the pile axis and the horizontal plane; The hydrodynamic pressure of each segment of the pile body is composed of two parts: the inertia component and the resistance component. The inertia component represents the dynamic force generated by the water flow acceleration on the pile body, reflecting the transient impact effect of the water flow on the pile body due to acceleration or deceleration. The inertia coefficient is related to the shape of the pile body. The pile body of a cylinder is usually taken as 1.5 to 2.0 to reflect the added mass effect. The cross-sectional area of the pile body represents the actual force area of a segment of the pile body. The greater the force area, the greater the inertia force, i.e. the vertical acceleration component, which represents the acceleration component of the water flow acceleration projected onto the normal vector direction of the pile body. The greater the vertical acceleration component, the greater the inertia force. The resistance component reflects the continuous drag force of the water flow on the pile body, reflecting the steady-state load caused by water flow erosion. The resistance coefficient is related to the roughness of the pile body surface. The value of a cylinder as a flood control pile is about 0.6 to 1.2. The formula of the resistance component is based on the fluid resistance formula . For a cylindrical pile body, when it is subjected to vertical impact of water flow, its incident area is the projected rectangular area, which is the diameter of the pile body x the segment length of the pile body. Instead of , , the direction information of the water flow velocity can be retained; the resistance component is proportional to the density of water, the vertical component of water flow velocity, the segment length and the diameter of the pile body; the hydrodynamic pressure at different depths is shown in Table 1, taken , , From the depth of 3m, a segment point is set every 0.6m, and the hydrological data at the segment point is collected, and then the hydrodynamic pressure at the sampling point is calculated. Based on the hydrological data at different depths, the hydrological phenomena at the corresponding positions can also be preliminarily judged.

[0025] Table 1. Dynamic water pressure changes with depth table

[0026] The formula for generating the dynamic water pressure of the unit length pile body is: ; Wherein, represents the dynamic water pressure of the unit length pile body; The dynamic water pressure of the unit length pile body is the average dynamic water pressure per meter of the pile body, which reflects the distribution load intensity of the water flow pile body, and is used to convert the actual non-uniform distribution of the dynamic water pressure on the pile body surface into an equivalent load acting uniformly along the pile body. The actual water flow velocity and acceleration change with depth, and the dynamic water pressure is unevenly distributed. By averaging after segmentation, the nonlinear load is converted into a uniformly distributed load.

[0027] The formula for calculating the static bearing capacity is: ; ; ; ; ; ; Wherein, represents the static bearing capacity, represents the pile end resistance, represents the pile side friction, represents the pile foundation cross-sectional area, represents the soil cohesion, represents the soil pressure on the pile end, represents the soil bulk density, represents the pile diameter, respectively represent the bearing capacity coefficients of the soil cohesion, the soil pressure on the pile end and the soil bulk density, represents the internal friction angle of the soil, represents the pile side friction, represents the pile length, represents the undrained shear strength of the soil, represents the cohesion coefficient, and ; Static bearing capacity consists of two parts: pile end resistance and pile side friction. Pile end resistance reflects the supporting capacity of the soil at the pile end for the pile foundation. Based on Terzaghi's bearing capacity theory, pile end resistance is decomposed into the contributions of cohesion, overburden pressure, and soil unit weight. Cohesion represents the chemical bond between soil particles and is the main parameter for cohesive soil to resist shear failure. Overburden pressure is the weight of the soil within the pile end embedment depth range. Soil unit weight reflects the influence of soil self-weight on shear failure, directly affecting the shear resistance and slip surface development of the soil. The greater the soil unit weight, the more difficult it is to form a slip surface. The bearing capacity coefficients of all three components depend on the internal friction angle. The internal friction angle of soil reflects its shear strength. A larger internal friction angle indicates stronger interlocking between soil particles, resulting in greater frictional resistance to overcome during shear failure. Furthermore, the inclination angle of the soil sliding surface is directly related to the internal friction angle, which determines the morphology of the failure surface. The formula for calculating the overburden bearing capacity index is based on slip line theory and reflects the contribution of overburden pressure to the pile tip resistance, i.e., the enhancing effect of the soil's self-weight above the pile tip on bearing capacity. This effect is exponentially related to the internal friction angle; a larger internal friction angle indicates a more significant influence of overburden pressure. When the pile tip is under stress, the soil enters a passive state, forming a sliding wedge. The angle between the boundary between the active and passive zones and the horizontal plane is [insert angle here]. For sandy soil, Larger Follow Exponential growth, with soil cover pressure contributing significantly to bearing capacity, is particularly relevant for clay. Approaching 0, When the value approaches 1, the soil pressure contributes almost nothing, and the bearing capacity is mainly determined by cohesion.

[0028] The cohesion bearing capacity coefficient reflects the contribution of cohesion to the pile end resistance, that is, the bond between soil particles. Based on this, Perform a Taylor expansion and take a first-order approximation. Substitute ,have to For cohesive soils, bearing capacity is mainly determined by cohesion; for non-cohesive soils such as sand, Smaller, load-bearing capacity mainly comes from and Decide.

[0029] The soil unit weight bearing capacity coefficient reflects the contribution of the soil's own weight to the pile end resistance, that is, the influence of soil weight on the development of the sliding surface. When the soil fails, the sliding surface is not only affected by... The effect is also influenced by the weight of the soil. For deep foundations or large-diameter piles, the soil's weight increases with depth. The contribution of dense sandy soil is significant. Larger, its Significant contribution, loose sand Smaller, Less impact.

[0030] Internal friction angle of soil is the core parameter of soil shear strength, which determines the shape of the sliding surface, the passive resistance of the soil, and the coupling effect of cohesion and soil bulk density. When tends to 0, the soil is almost pure clay, and the calculation regression Terzaghi bearing capacity theory at this time, when increases, and rapidly, reflecting the bearing capacity dominated by friction.

[0031] Pile side friction reflects the shear resistance between the pile and the surrounding soil, which mainly depends on the friction characteristics of the pile-soil contact surface, such as soil type and roughness, soil shear strength, and pile-soil contact area. represents the pile-soil contact area, where represents the circumference of the pile, which determines the lateral contact area of the friction force, represents the corrected actual length of the pile foundation, i.e. the contact length of the entire pile with the soil, represents the undrained shear strength of the soil, reflecting the shear resistance of cohesive soil under short-term load. The river embankment pile is in saturated soil for a long time, and the action time of dynamic hydrological load is short, so the soil drainage is limited. Therefore, the undrained shear strength of the soil is used for calculation, and the cohesion coefficient is an empirical coefficient, taking a value of 0.3 to 1.0, used to correct the deviation between theoretical friction resistance and actual value. The value of the cohesion coefficient is mainly affected by the type of soil and the roughness of the pile surface. The cohesion coefficient of cohesive soil is lower, and that of sand is higher. The rougher the pile surface, the higher the cohesion coefficient. Pile side friction is mainly used to resist horizontal load and share vertical load. Dynamic water pressure will push the pile to tilt. Pile friction provides anti-sliding force through pile-soil interaction, and pile side friction can share most of the vertical load, reducing the pile end pressure.

[0032] The formula for calculating dynamic bearing capacity is: ; where, represents the dynamic bearing capacity.

[0033] Dynamic bearing capacity is the comprehensive bearing capacity of river embankment flood control pile after superimposing dynamic hydrological load on the basis of static bearing capacity. The purpose is to reflect the stability and safety of the pile under real working conditions. Static bearing capacity reflects the ultimate bearing capacity of the pile in a static state. Dynamic water pressure reflects the impact of flowing water on the pile under different water flow velocities and accelerations. Unit length dynamic water pressure is The product of the dynamic water pressure of the whole pile body and the length of the pile body is the overturning moment generated by the dynamic water pressure on the pile body. The dynamic bearing capacity of the pile body under the influence of the dynamic water pressure is the static bearing capacity minus the dynamic water pressure. The dynamic bearing capacity is proportional to the static bearing capacity and inversely proportional to the length of the pile body and the dynamic water pressure per unit length of the pile body.

[0034] Step 3: Calculate the overturning moment generated by the dynamic water pressure on the pile body based on the dynamic water pressure at the location of each section of the pile body, calculate the anti-overturning moment of the soil on the pile foundation based on the depth of the pile foundation and the soil resistance, and generate the anti-overturning safety factor based on the overturning moment and the anti-overturning moment. In this embodiment, the principle for generating the anti-overturning safety factor is: The formula for calculating the overturning moment is: ; Wherein, represents the overturning moment, represents the distance from the midpoint of the first section of the pile body to the bottom of the pile foundation, The overturning moment reflects the rotational moment generated by the lateral force of the water flow on the pile body on the bottom of the pile. The lateral force of the water flow on the pile body is the dynamic water pressure, which may cause the pile to tilt or fall under the influence of the overturning moment. In the river embankment flood control pile foundation engineering, the dynamic water pressure is the main external load, and its action direction is perpendicular to the pile body, which will generate a lateral thrust on the pile body, and then form an overturning moment. The greater the value of the overturning moment, the poorer the stability of the pile foundation. The distance from the midpoint of the first section of the pile body to the bottom of the pile foundation represents the force arm, which can be directly measured from the distance from the midpoint of the first section of the pile body to the XOY plane, or calculated according to the known length from the midpoint of the first section of the pile body to the bottom of the pile foundation and the product of the sine value of the angle between the pile foundation and the horizontal plane. The distance from the midpoint of the first section of the pile body to the XOY plane can be directly measured, or calculated according to the known length from the midpoint of the first section of the pile body to the bottom of the pile foundation and the product of the sine value of the angle between the pile foundation and the horizontal plane. The dynamic water pressure of each section of the pile body is multiplied by the corresponding force arm, and then summed for all sections to obtain the overturning moment of the whole pile body. The greater the overturning moment, the more likely the pile foundation will tilt or fall, and the poorer the stability of the pile foundation. The formula for calculating the anti-overturning moment is:

[0035] ; ; ; Wherein, represents the anti-overturning moment, represents the soil pressure coefficient, represents the effective unit weight of the soil, represents the depth of the pile foundation, represents the self-weight of the pile body, represents the distance from the overturning rotation point to the bottom of the pile foundation. ​​​The overturning resisting moment represents the ability of the pile foundation and the surrounding soil to resist overturning, mainly composed of the soil resistance and the self-weight of the pile foundation, wherein the soil resistance represents the passive earth pressure generated by the soil around the pile foundation to resist the rotation of the pile foundation, and the self-weight of the pile foundation represents the stability moment provided by the weight of the pile foundation through the force arm; represents the soil resistance part, wherein, represents the earth pressure coefficient, reflecting the shear resistance of the soil in the passive state, and being positively correlated with the internal friction angle of the soil, and the effective unit weight of the soil represents the effective weight of unit volume of soil, which is the actual pressure stress of unit volume of soil on the underlying soil layer after deducting the buoyancy of water in the waterlogged state, reflecting the effective weight of the soil in the saturated state, and being used to represent the compactness and self-weight of the soil, and can be determined by experiments on different types of soil samples; and the pile depth represents the length of the entire pile underground, i.e. the burial depth of the pile foundation, the deeper the pile foundation is buried, the greater the passive earth pressure is, and the passive earth pressure is positively proportional to the square of the pile depth, is the total passive earth pressure per unit width, is the pile diameter, the larger the pile diameter is, the larger the contact area between the pile foundation and the soil is, and the wider the passive earth pressure is distributed, and the product of the two represents the actual moment caused by the passive earth pressure; represents the gravity of the pile body, directly increasing the stability of the overturning resistance, the higher the pile body is, the stronger the overturning resistance affected by the self-weight of the pile body is, and the overturning rotation point represents the assumed rotation fulcrum of the pile foundation when it is subjected to the overturning moment, when the pile foundation begins to tilt, the soil at a certain depth provides the maximum resistance, and this depth is the overturning rotation point, represents the distance from the overturning rotation point to the bottom of the pile foundation, i.e. the effective width of the pile foundation for overturning resistance, and the self-weight of the pile foundation is uniformly distributed, and the action point of the resultant force is located at the geometric center of the pile foundation section, i.e. , so the force arm of the self-weight moment is , represents the self-weight of the pile body which generates the overturning resisting moment through the force arm .

[0036] The formula for generating the overturning resistance safety factor is: ; wherein, represents the overturning resistance safety factor.

[0037] The overturning resistance safety factor is generated based on the ratio of the overturning resisting moment to the overturning moment, and is used to quantify the stability margin of the pile body, when ​When the anti-overturning torque is greater than the overturning torque, the pile foundation is stable, and the anti-overturning safety factor can be used to evaluate the multiple of the anti-overturning torque relative to the overturning torque, and the multiple minus 1 is the current safety margin; when the anti-overturning torque is equal to the overturning torque, the pile foundation is at an overturning balance point; when the anti-overturning torque is greater than the overturning torque, the overturning risk is greater than the resistance capacity, and the pile foundation may be unstable.

[0038] Step 4: generating a material cost based on the volume of the pile body and the material price per unit volume, generating a construction cost based on the construction parameters of the pile foundation, and generating a total cost based on the material cost and the construction cost; In this embodiment, the principle for generating the total cost is as follows: The formula for calculating the material cost is as follows: ; Wherein, represents the material cost, represents the length of the pile body, represents the material density of the pile body, represents the unit price of the pile body material; The material cost represents the cost of purchasing the entire pile body, which is the product of the material cost per unit mass and the total mass of the material.

[0039] The formula for calculating the construction cost is as follows: ; Wherein, represents the construction cost, respectively represent the influence coefficient of the drilling size and the inclination angle on the construction; The construction cost includes the drilling size part and the inclination angle part. The drilling size is determined by the pile foundation depth and the pile body diameter. The deeper the drilling and the larger the diameter, the greater the construction difficulty and resource consumption, including drilling power, time, energy consumption, etc. The drilling size is quantified by Dxd, and the influence coefficient is used to convert the drilling size into actual cost; the inclination angle represents the angle between the pile foundation and the horizontal plane. The larger the angle, the greater the construction difficulty, and more complex positioning, supporting and calibration techniques are required. The influence coefficient is used to convert the inclination angle into actual cost, based on the construction cost required per unit area or volume of drilling, based on the cost generated by inclined construction, which can be obtained based on expert evaluation based on historical construction data.

[0040] The formula for generating the total cost is as follows: ; Wherein, Total cost.

[0041] Step 5: Calculate the fitness value of each particle with the optimization objectives of maximizing dynamic bearing capacity, maximizing overturning safety factor and minimizing total cost, optimize the construction parameters based on particle swarm algorithm, record the optimal position of each particle and the optimal position of all particles at each iteration, adjust the particle velocity of the next iteration according to the fitness value and the particle velocity of the current iteration, output the historical optimal position of all particles as the optimal construction parameters when the maximum iteration number is reached.

[0042] The principle for optimizing the construction parameters based on the particle swarm algorithm is: The formula for calculating the fitness value is: ; Wherein, represents the fitness value, respectively represent the weight coefficients of dynamic bearing capacity, overturning safety factor and total cost, and ; The fitness value represents the comprehensive consideration of dynamic bearing capacity, overturning safety factor and total cost, which integrates the three objectives into a comprehensive index. Dynamic bearing capacity reflects the actual bearing capacity of pile foundation under dynamic water pressure, which is the core index of engineering safety. Overturning safety factor is used to measure the ability of pile foundation to resist tilting, which directly affects the stability of pile foundation. Total cost reflects the economy of pile foundation installation. For a set of construction parameters, the larger the fitness value, the better the scheme. The fitness value is proportional to dynamic bearing capacity and overturning safety factor, and inversely proportional to total cost. The core requirement of flood control pile foundation is safety and stability of pile foundation, and the cost is minimized under the premise of ensuring the two, so the fitness value is taken as , , . Each particle corresponds to a set of , wherein, represents the particle index, represents the pile depth corresponding to the th particle, represents the angle between the pile and the horizontal plane corresponding to the th particle, represents the pile diameter corresponding to the th particle, represents the pile length corresponding to the th particle; Randomly select a set of particles and randomly initialize the particle velocity, calculate the fitness value of the particle, generate dynamic weight based on the fitness value of the particle, and the formula is: ; ; wherein, denotes the dynamic weight of the i-th particle, denotes the initial weight, and , , denotes the current iteration number, denotes the maximum iteration number, denotes the normalized deviation of the i-th particle, denotes the fitness value of the i-th particle, denotes the minimum fitness value in the current iteration, denotes the maximum fitness value in the current iteration; adjusts the particle velocity based on the dynamic weight, and the formula is: ; ; wherein, denotes the velocity of the i-th particle in the t+1-th iteration, denotes the velocity of the i-th particle in the t-th iteration, denotes the individual learning factor, denotes the social learning factor, and , is a random number to avoid the algorithm falling into local optimum, and , denotes the position of the i-th particle in the historical iteration which makes the fitness value maximum, , denotes the position of all particles in the historical iteration which makes the fitness value maximum, i.e. the historical optimum position, denotes the position of the i-th particle in the t-th iteration, denotes the Euclidean distance between and denotes the Euclidean distance between and .

[0043] ​​​​​​The normalized deviation of the particle reflects the gap between the current solution of the particle and the optimal solution, the optimal solution being the maximum fitness value in the current iteration, the worst solution representing the minimum fitness value in the current iteration, and the current solution being the fitness value calculated in real time. The closer the current solution is to the optimal solution, the better the optimization process, and the smaller the normalized deviation. The dynamic weight combines the normalized deviation and the number of iterations. In the early stage of iteration, the number of iterations is much smaller than the maximum number of iterations, and the dynamic weight is larger, so the particle velocity is more strongly affected by the historical velocity, tending to global search and avoiding falling into local optimum. In the later stage of iteration, the number of iterations tends to the maximum number of iterations, The Euclidean distance between the particle in the current iteration and the position with the maximum fitness value of the particle in the historical iteration is represented. The larger the Euclidean distance, the closer the current solution is to the historical optimal position, and the speed change is slowed down to further search in the current solution region. The smaller the Euclidean distance, the farther the current solution is from the historical optimal position, and the particle speed change is accelerated to move away from the poor solution region. The iteration process is repeated until the upper limit of the number of iterations is reached. When the upper limit of the number of iterations is reached, the particle corresponding to the current solution is output as the global optimal solution. The optimal construction parameter is set according to the global optimal solution.

[0044] The above formulas are dimensionless values calculated, and the formulas are obtained by software simulation of a large amount of data to obtain a formula closest to the actual situation. The preset parameters in the formula are set by a person skilled in the art according to the actual situation.

[0045] The above embodiments can be realized wholly or partially by software, hardware, firmware or any combination thereof. When realized by software, the above embodiments can be realized in the form of a computer program product wholly or partially. Those skilled in the art can realize that the units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized by hardware or software methods depends on the specific application and design constraints of the technical solutions.

[0046] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, which can be located in one place or distributed on multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiments according to actual needs.

[0047] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for constructing river embankment flood control pile foundations based on BIM technology, characterized in that, The specific steps include: Step 1: Construct a three-dimensional geological model of the river embankment area based on BIM technology, determine the installation location of flood control pile foundations in the three-dimensional geological model, set multiple sampling points at different underwater depths at the installation locations, collect hydrological data at each sampling point, and generate continuous underwater depth hydrological data through Kriging interpolation. Determine the actual construction parameter range based on expert evaluation, and set different combinations of construction parameters within the construction parameter range. Step 2: For each combination of construction parameters, the pile body is divided into equidistant segments. Based on the hydrological data of the pile body at different depths and the angle between the pile body and the horizontal plane, the dynamic water pressure at the location of each segment of the pile body is calculated, thereby generating the dynamic water pressure per unit length of the pile body. Based on the soil parameters at the installation location, the static bearing capacity of the pile body is calculated. Based on the static bearing capacity of the pile body and the dynamic water pressure per unit length of the pile body, the dynamic bearing capacity is generated. Step 3: Calculate the overturning moment of the pile body based on the hydrodynamic pressure at the location of each pile segment, calculate the overturning moment of the soil on the pile foundation based on the pile depth and soil resistance, and generate the overturning safety factor based on the overturning moment and the overturning moment. Step 4: Generate material cost based on pile volume and material price per unit volume; generate construction cost based on pile foundation construction parameters; and generate total cost based on material cost and construction cost. Step 5: With the optimization objectives of maximizing dynamic bearing capacity, maximizing the overturning safety factor, and minimizing total cost, calculate the fitness value of each particle, optimize the construction parameters based on the particle swarm optimization algorithm, record the optimal position of a single particle and the optimal position of all particles in each iteration, adjust the particle velocity for the next iteration based on the fitness value and the particle velocity of the current iteration, and output the historical optimal position of all particles as the optimal construction parameters when the maximum number of iterations is reached.

2. The method for constructing river embankment flood control pile foundations based on BIM technology according to claim 1, characterized in that: The construction parameters in step 1 include pile foundation depth, the angle between the pile foundation and the horizontal plane, the pile diameter, and the pile length. The term "flood control pile body" refers to the entire flood control pile, which consists of the pile body and the pile foundation. The pile foundation refers to the underground part of the pile body, while the part of the pile body other than the pile foundation is the pile body. Hydrological data includes water flow velocity and water flow acceleration.

3. The method for constructing river embankment flood control pile foundations based on BIM technology according to claim 2, characterized in that: The formula used to generate continuous depth hydrological data in step 1 is: Establish a coordinate system with the horizontal plane as the XOY plane and the vertical upward axis as the Z-axis. The variogram is used to reflect the differences in hydrological data with distance, and the formula used is as follows: ； in, Indicates the distance between adjacent sampling points. Indicates distance as The degree of difference between the two sampling points, Indicates distance as Number of sampling points Indicates distance as The set of sampling point pairs Indicates distance as sampling point pairs, Indicates the index of the sampling point. Indicates the relationship with the first The distance between each sampling point is The index of the sampling points, Indicates the first The coordinates of each sampling point Indicates the first The coordinates of each sampling point Representing coordinates Hydrological data at the location, Representing coordinates Hydrological data at the location; For any unknown point, its hydrological data is the weighted sum of the hydrological data from all sampling points. The unknown point refers to all points on the pile body other than the sampling points. The formula upon which the Kriging equation is based is: ； in, To represent an unknown point, express Hydrological data at the location, Indicates the number of sampling points. Indicates the first Each sampling point pair The contribution weight.

4. The method for constructing river embankment flood control pile foundations based on BIM technology according to claim 1, characterized in that: The principle underlying the generation of dynamic bearing capacity in step 2 is as follows: The formula used to calculate the dynamic water pressure of each pile segment is as follows: ； ； ； in, Indicates the first The dynamic water pressure at the location of the pile segment, Indicates the index of the pile segment, and , Indicates the number of segments in the pile body, and , This indicates that the calculation result is rounded up. Indicates the length of the pile body. Indicates the length of each segment of the pile body. Indicates the first The inertial component of the pile segment, Represents the coefficient of inertia. This indicates the density of water. This represents the cross-sectional area of ​​a section of the pile. Indicates the first The component of the water flow acceleration perpendicular to the pile body at the location of the pile section. Indicates the first The water flow acceleration at the location of the pile section, Indicates the first The resistance component of the pile segment, Indicates the drag coefficient. Indicates the diameter of the pile. Indicates the first The component of the water flow velocity perpendicular to the pile body at the location of the pile section. Indicates the first The water flow velocity at the location of the pile section Indicates the angle between the pile axis and the horizontal plane; The formula used to generate the hydrodynamic pressure per unit length of the pile is: ； in, This indicates the hydrodynamic pressure per unit length of the pile. The formula used to calculate static bearing capacity is: ； ； ； ； ； ； in, Indicates static bearing capacity. Indicates the pile end resistance. This represents the frictional force on the pile side. This indicates the cross-sectional area of ​​the pile foundation. Indicates soil cohesion. Indicates the soil pressure at the pile tip. Indicates the unit weight of the soil. Indicates the diameter of the pile. These represent the bearing capacity coefficients of soil cohesion, pile tip overburden pressure, and soil unit weight, respectively. Indicates the internal friction angle of the soil. This represents the frictional force on the pile side. Indicates the length of the pile. Indicates the undrained shear strength of the soil. Indicates the adhesion coefficient, and ; The formula used to calculate dynamic bearing capacity is: ； in, This indicates dynamic bearing capacity.

5. The method for constructing river embankment flood control pile foundations based on BIM technology according to claim 4, characterized in that: The principle underlying the generation of the anti-overturning safety factor in step 3 is as follows: The formula used to calculate the overturning moment is: ； in, Indicates the overturning moment. Indicates the first The distance from the midpoint of the pile segment to the pile base; The formula used to calculate the overturning moment is: ； ； in, Indicates the anti-overturning moment. Indicates the earth pressure coefficient. Indicates the effective unit weight of the soil. Indicates the depth of the pile foundation. Indicates the self-weight of the pile. This indicates the distance from the point of overturning to the base of the pile; The formula for generating the overturning safety factor is: ； in, This indicates the overturning safety factor.

6. The method for constructing river embankment flood control pile foundations based on BIM technology according to claim 5, characterized in that: The principle underlying the generation of the total cost in step 4 is as follows: The formula used to calculate material costs is: ； in, Indicates material cost, Indicates the length of the pile. Indicates the density of the pile material. This indicates the unit price of the pile material; The formula used to calculate construction costs is: ； in, Indicates construction cost, These represent the influence coefficients of borehole size and inclination angle on construction, respectively. The formula for calculating the total cost is as follows: ； in, This represents the total cost.

7. The method for constructing river embankment flood control pile foundations based on BIM technology according to claim 6, characterized in that: The principle underlying the optimization of construction parameters based on the particle swarm optimization algorithm in step 4 is as follows: The formula for calculating fitness value is: ； in, Represents the fitness value. These represent the weighting coefficients for dynamic bearing capacity, overturning safety factor, and total cost, respectively. and ; Each particle corresponds to a group ,in, Indicates particle index, Indicates the first The pile depth corresponding to each particle Indicates the first The angle between the pile foundation and the horizontal plane corresponding to each particle Indicates the first The diameter of the pile corresponding to each particle. Indicates the first The length of the pile corresponding to each particle; A group of particles is randomly selected and their velocities are randomly initialized. The fitness values ​​of the particles are calculated, and dynamic weights are generated based on these fitness values ​​using the following formula: ； ； in, Indicates the first The dynamic weight of each particle Indicates the initial weights, and , Indicates the current iteration number. Indicates the maximum number of iterations. Indicates the first Normalization bias of individual particles Indicates the first The fitness value of each particle. This represents the minimum fitness value in the current iteration. This represents the maximum fitness value in the current iteration; The formula used to adjust particle velocity based on dynamic weights is: ； in, Indicates the first The velocity of a particle in the (t+1)th iteration Indicates the first The velocity of a particle in the t-th iteration Represents individual learning factors. Represents the social learning factor, and , To avoid the algorithm getting trapped in local optima of random numbers, and , Indicates the first Individual particles make, in the historical iteration The largest position, This represents the position where all particles maximize their fitness value throughout the historical iterations, i.e., the historical best position. Indicates the first The position of a particle at the t-th iteration express and The Euclidean distance between them express and The Euclidean distance between them.

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