Method and system for analyzing bearing performance of vertically-pressed foundation pile in self-weight collapsible loess

Abstract

The invention relates to the technical field of pile foundations, and provides a method and system for analyzing the bearing performance of a vertically-pressed foundation pile in self-weight collapsible loess, and the method comprises the steps that the foundation pile and soil around the foundation pile are discretized into strip blocks, and the exertion function of pile-soil interface side friction resistance of each block and the self-weight collapsible deformation amount of the soil around the foundation pile are obtained through indoor test analysis; for each strip block, obtaining the pile-soil interface side frictional resistance based on a exerting function, and sequentially calculating the normal stress of the lower section of each strip block from top to bottom according to a static balance relationship; based on the pile-soil interface side friction resistance and the pile end resistance of each block, after the pile end settlement amount is obtained through calculation, the pile end settlement amount and the pile top vertical displacement are compared, if the pile end settlement amount and the pile top vertical displacement are not equal, the pile top vertical displacement is adjusted, and the process returns to recalculate the normal stress of the lower section of each block; if yes, the strip blocks with the dead weight collapsing deformation equal to the vertical displacement of the pile top of the soil around the pile serve as neutral points, and negative frictional resistance distribution and positive frictional resistance distribution are determined. The problems of high cost and long period of an in-situ test method are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of pile foundations, and particularly relates to a method and a system for analyzing the bearing performance of vertical compression foundation piles in self-weight collapsible loess. Background Technique

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] When carrying out engineering construction in a self-weight collapsible loess foundation, the pile foundation has the advantages of large treatment depth, high bearing capacity, strong anti-deformation ability, wide formation adaptability, mature construction technology, etc., making it a widely used foundation form and foundation treatment method for engineering projects in industries such as transportation, electric power, energy, water conservancy, and construction. In a self-weight collapsible loess site, due to the settlement of the soil mass under the action of saturated self-weight, negative skin friction is generated on the pile, which increases the axial force of the pile body and significantly reduces the bearing capacity, and the settlement deformation of the pile foundation increases significantly. The distribution of negative skin friction and the position of the neutral point have very important effects on ensuring project safety and reasonably controlling project costs.

[0004] However, the process of exerting the bearing capacity of the pile foundation under the condition of self-weight collapse deformation is very complex, related to many aspects such as the properties of the soil around the pile, the pile top load, the pile bottom bearing stratum, and the settlement deformation distribution of the soil around the pile. There are many parameters involved and it cannot be simulated and calculated with a rigorous mathematical formula. At present, the methods for determining the distribution of negative skin friction and the position of the neutral point are mainly divided into in-situ testing methods, empirical analysis methods, numerical analysis methods, etc.

[0005] The in-situ testing method is mainly carried out through the single-pile vertical static load immersion test. This testing method is relatively close to the actual engineering conditions, and relatively reliable results can be obtained through reasonable testing means (soil deformation testing, pile body axial force or deformation testing, etc.). However, this method has a high cost, a long test period, and high requirements for deformation and internal force testing.

[0006] The empirical analysis method is to make an analogy through the experience of similar projects and directly recommend the values of negative skin friction and the position of the neutral point. This method is simple and easy to implement, and is also widely used in the current domestic specifications. However, it relies on existing engineering experience, cannot fully consider the influence of conditions such as pile top load and soil settlement distribution around the pile, and compared with the actual situation, the recommended values are mostly conservative.

[0007] The numerical analysis method is a method that emerged with the development of computer technology. It transforms complex physical problems into computable mathematical models through methods such as finite difference, finite element, and discrete element. However, due to the very complex constitutive model of soil and the fuzzy relationship between macroscopic and microscopic parameters, in the academic and engineering fields of geotechnical engineering, it is generally only used as a qualitative analysis tool, and its calculation results often deviate greatly from the actual situation. Summary of the Invention

[0008] In order to solve the technical problems existing in the above-mentioned background art, the present invention provides a method and system for analyzing the bearing performance of vertically compressed foundation piles in self-weight collapsible loess. The foundation pile and the soil around the pile are discretized into blocks. Through indoor tests, the side friction resistance at the pile-soil interface of each block and the self-weight collapsible deformation of the soil around the pile are obtained. An iterative calculation model is established using the static equilibrium relationship. By analyzing and calculating the iterative calculation model, multiple parameters such as pile top deformation, neutral point position, negative friction resistance distribution, positive friction resistance distribution, and pile tip resistance are obtained simultaneously, solving the problems of high cost and long cycle of in-situ testing methods.

[0009]

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011]

[0010] The first aspect of the present invention provides a method for analyzing the bearing performance of vertically compressed foundation piles in self-weight collapsible loess, which includes:

[0012]

[0011] The foundation pile and the soil around the pile are discretized into blocks. Through indoor test analysis, the mobilization function of the side friction resistance at the pile-soil interface of each block and the self-weight collapsible deformation of the soil around each block are obtained.

[0012]

[0012] The vertical displacement of the pile top is initialized. For each block, after obtaining the side friction resistance at the pile-soil interface of itself based on the mobilization function of the side friction resistance at the pile-soil interface, the normal stress of the lower section of each block is calculated sequentially from top to bottom according to the static equilibrium relationship, and the normal stress of the lower section of the pile tip is used as the pile tip resistance. After calculating the settlement of the pile tip based on the side friction resistance at the pile-soil interface of each block and the pile tip resistance, compare the settlement of the pile tip and the vertical displacement of the pile top. If the two are not equal, adjust the vertical displacement of the pile top and return to recalculate the normal stress of the lower section of each block. If the two are equal, the vertical displacement of the pile top is used as the pile top deformation, the block where the self-weight collapsible deformation of the soil around the pile is equal to the vertical displacement of the pile top is used as the neutral point, and the negative friction resistance distribution and the positive friction resistance distribution are determined based on the center point.

[0013]

[0013] Furthermore, the side friction resistance at the pile-soil interface of each block above the center point is the negative friction resistance distribution, and the side friction resistance at the pile-soil interface of each block below the center point is the positive friction resistance distribution.

[0014]

[0014] Furthermore, the indoor test analysis includes: determining the dry density through indoor geotechnical tests, calculating the actual unit weight of each block at a given water content based on the dry density, and calculating the self-weight stress of each block of soil. After calculating the earth pressure received by each block of soil based on the self-weight stress of each block of soil, the side friction resistance at the pile-soil interface of each block is obtained through the pile-soil interface friction resistance test experiment.

[0015]

[0015] Further, the indoor test analysis includes: determining the self-weight collapsibility coefficient of the soil around the pile through the collapsibility test of loess, and calculating the self-weight collapsibility deformation of the soil around the pile for each block by combining the thickness of each block.

[0016] Further, the calculation of the pile tip settlement adopts the Mindlin solution or the load transfer method.

[0017] Further, if the pile tip settlement is greater than the vertical displacement of the pile top, the vertical displacement of the pile top is increased by half of the difference between the two.

[0018] Further, if the pile tip settlement is less than the vertical displacement of the pile top, the vertical displacement of the pile top is decreased by half of the difference between the two.

[0019] The second aspect of the present invention provides a vertical compression pile bearing performance analysis system in self-weight collapsible loess, which includes:

[0020] A test analysis module, which is configured to: discretize the foundation pile and the soil around the pile into blocks, and obtain the mobilization function of the side friction resistance at the pile-soil interface of each block and the self-weight collapsibility deformation of the soil around the pile for each block through indoor test analysis;

[0021] An iterative analysis module, which is configured to: initialize the vertical displacement of the pile top; for each block, after obtaining the side friction resistance at the pile-soil interface of itself based on the mobilization function of the side friction resistance at the pile-soil interface, calculate the normal stress at the lower cross-section of each block in turn from top to bottom according to the static equilibrium relationship, and take the normal stress at the lower cross-section of the pile tip as the pile tip resistance; after calculating the pile tip settlement based on the side friction resistance at the pile-soil interface of each block and the pile tip resistance, compare the pile tip settlement with the vertical displacement of the pile top. If the two are not equal, adjust the vertical displacement of the pile top and return to recalculate the normal stress at the lower cross-section of each block; if the two are equal, take the vertical displacement of the pile top as the pile top deformation, take the block with the self-weight collapsibility deformation of the soil around the pile equal to the vertical displacement of the pile top as the neutral point, and determine the distribution of negative skin friction and positive skin friction based on the center point.

[0022] The third aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the steps in the method for analyzing the bearing performance of a vertical compression pile in self-weight collapsible loess as described above.

[0023] The fourth aspect of the present invention provides a computer device, which includes a computer-readable storage medium, a processor, and a computer program stored on the computer-readable storage medium and executable on the processor. When the processor executes the program, it implements the steps in the method for analyzing the bearing performance of a vertical compression pile in self-weight collapsible loess as described above.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The present invention discretizes the strip-shaped base piles and the soil around the piles. Through indoor tests and analysis, the side friction resistance of the pile-soil interface of each strip and the self-weight collapsible deformation amount of the soil around the piles of each strip are obtained. An iterative calculation model is established using the static equilibrium relationship. By analyzing and calculating the iterative calculation model, multiple parameters such as pile top deformation, neutral point position, negative friction resistance distribution, positive friction resistance distribution, and pile tip resistance are obtained simultaneously, solving the problems of high cost and long cycle of in-situ testing methods.

[0026] The present invention takes into account various factors such as pile top load, settlement distribution of the soil around the pile, self-weight of the pile body, and properties of the soil at the pile tip, solving the problem that the empirical analysis method considers too few factors.

[0027] The present invention has clear physical concepts, significantly reduces the calculation amount compared with the numerical analysis method, and also solves the problem of fuzzy parameters in the numerical analysis method. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0029] Figure 1 is a flowchart for iterative calculation of the static equilibrium of the pile body in the first embodiment of the present invention;

[0030] Figure 2 is a schematic diagram of the vertical bearing and discretization of the base pile in the first embodiment of the present invention;

[0031] Figure 3 is a schematic diagram of the deformation distribution of the pile and soil in the first embodiment of the present invention;

[0032] Figure 4 is a schematic diagram of the static equilibrium of each strip of the pile body in the first embodiment of the present invention;

[0033] Figure 5 is a schematic diagram of the structure of a computer device in the fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0036] Term Explanation:

[0037] Bearing pile: A pile is a vertical or inclined foundation member set in soil, whose function is to penetrate soft soil layers or water and transfer the load borne by the pile to a harder and denser deep foundation bearing stratum; A pile foundation is composed of piles and a pile cap connected to the pile top; A single pile in a pile foundation is called a bearing pile.

[0038] Negative skin friction: The downward frictional force exerted by the soil around the pile on the pile surface due to reasons such as self-consolidation, collapsibility, and ground load of the soil around the pile, which causes a settlement greater than that of the bearing pile.

[0039] Self-weight collapsible loess: Loess that, under the saturated self-weight pressure of the overlying soil and when wetted by water, undergoes rapid destruction of its structure and significant additional settlement.

[0040] Collapse deformation: The additional settlement that occurs when collapsible loess or other collapsible soils are wetted by water after settlement has stabilized under a certain pressure.

[0041] Coefficient of self-weight collapsibility: The additional settlement produced when a unit thickness of soil is saturated with water after settlement has stabilized under the saturated self-weight pressure of the overlying soil.

[0042] Neutral point: When the soil around the upper part of the pile undergoes downward settlement deformation relative to the bearing pile, it causes negative skin friction on the pile, which in turn drives the pile body to settle downward. At the same time, the soil around the lower part of the pile provides resistance to the settlement of the pile (positive skin friction). The point where the positive and negative skin frictions around the pile are converted is the neutral point. At the neutral point, the settlement deformation of the pile and the soil around the pile are equal, and the frictional force of the soil around the pile is zero.

[0043] Embodiment 1

[0044] This embodiment provides a method for analyzing the bearing performance of vertically compressed bearing piles in self-weight collapsible loess.

[0045] The purpose of this embodiment is to propose a method for analyzing the bearing performance of vertically compressed bearing piles in self-weight collapsible loess that can comprehensively consider various factors such as the properties of the soil around the pile, the load on the pile top, the properties of the pile bottom bearing stratum, and the settlement deformation distribution of the soil around the pile, and is consistent with the actual engineering situation, low-cost, short-cycle, and simple and easy to implement, so as to reasonably determine the distribution of negative skin friction of the bearing pile, the position of the neutral point, and parameters crucial for pile foundation design and construction such as the deformation of the bearing pile.

[0046] The method for analyzing the bearing performance of vertically compressed bearing piles in self-weight collapsible loess provided in this embodiment determines the basic physical and mechanical parameters (natural unit weight γ, dry density ρ d , water content w, degree of saturation S r (parameters related to the water content), effective internal friction angle ), calculate the unit weight and self-weight stress distribution of each soil layer in the site under different water contents, and determine the correlations between the pile-soil interface friction resistance, soil pressure, water content (saturation), and relative displacement between various loess layers and the pile shaft through laboratory tests, obtaining the pile-soil interface friction resistance f si and soil pressure e si , water content (saturation S ri ), and relative displacement ds i . Based on the above functional relationships, analyze the development of the friction resistance at the pile-soil interface. si (e si , S ri , ds i ).

[0047] The method for analyzing the bearing performance of vertical compression foundation piles in self-weight collapsible loess provided in this embodiment includes the following steps:

[0048] Step 1: Since the stiffness of the foundation pile is much greater than that of the surrounding soil, the foundation pile is regarded as a rigid body, and its shaft deformation under vertical load is not considered.

[0049] Step 2: For the water content and saturation distribution of the soil around the pile, obtain them through manual setting or other methods for calculation or testing.

[0050] The water content and saturation distribution of the soil around the pile can be obtained through manual setting or other methods for calculation and testing, and used as known conditions for calculating the self-weight stress (Step 4), self-weight collapse amount (it is generally considered that soil layers with a saturation Sr greater than 85% may undergo self-weight collapse deformation), and the calculation of the lateral friction resistance τ i at the pile-soil interface of each strip in the iterative calculation of Step 6.

[0051] Step 3: Discretize the foundation pile and the surrounding soil into strips, as Figure 2 shown.

[0052] Step 4: According to the dry density ρ di of the soil around the pile measured by indoor geotechnical tests, calculate the actual unit weight γ i of each strip under the given water content w i , and then calculate the self-weight stress G si of each strip of soil. The calculation process is as follows:

[0053] γ i = (1 + w i )ρ di g

[0054]

[0055] where g is the acceleration due to gravity, and h m is the thickness of the m-th strip.

[0056] According to the self-weight stress G of each soil mass block si , calculate the earth pressure e received by each soil mass block si , and use it to calculate the side friction τ between the pile and the soil for each soil mass block according to the function f of the mobilization of the friction resistance at the pile-soil interface si (e si , S ri , ds i )(The function of the mobilization of the friction resistance at the pile-soil interface is obtained through the test of the friction resistance at the pile-soil interface) as follows: i :

[0057]

[0058] In the formula, K0 is the coefficient of lateral earth pressure at rest, which is calculated through , is the effective internal friction angle. f si () refers to the function itself, e si refers to the earth pressure received by each soil mass block, S ri refers to the degree of saturation of each soil mass block, ds i is the relative displacement between the pile and the soil interface.

[0059] Step 5: According to the "Building Standards for the Loess Region with Collapsible Soils", use the coefficient of self-weight collapsibility δ of the soil around the pile zsi (δ zsi determined through the collapsibility test of loess) to obtain the self-weight collapsible deformation Δ of the soil around the pile for each soil mass block zsi (as shown in Figure 3 ), and the calculation process is as follows:

[0060]

[0061] Among them, means that m accumulates from the lower limit depth of collapsibility to the i-th soil mass block from bottom to top; β0 is the calculation correction coefficient, and the value is selected according to Table 4.4.3 of the "Building Standards for the Loess Region with Collapsible Soils"; h m is the thickness of the m-th soil mass block.

[0062] The calculation result of the self-weight collapsible deformation is used in step 601. According to the self-weight collapsible deformation and the pile top displacement value, determine the position l0 of the neutral point (that is, the position of the pile body corresponding to the point where the two values are equal).

[0063] Step 6: Perform iterative calculation on the static equilibrium of the pile body. The iterative calculation process is as shown in Figure 1 , and the specific calculation method and steps are as follows:

[0064] Step 601: Randomly set the initial value S1 of the iterative calculation of the vertical displacement of the pile top. Since the foundation pile is a rigid body, the vertical displacement at each part of the pile body is S1.

[0065] Step 602: For the 1st block, calculate the normal stress σ of the lower cross-section according to the static equilibrium relationship d1 :

[0066]

[0067] where R refers to the radius of the foundation pile.

[0068] Step 603: Calculate the normal stress σ of the lower cross-section of the 2nd to the i-th block successively from top to bottom according to the static equilibrium relationship di :

[0069] For the 2nd block,

[0070]

[0071] For the i-th block,

[0072]

[0073] In the formula: N is the vertical load applied to the pile top; G i is the self-weight of the pile body of the i-th block; l i is the height of the pile body of the i-th block, τ i is the side friction of the i-th block of the pile, and the downward direction is negative and the upward direction is positive.

[0074] As Figure 4 shown, according to the static equilibrium, the normal stress σ of the upper cross-section of the i-th block of the pile ui is equal to the normal stress σ of the lower cross-section of the (i - 1)-th block of the pile, that is: σ di-1 = σ ui = σ di-1 .

[0075] Step 604: For the pile tip (the last block, denoted as the n-th block), the normal stress σ of its lower cross-section dn is the pile tip resistance q p .

[0076] Step 605: Calculate the pile tip settlement S i according to the distribution of the pile side friction (i.e., the side friction τ dn ) at the pile-soil interface of each block and the value of the tip resistance (σ b ). Calculation methods such as the Mindlin solution or the load transfer method can be selected.

[0077] Among them, the steps of the Mindlin solution include:

[0078] ① Use the Mindlin solution to calculate the distribution of the additional stress in the soil around the pile under the action of the pile side friction and the tip resistance. The formula for the additional stress σ at any point (x, y, z) in the half-space is as follows: z The calculation formula is as follows:

[0079]

[0080] The calculation here is to equate the side resistance and end resistance of each strip to a concentrated load, and calculate the additional stress σ of the equivalent concentrated load at any coordinate (x, y, z) point under the ground surface through the Mindlin solution. z , z0 refers to the depth of the equivalent concentrated load from the ground.

[0081] Where P is the concentrated load at depth z0 below the surface of the elastic half-space (i.e. P in ② and ③). si and P b ), v is the Poisson’s ratio of the soil (according to the type of soil around the pile, the empirical value can be taken according to Article 10.2.5 of the Code for Geotechnical Engineering Investigation. For collapsible loess, its range is generally between 0.35 and 0.42).

[0082]

[0083] ② The pile side friction resistance τ of each block i , which is approximately equivalent to the concentrated load P si =2τ i πRl i , P si is the concentrated load equivalent to the lateral friction of the i-th block, τ i is the lateral friction of the ith block, R is the radius of the pile, l i is the length of the i-th bar, and the side resistance τ of each bar is calculated using the formula in step ①. i The additional vertical stress σ generated at any point (x, y, z) in the soil around the pile zsi , and then accumulate them to obtain the total additional stress generated by the pile side resistance at any point (x, y, z) in the soil around the pile:

[0084] ③ The pile end resistance q p The equivalent is a concentrated load P acting on the center of the pile end plane. b =q b πR 2 , use the formula in step ① to calculate P b The additional vertical stress σ generated at any point (x, y, z) in the soil around the pile zb (x,y,z).

[0085] ④ The soil layer from the pile end to the calculated depth is divided into a layers. The calculated depth is generally taken as the depth where the ratio of additional stress to self-weight stress is less than a certain limit value (such as 0.2).

[0086] ⑤ For the jth layer of soil, determine the coordinates of its midpoint (x j ,yj , z j ), calculate the total additional stress generated by the shaft resistance and tip resistance of the pile at this point, and use it as the average total additional stress of this layer:

[0087]

[0088] ⑥ According to the compression modulus E of each layer of soil sj , use the formula to calculate the layer-by-layer compression of each layer of soil below the pile tip. Δhj refers to the thickness of the j-th layer of soil below the pile tip, Esj refers to the compression modulus of the j-th layer of soil below the pile tip, and Δs j refers to the compression deformation of the j-th layer of soil below the pile tip under the action of shaft resistance and tip resistance of the pile.

[0089] ⑦ Accumulate the layer-by-layer compression Δs j to obtain the settlement of the pile tip

[0090] Step 606, compare the magnitude relationship between S b and S1:

[0091] If S b > S1, increase S1, and the increase amount can be (S b - S1) / 2, then return to step 602 to start the next iterative calculation;

[0092] If S b < S1, decrease S1, and the decrease amount can be (S1 - S b ) / 2, then return to step 602 to start the next iterative calculation;

[0093] If S b = S1, it indicates that the iterative calculation has converged, the iterative calculation ends, and the position where the self-weight collapsible deformation amount Δ of the soil around the pile is equal to the settlement value S1 of the pile foundation is the neutral point position. zsi

[0094] Step 607, in the last iterative calculation, the pile top deformation at which the iterative calculation converges (i.e., S1 at the time of calculation convergence), the neutral point position (i.e., l0 at the time of calculation convergence), the negative skin friction distribution (i.e., τ of each block above the l0 point at the time of calculation convergence) i ), the positive skin friction distribution (i.e., τ of each block below the l0 point at the time of calculation convergence) i ), and the tip resistance of the pile (i.e., σ of the bottommost block at the time of calculation convergence) dn ), are the reasonable and finally required results.

[0095] The method for analyzing the bearing capacity of vertically compressed foundation piles in self-weight collapsible loess provided by this embodiment first obtains the function of the mobilization of the frictional resistance at the pile-soil interface through indoor geotechnical tests, discretizes the foundation pile and the soil around the pile into blocks, and establishes an iterative calculation model using the static equilibrium relationship; through the analysis and calculation of the model, multiple parameters such as the pile top deformation, the position of the neutral point, the distribution of negative skin friction, the distribution of positive skin friction, and the pile tip resistance are obtained simultaneously, solving the problems of high cost and long cycle of in-situ testing methods; at the same time, multiple factors such as the pile top load, the settlement distribution of the soil around the pile, the self-weight of the pile body, and the properties of the soil at the pile tip are taken into account, solving the problem that the empirical analysis method considers too single factors.

[0096] The method for analyzing the bearing capacity of vertically compressed foundation piles in self-weight collapsible loess provided by this embodiment has clear physical concepts, greatly reduces the calculation amount compared with the numerical analysis method, and also solves the problem of fuzzy parameters in the numerical analysis method.

[0097] Embodiment 2

[0098] This embodiment provides a system for analyzing the bearing capacity of vertically compressed foundation piles in self-weight collapsible loess, which specifically includes:

[0099] The test analysis module is configured to: discretize the foundation pile and the soil around the pile into blocks, and through indoor test analysis, obtain the function of the mobilization of the side frictional resistance at the pile-soil interface of each block and the self-weight collapsible deformation amount of the soil around the pile of each block;

[0100] The iterative analysis module is configured to: initialize the vertical displacement of the pile top; for each block, after obtaining the side frictional resistance at the pile-soil interface of itself based on the function of the mobilization of the side frictional resistance at the pile-soil interface, calculate the normal stress of the lower cross-section of each block in turn from top to bottom according to the static equilibrium relationship, and take the normal stress of the lower cross-section of the pile tip as the pile tip resistance; after calculating the settlement amount of the pile tip based on the side frictional resistance at the pile-soil interface of each block and the pile tip resistance, compare the settlement amount of the pile tip and the vertical displacement of the pile top. If the two are not equal, adjust the vertical displacement of the pile top and return to recalculate the normal stress of the lower cross-section of each block; if the two are equal, take the vertical displacement of the pile top as the pile top deformation, take the block with the self-weight collapsible deformation amount of the soil around the pile equal to the vertical displacement of the pile top as the neutral point, and determine the distribution of negative skin friction and the distribution of positive skin friction based on the center point.

[0101] Furthermore, the side frictional resistance at the pile-soil interface of each block above the center point is the distribution of negative skin friction, and the side frictional resistance at the pile-soil interface of each block below the center point is the distribution of positive skin friction.

[0102] Furthermore, the indoor test analysis includes: determining the dry density through indoor geotechnical tests, calculating the actual unit weight of each slice at a given water content based on the dry density, and calculating the self-weight stress of the soil mass of each slice; after calculating the earth pressure exerted on each slice based on the self-weight stress of the soil mass of each slice, obtaining the side friction resistance of the pile-soil interface of each slice through pile-soil interface friction resistance test experiments.

[0103] Furthermore, the indoor test analysis includes: determining the coefficient of self-weight collapsibility of the soil around the pile through loess collapsibility experiments, and calculating the self-weight collapsibility deformation of the soil around the pile of each slice in combination with the thickness of each slice.

[0104] Furthermore, the calculation of the pile tip settlement adopts the Mindlin solution or the load transfer method.

[0105] Furthermore, if the pile tip settlement is greater than the vertical displacement of the pile top, increase the vertical displacement of the pile top, and the increase amount is half of the difference between the two.

[0106] Furthermore, if the pile tip settlement is less than the vertical displacement of the pile top, decrease the vertical displacement of the pile top, and the decrease amount is half of the difference between the two.

[0107] It should be noted here that each module in this embodiment corresponds to each step in Embodiment 1 one by one, and the specific implementation process is the same, so it will not be repeated here.

[0108] Embodiment 3

[0109] This embodiment provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the steps in the method for analyzing the bearing performance of vertically compressed foundation piles in self-weight collapsible loess as described in Embodiment 1 above.

[0110] Embodiment 4

[0111] This embodiment provides a computer device, as Figure 5 shown, including a display device, an input device, a computer-readable storage medium (volatile memory and non-volatile storage medium), a processor, a communication interface (i.e., a network interface), and a computer program stored on the computer-readable storage medium and executable on the processor. Among them, the processor, the communication interface, and the computer-readable storage medium can be connected through a bus or other means. Among them, the communication interface is used to receive and send data, and when the processor executes the program, it implements the steps in the method for analyzing the bearing performance of vertically compressed foundation piles in self-weight collapsible loess as described in Embodiment 1 above.

[0112] Among them, any reference to a memory, storage, database, or other medium provided in this application and used in the embodiments may include non-volatile and / or volatile memories. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct Rambus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0113] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce a means for implementing the specified functions in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0114] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction means that implements the specified functions in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0115] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the specified functions in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0116] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for analyzing the bearing performance of vertically compressed piles in self-weight collapsible loess, characterized in that: include: The foundation pile and the soil around the pile are discretized into strips and blocks. Through indoor test analysis, the function of the pile-soil interface side friction resistance of each strip and the self-weight shrinkage deformation of the soil around the pile of each strip are obtained. Initialize the vertical displacement of the pile top; for each strip, after obtaining its own pile-soil interface lateral friction resistance based on the function of the pile-soil interface lateral friction resistance, calculate the positive stress of the lower section of each strip from top to bottom according to the static equilibrium relationship, and use the positive stress of the lower section of the pile end as the pile end resistance; based on the pile-soil interface lateral friction resistance and pile end resistance of each strip, calculate the pile end settlement, compare the pile end settlement and the pile top vertical displacement, if the two are not equal, adjust the pile top vertical displacement, return to recalculate the positive stress of the lower section of each strip; if the two are equal, use the pile top vertical displacement as the pile top deformation, use the strip with the pile surrounding soil self-weight wetting deformation equal to the pile top vertical displacement as the neutral point, and determine the negative friction resistance distribution and positive friction resistance distribution based on the center point.

2. The method for analyzing the bearing performance of vertically compressed piles in self-weight collapsible loess according to claim 1, characterized in that: The pile-soil interface lateral friction resistance of each strip block above the center point is a negative friction resistance distribution, and the pile-soil interface lateral friction resistance of each strip block below the center point is a positive friction resistance distribution.

3. The method for analyzing the bearing performance of vertically compressed piles in self-weight collapsible loess according to claim 1, characterized in that: The indoor test analysis includes: obtaining the dry density through indoor geotechnical test, calculating the actual weight of each block at a given moisture content based on the dry density, and calculating the self-weight stress of the soil of each block; calculating the soil pressure on each block based on the self-weight stress of the soil of each block, and obtaining the pile-soil interface lateral friction resistance of each block through a pile-soil interface friction resistance test experiment.

4. The method for analyzing the bearing performance of vertically compressed piles in self-weight collapsible loess according to claim 1, characterized in that: The indoor test analysis includes: determining the self-weight collapsibility coefficient of the soil around the pile through a loess collapsibility experiment, and calculating the self-weight collapsibility deformation of the soil around the pile in each block in combination with the thickness of each block.

5. The method for analyzing the bearing performance of vertically compressed piles in self-weight collapsible loess according to claim 1, characterized in that: The calculation of the pile tip settlement adopts the Mindlin solution or the load transfer method.

6. The method for analyzing the bearing performance of vertically compressed piles in self-weight collapsible loess according to claim 1, characterized in that: If the pile end settlement is greater than the vertical displacement of the pile top, the vertical displacement of the pile top shall be increased by half of the difference between the two.

7. The method for analyzing the bearing performance of vertically compressed piles in self-weight collapsible loess according to claim 1, characterized in that: If the pile end settlement is less than the vertical displacement of the pile top, the vertical displacement of the pile top should be reduced by half of the difference between the two.

8. The bearing performance analysis system of vertically compressed piles in self-weight collapsible loess is characterized by: include: The test analysis module is configured to: discretize the foundation pile and the soil around the pile into strips and blocks, and obtain the function of the pile-soil interface lateral friction resistance of each strip and block and the self-weight collapse deformation of the soil around the pile of each strip and block through indoor test analysis; The iterative analysis module is configured as follows: initializing the vertical displacement of the pile top; for each strip, after obtaining the side friction resistance of the pile-soil interface based on the function of the side friction resistance of the pile-soil interface, the positive stress of the lower section of each strip is calculated in turn from top to bottom according to the static equilibrium relationship, and the positive stress of the lower section of the pile end is used as the pile end resistance; after calculating the pile end settlement based on the side friction resistance of the pile-soil interface and the pile end resistance of each strip, the pile end settlement and the vertical displacement of the pile top are compared. If the two are not equal, the vertical displacement of the pile top is adjusted, and the positive stress of the lower section of each strip is returned to recalculate; if the two are equal, the vertical displacement of the pile top is used as the pile top deformation, the strip with the pile surrounding soil self-weight collapsible deformation equal to the vertical displacement of the pile top is used as the neutral point, and the negative friction resistance distribution and the positive friction resistance distribution are determined based on the center point.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method for analyzing the bearing performance of vertically compressed piles in self-weight collapsible loess as described in any one of claims 1 to 7 are implemented.

10. A computer device comprising a computer-readable storage medium, a processor, and a computer program stored in the computer-readable storage medium and executable on the processor, characterized in that: When the processor executes the program, the steps in the method for analyzing the bearing performance of vertically compressed piles in self-weight collapsible loess as described in any one of claims 1 to 7 are implemented.

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