CN-121997569-A - Red clay pile foundation parameter determination method and system

CN121997569ACN 121997569 ACN121997569 ACN 121997569ACN-121997569-A

Abstract

The application discloses a method and a system for determining parameters of a red clay pile foundation, relates to the technical field of geotechnical engineering, and solves the problem that the existing method is inaccurate in pile end resistance value of the red clay pile foundation. According to the embodiment of the application, the CPTU continuous in-situ test parameters are dynamically associated with the red clay soil parameters, so that the identification and partition of the mechanical properties of the pile end soil body are realized, and the defects of sparse dependence and sample disturbance in the prior art are overcome. Meanwhile, a differential calculation sub-model is established aiming at different plastic state partitions, so that the end resistance value is changed from a single experience value to a dynamic calculation value based on the real state of the soil body, the accuracy and reliability of calculating the end resistance in the soil body with strong variability of red clay are improved, unreasonable pile length design caused by incorrect parameter value is effectively avoided, and therefore, on the premise of ensuring engineering safety, engineering cost is optimized, and construction risk is reduced.

Inventors

ZHANG YUANYIN
YANG ZIXIAO
YOU CAIYUN
ZHANG QIKE
ZHANG TINGLIANG
ZHOU YAO
HE LI
LI ZHONGNING
LIU KAIPENG
Lu Yanjia
TANG XINHONG
TIAN YU
WEI CHAOZHI
YANG LIU

Assignees

贵州送变电有限责任公司

Dates

Publication Date: 20260508
Application Date: 20251231

Claims (10)

1. A method for determining parameters of a red clay pile foundation, the method comprising: Carrying out a CPTU test on the pile position area to obtain a CPTU curve; Collecting a target undisturbed soil sample at a key depth of the pile position area, and measuring a soil parameter of the target undisturbed soil sample, wherein the key depth comprises a first key depth determined based on cone tip resistance and pore water pressure in the CPTU curve and a second key depth at which a preset pile end bearing layer is positioned; based on the soil parameters, generating a three-dimensional partition map of the red clay plastic state of the pile location area; Obtaining pile end resistance actual measurement values in different plastic state partitions, and establishing pile end resistance calculation sub-models applicable to the different plastic state partitions based on the pile end resistance actual measurement values and soil parameters of the same depth to form a calculation sub-model library; And extracting soil layer plastic state and soil parameters in a depth range of influence of the corresponding pile end from the three-dimensional partition map based on the designed pile end elevation of the target pile, and calling a corresponding calculation sub-model to calculate a pile end resistance characteristic value of the target pile after the target pile is deployed at the pile position.
2. The method of claim 1, wherein the CPTU profile comprises a cone tip resistance, a sidewall friction resistance, and a pore water pressure versus depth profile, wherein the collecting a target undisturbed soil sample at a critical depth in the pile zone and determining a soil parameter for the target undisturbed soil sample comprises: Determining a first key depth based on the characteristic points of the change curve, and collecting the target undisturbed soil sample at the first key depth and the second key depth; measuring the natural water content, liquid limit and plastic limit of the target undisturbed soil sample, and calculating the water content ratio of the target undisturbed soil sample; and matching the water content, the natural water content, the liquid limit and the plastic limit of the same depth to form the soil parameters.
3. The method of claim 2, wherein generating a three-dimensional partition map of a red clay plastic state of the pile area based on the soil parameters comprises: Calculating normalized cone tip resistance and normalized friction ratio of each key depth based on the soil parameters; Calculating a soil body behavior type index based on the normalized cone tip resistance and the normalized friction ratio, and obtaining a soil body behavior type index profile; establishing a site specificity statistical relationship model between a soil body behavior type index and the water content ratio based on the soil parameters; Inputting the soil body behavior type index profile into the statistical relation model, and inverting to obtain an equivalent water ratio profile; Converting the equivalent water ratio profile into a plastic state profile according to a preset mapping relation between the equivalent water ratio and the plastic state; the three-dimensional partition map is generated based on the plastic state profile and the soil parameters.
4. The method of claim 3, wherein the obtaining obtains pile end resistance actual measurement values in the different plastic state partitions, and builds a pile end resistance calculation sub-model applicable to the different plastic state partitions based on the pile end resistance actual measurement values and the soil parameters of the same depth, and forming a calculation sub-model library, comprising: obtaining pile end resistance actual measurement values in different plastic state partitions through a deep flat plate load test or a pile foundation static load test; determining the space position and pile end elevation of each test point corresponding to the pile end resistance actual measurement value, confirming the main plastic state category of the depth influenced by the test point corresponding to the test point in the three-dimensional partition map, and extracting the normalized cone tip resistance and equivalent water ratio of the same depth; Grouping the test data according to the plastic state categories, and performing multiple regression analysis on each group of test data by taking the normalized cone tip resistance and the equivalent water ratio as independent variables and the pile end resistance actual measurement value as dependent variables to establish a pile end resistance calculation sub-model under the corresponding plastic state categories; And collecting all the calculation sub-models of the plastic state categories to form the calculation sub-model library.
5. The method according to any one of claims 1 to 4, wherein the extracting soil layer plastic state and soil parameters in a depth range of influence of a corresponding pile end from the three-dimensional partition map based on a designed pile end elevation of the target pile, and calling a corresponding calculation sub-model to calculate a pile end resistance characteristic value of the target pile after being deployed at a pile position comprises: Obtaining the pile end design elevation and the pile diameter of a target pile; determining the depth range of the influence of the pile end based on the designed elevation and the pile diameter; extracting soil layer information in the depth range affected by the pile tip from the three-dimensional partition map, wherein the soil layer information comprises plastic state types and layer thicknesses of all soil layers, and normalized cone tip resistance and equivalent water ratio of each soil layer; For each soil layer, calling a corresponding calculation sub-model from the calculation sub-model library based on the plastic state category of the soil layer, substituting the corresponding normalized cone tip resistance and equivalent water ratio, and calculating a unit end resistance contribution value of the soil layer; and calculating the pile end resistance characteristic value based on the unit end resistance contribution value of the soil layer, the layer thickness and a preset weight coefficient.
6. The method of claim 5, wherein the weight coefficient is associated with a plastic state class of the soil layer, wherein the weight coefficient of the hard plastic state soil layer is higher than the plastic state soil layer, and wherein the weight coefficient of the plastic state soil layer is higher than the soft plastic state soil layer.
7. The method of any one of claims 1-4, wherein after the invoking the corresponding computing sub-model to compute the tip drag characteristic value of the target pile after deployment at the pile site, the method further comprises: and calculating the vertical bearing capacity characteristic value of the single pile of the target pile based on the pile end resistance characteristic value.
8. A red clay pile foundation parameter determination system for use in the method of any one of claims 1-7, said system comprising: The CPTU module is used for carrying out a hole-pressure static cone penetration CPTU test in the pile position area to obtain a CPTU curve; The measuring module is used for collecting a target undisturbed soil sample at the key depth of the pile position area and measuring soil parameters of the target undisturbed soil sample, wherein the key depth comprises a first key depth determined based on cone tip resistance and pore water pressure in the CPTU curve and a second key depth of a preset pile end bearing layer; the generation module is used for generating a three-dimensional partition map of the red clay plastic state of the pile position area based on the soil parameters; The modeling module is used for obtaining pile end resistance actual measurement values in different plastic state partitions, and building pile end resistance calculation sub-models applicable to the different plastic state partitions based on the pile end resistance actual measurement values and soil parameters of the same depth to form a calculation sub-model library; and the calculation module is used for extracting soil layer plastic state and soil parameters in the depth range of the corresponding pile end influence from the three-dimensional partition map based on the designed pile end elevation of the target pile, and calling a corresponding calculation sub-model to calculate the pile end resistance characteristic value of the target pile after being deployed at the pile position.
9. A computing device, comprising: A memory for storing a program; a processor for loading the program to perform the method of any of claims 1-7.
10. A computer readable storage medium, characterized in that the computer readable storage medium comprises a stored program, wherein the program, when run, controls a device in which the computer readable storage medium is located to perform the method of any one of claims 1-7.

Description

Red clay pile foundation parameter determination method and system Technical Field The invention relates to the technical field of geotechnical engineering, in particular to a method and a system for determining parameters of a red clay pile foundation. Background When the engineering construction is carried out in the red clay distribution area, the large-diameter pile foundation has the advantages of strong bearing capacity, good stability and the like, and is widely applied to the foundation structures of important engineering such as buildings, bridges and the like. The pile end resistance is used as a core parameter for determining the vertical bearing capacity of the large-diameter pile foundation, the accuracy of the value is directly related to the safety, economy and rationality of the pile foundation design, and the pile end resistance is a key core link in the design process of the large-diameter pile foundation in the red clay region. At present, the traditional method for determining the pile end resistance of the large-diameter pile foundation in the red clay region in the engineering field mainly obtains an end resistance reference value by referring to an empirical table in national or regional geotechnical engineering specifications. The empirical form is summarized based on limited geological conditions, piles and engineering cases, has insufficient adaptability to the soil body with special causes and complex mechanical properties, and especially does not fully consider the remarkable difference of the plastic states of the red clay, and has extremely large difference of mechanical properties under different plastic states, so that the pile end resistance value is directly influenced. The adoption of unified experience values easily causes the design to be too conservative, greatly increases the cost performance of engineering, or has the value being deviated from risk, and buries the potential safety hazard of the structure. In view of the above, a method and a system for determining parameters of a red clay pile foundation are needed. Disclosure of Invention Aiming at the problem that the pile end resistance of the red clay pile foundation is inaccurate in the prior art, the invention provides a method and a system for determining parameters of the red clay pile foundation, and more accurate pile end resistance of the red clay pile foundation can be obtained. The specific technical scheme is as follows: in a first aspect, an embodiment of the present application provides a method for determining parameters of a red clay pile foundation, including: The method comprises the steps of carrying out a pore-pressure static cone penetration test (Cone Penetration Test with Pore Pressure Measurement, CPTU) in a pile location area to obtain a CPTU curve, collecting a target undisturbed soil sample at a key depth of the pile location area, and measuring soil parameters of the target undisturbed soil sample, wherein the key depth comprises a first key depth determined based on cone tip resistance and pore water pressure in the CPTU curve and a second key depth where a preset pile end bearing layer is located, generating a three-dimensional partition map of a red clay plastic state of the pile location area based on the soil parameters, obtaining pile end resistance actual measurement values in different plastic state partitions, building pile end resistance calculation sub-models applicable to different plastic state partitions based on the pile end resistance actual measurement values and the soil parameters of the same depth, forming a calculation sub-model library, extracting a soil layer plastic state and soil parameters in a corresponding pile end influence depth range from the three-dimensional partition map based on the designed pile end elevation of a target pile, and calling the corresponding calculation sub-model to calculate an end resistance characteristic value of the target pile after the target pile is deployed in the pile location. Preferably, the CPTU profile includes a cone tip resistance, sidewall friction and pore water pressure versus depth profile; the method comprises the steps of collecting a target undisturbed soil sample at a key depth of a pile area, and measuring soil parameters of the target undisturbed soil sample, wherein the method comprises the steps of determining a first key depth based on characteristic points of a change curve, collecting the target undisturbed soil sample at the first key depth and the second key depth, measuring natural water content, liquid limit and plastic limit of the target undisturbed soil sample, calculating the water content ratio of the target undisturbed soil sample, and matching the water content ratio, the natural water content, the liquid limit and the plastic limit of the same depth to form the soil parameters. The method comprises the steps of calculating normalized cone tip resistance and normalized friction ratio of each key d