CN-122016601-A - Fine-grained soil permeability coefficient calculation method considering internal communication pore characteristics

CN122016601ACN 122016601 ACN122016601 ACN 122016601ACN-122016601-A

Abstract

The invention discloses a fine soil permeability coefficient calculation method considering internal communication pore characteristics, belongs to the technical field of foundation foundations, and can solve the problems that a microscopic pore structure is ignored, calculation accuracy is insufficient and a test period is overlong in the existing method. The method comprises the steps of S1, constructing a first quantitative relation between a pore parameter, a permeability characterization parameter and a permeability coefficient of fine-grained soil, S2, determining plasticity index data and permeability characterization data of various fine-grained soil samples, constructing a second quantitative relation between the plasticity index and the permeability characterization parameter of the fine-grained soil according to the plasticity index data and the permeability characterization data, S3, determining a permeability characterization parameter predicted value of the target fine-grained soil according to a plasticity index actual measurement value and the second quantitative relation of the target fine-grained soil, and S4, determining a permeability coefficient predicted value of the target fine-grained soil according to the pore parameter actual measurement value, the permeability characterization parameter predicted value and the first quantitative relation of the target fine-grained soil. The method is used for calculating the permeability coefficient of the fine soil.

Inventors

WANG ZHANG
Yan hengyu
LI ZHENGZHENG
DI SHENGJIE
WU ZILONG
SONG MINGGANG
TONG YAN
CHEN HAIYUN
YE XINLING

Assignees

中国电建集团西北勘测设计研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20260305

Claims (8)

1. A method for calculating a permeability coefficient of fine-grained soil taking into account internal connected pore characteristics, the method comprising: s1, constructing a first quantitative relation between pore parameters, permeation characterization parameters and permeation coefficients of fine-grained soil; S2, determining plastic index data and penetration characterization data of various fine soil samples, and constructing a second quantitative relation between the plastic index and penetration characterization parameters of the fine soil according to the plastic index data and the penetration characterization data; S3, determining a plastic index actual measurement value of the target fine soil, and determining a permeation characterization parameter predicted value of the target fine soil according to the plastic index actual measurement value and the second quantitative relation; S4, determining an actual pore parameter value of the target fine soil, and determining a permeability coefficient predicted value of the target fine soil according to the actual pore parameter value, the permeability characterization parameter predicted value and the first quantitative relation.
2. The method according to claim 1, wherein determining penetration characterization data for a plurality of fine soil samples in S2 comprises: Preparing each fine-grained soil sample in a plurality of fine-grained soil samples into a plurality of sub-samples with different dry densities, and determining pore parameter data and permeability coefficient data of each sub-sample; And determining penetration characterization data of the corresponding fine grained soil sample according to the pore parameter data and the penetration coefficient data of all sub-samples in the same fine grained soil sample.
3. The method according to claim 2, wherein determining pore parameter data for each sub-sample, in particular comprises: and carrying out mercury-pressing test on each part of sub-sample to obtain pore parameter data of the corresponding sub-sample.
4. The method according to claim 2, characterized in that determining the permeability coefficient data for each sub-sample comprises in particular: And carrying out an indoor constant water head permeability test on each part of sub-sample to obtain permeability coefficient data of the corresponding sub-sample.
5. The method according to claim 2, wherein determining penetration characterization data of the corresponding fine-grained soil sample from the porosity parameter data and the penetration coefficient data of all sub-samples in the same fine-grained soil sample, specifically comprises: Presetting a plurality of assumed values of permeation characterization parameters, substituting the assumed values and pore parameter data of each sub-sample into an independent variable part of the first quantitative relation to obtain an independent variable part calculated value of each sub-sample under each assumed value, wherein the expression of the independent variable part is as follows: ; Wherein PSP is an independent variable part of the first quantitative relation; The assumed value of the permeation characterization parameter is an integer greater than or equal to 1; Is porosity; The number of pore channels of each section in the fine-grained soil; the smallest pore diameter in the pore diameters of all pore channels; Is that Hole in The proportion of the section pores; Determining a theoretical straight line of the permeability coefficient of the corresponding fine soil sample under the corresponding assumed value according to the independent variable part calculated values of all sub-samples in the same fine soil sample under each assumed value and the first quantitative relation; and determining penetration characterization data of the corresponding fine soil samples according to the penetration coefficient theoretical straight line of each fine soil sample under each assumed value and the penetration coefficient data of all sub-samples of the corresponding fine soil samples.
6. The method according to claim 1, wherein determining plasticity index data for a plurality of fine soil samples in S2 comprises: and respectively carrying out liquid plastic limit tests on a plurality of fine soil samples to obtain the plastic index data of each fine soil sample.
7. The method according to claim 1, wherein the constructing a second quantitative relationship between the plasticity index and the penetration characterization parameter of the fine-grained soil according to the plasticity index data and the penetration characterization data in S2 specifically comprises: And performing nonlinear fitting on the plasticity index data and the penetration characterization data to obtain a second quantitative relation between the plasticity index and the penetration characterization parameter of the fine soil, wherein the second quantitative relation is a power function.
8. The method of claim 1, wherein the pore parameters include porosity, number of cells per cross section in the fine-grained soil, and diameter of each cell.

Description

Fine-grained soil permeability coefficient calculation method considering internal communication pore characteristics Technical Field The invention relates to a fine soil permeability coefficient calculation method considering internal communication pore characteristics, and belongs to the technical field of foundation foundations. Background Fine-grained soil (such as clay and powdery clay) is widely distributed in foundation, slope engineering, environmental rock-soil partition wall and other engineering. The permeability coefficient is used as a core parameter for representing the water permeability, and the sedimentation rate of the foundation, the stability of the side slope and the seepage prevention effect of the partition wall are directly determined. Therefore, the permeability coefficient of fine soil is accurately obtained, and the method has irreplaceable effects on engineering design and safety control. At present, the calculation method of the permeability coefficient of fine soil is mainly divided into two major categories of an empirical formula method and a test method, but the two major limitations exist, and the method is specifically as follows: (1) Empirical formulas typically use macroscopic physical indicators of dry density, void ratio, etc. to establish a relationship with permeability coefficients. However, this method simplifies the internal pores of the soil body into a uniform communication medium, failing to take into account the "communication variability" of the pore system, i.e. the distinction between "communication pores" that actually contribute to infiltration and "closed pores" that do not contribute. Because the key micro-characteristics such as the number of the communicated pores and the pore size distribution are ignored, when the method is used for calculating the heterogeneous fine-grained soil with high pore ratio, the error of the result can reach 1 to 3 orders of magnitude, and the requirement of high-precision engineering is difficult to meet. (2) Although the test method (such as a constant head method or a variable head method) can directly measure the permeability coefficient, the permeability of fine soil is extremely low (for example, the permeability coefficient of expansive soil is often lower than 1X 10 -9 cm/s), and the single indoor test period can be as long as weeks or even months, so that the efficiency is low. In addition, mechanical disturbance in the original soil sampling process can change the pore structure in the soil body and destroy the original distribution state of the communicated pores, so that a test result is deviated from the permeability coefficient under the actual working condition, and the method is not suitable for an engineering site needing quick calculation. In summary, aiming at the technical bottlenecks of the existing method in terms of neglecting the micro-pore structure, insufficient calculation precision, overlong test period and the like, a new permeability coefficient calculation method needs to be established. Disclosure of Invention The invention provides a fine soil permeability coefficient calculation method considering internal communication pore characteristics, which can solve the problems that the existing method ignores microscopic pore structures, has insufficient calculation precision and has overlong test period. The invention provides a fine soil permeability coefficient calculation method considering internal communication pore characteristics, which comprises the following steps: s1, constructing a first quantitative relation between pore parameters, permeation characterization parameters and permeation coefficients of fine-grained soil; S2, determining plastic index data and penetration characterization data of various fine soil samples, and constructing a second quantitative relation between the plastic index and penetration characterization parameters of the fine soil according to the plastic index data and the penetration characterization data; S3, determining a plastic index actual measurement value of the target fine soil, and determining a permeation characterization parameter predicted value of the target fine soil according to the plastic index actual measurement value and the second quantitative relation; S4, determining an actual pore parameter value of the target fine soil, and determining a permeability coefficient predicted value of the target fine soil according to the actual pore parameter value, the permeability characterization parameter predicted value and the first quantitative relation. Optionally, determining penetration characterization data of the plurality of fine soil samples in S2 specifically includes: Preparing each fine-grained soil sample in a plurality of fine-grained soil samples into a plurality of sub-samples with different dry densities, and determining pore parameter data and permeability coefficient data of each sub-sample; And determining penetration characteriza