A Determination Method of Borehole Shrinkage Level and Influencing Factors in Soft Soil Layer

Abstract

The invention relates to a method for measuring the diameter reduction level of boreholes in soft soil layers and influencing factors, which belongs to the field of prevention and control of diameter reduction deformation of borehole walls of foundation bored cast-in-place piles. It includes borehole wall shrinkage test and borehole geometric elements, borehole wall shrinkage rate benchmark evaluation parameters, different soil layer shrinkage deformation influence rates and primary and secondary shrinkage deformation levels, bored pile hole wall Determination of diameter reduction influencing factors, diameter reduction deformation influencing factors initialization decision matrix, diameter reduction deformation influencing factors standardization decision matrix, diameter reduction deformation influencing factors gray correlation coefficient and primary, secondary and insignificant factors of hole wall reduction diameter deformation. The beneficial effects of the present invention are: through the gray relational analysis of the influencing factors of hole wall shrinkage, the problem of mutual conversion of multiple correlations among various factors is solved, and a comprehensive analysis of the correlation degree is used to determine and evaluate different drilling shrinkage prevention and control factors. The method of influence and effect size has important practical value for the analysis and evaluation of the prevention and control factors of borehole shrinkage of cast-in-situ piles.

Description

technical field [0001] The invention relates to the field of prevention and control of borehole wall shrinkage and deformation of bored piles on soft soil foundations, in particular to a method for measuring the shrinkage level of boreholes in soft soil layers and influencing factors. Background technique [0002] In my country's Yangtze River, Pearl River Delta and other coastal areas, there are widely distributed marine, lacustrine and fluvial deposits of sticky soft soil and silty soil layers, which have high water content, low strength, high compressibility, poor water permeability and deep burial. Due to the characteristics of soil, it will produce great settlement and settlement difference under the action of load, and its bearing capacity and stability often cannot meet the engineering requirements. Therefore, bored piles have become the most commonly used and most effective foundation reinforcement for foundation treatment in this area. measure. However, the hole wall...

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Problems solved by technology

Since this type of method cannot analyze and evaluate the qualitative hole wall shrinkage prevention and control factors, there is a gap between the obtained model and the actual situation, resulting in a large error between the quantitative index and the actual situation, and different results will be obtained by using different statistical processing methods , the prediction effect is often unsatisfactory, which affects the further treatment of bored pile hole wall shrinkage; the third is to use finite element software to simulate and analyze various factors that affect the stability of the hole wall, and qualitatively distinguish the hole wall of bored piles. However, this method is only aimed at the analysis of the factors affecting the borehole diameter reduction in the specified project or area and the evaluation of the stability, and cannot obtain a unified analysis method, which is difficult to promote and use, and has certain limitations

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