Quantitative Analysis Of The Parameter Uncertainty In Geotechnical Engineering

Geotechnical materials are natural materials with strong uncertainty.Due to the uncertainty of geotechnical materials,especially the spatial variability,the accurate characterization of geotechnical parameters becomes particularly difficult.It is important for the safety and economy of geotechnical engineering to accurately describe the uncertainty and spatial variability of geotechnical materials.This paper studies the precise characterization method of rock and soil uncertainty in actual engineering.The main research work is as follows:1.A reliability method for calculating shear strength index is proposed.In addition,based on the existing test data,three methods are used to calculate and compare the shear strength index.The results show that the results of reliability method and linear regression method are close and have small standard deviation,which is better than moment method.Both two methods are worth recommending.2.The maximum likelihood estimation method is used to calculate the scale of fluctuation of the single-pole TPI in the Yinchao-Jiliao tunnel project,and the influence of segmentation trend and data volume on the calculation result of the scale of fluctuation is discussed.The results show that segmented trend has a significant impact on the calculation result of the scale of fluctuation,so this effect must be considered in the calculation of the scale of fluctuation.Data volume also has an impact on the calculation result.As the amount of data increases,the calculation of the scale of fluctuation will be more accurate.In the Yinchao tunnel project,the scale of fluctuation of the surrounding rock is about 7-16 meters.3.The modified spatial recursive average method,the modified correlation function method and the maximum likelihood estimation method are used to calculate the scale of fluctuation from 1D to 3D of Xiaolangdi dam,and further compare the scale of fluctuation in different directions.The results show that due to the influence of compaction technology and load,the vertical scale of fluctuation is small,about 2meters,while the horizontal scale of fluctuation is about 8 meters.Therefore,in the stochastic finite element analysis,different correlation distances should be used in the vertical and horizontal directions.In this paper,the problem of accurate representation of rock and soil uncertainty in practical engineering is studied,which improves the representation accuracy of rock and soil uncertainty.It is of great significance to improve the accuracy of reliability analysis and risk assessment of practical engineering,especially the accuracy of stochastic finite element calculation.