Analysis Of Spatial Variability Of Soil Properties Of Hongshiyan Barrier Accumulation

It is increasingly important to study and analyze the mechanical properties of the target soil with the continuous improvement of society's requirements for basic engineering construction in geotechnical engineering.But the formation of the soil itself is a complex geological process,which is affected by the sedimentary history,complex stress changes,etc.From a large amount of engineering experience and geotechnical engineering practice in the past,the physical and mechanical properties of the soil itself are uncertain and most of the engineering soil parameters have spatial variability,that is to say,the soil property index changes randomly with space.The spatial variability of soil mechanical parameters will directly affect project operation and project safety.Therefore,it is of great significance to analyze the spatial variability of soil mechanical parameters before large-scale geotechnical engineering is carried out.This article takes the Hongshiyan dammed accumulation remediation project in Ludian County,Yunnan as an example and applying random field theory to the study of spatial variability of Hongshiyan accumulation.Processing of the engineering properties of the Hongshiyan dam have been done by combining limited survey data,basic analysis and data,which shows that the compactness and water content of the dammed deposit formed by the collapse and landslide have a tendency to increase along the depth.Subsequently,the shear wave velocity,surface wave velocity and resistivity data were used to construct vertical and horizontal Hongshiyan geotechnical parameter random field models,and verify that the soil profile meets the stability and ergodicity.Completed actual survey data collection and data standardization,while analyzing and giving out the principles of determining the sampling distance,trend function and calculation of soil thickness h in actual engineering.The relationship between the relative distance and the fluctuation range is discussed,the pros and cons of the calculation method of the fluctuation range are analyzed,and a new recursive space method is proposed.Further comparison and analysis of the five correlation function types have determined that the correlation function type of the Hongshiyan dammed accumulation body is Gaussian.The vertical and horizontal fluctuation amplitude of the Hongshiyan rock mass is calculated by the improved recursive space method,correlation function method and fitting variance reduction method,and give reliable engineering reference values for the vertical and horizontal fluctuation range of Hongshiyan rock accumulation body respectively that are3.28±0.55 m and 34.25±5m.Discussed the influence of different calculation methods and different calculation indicators on the obtained fluctuation range,which shows that the results of the fluctuation range values calculated by different methods are similar,and the calculation results of the correlation function method are greater than the recursive space method and the fitting variance reduction method.The results of the fluctuation range calculated by different indicators are in good agreement and the result of the resistivity calculation is greater than the surface wave velocity and the shear wave velocity.Refer to domestic and foreign literature and give the fluctuation range value of different regions as engineering reference.Finally,different random field discrete methods and their advantages and disadvantages are introduced,while random field discrete methods based on local averaging method,Karhunen-Loeve expansion method and covariance decomposition method are introduced.Corresponding calculation programs were compiled and the two-dimensional random field of Young's modulus of redstone rock dammed deposits was realized through different methods.At the same time,the influence of the change of the fluctuation range on the parameter random field is analyzed.The research shows that the local average method and the K-L expansion method have better effects on random field simulation and the spatial variability of the random field of accumulation soil parameters mainly changes along the depth direction.The spatial variability of the parameter random field generally has a negative correlation with the fluctuation range.