Spatial Correlation Research On The Typical Soil In The Yellow River Flood Area In Shandong Province

It is well-known that the geotechnical material has the following dual characteristics: the spatial structural characteristics in the total space domain and the randomness in local space.It is the unification of structural and random.The geotechnical parameters are usually considered as random variables that ignore the characteristics of geotechnical parameters on the space.This thesis mainly analyzes the spatial correlation of soil parameter based on the Cone Penetration Test(CPT)data collected from six different sites in the Yellow River flood area in Shandong province.The main stochastic parameters,such as mean and variance were calculated.Research found that no significant increase along the depth direction.Thus,the soil parameters were studied based on different soil layers.At the same time,typical soil layers of six sites were divided into silty clay,silt,clay and sandy soil,and the corresponding mean and variance were obtained.The stationarity and ergodic tests about four types of soil were carried out.From the results of the study,after the trend processing,the stationarity of the data was better and could be considered as stationary random fields.On the basis of the stationary assumption,the spatial correlation functions of the aforementioned four types of soil were obtained by the method of moment calculation.In order to solve the problem that the tail of correlation function has obvious fluctuations with the increase of the distance,three methods were adopted:(1)to weaken or delete the invalid points with large dispersion,(2)to weight the correlation function,(3)effective points method.The correlation of the function after treatment was significantly improved.At the same time,the correlation model analysis was conducted to the four soil types of silty clay,silt,clay and sandy soil.A new modified correlation function model was put forward considering the negative value of correlation function.At the same time,the method of calculating the correlation distance was obtained based on the correlation model parameters.This work can provide a reference for the engineering application of typical soil layer,at thesame time will become the basis for the future random field analysis.