基于剪切波速的玉溪粉质黏土不排水抗剪强度空间变异性表征

Characterization of inherent spatial variability of undrained shear strength of Yuxi silty clay based on shear wave velocity

稳态随机场模型被广泛应用于岩土体参数空间变异性表征,但土体不排水抗剪强度沿深度方向存在明显的变化趋势,不符合稳态假设,由于非稳态随机场模型参数较多,有限数据条件下统计不确定性对基于非稳态随机场的岩土体参数空间变异性表征结果的影响更为显著。选择基于趋势函数为线性函数的非稳态随机场表征了云南玉溪粉质黏土不排水抗剪强度的空间变异性,并基于贝叶斯理论提出了考虑统计不确定性条件下岩土体参数非稳态空间变异性表征方法,所提方法能够同时表征岩土体参数非稳态空间变异性和统计不确定性。最后,以基于剪切波速数据表征云南玉溪粉质黏土不排水抗剪强度空间变异性为例来验证所提方法,结果表明:采用趋势函数为线性函数的非稳态随机场模型可以合理地表征不排水抗剪强度的空间变异性,忽略统计不确定性导致不排水抗剪强度的空间变异性被低估。

Currently,steady-state random field model is widely used to characterize inherent spatial variability of rock-soil parameters.However,undrained shear strength usually increases with depth,which is inconsistent with the steady-state assumption.Due to the large number of unsteady random field model parameters,the statistical uncertainty under the condition of limited data has a more significant impact on the spatial variability characterization results of rock-soil mass parameters based on unsteady random field.This paper makes use of a unsteady random field with a linear trend function to characterize inherent spatial variability of undrained shear strength of silty clay in Yuxi,Yunnan Province,and develops an approach based on Bayesian theory for characterizing unsteady inherent spatial variability of soil parameters considering statistical uncertainty.The proposed approach characterizes non-stationary inherent spatial variability and statistical uncertainty simultaneously.Finally,the proposed method is illustrated by the shear wave velocity data characterization of undrained shear strength spatial variability of silty clay in Yuxi,Yunnan Province.Results show that the inherent spatial variability of undrained shear strength is properly characterized by the non-stationary random field with a linear trend function,and ignoring statistical uncertainty leads to underestimation of the inherent spatial variability of undrained shear strength.