Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5787533 | Engineering Geology | 2017 | 14 Pages |
Abstract
Field data have shown the fact that soil spatial variability could aggravate the uncertainty of tunnel convergence ÎD (a key indicator for serviceability and safety of tunnels). This paper presents a detailed numerical analysis to investigate the probabilistic response of tunnel convergence in spatially varied soft soils. The soil Young's modulus Es is highlighted and modeled with isotropic and horizontally stratified anisotropic random fields, respectively. The influence of scale of fluctuation (SOF) δ of the Es on convergence ÎD is discussed in detail with respect to different directions, i.e., the vertical and horizontal directions both for δ and ÎD. It is observed that ignoring the spatial variability of Es, i.e., disregarding the possibility of unfavorable soft soil (low stiffness soil) locally around tunnel, can underestimate the mean value of ÎD. The horizontally stratified anisotropic random field is more appropriate than isotropic random field in the sense of an accurate prediction, especially when extreme tunnel convergence occurs. In horizontally stratified anisotropic random fields, the influence of horizontal and vertical SOF is different on tunnel convergence. The surrounding soils near tunnel crown and invert or across tunnel horizontal diameter are very critical to the tunnel convergence. In addition, the effect of horizontal SOF δx on failure probability of the calculated ÎD exceeding the specified allowable ÎDlim is limited when the δx is larger than 4.84 times of tunnel outer diameter.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geotechnical Engineering and Engineering Geology
Authors
H.W. Huang, L. Xiao, D.M. Zhang, J. Zhang,