隧底溶洞对结构稳定影响的正交试验-《地球科学与环境学报》

文章信息/Info

Title:: Effects of Bottom Karst Caves on Tunnel Structure Stability Using Orthogonal Test

Author(s):: LAI Jin-xing; WANG Ke; GUO Chun-xia; LIU Bang-zhe; 1. School of Highway, Chang’an University, Xi’an 710064, Shaanxi, China; 2. School of Science, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi, China

Keywords:: tunnel; karst cave; orthogonal test; displacement; stress; non-safety distance; envelope diagram

摘要:: 依据正交试验原理，采用弹塑性有限元方法，运用MIDAS NX有限元软件，系统分析了溶洞大小、距离对隧道结构位移和轴力的影响，计算得出不同径跨比情况下位移和轴力随溶洞上壁距隧道底板的垂直距离变化规律和函数关系，从而确定各径跨比条件下隧底溶洞的非安全距离，并绘制隧道非安全距离包络图。结果表明：隧道各部位位移受径跨比影响显著；在径跨比一定的情况下，随着溶洞上壁距隧道底板垂直距离的增加，位移变化趋势符合对数函数规律；仰拱中心轴力受隧底溶洞影响较大且随垂直距离呈对数变化趋势；根据隧道结构竖向位移得出的隧底溶洞非安全距离较大，根据水平位移和轴力得出的非安全距离较小，出于安全考虑，应将竖向位移得出的隧底溶洞非安全距离作为溶洞处置的主要依据。

Abstract:: Based on orthogonal test and elastic plastic finite element method, the effect of the size and distance of karst cave on displacement and axial force of tunnel structure were discussed with MIDAS NX finite element software; the changes and function relationships of displacement and axial force to vertical distance from the top of karst cave to the bottom of tunnel under the conditions of different span ratios were calculated; non-safety distances of karst cave beneath the tunnel under the conditions of different span ratios were calculated; non-safety distance envelope diagrams of tunnel were drawn. The results show that the displacements of different parts of tunnel are significantly influenced by span ratios; when the span ratio is certain, the changes of displacement to the increase of vertical distance from the top of karst cave to the bottom of tunnel are logarithmic function; axial force of inverted arch center is significantly influenced by karst cave beneath the tunnel, and is logarithmic function of vertical distance; non-safety distance calculated by the vertical displacement of tunnel structure is large, while non-safety distance calculated by the horizontal displacement and axial force is small, so that the former should be taken as the main basis for the karst cave treatment because of the safety.