贵州坝陵河大桥西锚碇区围岩稳定性分析

运用岩体质量评价、现场模型试验、极限平衡法和FLAC3D数值仿真试验多种方法结合,对贵州坝陵河大桥西锚碇区围岩稳定性进行了研究.岩体质量评价表明,锚碇区岩体较破碎、质量差;现场模型试验发现,过大的位移将导致结构不能正常使用,锚体后锚面圆拱顶点、矩形底边中点及其6 m范围内的围岩变形较大.运用极限平衡法对边坡8种可能的破坏位置进行验算表明,边坡基本稳定,最危险滑动面发生在基坑上部的强风化、弱风化带岩体中.FLAC3D数值试验表明,围岩可能发生拉剪破坏,破损区集中在锚塞体后部右上角等5个部位,锚碇上部岩体水平位移大,位移等高线近半椭圆形扩散.设计和施工过程中,应对塑性区及显著变形区内的岩体重点加固.

Rock mass stability analysis in west tunnel-type anchorage zones of Baling suspension bridge in Guizhou, China

The surrounding rock mass stability of the Baling river west anchorage zones is studied by the way of integrating the rock mass quality evaluation,insitu model testing,limit equilibrium analysis and FLAC3D numerical analysis.The rock mass quality evaluation shows that the rock mass is poor or fair.The insitu testing shows that a too big displacement will make the structure off.A big displacement is found at the vertex of the arch,the midpoint of the rectangle bottom side,and the surrounding rock around six meters.The rock slope is stable according to the limit equilibrium analysis,and a possible unsafe slipping may happen in the upper highly-weathered and weakly-weathered rock of the foundation ditch if the force is large enough.FLAC3D analysis shows that the tension-shear failure may happen in the rock mass,and the failure mainly happens in five areas including the upper-right of the anchorage.The horizontal displacement at the upper rock mass of the anchorage is large and distributed in a half-ellipse style.The plastic and prominent deformation zones in the rock mass should be paid more attention during design and construction.