锦屏一级左岸导流洞出口边坡开挖支护有限元模拟

锦屏一级水电站左岸导流洞出口边坡岸坡陡峻,层间挤压破碎带、顺坡卸荷裂隙及深部裂缝发育。边坡开挖将切除部分维持边坡稳定的坡脚岩体,从而对工程边坡及上部变形拉裂岩体的稳定性产生不利影响。基于锚固岩体弹塑性等效本构关系,采用弹塑性有限元法对边坡开挖、加固及地震作用进行了数值模拟,分析了开挖边坡的稳定性,并对初拟的"先锚后挖、边挖边锚"的施工程序的合理性进行了评价,提出了若干对工程建设具有一定指导意义的建议。

3D elastoplastic finite element simulation on excavation and reinforcement of the diversion tunnel outlet slope at the left bank of Jinping-I Hydropower Project

The diversion tunnel outlet slope at the left bank of the Jinping-I Hydropower Project is naturally steep,with deep fractures,compressive fracture zones between layered strata,and release fractures oriented parallel to slope surface heavily developed.After excavation of the rock mass near the slope toe that maintains the stability of the slope,negative effects will occur on the stability of the cut slope and the upper rock mass developed with deep fractures.Based on an elastoplastic constitutive model of rock mass reinforced with rock bolts and cables,numerical simulations are performed by elastoplastic FEM to evaluate the stability of the slope during slope excavation,reinforcement and under seismic loading,and to evaluate the effectiveness of a suggested construction procedure of "anchoring before excavation and anchoring immediately after excavation".Finally,several suggestions that may be helpful to construction of the slope,are presented.