开挖和隧洞掘进对洞脸边坡影响的有限元分析

水电站引水洞进口边坡一般都比较陡峻,该边坡的变形、稳定情况是引水隧洞乃至整个工程建设的关键问题。为了解边坡开挖、隧洞掘进对边坡的影响,采用有限元方法,利用单元生死技术全真模拟边坡开挖、隧洞掘进。根据分析结果进行了边坡支护设计,并采用强度折减法得到安全系数,通过分析该边坡变形、应力、屈服破坏情况,对其稳定性及支护措施的合理性进行评价。计算结果表明:边坡开挖使坡体产生一些竖直方向的回弹变形和水平向坡外的变形,并出现不同程度的张拉应力区域;深埋隧洞开挖仅对隧洞附近边坡影响较大;采取的支护形式能够有效的加固边坡,符合工程要求。

Finite Element Simulation of Influence of Slope and Tunnel Excavation on Tunnel Slope

The diversion tunnel of a hydropower station is steep. The stability of slope and its deformation is the key to the water diversion tunnel construction and the whole project. In order to understand the influence of slope and tunnel excavation, finite element software and element birth and death technology simulation are applied to research. The supporting design of slope reinforcement measures is on the basis of calculation results, and safety coefficient through strength reduction is got. After analyzing the slope deformation, stress and yield damage, the stability of the slope has been evaluated. Calculation results show that slope excavation induce slope deformation of some vertical and horizontal deformation and tension stress area, and deep tunnel excavation only influence the slope near tunnel, and the design of supporting structure can effectively reinforce slope.