三峡升船机上闸首——基岩的整体稳定性研究

Stability analysis of the up stream lock head of Three Gorges ship lift

采用基于塑性极限理论的弹塑性极限平衡法研究三峡升船机上闸首———基岩的整体稳定性 ,该方法以逐渐降低材料强度来逼近系统的极限平衡状态 ,以塑性区的贯通表示系统的临界失稳状态 ,无需事先确定滑裂面 ,适合于复杂基岩的稳定性分析。研究中模拟施工过程 ,把开挖卸载后的基岩应力作为再加载时的初应力 ,并考虑到基础固结灌浆等加固措施 ,假定基岩从弹性状态开始再加载。结果表明 ,上闸首———基岩系统的整体稳定安全系数为 3 .3 。

The stability of the up stream lock head of Three Gorges ship lift is analyzed with elasto plastic limit equilibrium method in which the critical instability state is defined as the state where the plastic zone runs through the rock foundation, and the pre determined sliding surface is unnecessary. The limit equilibrium state is approximated stepwise with decrement of material strength. The construction sequence is taken into account in the study, and the stresses of rock after excavation are treated as initial stresses when reloaded. And because of the consolidation grouting in rock after excavation, rock reloading begins in elastic state. Results show that the safety factor of stability of the up stream lock head is 3.3.