纳界河特大桥桥址岸坡岩体稳定性数值分析

Numerical Analysis on Rocky Slope Stability at Bridge Site in Najie River

采用有限元法,结合现场工程地质勘察资料,分别对桥北岸坡岩体在天然状态下和桥梁荷载条件下的位移、应力状态进行了数值模拟分析。通过有限元折减系数法对岸坡的整体稳定性等进行了分析,得出了在自然状态下和荷载条件下的稳定性系数、天然状态下两岸谷底及陡坡段坡脚存在主应力集中现象,以及坡面和坡顶局部存在拉应力且对边坡岩体稳定不利的结果。桥梁荷载作用对边坡岩体应力的影响主要集中在基础附近,荷载对坡面岩体应力的影响较大。桥址右岸整体稳定,左岸在桥基荷载作用下桥基下方岩体产生局部塑性区,可能发生破坏,应采取措施加固,以策安全。

Combined with the site geological survey data,the displacement and stress of rocky slope at the north of bridge under natural state and load condition are separately numerically simulated using finite element method.Then the overall stability of slope is analyzed using strength reduction finite element method.Thus stability factor under natural state and load condition are separately obtained.It is also concluded that principal stress is centralized in the valley bottom and the foot of steep section under natural state,and pulling stress exists in local part of the surface and top of slope,which affects the stability of rocky slope.Bridge load mainly centralizes near the foundation,which largely affects the stress on slope surface.The right bank of bridge is basically stable.The left bank generates a local plastic zone below bridge foundation under loading effect,which may be damaged.Therefore,the left bank shall be reinforced to ensure safety.