大瑞铁路澜沧江特大桥岸坡稳定性分析

Stability Analysis of Bank Slope of Lancang River Super Major Bridge on Dali-Ruili Railway

大瑞铁路澜沧江特大桥为大瑞铁路控制性工程之一。桥址位于澜沧江断裂内,地形地质条件复杂,岩体结构特征复杂,岸坡稳定性控制拱座基础的稳定。通过工程地质调绘、物探、钻探等方法和手段,查明岸坡的地质条件,采用赤平投影、离散元法、强度分析等方法对岸坡稳定性进行研究。分析表明瑞丽岸存在形成危岩体的条件,易形成大型崩塌;岸坡坡面岩体存在拉应力区,瑞丽岸拱座下方易引起拉裂破坏。分析岸坡天然状态、加载后、地震条件下的稳定性以及水位以上及以下的稳定坡角,并对岸坡及墩台基础进行稳定性评价,为基础的布置及设计提供依据。

Lancang River Super Major Bridge is one of the controlled engineering projects of Dali to Ruili Railway. The bridge is situated in Lancang River fault zone with complex regional geological structure and rock structure. The stability of the abutment foundation is controlled by the slope stability. This paper ascertains the geological conditions of the bank slope by means of remote sensing, engineering geological survey, geophysical prospecting, drilling and other means, and addresses the stability of the bank slope based on empirical formula method, discrete element method and strength analysis. The results show that the dangerous rock formation conditions are present in the Ruili Bank, which is likely to lead to heavy collapse ; the stress areas in the rock mass of the bank slope may cause pull cracking of the lower part of the abutment. The stability of the bank slope under such conditions as natural state, loading and earthquake, and the stable slope angle above or bellow water level are analyzed, and the stability of the bank slope and abutment foundation is assessed to provide the basis for the layout of the abutment foundation.