长江三峡巫峡岸坡望霞危岩发育机理研究

Developing mechanism of dangerous rock at bank slope of Wuxia Gorge in Three Gorges

以长江三峡巫峡岸坡望霞危岩为例,从地质构造、软硬岩层组合、水动力特性等方面分析了危岩形成条件。结合三峡层状地貌,演绎了陡崖后退和危岩发生过程,归纳出三峡灰岩岸坡危岩崩塌发育、加速崩塌、崩塌循环发育和堆积4个阶段,说明了陡崖台阶地貌形迹是危岩阶段性演化的宏观表象。根据望霞危岩W2危岩体的地质模型,建立其在不同荷载组合情况下的力学模型,并计算了危岩稳定性状态。

With the case of Wangxia dangerous rock at the bank slope of Wuxia Gorge, Three Gorges area, its forming condition is analyzed from the respects of geological structure, soft-hard alternant strata and hydrodynamic characteristics. The cliff receding and dangerous rock progressing are deduced according to stratified landform in the Three Gorges Area. Four phases of collapse initiation, collapse acceleration, collapse cycling and accumulation of developing mechanism of limestone dangerous rock in Three Gorges area are summarized. It is indicated that geomorphologic formalities of cliff terraces are macroscopic manifestation of staged evolution of dangerous rock. The mechanical model under different load combinations is built to calculate the stabilities of Wangxia W2 dangerous rock.