倾倒变形岩体发育强度与极限深度的确定方法

以澜沧江某水电站右坝肩倾倒变形岩体为例,根据倾倒变形岩体的宏观地质特征及其地质环境背景条件,系统分析了影响倾倒变形岩体发育的地质因素。运用离散元数值分析方法,模拟了不同影响因素对岩体变形强度的影响程度,并与实际边坡开挖揭露的岩体变形特征进行对比分析,得到了发生岩体变形的控制因素、变形发展过程的时间效应与空间分布特征。研究结果表明,导致岩体发生倾倒变形的外部因素是重力、地应力、卸荷方向与卸荷强度,提出了倾倒变形极限深度的概念。通过地质成因分析、离散元数值分析和理论公式推导,建立了由地表变形弯折强度确定变形随深度变化的计算模型,为开挖边坡的稳定性评价及系统锚索深度设计提供了重要的依据。

DISTRIBUTION PROPERTIES AND LIMIT DEPTH DETERMINING METHODS OF ROCK MASS WITH TOPPLING DEFORMATION

According to the deformation properties and geological conditions at field, the factors affect the toppling deformation of rock mass are analyzed. Contrasted to the real deformation strength, which exposed by excavated slope, the numerical simulation method called UDEC is used to simulate the toppling strength along the limit depth. The factors, time-dependent process and distribution are researched. The research result is that the external factors are gravity force, earth stress, unloading direction and magnitude. A calculating model of limited toppling depth according to the shallow deformation strength is put forward based on geological mechanism analysis, numerical method and formula reduction.