顺层岩质路堑边坡破坏模式及设计对策

FAILURE MODES OF BEDDING ROCK CUTTING SLOPE AND DESIGN COUNTERMEASURES

在对大量顺层边坡进行详细调查研究基础上,总结提出顺层岩质路堑边坡的分类及8种顺层边坡破坏模式,并对较为常见的滑移–拉裂和滑移–弯曲破坏模式的稳定性分析方法进行讨论。指出在实际工程中,对于滑移–拉裂型顺层边坡,其稳定性分析可通过计算失稳岩层临界长度进行,为避免开挖过程中边坡出现顺层滑动,宜先加固后开挖或边开挖边加固;对顺层清方边坡,可能出现滑移–弯曲破坏,宜采用弹性受压板稳定理论进行边坡稳定性分析后,确定分级高度和加固措施。水是诱发顺层边坡失稳的主导因素,设计中应加强防排水措施。

Based on the geological investigation on many bedding rock slopes, a slope classification system and eight types of failure modes with respect to bedding rock slope are presented. Furthermore, the analytical methods for stability of slip-fracture and slip-bending failure mode slopes are studied. It is pointed out that the stability analysis of the slip-fracture failure mode slope can be carried out by calculating the ultimate length of the unstable rock formation; slope reinforcement in advance or reinforcement and excavation simultaneously should be adopted to avoid slope failure for this kind of bedding rock slope. For the bedding slopes whose failure mode would be slip-bending due to the excavation of the rock mass along the bedding surface, the slope stability analysis should be introduced firstly by using the compressive elastic slab stability theory, and the step excavation height and reinforcement measures then could be determined. Water is the key factor inducing the failure of bedding rock slope, so the issue to ensure waterproofing and drainage must be considered in the slope design.