危岩支撑及支撑-锚固联合计算方法研究

危岩是三峡库区典型的地质灾害类型之一 ,根据失稳类型本文将危岩分为坠落式危岩、滑塌式危岩和倾倒式危岩三类。其中坠落式危岩和滑塌式危岩的破坏机理主要属于危岩体沿着主控裂隙面剪切破坏 ,而倾倒式危岩则主要属于危岩体围绕基部倾覆点拉裂转动破坏。实践表明 ,具有支撑条件时 ,支撑是极其有效的技术类型 ,尤其对坠落式危岩和倾倒式危岩更为适用。作用在危岩体上的荷载主要有自重、裂隙水压力和地震力 ,可构成三种荷载组合。基于支撑体的容许承载力及危岩体的极限平衡理论 ,本文建立了坠落式危岩的支撑计算方法 ,建立了倾倒式危岩的支撑 -锚固联合计算方法 ,量化了支撑体尺寸 ,获得了倾倒式危岩所需的锚杆 (索 )数量。文中所提出的危岩支撑计算方法两年来已经在三峡库区的数百个危岩体治理中得到成功应用 ,并被录入《重庆市(三峡库区 )滑坡、塌岸、危岩防治工程设计技术规范》中 ,用于指导三峡库区重庆境内的危岩防治工程。

Researches on calculation method of support and support-anchorage union to unstable rock

As a typical geologic disaster in the Three Gorges Reservoir,unstable rock is classified into falling unstable rock,sliding unstable rock and toppling unstable rock in view of unstable modes.Shear fracture along controlling fissure is the failure mechanism for falling unstable rock and sliding unstable rock,while tension fracture is that for toppling unstable rock around turning point.It is proved in much practice that support is the best measure when some conditions are satisfied, especially for falling unstable rock and toppling unstable rock.Loads acting on unstable rock mass can be divided into self-weight,fissure pressure in controling fissure and earthquake forces,and three are three load combinations.Based on the allowable bearing capacity of support mass and equilibrium theory of unstable rock mass, the authors have established calculation method for support to falling unstable rock and for support-anchorage union to toppling unstable rock. These methods can calculate geometrical dimensions of support and anchorage pile or rope numbers.The proposed methods have been successfully applied in hundreds of unstable rocks in the Three Gorges reservoir for two years. All the methods in the paper are adopted by “The Design Technique Standard of Landslide, Bank Collapse, Unstable Rock in Chongqing City (the Three Gorges Reservoir)”.They are valuable for controlling unstable rock disasters in the Three Gorges Reservoir.