陡倾硬岩和软岩基座组成的差异风化型危岩是地质灾害的常见形态。在建立危岩的力学分析模型的基础上，研究了边坡中张性地应力和岩腔发育深度对差异风化型危岩形成与破坏的影响。以重庆洪崖洞危岩边坡为工程背景，采用空心包体应力计对边坡地应力进行了现场测试和分析，判定了危岩松动发育区范围。用算例分析了差异风化型危岩体的形成和破坏过程，结果表明张性地应力和岩腔深度对主控裂隙的形成具有最强的相关性，并分析了各种参数的影响，提出了预测差异风化型危岩控制性破坏模式的方法。分析方法和结果适用于类似条件下的危岩边坡，可供相关研究和工程参考。

Differential weathering overhanging rock by hard rock and soft rock interlayer is common for geological failure.To study the influence of ground stress in rock slope and cave deepness to differential weathering overhanging rock,a mechanical model was proposed.And hollow cylinder stress meter was used to test and analyze onsite ground stress at Hongyadong in Chongqing.Moreover, the development range of overhanging rock was determined.And a case studywas used to analyze the relationship among tension ground stress, cave deepness and growth of controlling crack.A method for forecasting overhanging rock failure pattern was proposed.

国家杰出青年科学基金(50625824)；重庆市科技攻关计划项目(CSTC2008AC0077)