岩体结构控制下的斜坡变形特征

为了分析岩体结构与斜坡变形的作用关系，以巴东城区为例，探讨了区内主要地层（三叠系巴东组第2段T2b2、第3段T2b3）岩体结构在内、外动力地质作用下的演化过程，进而分析了不同类型岩体结构控制下的表层斜坡的变形特征。结果表明：内动力地质作用过程中形成了岩体结构，而外动力地质作用改造着岩体结构；根据沉积成岩、构造作用过程中所形成层理、节理、劈理的发育程度，可将岩体划分为层状结构、块裂结构和碎裂结构；风化、水等外动力地质作用对岩体结构的改造结果受控于原岩结构；巴东组第3段层状岩体多沿层间软弱夹层顺层滑动；巴东组第2段互层状岩体，层间差异崩解作用易形成崩塌；结构面的组合关系、发育规模控制着块体失稳的形式和规模；密集发育的劈理将岩体分割呈碎裂状结构，卸荷松动下呈膝状弯曲。这些认识对巴东地区斜坡灾害分析、防治具有一定的指导意义。

Analysis of slope deformation under control of rock mass structure

To analyze the action relation of rock mass structure and slope deformation, taking Badong county for example, the rock mass structures evolution under endogenic and exogenic geological process of main strata in the region is discussed. Then, the deformation characteristics of surface slope under the control of rock mass structure is analyzed. It is shown that the structure of rock mass is generated by endogenic geological process but rebuilt by exogenic geological process. Based on the scale of laminations, joints and cleavages generated by sedimentation and tectonic processes, the structures of rock mass are classified as layered structure, blocky structure and cataclastic structure. Rebuilding result of weathering and karst process is controlled by the initial structure of rock mass. The layered structure rock mass of T2b3 usually slides along the weak interlayer. However, the interbeded structure rock mass of T2b2 easily collapses because of the different disintegration of layers. The model and scale of blocks failure are controlled by the combination relations and size of discontinuities. The dense cleavages make rock mass cracked, which may bend when unloading. The obtained results will provide an importance reference to analyze and prevent slope hazards.