秦巴山区浅表层滑坡成灾规律研究

Disaster Law of Shallow Landslide in Qin-ba Mountain Region

以陕南秦巴山区的紫阳县域为例,通过对全县地质环境与地质灾害的详细调查,总结了浅表层滑坡的时空分布规律,分析了滑坡的各种致滑因素,在此基础上,将滑坡整个发展演化划分为四个阶段,并从破坏形式上将其归纳为两类力学模式和6种表现形式。结果表明,秦巴山区内浅表层滑坡受地形地貌、地层岩性、地质构造、气象水文、人类活动等因素影响非常敏感,尤其表现为滑坡灾害与暴雨同期,但受物源条件限制大规模灾害之间存在9~10年的平静期。浅表层滑坡特有的发展演化可划分为表层卸荷阶段、加速风化阶段、风化堆积阶段、浅表层滑坡发生阶段等四个阶段,根据其变形破坏特征归纳为剧滑—平推和蠕滑—拉裂两种力学模式以及6种表现形式。

Based on detailed investigation on geological environment and hazards of Ziyang County in Qin-ba mountain region of south Shaanxi province,spatial and temporal distribution of shallow landslide is summed up and the various factors of landslide induced slip are analyzed. On this basis,the whole landslide evolution is divided into four stages and summarized into two mechanical modes and six kinds of manifestations from the destruction form. The results show that shallow landslides in the area are quite sensitive to factors as topography,lithology,geological structure,meteorology,hydrology,human activities and so on. Especially,the landslides are often performed with heavy rain,large-scale disaster is also controlled by provenance conditions,and the quiet period would be about 910 years between two disasters. The peculiar evolution of shallow landslide can be divided into four stages as surface unload stage,accelerated weather stage,weather and accumulation stage,and shallow landslide-occurring stage. According to deformation and failure characteristics,shallow landslides are summarized into two kinds of mechanical models that are dramatic slide-horizontal push and creep-pull split,as well as six kinds of manifestations.