峨眉山玄武岩区地质灾害的地质约束——以贵州省水城县为例

玄武岩在贵州省境内出露仅占省域面积的2.08%, 但却孕育着较大的地质灾害风险隐患. 这些区域植被覆盖率较高, 使地质灾害具有隐蔽性和突发性, 常常难以有效进行识别和防范. 本文以水城县为例, 采用ArcGIS软件对玄武岩区发育的各类地质灾害风险隐患点数据和地质、地理信息进行叠加和系统处理分析, 再结合野外现场大比例尺调查检验, 得出水城县玄武岩区地质灾害风险隐患发育的地质约束明显的结论, 即呈土岩二元结构的滑坡、不稳定斜坡、风险斜坡为该区主要地质灾害风险隐患, 较集中展布于北西向褶皱构造翼部和北西向、北东向断褶构造交汇部位, 这些区域通常地势较为平缓, 土地资源丰富, 自然村寨分布较多. 玄武岩体的内生条件和外生条件影响了其风化程度, 风化土的物理力学性质又决定了其对环境的极其敏感性.

GEOLOGICAL CONSTRAINT OF GEOHAZARDS IN EMEISHAN BASALT AREAS: A Case Study of Shuicheng County in Guizhou Province

Basalts in Guizhou Province carry great hidden danger of geohazards, although they account only for 2.08% of the total area. Due to the dense coverage of vegetation, it is often difficult to identify and prevent the hidden and sudden geological disasters effectively in these basalt areas. Taking Shuicheng County as an example, the paper uses ArcGIS for the superposition and systematic analysis of various geohazard hidden point data as well as geological and geographic information in the basalt areas. Combined with the large scale field investigation and verification, it is concluded that the constraint of geohazards in the basalt areas of Shuicheng County is obvious. The main hidden geohazards in the area include soil-rock dual structure landslide, unstable slope and risk slope, which are distributed in the intersection of NW fold structure wing and NW and NE fault-fold structure. The terrain in the area is relatively gentle, rich in land resources and distributed with multiple natural villages. The endogenous and exogenous conditions of basalts affect the weathering degree, and the weathered soil is extremely sensitive to the environment due to its physical and mechanical properties.