珠江-西江经济带梧州段地质灾害发育规律及成因

为了查明珠江-西江经济带梧州段地质灾害发育特征及时空分布规律,进而分析其成因机制,为区内国土规划、重大工程建设、区域防灾减灾提供参考,在取得翔实面上调查数据资料的基础上,对其灾害类型、规模、发育特征和时空分布规律进行了统计分析。调查表明:研究区共调查地质灾害点151处,以滑坡、崩塌(危岩)、不稳定斜坡为主,泥石流仅2处,地质灾害规模均以小型为主;空间上,地质灾害70%分布在高程50～150 m之间,75%以上分布在坡度为25°～55°的斜坡,55%以上发育在顺向、逆向结构斜坡中,并沿主要构造断裂呈条带状发育;时间上,地质灾害多集中发生在汛期降雨密集的5～8月份;岩性上,地质灾害80%以上发育在寒武系、震旦系碎屑岩中。研究区地质灾害点多、面广、规模小,区内地质灾害成因机制的内在控制因素为地形地貌、地层岩性、斜坡结构类型和地质构造;外在控制因素为降雨、江水位升降和人类工程活动。

Analysis on geological hazard development and genetic mechanism inWuzhou district of Pearl River-Xijiang River Economic belt

In order to find out the development characteristics and temporal-spatial distribution of geological disasters in Wuzhou district of Pearl River-Xijiang River Economic Belt, analyze its genetic mechanism, and provide reference for regional land planning, the major engineering construction, regional disaster prevention and mitigation, the types, scale, development characteristics and temporal-spatial distribution of geological disasters were statistically analyzed based on the detailed survey data. A total of 151 geohazards were investigated in the study area, including landslide, collapse (dangerous rock), unstable slope and 2 debris flows. The scale of disaster was mainly small. In space scale: 70% of the geohazards were distributed in the height of 50 to 150 m, more than 75% of the geohazards distributed in the slope of 25~55 degrees, more than 55% of them developed in the slope of consequent and reverse structures, which develop along the main structural faults in a strip-shape . In time scale: the geohazards mostly happened in May to August in rainy season. In lithology: more than 80% of the geohazards were developed in Cambrian and Sinian clastic rocks. The characteristics of geohazards in the study area were large quantiyty, wide area and small volume. The internal controlling factors of geohazards mechanism were topography, stratigraphy, lithology, slope structure and geological structure; the external controlling factors were rainfall, rising and falling of river water and human engineering activities.