摘要
在面上调查、资料收集与数据分析的基础上,对粤桂合作特别试验区地质灾害的地质背景、发育特征、失稳模式及致灾机理进行研究。研究区大地构造上位于华南加里东褶皱系钦州残余海槽与大瑶山凸起交汇处,滨太平洋构造域与特提斯构造域的复合区内,断裂构造极其发育。地层岩性以寒武系、震旦系碎屑岩和燕山期花岗岩为主。特殊的地质背景决定了该区地质灾害的发育特征:区内共发现地质灾害点238处,以滑坡、崩塌(危岩)、不稳定斜坡为主,泥石流仅2处,以小型为主;空间上,75%以上灾害点分布在高程50~150m之间,65%以上分布在坡度35°~55°斜坡,且80%以上发育在顺向、逆向结构和花岗岩类斜坡中;地层岩性上,95%以上发育在寒武系、震旦系碎屑岩和花岗岩中;时间上,地质灾害多集中发生在汛期降雨密集的5~8月份。碎屑岩区地质灾害主要失稳模式为沿基-覆界面滑移型、顺层滑移型、压溃-剪切滑移型、风化-坠落型和拉裂倾倒型5种类型;花岗岩区地质灾害主要失稳模式为拉裂-倾倒型、风化-坠落型、拉裂-溜滑型和沿基-覆界面滑移型4种类型。地质灾害影响和诱发因素主要为地层岩性、地质构造、人类工程活动和降雨。实验区地质灾害发育特征和变形破坏机理的研究,可以为区内防灾减灾提供依据。
On the basis of surface investigation, data collection and analysis, the geological background,developmental characteristics, instability mode and disaster-causing mechanism of geological hazards in Special Experimental Area of Guangdong-Guangxi Cooperation were studied. The study area is located at the intersection of Qinzhou residual trough and Dayaoshan uplift of Caledonian fold system in South China, and in the composite area of coastal Pacific tectonic domain and Tethys tectonic domain. The fault structure and its development are mainly composed of Cambrian, Sinian clastic rocks and Yanshanian granites. Special geological background determines the development characteristics of geological disasters. There are 238 geological hazards in the area, mainly landslides, collapses (dangerous rocks), unstable slopes, only two debris flows, mainly small. Spatially, more than 75% of them are distributed in the elevation range of 50-150 m, 65% in the slope of 35°-55°, and more than 80% in the slope of forward and reverse structure and granitoid. More than 95%are developed in Cambrian, Sinian clastic rocks and Yanshanian granites. Most of the geological hazards occurred in May to August during the flood season. The main instability modes of geological hazards in clastic rock areas are slip along the base-overburden interface, bedding slip, collapse-shear slip, weathering-falling (denudation) and tension-dumping. The main instability modes of geological hazards in granite area are tensile-dumping, weathering-falling, tensile-sliding and sliding along the base-overburden interface. Geological hazards are mainly caused by stratum lithological characters, geological structure, human engineering activities and rainfall. The study on the development characteristics and formation mechanism of geological hazards in the experimental area can provide basis for disaster prevention and reduction in the area.
作者
刘广宁
齐信
黄长生
王芳婷
LIU Guang-Ning;QI Xin;HUANG Chang-Sheng;WANG Fang-Ting(Wuhan Center of China Geological Sunvey (Central South China Innovation Center for Geosciences), Wuhan 430205, Hubei, China)
出处
《华南地质与矿产》
CAS
2019年第3期361-372,共12页
Geology and Mineral Resources of South China
基金
中国地质调查局地质调查项目(DD20160257、DD20190263)
关键词
地质灾害
发育特征
变形破坏机理
粤桂合作特别试验区
geological hazards
characteristics of development
mechanism of deformation and failure
Special Experimental Area of Guangdong-Guangxi Cooperation
