赣南花岗岩风化边坡破坏模式及其失稳预测

Failure Mode and Instability Prediction of Weathered Granite Slope in South Jiangxi

赣南地区花岗岩分布广泛,构造裂隙发育,风化作用强烈,在降雨及人类工程活动影响下边坡地质灾害频发.研究这一地区花岗岩边坡破坏模式和失稳运动过程,可以有效科学地进行边坡防治.基于现场地质调查和资料收集,分析了赣南花岗岩边坡地质灾害分布特征,并将该地区边坡地质结构分为土质边坡、浅层风化边坡、岩质边坡和岩土混合边坡4类;边坡破坏模式主要有坍滑型、崩滑型、混合型、沿结构面滑移型4类.采用非连续性变形分析(DDA)方法模拟了各类边坡失稳运动破坏过程,对其破坏影响范围进行了预测,其中混合型以及沿结构面滑移型危害最大,影响范围最广.根据赣南花岗岩边坡4类破坏模式特点,提出了相应的防治对策,可望为赣南花岗岩区居民建房选址及地质灾害防治提供理论和技术支撑.

Granite is widely distributed in the south of Jiangxi province(Gannan), with developed tectonic fissures, strong weathering, and frequent slope geological disasters under the influence of rainfall and human engineering activities. Studying the failure mode and instability process of granite slopes in this area can effectively and scientifically prevent and control the slope. Based on the field geological survey and data collection, the distribution characteristics of geological hazards of granite slope in southern Jiangxi are analyzed, and the geological structure of the slope in this area is divided into four categories: soil slope, shallow weathered slope, rock slope, and rock soil mixed slope. There are four types of slope failure modes: landslide, collapse, mixed and sliding along the structural plane. The discontinuous deformation analysis(DDA) method is used to simulate the failure process of various slope instability movements and predict the impact range of the failure. Among them, the mixed type and the slip type along the structural plane are the most harmful and have the most extensive influence. According to the characteristics of four types of failure modes of granite slope in southern Jiangxi, the corresponding prevention and control measures are proposed, which are expected to provide theoretical and technical support for residential building site selection and geological disaster prevention in the granite area in southern Jiangxi.