断裂构造对滑坡的水力补给类型及作用机理分析

ANALYSIS OF THE TYPE AND MECHANISM OF WATER SUPPLY FROM FAULT STRUCTURE ON LANDSLIDE

大型复杂滑坡受断裂构造的水力补给作用,常发育丰富的地下水。断裂构造水力补给主要受区域水文地质条件控制,具有水质、水量较为稳定等特点,对滑坡稳定性影响巨大且具有长期性。目前,有关断裂构造对滑坡的水力补给作用的研究成果较少,缺乏断裂构造对滑坡水力补给作用类型、形成条件等共性规律的系统性研究。本文通过分析研究国内断裂构造水力补给滑坡的典型实例,根据断裂构造的分布位置、力学性质及其对滑坡地下水的补给方式和水力联系等,将断裂构造对滑坡的水力补给类型划分为边界补给型、滑床补给型及复合型3种类型,分析了地下水对滑坡的4种作用机理——滑带孔隙水压力增高、滑床承压水顶托、滑带黏土矿物遇水膨胀及滑带化学溶蚀。研究成果对于揭示滑坡地下水运移规律、定量评价地下水对滑坡的作用及合理确定地下截排水设计等具有重要指导价值。

Large and complex landslides are often rich in groundwater due to the hydraulic recharge of fault structures.Regional hydrogeological conditions mainly control the water supply of fault structure,and have the characteristics of stable water quality and quantity,which has a great and long-term influence on the stability of landslide.At present,there are few studies on the effect of fault structure on the water supply of landslide,and there is no systematic study on the type and formation conditions of fault structure on the water supply of landslide.This paper studies the typical example of water supply landslide in fault structure,according to the distribution location of the fault structure,the mechanical properties,the way to recharge the groundwater of the landslide and the hydraulic connection.Fault structure causes on the water supply types of the landslide are divided into three types:boundary supply type,sliding bed supply type and compound type.Four mechanisms of groundwater action on landslide are analyzed,including increasing pore water pressure in the sliding zone,lifting of confined water in the sliding bed,sliding zone clay minerals swell with water,and sliding zone chemical dissolution.The research results have important guiding value for revealing the law of groundwater migration,quantitatively evaluating the effect of groundwater on landslide,and reasonably determining the design of interception and drainage of groundwater.