裂隙岩体渗流补给特性及边坡稳定对策研究

“岩土二元结构体”边坡失稳现象由于其物质组成、形成年代、地质结构等方面的特点，与其他岩土边坡失稳有不同的表现.为探讨降雨诱发“岩土二元结构体”边坡失稳的机理及保证边坡稳定的对策，采用自记雨量计、时域反射仪（TDR）、翻斗式自记流量测定仪对“岩土二元结构”小流域的降雨特性、坡地岩土水分的动态变化以及裂隙岩体渗流的动态过程进行了测定分析.结果表明，降雨特性、坡地岩土前期水分含量以及坡地的地质结构特性是影响降雨入渗补给渗流及降雨诱发边坡失稳的重要因素；在强降雨条件下，距坡地表层50cm深度的土壤层与岩体层结合部位存在暂时饱和区，该饱和区通过对滑动面的浸泡软化，可以促使滑坡体的滑动；降雨入渗补给裂隙岩体渗流在坡面尺度上存在“优先流”现象，这主要是由于太行山区坡面尺度介质的非均匀性与空间变异性所造成的，同时，暂时饱和区的形成也起了重要的促进作用，这有利于区域地下水资源的形成，但也为诱发边坡失稳提供了条件；可以通过渗流集蓄技术降低暂时饱和区内的水分含量及裂隙网络中的侧向水压力，从而保证边坡的稳定. 

Fractured rock seepage characteristics and its impact on slope stability

Catchments characterized by shallow soil and deep stony layers in weathered gneiss(otherwise known as 'rock-soil dual entity' catchments) have very low stability in comparison with common slopes with similar soil and weather rock layers. To clarify the mechanism leading to low stability of 'rock-soil dual entity' catchments as well as slopes and to identify the countermeasures retaining slope stability,catchment slope hydrological processes such as rainfall characteristics,soil water movement and seepage were monitored and analyzed during rainfall events,using auto-recording ombrometer,time domain reflector(TDR),and tipping bucket flow meter.The results showed that: 1) rainfall characteristics such as intensity and duration,soil moisture content of slope before rain events,and slope geology were the major elements driving water seepage and slope stability.2) during heavy rainfall events,saturated zone instantaneously existed at the soil-gneiss interface,about 50 cm beneath the slope surface.Water in the instantaneous saturated zone softened the slope surface and caused sliding.3) because of spatial variations in the slope layer and the formation of instantaneous saturated zone at the soil-gneiss interface,preferential flow occurred in the slope.This phenomenon,on the one hand is good for the formation of slope runoff and further,for water supply in the downstream;but highly increases the possibility of landslide on the other hand.To retain slope stability,instantaneous saturated water is suggested to be artificially drained to reduce the incidence of hydraulic pressure build-up by collecting seepage water on slopes.