持续降雨条件下黄土边坡稳定性试验研究

Experimental Study on Stability of Loess Slope Stability Under Continuous Rainfall

滑坡是黄土丘陵沟壑区常见的重力侵蚀,降雨是黄土边坡失稳的主要诱因。为了研究持续降雨条件下黄土边坡的稳定性,采用人工降雨装置进行室外现场试验,测量土体含水率、密度、滑坡剪切带位置以及裂缝的发育等情况,并使用FLAC3D软件计算模拟持续降雨条件下裂缝发育对边坡稳定性的影响。结果表明:随着降雨历时的增加,黄土边坡土体的含水率逐渐增大,土体强度降低,而且自重增大,坡面冲蚀沟逐渐发育,坡脚出现滑塌,坡顶出现拉裂缝,裂缝加剧了降雨的集中入渗,使得裂缝周边土体强度快速降低,最终导致在降雨历时至308.8 h时发生滑坡,持续降雨和裂缝引起的集中入渗加速了土体强度的降低,导致了滑坡,裂缝发育得越深、数量越多,对边坡稳定性危害越大。研究结果为降雨条件下的黄土边坡稳定分析研究和地质灾害防治提供方法和技术支撑。

Landslide is the common geological disaster in loess hilly and gully areas, and rainfall is the main cause of instability of loess slopes. In order to study the stability of loess slopes under continuous rainfall conditions, an artificial rainfall device was used to carry out experimental studies on the outdoor site. The soil moisture content, density, shear zone location and crack development were measured. The FLAC3 D geotechnical engineering numerical calculation software was used to analyze the slope stability. The results showed that with the increase of rainfall duration, the moisture content of the loess slope soil gradually increased, the soil strength gradually decreased, and its own weight gradually increased. The gully erosion on the slope gradually developed, the slope toe collapsed, and the tensile cracks occurred on the top of the slope. The cracks increased the infiltration of rainfall, which made the strength of soil around the crack decrease rapidly, and finally caused a landslide when the rainfall lasted 308.8 h. Rainfall infiltration and concentrated infiltration caused by cracks accelerated the reduction of soil strength and led to the landslide. The deeper and more cracks developed, the greater their damage to slope stability.