持续强降雨对有限土体土压力的影响规律

Effect of Continuous Heavy Rainfall on the Earth Pressure of Finite Soil

以安徽繁昌某小区南侧大型滑坡为研究对象,该滑坡在持续强降雨作用下复滑,导致原有挡土墙破坏。运用野外地质调查、工程地质勘察、数值模拟及物理模型试验等方法,研究了暴雨对滑体土压力的影响规律、滑体在暴雨作用下的破坏机制,查明了滑坡的稳定性,以及不同工况下墙后土压力的分布规律。调查研究结果表明:该滑坡在天然状态下处于稳定-欠稳定状态;在暴雨状态下处于欠稳定-不稳定状态,在持续强降雨状态下处于不稳定状态,自墙顶至土岩接触面,墙后土压力分布呈先增大后减小再增大的趋势;持续强降雨作用下,土压力相较于天然状态显著增大,斜坡塑性区逐渐发展,直至形成贯通滑面,斜坡水平位移陡增,发生滑动破坏;在稳定状态下,抗剪强度参数的变化对墙后土压力及滑坡稳定性并无影响,当土体抗剪强度参数小于某一临界值时,土压力随着抗剪强度参数减小呈非线性增长。

Taking a large landslide on the southern side of a residential district in Fanchang Anhui Province as the research object,the landslide slides again under the action of continuous heavy rainfall,resulting in the destruction of the original retaining wall.By means of field geological survey,engineering geological survey,numerical simulation and physical model test,the stability of the landslide and the distribution law of earth pressure behind the wall under different working conditions were ascertained.The investigation results show that the landslide is in a stable to unstable state under natural conditions.The distribution of earth pressure behind the wall increases first,then decreases and then increases from the top of the wall to the interface of soil and rock.Under the continuous heavy rainfall,the earth pressure increases significantly compared with the natural state,and the plastic zone of the slope develops gradually until a through slip surface is formed.The horizontal displacement of the slope increases sharply and sliding failure occurs.In the stable state,the change of shear strength parameters has no effect on the earth pressure behind the wall and the stability of the landslide.When the shear strength parameter of soil is less than a critical value,the earth pressure increases nonlinearly with the decrease of the shear strength parameter.