降雨强度对非饱和土降雨入渗的影响

The influence on rainfall infiltration of unsaturated soil

降雨入渗机理是非饱和土边坡稳定性的核心问题。该文开展不同降雨强度下不同压实度非饱和土降雨入渗室内模型试验。试验结果表明,降雨下,土柱从上到下的体积含水率波动剧烈程度依次递减,且下层的体积含水率变化较上层有滞后。上层土不同深度的体积含水率在小雨、大雨及暴雨条件下基本表现为先瞬时攀升而后逐渐降低至稳定状态。而下层土体积含水率在空间和时间上均表现有所差别。小雨和大雨工况,最大迁移深度范围分别为0.21~0.36 m和0.15~0.3 m;而暴雨时,最大入渗深度超过0.67 m。随着土柱压实度的增大,引起的水分迁移到达稳态所需的持时明显增大,近似呈抛物线型增长趋势。

Rainfall infiltration mechanism is the core problem of unsaturated soil slope stability.In this paper,the indoor model test of unsaturated soil rainfall infiltration under different rainfall intensity is carried out.The results show that:the volume moisture content fluctuation of soil column from top to bottom decreases sharply,and the change of volume moisture content in the lower layer lags behind that in the upper layer.Under light rain,heavy rain and rainstorm conditions,the volumetric moisture content of the upper layer soil at different depths increases first and then decreases to a stable state.The volume moisture content of subsoil is different in space and time.The maximum migration depth ranges from 0.21 m to 0.36 m in light rain and 0.15 m to 0.3 m in heavy rain;In rainstorm,the maximum infiltration depth is more than 0.67 m.With the increase of soil column compactness,the time required for water migration to reach the steady state increases significantly,which shows a parabolic growth trend.