降雨条件下的非饱和有限土体主动土压力分析

Active earth pressure analysis of unsaturated finite soil under rainfall

有限土体土压力的计算理论多采用总应力法进行计算,忽略了非饱和状态时基质吸力变化对有限土压力的影响。针对此问题,在饱和土的有限土体主动土压力理论基础上,应用Bishop有效应力原理,并结合暂态水分布场解析解,建立了引入基质吸力作用的非饱和有限土体土压力模型,推导了降雨入渗作用下的非饱和有限土体主动土压力计算公式。结果表明,该方法得出的有限土体主动土压力值较未降雨条件下的计算结果偏大,但随深度增加土压力值所呈现的先增大后减小的趋势并未改变;此外,降雨入渗对基质吸力影响会使主动土压力产生相对滞后的波动。

The calculation theory of finite earth pressure is usually analyzed by using total stress method, which ignores the influence of matric suction change in the unsaturated condition. Based on the finite active earth pressure theory of saturated soil, the calculation model under the condition of rainfall is established by the combination of Bishop’s effective stress principle and analytical solution of transient water distribution field, and then deduced the calculation formula. The results show that the active earth pressure calculated by this method is larger than that without rainfall, but the trend does not change when the earth pressure increases and then decreases with increasing depth. In addition, the influence of rainfall infiltration on matrix suction leads to a relatively lagging fluctuation for the active earth pressure.