一维非饱和土固结简化计算的改进方法

An Improved Method of Simplified Computation of 1D Consolidation for Unsaturated Soil

对于较高饱和度的非饱和土,通过将孔隙中水、气看作一种混合介质简化固结过程,提出了改进的计算方法。考虑加荷初期,由水、气、土骨架共同承担荷载建立平衡方程,求得三者分担的应力和土体体积压缩量;固结过程中,将水和气看成混合的可压缩流体,建立混合流体的连续性方程,求解混合流体压力;同时考虑孔隙比和饱和度的变化,将孔隙水与混合流体的流量联系,建立改进的水连续性方程,求解水压力,进而求得气压力,吸力和土体的压缩量。结果表明:一维非饱和土的加载及固结中孔隙水压、有效应力、体变及饱和度的变化合理,体变计算值接近于试验值,该方法正确。

The water and air in the pores were regarded as mixed fluid to simplify the consolidation process of unsaturated soil with high degree of saturation, and a simplified computation method of 1D consolidation was improv ed. At initial loading stage, water, air and soil skeleton support the load together, and the balanced deferential equation was established for solving the shared stresses and the compression volume of soil. At consolidation stage, the water and air were regarded as compressed mixed fluid, and the continuity equation of mixed fluid was set up for the variation of mixed fluid pressure with time. Because the pore-water flow not only depends on the void ratio and the degree of saturation but also is related to mixed fluid flow, the improved continuity equation of water was established for water pressure to calculate suction, air pressure and soil compression. The result shows that （1） the loading of 1D unsaturated soil, the variation of pore-water pressure, effective stress, volume strain and degree of saturation at consolidation stage are reasonable; （2） the volume strain of computation is consistent with that of experiments. Therefore, the approach is reasonable.