In order to accelerate the consolidation rate of double-layered unsaturated ground with poor hydraulic conductivity, the sand blanket is always set between two adjacent unsaturated soil layers to produce drainage paths along the horizontal direction in practical engineering. Based on the one-dimensional consolidation theory of unsaturated soil proposed by Fredlund and Hassan(1979), the semi-analytical solutions of excess pore-air and pore-water pressures, and settlement of the double-layered unsaturated ground with the horizontal drainage blanket are obtained by Laplace transform technique in this paper. Additionally, the current solutions can degenerate into those under the single-layered unsaturated model, which are then utilized to compare with existing solutions in literature, the significant agreement indicates that the present solutions are reliable and general. At last, a case study is adopted to investigate the influence of the vertical position of the drainage blanket, and permeability coefficients ratio of two adjacent soil layers on the consolidation of the double-layered unsaturated ground. Results show that the horizontal drainage layer will effectively accelerate the consolidation process, and the setting depth of 0.7H works best. Moreover, the smaller the ratio of the permeability coefficient of the upper layer to that of the lower layer (with the permeability coefficient of the upper layer remaining constant), the faster consolidation will develop.

为加快导水性差的双层非饱和土层的固结速度，实际工程中通常在相邻的两层非饱和土层之间设置砂毯，以产生沿水平方向的排水通道。基于Fredlund和Hassan(1979)提出的非饱和土一维固结理论，超孔隙空气压力和孔隙水压力的半解析解，以及水平排水层双层非饱和地层的沉降本文采用拉普拉斯变换技术获得。此外，当前的解决方案可以退化为单层不饱和模型下的解决方案，然后将其与文献中的现有解决方案进行比较，重要的一致表明目前的解决方案是可靠和通用的。最后通过算例研究了排水毯的垂直位置、相邻两土层的渗透系数比值对双层非饱和地基固结的影响。结果表明，水平排水层将有效加速固结过程，0.7的凝固深度H效果最好。而且，上下层渗透系数之比越小（上层渗透系数不变），固结发展越快。