通过引入单一安全系数，基于极限平衡法，推导土工袋修复体两种滑动模式的抗滑稳定性计算公式。通过土工袋摩擦试验，研究不同袋内材料、土工袋排列方式、竖向压重以及运行环境（水上或水下）等条件下的土工袋袋体层间和袋土之间的摩擦特性，试验结果表明：袋装膨胀土土工袋堆叠为交错排列的过程中形成的咬合作用和嵌固作用将土工袋袋体无缝排列的层间摩擦因数0.714提升至0.920；土工袋浸泡于水下进行摩擦试验，水的润滑作用会导致土工袋袋体层间以及土工袋袋土之间的摩擦因数从0.920降低至0.901。采用土工袋抗滑稳定公式与摩擦试验得出的摩擦因数，对南水北调中线工程中土工袋修复膨胀土边坡案例的两种滑动形式进行抗滑稳定性分析，得出土工袋修复体最小安全系数为1.25，论证了土工袋修复膨胀土边坡的效果。

Soilbags can enhance the strength and restrict the swelling deformation of the expansive soil,and the assembly of soilbags on the expansive soil slope acts as an overburden can avoid the collapse of expansive soil slope during operation period .It has been proved that the soilbag layer arranged on the slope can effectively retard the moisture movement into the underlying expansive soil/rock slope and can be regarded as a reinforcement layer to take effect of restraining the expansion and contraction of expansive soils.It is a promising method to repair the failed expansive soil slopes by the use of soilbags.Unlike other methods such as chemical and mechanical stabilization,when dealing with shallow slope failure,the collapsed expansive soils can be directly filled into bags,and large construction machines are not required for the repairing work.It is particularly suitable for repairing the expansive soil channel slope on a small scale during the operation of the project as it is very flexible and convenient.A method to analyze the sliding stability of the soilbags-repaired expansive soil slope was proposed by introducing a single safety factor.And,a series of laboratory tests were conducted to study the frictional characteristics of stacked soilbags with different filling materials under different inter-layered arrangements of soilbags and the applied vertical stresses.Different filled materials refer to 10%,20%,and 30% of the gravel content and different gravel particle size in the expansive soil.The inter-layered arrangements of soilbags mainly include four kinds.The influence of the water on the interlayer friction of soilbags was also investigated.The results show that the interlayer frictional coefficient between the vertically stacked soilbags is around 0.714,and it can increase up to 0.920 for the staggered soilbags owing to the interlocking effect.When soilbags are soaked in water,the interlayer friction coefficient between the staggered soilbags will decrease to 0.901 owing to the lubrication of water.The case study on a failed expansive channel slope in the South-to-North Water Transfer Project showed that the proposed stability analysis method based on the limit equilibrium of the soilbags-repaired assembly is appropriate for the design of a soilbags-repaired expansive soil channel slope.