Slope failures and slope slides of expansive soils are usually characterized by shallow sliding along the surface crack. Soilbag is an effective method to prevent and control slope failures and slope slides of expansive soil. Currently, soilbag protection for expansive soil slopes has been commonly designed using empirical methods, which led to many failures of soilbag-protected slopes, or high-cost. In this paper, a new design method of the soilbag-protected slopes in expansive soils is proposed based on the balance between the soilbag friction and the active lateral earth pressure induced by the swelling pressure of expansive soils. Specifically, the friction between the soilbags is assumed to be in direct proportion to the soilbag heap-up height. The active lateral earth pressure acted on a layer of soilbag is calculated along with the total height of the slope. Moreover, the width of soilbag layers is calculated from the balance of the sum of soilbag friction and the total active lateral earth pressure along with the soilbag height and expressed by the height of slopes. For the convenience of soilbag construction, the heap-up unit of soilbags is proposed for different slope heights of expansive soils.

膨胀土的边坡破坏和边坡滑坡通常表现为沿地表裂缝的浅层滑移。土袋是防治膨胀土边坡失稳和滑坡的有效方法。目前，膨胀土边坡的土袋保护设计普遍采用经验方法，导致土袋保护边坡失效多，成本高。本文基于土袋摩擦力与膨胀土膨胀压力引起的主动侧向土压力之间的平衡，提出了一种新的膨胀土土袋保护边坡设计方法。具体来说，假设土袋之间的摩擦力与土袋堆积高度成正比。作用在一层土袋上的主动侧向土压力与边坡的总高度一起计算。此外，土袋层的宽度由土袋摩擦力和总主动侧向土压力的总和与土袋高度的平衡计算，并用坡高表示。为方便土袋施工，针对不同坡高的膨胀土提出土袋堆放装置。