中文摘要：

基于非饱和土双应力状态变量抗剪强度统一解,合理考虑中间主应力效应,建立了非饱和土库仑主动土压力统一解,并对其进行可比性分析,将其计算结果与非饱和土朗肯主动土压力统一解进行对比,得出各因素的影响特性。研究结果表明,中间主应力和基质吸力对库仑主动土压力的影响显著,随统一强度理论参数和基质吸力的增加,库仑主动土压力不断减小直至为0,证明了考虑中间主应力可以充分发挥材料的自承载能力和强度潜能,具有可观的经济效益;库仑主动土压力随墙背倾角与填土倾角的增大而增大,随有效内摩擦角和基质吸力角的增大而减小,外摩擦角的影响不显著。非饱和土库仑主动土压力统一解具有更广泛的适用性,朗肯主动土压力统一解为其特例,其结果对边坡、基坑等工程的土压力确定和支挡结构设计有很好的借鉴作用。

英文摘要：

Based on the unified solution of shear strength in terms of two stress state variables for unsaturated soils, the unified solution of Coulomb＇s active earth pressure for unsaturated soils is proposed which considers the effect of the intermediate principal stress rationally. Moreover, the comparability of this unified solution is analyzed. Influential characteristic of each factor is discussed by comparing with the unified solution of Rankine active earth pressure. The result shows that： the effects of intermediate principal stress and matric suction are significant; the Coulomb＇s active earth pressure decreases until zero with the increase of the unified strength theory parameter and matric suction, which indicates that the consideration of the intermediate principal stress effect can make materials give full play to their self-bearing capacities and strength potential, bringing obvious economic benefits to the project; the Coulomb＇s active earth pressure increases with the increase of the grading angle of retaining wall and slope angle of backfill, but decreases with the increase of the effective internal friction angle and matric suction angle; meanwhile, the influence of external friction angle is less significant. The proposed solution has very broad applications to the determination of soil pressure. The unified solution of Rankine active earth pressure is its a special case. It provides references for design of slope and foundation pit.