平移变位模式下黏性土非极限主动土压力

Non-limit active earth pressure of cohesive backfill under translation mode

针对经典朗肯与库仑土压力理论不能计算非极限土压力的事实.根据土体渐进破坏机理,结合已有文献对准主动状态下土体摩擦角、黏聚力发挥值与墙体位移关系的研究,采用水平层分析法,通过建立水平微元体基本受力平衡方程,推导出非极限状态下黏性土主动土压力分布的一阶微分方程式.在此基础上给出了土压力合力及其作用点位置计算式,相应简化条件下,所提公式能够简化为朗肯、库仑主动土压力公式.算例分析结果表明:理论计算值与实测值基本吻合,获得了平移变位模式下黏性土非极限土压力随位移变化的规律,对实际工程挡土墙的设计计算具有一定的参考价值.

The classic Rankine and Coulomb earth pressure theory can not be used to calculate the non-limit earth pressure.Based on the progressive rupture mechanism,and combined with the existing research on the relationships between the mobilized friction angle,cohesion force and the displacement of rigid retaining wall under inter-mediate active state,the horizontal slices analysis method is used to de-duce the first-order differential equations of the active earth pressure distribution of cohesive backfill un-der unlimited state by establishing the basic force equilibrium equations of horizontal element.Based on this,the formula of the earth pressure resultant force and its action point are given,which can be simpli-fied to Rankine’s and Coulomb’s earth pressure formula under corresponding simplified conditions.The result of example analysis show that the calculated and measured earth pressure match with each other, the change regulation of non-limit earth pressure of cohesive backfill under translation mode is obtained, and which can be used for the design of retaining wall in practical engineering.