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对于临近既有地下室或竖直基岩面的挡土墙,由于墙后填土宽度有限,采用经典的库伦、朗肯土压力理论计算挡土墙主动土压力是不合适的。采用有限元分析软件ABAQUS,对狭窄黏性填土刚性挡土墙的主动土压力问题进行研究,探讨了墙后土体的临界裂缝深度和滑裂面的发展规律。考虑墙土之间的黏着力和填土竖向裂缝,建立新的理论分析模型,得到了挡土墙水平主动土压力合力的求解方法和主动土压力分布的解析公式。土压力合力系数与土压力强度的理论解和数值解吻合较好,验证了本文理论解的合理性。研究表明,主动极限状态下,填土表面两侧均将产生竖向裂缝,且临界裂缝深度不随填土宽度变化,其值与朗肯裂缝深度接近;随着填土宽度的减小,填土内将产生一道甚至多道滑裂面,挡土墙主动土压力也从基于半无限土体假定的广义库伦土压力值逐渐减小。
For retaining walls adjacent to existing basements or vertical bedrock surfaces, it is unsuitable to calculate the active earth pressure on the retaining wall using the classical Coulomb and Rankun earth pressure theory due to limited width of backfill. The finite element analysis software ABAQUS was used to study the active earth pressure of the rigid retaining wall with narrow viscous soil. The critical crack depth and the development of the slip surface were discussed. Considering the adhesion between wall and soil and vertical cracks in fill, a new theoretical analysis model is established, and the solution of horizontal earth pressure on retaining wall and the analytical formula of active earth pressure distribution are obtained. The theoretical solution and numerical solution agree well with the earth pressure force coefficient and soil pressure strength, which proves the rationality of this theoretical solution. The results show that under the active limit state, vertical cracks will be generated on both sides of the fill surface and the critical crack depth will not change with the fill width, which is close to the Rankinen crack depth. With the decrease of fill width, There will be one or even more slip surfaces within. The active earth pressure on the retaining wall also decreases gradually from the generalized Coulomb earth pressure based on the semi-infinite soil assumption.