挡土墙黏性分层填土土压力及开裂深度的计算

Calculation of earth pressure for layered cohesive backfills and cracking depth behind retaining wall

挡土墙后分层填土过程中,土压力的生成与分布情况直接影响挡土墙的设计。利用Mohr-Coulomb屈服面非相关联的Drucker-Prager准则作为塑性势面,对墙后黏性分层填土过程中作用墙背上的土压力进行了有限元计算。将数值计算结果与广义土压力的计算结果进行比较,结果显示:有限元计算的土压力分布比广义土压力公式计算的更加合理;由广义库伦土压力公式计算出来的零压力区与塑性理论计算的开裂深度相吻合,进一步证实了分层填土使用塑性理论和有限元进行计算结果的可靠性。建议挡土墙后填土尽量考虑低塑性土进行分层填筑,降低填土的开裂深度。

The distribution of earth pressure will directly impact on the design of retaining walls in the process of backfill behind the retaining wall. The Drucke-Prager law is non associated with the Mohr Coulomb yield surface, and Drucke〉Pagers as the plastic potential surface. The earth pressure was calculated in the process of backfill behind the retaining wall by using finite ele-ment method. The earth pressure come from numerical analysis method was compared with generalized Coulomb earth pressure, which indicates that the finite element analysis of earth pressure was reasonable. The results also indicated that the zero pressure area was almost the same with the crack depth. It was concluded that the plastic theory and finite element method can be used to analyze the earth pressure of layered backfill soil. The low plasticity soil was recommended for the layered backfill soil to reduce the cracking depth.