Active earth pressure for subgrade retaining walls in cohesive backfills with tensile strength cut-off subjected to seepage effects

• Published in: Journal of Central South University Vol. 27; no. 7; pp. 2148 - 2159
• Main Authors: Fu, He-lin, Wang, Cheng-yang, Li, Huan
• Format: Journal Article
• Language: English
• Published: Changsha Central South University 01.07.2020; Springer Nature B.V
• Subjects: Cohesion; Cohesive soils; Conservation equations; Cut-off; Earth pressure; Energy conservation; Engineering; Failure mechanisms; Fluid flow; Metallic Materials; Mohr-Coulomb theory; Optimization; Pressure effects; Retaining walls; Seepage; Soil stability; Soil strength; Stress concentration; Tensile strength; 抗拉强度截断; subgrade retaining wall; 渗流效应; 路基挡土墙; seepage effect; active earth pressure; tensile strength cut-off; 主动土压力
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-020-4437-4

The commonly used Mohr-Coulomb (M-C) failure condition has a limitation that it overestimates the tensile strength of cohesive soils. To overcome this limitation, the tensile strength cut-off was applied where the predicted tensile strength is reduced or eliminated. This work then presented a kinematical approach to evaluate the active earth pressure on subgrade retaining walls in cohesive backfills with saturated seepage effects. An effective rotational failure mechanism was constructed assuming an associative flow rule. The impact of seepage forces, whose distribution is described by a closed-form solution, was incorporated into the analysis. The thrust of active earth pressure was derived from the energy conservation equation, and an optimization program was then coded to obtain the most critical solution. Several sets of charts were produced to perform a parameter analysis. The results show that taking soil cohesion into account has a distinct beneficial influence on the stability of retaining walls, while seepage forces have an adverse effect. The active earth pressure increases when tensile strength cut-off is considered, and this increment is more noticeable under larger cohesion.