Towards an improved analytical framework to estimate active earth pressure in narrow c - φ soils behind rotating walls about the base

Retaining walls are sometimes unavoidably constructed near existing stabilized structures to maintain stability of narrow retained c- phi soils. Although some analytical approaches have been presented to estimate active earth pressure on the wall undergoing rotation about the base (RB), the contributions of soil cohesion and horizontal shearing forces in c- phi soils are typically neglected for brevity. Hence it is always expected to be improved, and to seek a more economical design framework used in the retaining wall with narrow c- phi soils. This paper first uses finite element limit analysis (FELA) to study the developed failure mechanisms under RB mode, which provides a basis to establish a calculation model. An analytical framework using arched differential element method is further presented with overall considerations of soil cohesion, soil arching effect, shearing forces between adjacent elements and the studied failure mechanism. The calculation flowchart is mapped and executed under C++ environment. The results from centrifuge test, existing analytical approaches and FELA are compared for validation in both purely-frictional and cohesive-frictional soils. A parametric study considering the effects of sensitive variables (e.g. aspect ratio, soil strength parameters and wall-soil interface friction angle) on the design is carried out. For the use of proposed analytical framework in practice, two simplified design equations are provided to correlate standard Coulomb's solutions.