Abstract: Based on the sliding plane hypothesis of Coulomb’s earth pressure theory and the limit equilibrium theory, a modified formulation for active earth pressure is derived according to the relationship between limited soils’ width b₀ (a distance between a supporting structure and an existing building) and triangular sliding wedge’s width b. Assumptions of formulation are that the limited soil is in horizontal and the support structure is in vertical. In addition, the formulation takes into account not only the adhesion between the supporting structure and soils but also the cohesion between the static soils and sliding soils. It is then analyzed that the impact of the external friction angle as well as the adhesion between the supporting structure and soils on the sliding soil mass’ cracking angle (failure angle of sliding soils) and active earth pressure. A viewpointabout generalized active earth pressure coefficient is also put forward in this paper. All results gaining from our calculated examples show that the formulation becomes more effective in practices. Evidently, taking the impact of the external friction angle into account in the formulation will reduce cost indeed.

Key words: active earth pressure, coefficient of generalized active earth pressure, limited soils, adhesion, failure angle