Continuous field based upper-bound analysis for the undrained bearing capacity of strip footings resting near clay slopes with linearly increased strength

摘要

The total-displacement loading EMSD (T-EMSD) method is applied in analyzing the undrained bearing capacity of strip footing near clay slope with linearly increased strength. According to the continuous field based upper-bound solutions obtained by the T-EMSD method, the consideration of strength gradient weakens the influence of strength ratio and slope height on the bearing capacity result. Investigation on corresponding velocity fields reveals that with the increase of the strength gradient the mobilized mechanism tends to contract around the foundation edge, thereby weakening the effect of the slope. Design equations are proposed based on the continuous field based upper-bound solutions. For subgrade with significant strength gradient, bearing capacity calculation with representative strength might lead to unacceptable overestimation and the present equation should be used in such case.