Analysis on Scale Effect of Bearing Capacity of Foundation by Discrete Element Method

Abstract:

Based on the previous experimental results and a simulation loading test with 4 widths of the footing by employing the discrete element software of PFC2D, a study was made on the general law of scale effect and the causes of the scale effect. The result indicates that with the increasing of the width of the footing, bearing capacity factor decreases, and the amount of reduction decreases with the increasing of the width of the footing. Maximum curvature of p s curve (i.e., the curvature of the inflection point) decreases with the increasing of the width of the footing, and the overall shape of p s curve gradually gets smooth. In the discrete element method(DEM) simulation of net sand, the soil strength envelope is a straight line. When peak internal friction angle of particles remains as a constant with an increasing confining pressure, the scale effect remains on the bearing capacity of the foundation, which suggests that the strength envelope of nonlinear is not the fundamental cause of scale effect.

Key words:foundation bearing capacity; bearing capacity factor; scale effect; strength envelope