Estimation of bearing capacity of bimsoils under shallow foundations
Xiusong Shi, Xinbo Miao, Hao Xiong, Xia Bian
Abstract
Bimsoils, consist of fine soil matrix and coarse rock aggregates, and are widespread as sedimentary soils. The bearing behavior of bimsoils are significantly affected by rock fraction. However, the mechanism governing the coarse fraction effect remains unclear. The traditional analysis methods are not effective in describing the rock fraction effect due to heterogeneous structure. To this end, 91 simulations have been performed to investigate the bearing capacity of bimsoils (mainly of two-dimensional, 2D) under shallow foundations using finite element method (FEM). It is found that the densified matrix bridge as well as the coarse aggregates forms a strong contact network which is responsible for the coarse fraction effect. A structure variable is introduced to quantify the reinforcing effect of rock aggregates. Then, a model incorporating the structural variable is proposed to evaluate the coarse fraction effect on the bearing capacity of bimsoils. Compared with the conventional method for pure soil matrix, only two additional parameters are required, and they can be readily calibrated by laboratory tests. The model is further validated by data available in literature, which can effectively estimate the bearing capacity of bimsoils under shallow foundations with a various of rock contents and rock characteristics.