Experimental Study on the Bearing Behavior and Failure Model of Digging Hold Foundation in Rock Ground

Abstract

The physical model test is an effective method to study the bearing behavior of digging hold foundations due to its low cost and clear boundary conditions. Here, similar materials of rocks were configured and employed to study the bearing capacity and failure model of digging hold foundations in rock ground. Firstly, sixteen groups of material proportion schemes were employed to make similar materials of rocks, and the effects of four mix parameters were analyzed. Then, similar materials of rocks were employed to perform the uplift tests of digging hold foundations. The results show that the mass ratio of fine particles and aggregate has the greatest influence on the density and internal friction angle, while the cement moisture content has the greatest influence on the cohesion and compressive strength of similar materials of rocks. During the pull-out process of the digging hold foundation, the radial cracks radiate outward from the circumferential cracks, which is different from those in the field test because the ground is small and uniform without fissures inside. The foundation drives the surrounding similar materials to be pulled up as a whole with a certain failure angle, which increases from 35.7° to 42.5° as the internal friction angle decreases from 56° to 41°. In addition, the ratio between the equivalent shear strength in Chinese Code and uniaxial compressive strength falls in the range of 0.027–0.05.