NUMERICAL INVESTIGATION FOR THE LOESS TENSILE STRENGTH USING PFC3D

The soil tensile strength is a critical parameter in controlling the increasingly serious cracking and tensile failure of engineering projects in the Loess Plateau region. In this study, we firstly experimentally studied the loess tensile strength using the unconfined penetrated test proposed by Fang , mainly concentrating in the effect of the sample heights (i.e. 6.18cm, 9.27cm, 12.36cm), initial water contents (i.e. 14.4%, 18.4%, 22.4%) on the loess tensile strength. Besides, we further numerically explored the mechanism that the tensile strength varies with the sample height and initial water content using a commercially available discrete element software (PFC 3D). In general, the tensile strength of loess increases with the increased sample height, while decreases with the increased initial water content. The simulation results clearly present the variation process of the internal shear, compressive, and tensile stress of sample; and further provide the tensile stress-penetrate depth curves of the sample with different heights and initial water contents, highly being similar with those obtained in this indirectly tensile experiment. This study shows the discrete element method, although having some drawbacks (e.g. the unreal particle numbers and particle distribution), is suitable for simulating the loess tensile strength variation, thus providing us a relatively convenient way to explore the internal stress variation of sample under loading process.