Influence of Fracture Filling on Mechanical Behavior of Loess

Natural loess and natural loess with filling at ground fissures in Jingyang, Shanxi Province, China, were experimentally studied to investigate the effect of crack filling on the mechanical behavior of loess and the crack development by conventional triaxial compression test (CTC), reduced triaxial compression test (RTC) and reduced triaxial extension test (RTE) under constant water content condition. The tests were carried out at the consolidation pressure near in-situ stress. Different failure types were observed in the tests. In the CTC test, each soil demonstrates strain-hardening behaviour and shear failure plane is the interface between loess and filling for the natural loess with filling sample. In RTC test, each soil behaves strain-softening. Shear failure planes are conjugate planes for the loess sample and shear failure plane is the interface between loess and filling for the natural loess with filling sample. In RTE test, rupture is observed and the failure surface does not cross the filling for natural loess with filling, that is, the failure surface lies in loess totally. The shear strength of loess with filling is almost the same as that of loess.