Seismic stability analysis against overturning for a tension-crack rock slope subjected to water pressure and surcharge

In practice, a rock slope with tension crack is frequently subjected to water pressure, surcharge even earthquake inertia force. Under the combined environmental loadings, the slope intends to slide against plane failure or overturn around the toe of slope. Earlier researches focused on the sliding failure along the potential failure surface (joint plane), while the overturning failure has not yet been concentrated. In order to reveal the overturning phenomena, an analytical expression on the factor of safety against overturning for a rock slope with tension crack was derived based on the moment equilibrium approach. Moreover, seismic inertia loading, water pressure distribution modes and local surcharge on the top of slope are also included in the present formulations. In particular, a series of design charts were made to investigate the effect of water pressure, local surcharge intensity on the stability of rock slope against overturning. Further, the unstable region composed of the critical inclination line of slope surface and joint plane were also outlined to rapidly guide the practical cut (critical cut angle) in construction engineering.