Because pseudo static method ignores the dynamic characteristics of rock and effect of seismic characteristics, time history method is used to analyze the dynamic response of the bedding rock slope under seismic action. Using the finite difference software FLAC3D, a model of the bedding rock slope with weak intercalated layer is established. The probability density function is determined by the maximum entropy principle which makes full use of high order moment information of random variables. The failure probability time history curve and the reliability index time history curve are calculated considering the fuzziness of the slope stability and the average maximum failure probability is presented as the evaluating index. The results show that the time history analysis method reasonably considering the effects of main factors can show the dynamic response of slope accurately which is more secure and reliable compared to the traditional methods.
The problem of slope stability caused by the earthquake has been highly concerned by the field of geotechnical engineering and geological disaster prevention. Pseudo-static method, slider displacement analysis, time history analysis method are the mainly three calculation methods of slope seismic stability. Pseudo-static method recommended by specification to analyze slope seismic stability needs less parameters and easy to implement, but it ignores characteristics of earthquake and dynamic properties of slope material so that cannot reflect the seismic response characteristics of slope accurately. Based on the rigid body limit equilibrium method, the sliding block displacement analysis method firstly proposed by Newmark (Liu et al. 2001) calculates the permanent deformation may occur after the earthquake, but it is unable to put forward reasonable stability criteria due to lack of practical engineering experience. The time history analysis method is difficult in calculation and complex in data processing, but it can directly reflect the dynamic response of slope under seismic action, including speed, displacement, stress, and so on. Yan et al. (2011) and Li et al. (2007) studied the seismic dynamic response of bedding rock slope by numerical simulation to obtain the time history curve of the relevant parameters. Because the slope stability is a dynamic process under seismic action, it is very important to select a reasonable safety factor to evaluate the seismic stability of the slope. Zhang et al. (1999, 2000) evaluated the slope seismic stability by the minimum dynamic safety factor in dynamic safety factor time history of slope. Zhao et al. (2002) put forward the dynamic equivalent method to average the seismic safety. Liu et al. (2003) proposed minimum average safety factor as the index to evaluate the slope seismic stability. The minimum average safety factor is the most reasonable, but it is still based on the deterministic theory framework, so the evaluation result is lack of the consideration of risk, which leads to the dynamic reliability analysis of the slope.
