Abstract:

Considering uncertainties and spatial variability of soil parameters, the reliability analysis method can reflect objectively the real safety character of retaining structure for foundation pit engineering instead of the safety factor method. The reliability index increased and the variability of soil parameters decreased after being reduced by the random field theory. Compiled with project example, this paper provided the detailed analysis of the mean value and the variability of the design parameters which affected the stability of soil foundation pit. The results show that, the sensitivity of the parameters of cohesion c, angle of internal friction φ and the embedded depth hd which affected the reliability index β was much more than those affected the safety factor K. The reliability index β was affected significantly by the coefficients of variation δc, δφ, and δhd. The δq affected the reliability index β obviously when μq was large. It’s reasonable to appraise the overall stability of retaining structure of foundation pit by reliability analysis method than by the safety factor method.

Key words: foundation pit project, stability analysis, variability of parameters, safety factor, reliability index