关键词: 重力式挡土墙, 安全系数, 可靠度分析, 相对安全率, 分项系数

Abstract: The allowable values of the factor of safety in gravity retaining wall design in various Chinese codes are discussed, and it is concluded that these allowable values are generally smaller than those adopted in many foreign country codes. Theoretically, the factor of safety is defined as the resistance divided by earth pressure, where the earth pressure is the one determined by using the non-corrected strength parameters instead of the reduced strength, and thus the resulting allowable factor of safety should be larger than that adopted in the design of the equivalent retaining structure. To resolve this problem, limit state design with partial factors is applied to retaining wall design problem. For Class 1 structures, its target reliability index is 3.7. Assuming the coefficients of variability of 0.2 and 0.1 for cohesion and friction, respectively, the calibrated partial factors are 1.301, 1.209 and 1.170. The calibrated partial factors are validated by the ‘ratio of safety margin’ theory proposed by the authors’ research team. The discussion of this paper provides some useful guidelines for code makers.

Key words: gravity retaining wall, factor of safety, reliability analysis, ratio of safety margin, partial factor