Discuss on Expression of Retaining Wall's Overturning Stability in Specification for Design of Highway Subgrade

The design of retaining wall centering partial coefficient for the loads is firstly proposed in "Specifications for Design of Highway Subgrades"(JTG D30-2004),which designs slip and overturning stability by partial coefficient and bearing capacity of foundation by allowable stress.Thus the same partial coefficient will take different values because load acts on retaining wall structure differently,but the expression of overturning stability in the Specification is ambiguous resulting in errors easily.According to these different values of partial coefficient,through the massive calculation of overturning stability and then comparision to the result of total safety factor method,the revised of overturning stability equation is put forward for discussion.