The discrimination of unloading zones influent the long-term stability and safety of rock slopes.For homogenous rock slope

the unloading mechanics model of excavated rock slope is got based on elastic wedge theory.The method used for calculating the width of unloading zones is deduced.Some parameters that affect the width of unloading zones

such as height

angle and width of excavation

cohesive strength

friction angle and density of rock mass are discussed through sensitivity analysis.Finally a formula is established to calculate the width of unloading zones by using dimensional analysis method.