the slope excavation is increasingly manifold. The slope ratio has influence on the design and investment of project. Hence
the study of optimal slope ratio will make a lot of benefit of economy and society. In order to make sure the excavation engineering safe and economical
on the basis of engineering geological condition analysis
the residual thrust method is used to calculate the stability of nature slope. Then according to the economic analysis
the excavation slope ratio which made the excavation and timbering charge lowest is the optimal slope ratio. The example analysis showed that the optimal ratio of Shitanba Slope was 1:0.65 and the stability analysis and optimal design scheme are practical and reasonable.