中文摘要：

工程开挖卸荷后岩体参数研究一直是工程界关注的焦点,是稳定性评价的基础性工作。本文以锦屏地下厂房开挖工程为背景,通过对上下游边墙不同桩号段开挖揭露的岩体进行工程地质岩组划分,进行了开挖后岩体质量评价并对其进行分类,通过在GSI（Geological Strength Index）评价体系中引入Jv（节理数/m^3）,使评价体系相对合理化,经回归分析,对不同风化程度的岩体进行了力学参数求解,发现内聚力及内摩擦角的计算值与建议值吻合较好。

英文摘要：

The study on rock mass parameters after the excavation is always the focus of the engineering.It is the basic work of the rock stability evaluation.This paper is based on the engineering of JinPing Underground Caverns.It classifies the engineering geological rock group about different stake Nos,re-classify the rock mass and evaluation of its quality.It uses the Geological Strength Index（GIS）method and introduces the the number of joint per cubic meter.It can make the evaluation system reasonable.At last the rock mass parameters can be found by regression method.It is found that the calculated values of the cohesion and Internal friction angle are similar to the recommended values.This method is relatively easy.It can provide reference for the selection of mechanical parameters of other underground excavation engineering with similar geological conditions.