针对复杂地质条件下高地应力大变形隧道地应力复杂多变的特点，为满足该类隧道动态设计对地应力资料的要求，提出基于上台阶开挖后拱腰水平收敛与拱顶下沉的相对比值并结合开挖揭示的围岩情况，建立二维数值模型反算地应力的方法。以丽江至香格里拉铁路中义隧道为例，对该方法进行详细说明。研究表明所述方法具有无需地应力测试、计算方便的优点，施工期间可用于地应力分析、预测。中义隧道典型区段地应力反算结果表明： 1）隧道出口及2号横洞工区的地应力分布特点并不相同； 2）围岩及埋深差别不大的区段，隧道水平收敛变形出现较大差异主要是由于地应力侧压力系数不同引起的。

The geostress in tunnels with high geostress and large deformation under complex geological conditions is often complex and variable. In order to meet the requirements of dynamic design for geostress data, a method is proposed based on the relative ratio of hance horizontal convergence to vault settlement after upper step excavation and the surrounding rock conditions revealed by excavation, then twodimensional numerical model to determine geostress by back calculation is established. Zhongyi tunnel of LijiangShangriLa Railway is taken as an example to explain the method in detail. Research shows that the method described has the advantages of no requiring for geostress test and being convenient to calculate. And it is feasible for geostress analysis and prediction during construction. The back calculation result of geostress in typical sections of Zhongyi tunnel shows that: (1)The distribution characteristics of geostress in the exit and No. 2 transverse tube construction area of the tunnel are different; (2)In the sections surrounding rock and buried depth are similar, the large distinction of horizontal convergence deformation in tunnel is mainly caused by different lateral pressure coefficients.