为考虑地形地貌以及节理、断层等岩体构造对原始地应力场的影响，通常选用较大计算范围以模拟原始地应力场。然后取较小计算范围进行二次细分网格，以便较准确地模拟地下厂房分步开挖的动态过程。二次细分网格位移边界值采用等参逆变换法由一次网格的计算结果插值得到。计算算例及工程实例均表明等参逆变换法用于水布垭地下厂房原始地应力场计算中，具有较高的精度，可以满足工程要求。

The large domain model is universally used to simulate the effects of terrain, physiognomy etc. on original geostress. The small range model, in which mesh is refined, is exactly used to simulate excavation process of the underground powerhouse. The displacement boundary values of the small model use the results of the large model, which are obtained by interpolating with numerical inverse isoparametric mapping. The example and the case verify that the method of numerical inverse isoparametric mapping has high precision, and can be used in geotechnical engineering.