岩体初始地应力对于地下工程的稳定性和仿真计算都十分重要，了解工程区域中的岩体初始地应力大小和分布情况通常采用现场测量和反演计算相结合来实现。粒子群优化算法是一种很好的优化反演方法，具有算法简单、收敛较快、容易实现等特点；而FLAC(3D)适用于大多数工程力学问题，并得到了国内外广泛认可和应用，而且内嵌有FISH语言，容易进行二次开发。因此，在研究粒子群算法原理以及地应力反演方法的基础上，利用FISH语言研制了基于粒子群算法的岩体初始地应力反演程序，并对锦屏二级水电站岩体初始地应力进行反演研究。工程实例表明，在FLAC(3D)中运用粒子群算法对岩体地应力反演简单易行而且精度较高，反演结果可靠。

Initial ground stress for stability and emulation calculation of underground engineering is very important. To know the values and distribution of initial ground stress, the method of combining surveying in-situ with inversion calculation is usually applied. Particle swarm optimization(PSO)is a good inversion method with characterizing simple algorithm, fast convergence, and easy operation. And FLAC3D is suitable for most mechanical problem of engineering, which is approved and applied widely, and, further more, is easy to develop secondarily with the letin FISH language. Therefore, a program of inverting initial ground stress is compiled by means of studying the theory of PSO and the inversion method of initial ground stress. This program was used to study on inverting the initial ground stresses of Jinping Cascade 2 HydropowerStation Project. The inverting case indicated that this method is simple to implement and the inversion results are accurate.