中文摘要：

介绍了小浪底水利枢纽地下厂房岩体力学行为数值分析的过程和方法,包括采用的屈服准则、三维几何模型、岩体力学参数、地应力场、开挖过程模拟和支护结构模拟方法.给出了1.0和0.8两种侧压力系数下,无支护结构、无预应力锚索有锚杆有衬砌、有预应力锚索有锚杆有衬砌3种情况的计算结果,研究结果表明：（1）支护结构对限制围岩位移和塑性区开展作用不大,但对于固定松动破碎岩块、防止洞周局部崩塌脱落有不可缺少的作用;（2）开挖过程对预应力锚索拉力影响不大;（3）开挖过程引起混凝土衬砌较大拉应力,围岩表面的钢筋网,对于限制衬砌开裂和防止其脱落,有重要作用.

英文摘要：

Xiaolangdi Key Water Control Project is located at the Yellow River; it has comprehensive effects of flood control, water supply, generating electricity, etc. Its underground powerhouse caverns belong to large-scale type and have a buried depth of 70-100 m. The process and method of numerical analysis was introduced, including： rock plastic yielding criteria adopted; three-dimension geometrical model; rock mass mechanical parameters; initial earth stress field; excavating process simulating method; sustaining structure simulating method. Calculation results of three cases under conditions of two earth horizontal stress coefficients 1.0 and 0.8 are given. The three cases are： （1） having no sustaining structures; （2） having rock bolts and concrete lining but no pre-tensioning cables ; （3） having pit-tensioning cables and rock bolts and concrete lining. Several conclusions of this study are drawn as follows： （1） the sustaining structure has not significant effect in limiting rock displacement and plastic area, but has an indispensable role in fixing loose and broken rock pieces and preventing partial rocks around caverns from falling; （2） excavating process has little influence on pit-tensioning cable force; （3） excavating process causes great tension stress in concrete lining; and the steel-net on rock surface has important effect on confining lining cracking and preventing lining from falling.