柱状节理开挖模拟洞数值原位试验

Numerical in situ testing of excavation experimental cavity on columnal joints

在西南水电大开发中,柱状节理岩体的工程力学性质逐渐受到水利工程的重视。白鹤滩水电站坝基揭露的柱状节理玄武岩体,RQD值普遍较低,完整性较差,其变形模量等力学指标相对较低,表现出显著的各向异性特征,对拱坝变形、坝肩稳定、边坡稳定、地下洞室群围岩稳定有重要影响,已成为该水电工程的关键技术问题之一。针对国内外对柱状节理岩体的研究及相关工程的经验甚少,白鹤滩水电站拟开展的大尺度柱状节理玄武岩试验洞,目的是获得反映柱状节理玄武岩力学特性的第一手观测资料。介绍了白鹤滩柱状节理的地质成因和工程特性及柱状节理试验洞的设计布置,探讨了原位试验和数值试验结合的分析方法,并采用各向异性本构模拟了试验洞开挖和原位试验,对不同位置试验点的代表性进行了评价。

During the development of hydropower stations in Southwest China,more and more attentions have been paid to the engineering mechanical properties of columnar joints rock mass.As dam foundation of Baihetan Hydropower Station is composed of columnar joints basalt,of which the magnitude of RQD is widely lower and integrity is poor;and the mechanical indices such as deformation modulus,is relatively lower.Meanwhile,the rock mass significantly shows anisotropy.Therefore,it has imposed a certain impacts on the deformation of arch dam,and the stability of abutment,high slope,and underground rock caverns;it has become one of the key technical issues of Baihetan Hydropower Station.As we know,the researches on columnar joints rock mass and related engineering experiences at home and abroad are few.Therefore,in order to obtain the first-hand observation data reflecting mechanical properties of columnar joints rock mass,we plan to develop the large-scale columnar joints experimental cavity.The geologic origin and characteristics of columnar basalt and the design proposal of experimental cavity are introduced here;the combination of in situ experiment and numerical experiment is discussed.Then anisotropic constitutive is use to simulate the excavation and in-situ experiment and the representation sites are appraised.