两河口水电站地下厂房岩体力学特性试验研究

Experimental Study on Rockmass Mechanical Properties of Lianghekou Hydropower Station Underground Powerhouse

两河口水电站地下厂房位于高地应力区,地质条件复杂,厂址区岩性以粉砂质板岩为主,具有明显的层理分布特征。基于现场取样基础,开展不同层理倾角板岩的三轴试验分析,对板岩的强度特征、变形特征、弹脆性破坏模式等进行深入研究。试验成果表明:(1)厂址区板岩的强度具有显著的倾角效应,且强度离散性极大;(2)岩样弹性模量、内摩擦角和内聚力随着层理面倾角的变化都呈U形规律,在45°左右达到最低值。(3)各种倾角的板岩在试验中均表现出明显的弹脆性破坏特征。试验结果为合理选取厂房纵轴线、洞群布置、开挖支护设计、及有效控制大型地下洞群大变形破坏和围岩稳定提供依据。

The underground powerhouse of Lianghekou Hydropower Station is located in the high stress area,and the geological conditions are complicated. The lithology of the site is dominated by silty slate,which has obvious bedding distribution characteristics. Based on the field sampling,the three-axis test analysis of different bedding slabs was carried out,for depth study of the strength characteristics,deformation characteristics and brittle failure modes of slate. The experimental results show that:( 1) the strength of slate in the site has significant inclination effect and the dispersion of the strength is very great;( 2) The elastic modulus,internal friction angle and cohesion of the rock specimen are U-shaped with the inclination of the bedding plane,and the minimum value is about 45 degree.( 3)Slate of various inclinations showed obvious brittle fracture characteristics in the experiment. Experimental results can provide the basis for reasonable selection of powerhouse longitudinal axis,the layout of the cave,the design of the excavation support,and the effective control of the large deformation and the stability of the surrounding rock.