地下厂房围岩稳定分析若干问题探讨

地下厂房稳定分析首先要确定围岩变形破坏运动类型。本文按照四种岩石力学条件从工程实践中归纳了五种变形破坏运动类型,以便在设计阶段进行初步判断和选择岩体力学模型,并以三峡工程地下厂房为实例,着重研究了块体结构的围岩稳定分析方法。在建立围岩力学模型时,要结合地下洞室的尺寸处理不同规模的不连续面。三个方向的应力对块体稳定性的响影同样重要,在没有条件使用三维有限单元法时,可用全空间赤平投影法与二维有限单元法结合计算。研究结果表明,在设计地下洞室方向时,不仅要考虑初始应力的方位,同时还应考虑软弱结构面的方向。

Some Problems on The Stability Analysis of Underground Openings

The first thing in the stability analysis of underground opennings is the determination of the deformation failure-movement type of rock masses. In this paper five main types of deformation failure-movement has been mentioned, according to different combinations of the four rock mechanics factors. Thus, primary appreciation of stability and selection of mechanical model for the rock mass can be made in design work. Some methods of stability analysis for rock mass composed of rock blocks has been discussed, referring to the underground power station of The Three Gorges project as an example. Planes of discontinuity should be simplified according to their relative size to the dimensions of the cavity. The influence of the stress component along the axis of the cavity on the stability of rock blocks has been emphasized. In those cases when finite element method in three-dimensions can not be used, calculations may be carried out by two-dimensional finite element method in combination with the method of the whole space projection on equatorial plane. When the orientation of the axis of cavity is to be determined, not only the direction of the maximum in-situ stress but also the azimuth of planes of discontinuity should be considered.