(东北大学土木工程系，沈阳 110006)
摘 要: 概要性地介绍了块体理论和岩体中节理迹长的测量和计算方法，并对被节理切割的岩体中可能滑落的岩块——关键块进行了分析；把概率理论引入节理迹长分布的研究之中， 对岩体中无限长的节理假定作出有限长的修正。 采用概率分析的方法， 推导了多组节理切割岩体形成关键块体概率的计算公式， 从而使原来的一些关键块体转化为稳定块体，减少了关键块的数量。 着重对三组节理切割岩体形成的关键块体进行了详细的分析， 得到了关键块滑落的概率值，并证明了体积愈小的关键块愈容易滑落。
关键字: 块体理论 关键块 节理迹长
BLOCK THEORY
（Department of Civil Engineering, Northeastern University, Shenyang 110006, P. R. China）
Abstract:The measurement and calculation method of the joint trace length were introduced and the key blocks, which probably fall in the rockmass cut by joints, were analyzed. By using the probability theory, the joint was finite instead of infinite. The formula of probability that rockmass including several group of joints formed key blocks was deduced, which converted some original key blocks into stable blocks, so the key blocks' amount was reduced. Based on the detailed analysis for the key blocks formed by three group of joints, the probability value of the sliding of key blocks was obtained. It was proved that the smaller the volume is, the more easily the key blocks fall.
Key words: block theory key block joint trace length
