变质片岩区边坡稳定性的块体理论分析

变质片岩区的边坡破坏与结构面和坡面的组合密切相关，块体理论在分析结构面和坡面组合方面有独特的优势。本文以秦岭北坡西安市黑河水库左岸108国道边坡为例，说明变质片岩区边坡稳定性的块体理论分析方法。作为准备工作，本文编制了块体理论相关程序和制作等密度图的相关程序。通过现场调查，本文将黑河库区108国道沿线边坡分成了15段，其中有4个潜在崩塌段。针对这4个潜在崩塌段，本文在每段中选取一个典型点，借助自编程序，使用块体理论分析方法寻找可动块体、关键块体并计算剩余下滑力。计算所得关键块体的结构面组合形式和实际相吻合，所得剩余下滑力计算结果表明4个潜在崩塌段中有3段崩塌危险性较高，且需要采取工程措施以防止崩塌阻断108国道。说明了变质片岩区边坡稳定性的块体理论分析方法，对变质片岩区其他工程具有一定借鉴意义。

BLOCK THEORY BASED STABILITY ANALYSIS OF METAMORPHIC SCHIST ROCK SLOPES

The failure of slopes composed of metamorphic schist is closely related to the combination of structural planes and slope surfaces. The block theory is outstanding in the field of analyzing the combination of structural planes and slope surfaces. The paper takes the slopes along the State Road 108 in Heihe reservoir for example and explains the method of analyzing slope stability in metamorphic schist zone with the block theory. As a preparation, the paper designs a program about the block theory and a program about the isopycnic graph of structure plane. Through the site investigation of slopes along the State Road 108 in Heihe reservoir, the slopes are divided into 15 sections and 4 of them are potential rockfall sections. This paper selects one typical point in each of the potential rockfall sections. At each point, we find out the movable block, the key block and the residual sliding force by the block theory and the self-compiling program. The combination of the structure planes of the calculated key blocks is identical to that of the fact. The results of the residual sliding force show that three of them are of high risk of rockfalls, and need engineering measures to prevent landslides from blocking the State Road 108. The paper explains the method of analyzing slope stability in metamorphic schist zone with the block theory, which has special reference to some other engineering projects.