小间距隧道围岩局部稳定性的块体理论分析

Application of Block Theory to the Stability of Rock Mass Surrounding Closely-Spaced Tunnel

在对勘察资料的详细研究基础上,运用块体理论赤平解析法可知,若开挖顺序不合理,对中夹岩中块体将造成两种影响,第一种是施工中对先开挖隧道的可动块体进行了支护,但当另一隧道施工后,切割了前期支护的块体,使最终形成的块体与初始支护的块体存在体积差,从而下滑力减小,造成锚固力的浪费;第二种是当先开挖的隧道施工时,中夹岩中的块体为无限块体,无需支护,随着另一条隧道的施工,将此无限块体切割成关键块体,对已施工完毕的隧道可能造成坍塌的危险。作者运用块体理论赤平解析法分析这两种影响,为工程合理施工顺序的确定提供了科学的依据。

Based on the detailed study on survey data,according to Stereo - analytical method for block theory, it is known that the excavating in unreasonable order will cause two kinds of influence on the blocks in pieces of rocks.The first influence:to protect the moving blocks in the construction of first excavated tunnel,during second tunnel construction,the earlier protecting blocks are cut,there will the volume difference between initially protected blocks and finally formed blocks,which cause the waste of the anchor strength.The second influence:the blocks in the inner rocks are limitless pieces of blocks,no protection is needed in the first excavated tunnel construction and with construction of another tunnel,limitless pieces of blocks are cut into key blocks,which may cause the collapse to the finished tunnel.These two kinds of influence will be analyzed by Stereo - analytical method for block theory,it can offer the scientific basis for determination of the rational construction order of the project.