一、引言隧洞衬砌顶部混凝土浇捣条件较差,不容易填得密实;因而顶部衬砌与岩石之间往往有空隙存在,对衬砌受力有不利影响。所以在工程实践中多规定在隧洞顶部进行回填灌浆,填满这些空隙,使山岩压力均匀地作用在衬砌上;在承受内水压力时,也能传递一部分荷载到岩石上去,从而改善衬砌的受力情况。回 I. INTRODUCTION The conditions of concrete pouring at the top of tunnel lining are poor and it is not easy to fill densely. Therefore, there is often a gap between the top lining and the rock, which adversely affects the lining’s force. Therefore, in engineering practice, it is required to carry out backfill grouting at the top of the tunnel to fill these voids so that the pressure of the rock can be uniformly applied to the lining. When the internal water pressure is applied, a part of the load can also be transmitted to the rock so as to improve the lining Force situation. Back