摘要
Abstract
Based on Changqiu Mountain large section tunnel project of Jianyang—Pujiang expressway,the dynamic excavation of the tunnel with the method of three steps is simulated by the finite difference software FLAC3D,the influence of the step's length on the peripheral displacement of tunnel under different dip angles is analyzed.The results show that under three steps'method construction of shallow buried large section highway tunnel,the order of the peripheral displacement of the tunnel is that:inverted arch uplift ＞ vault settlement ＞ horizontal convergence;The variation of the vault settlement and the inverted arch uplift of the tunnel are mainly between the step length of 4 m and 6 m,it is shown that the short step or the ultra short step method can well control the peripheral deformation of the tunnel,which are more suitable for the construction of large-scale tunnel with weak surrounding rock;the peripheral displacement of the tunnel are gradually converged from 10 m of the step's length,so l0 m can be used as the'initial convergence point'of the peripheral displacement of shallow buried large section tunnel under the step method construction.The different dip angles of tunnel have great influence on the change of tunnel's peripheral displacement,therefore,in the actual construction,the more reasonable step length should be chosen to ensure the safety construction of the large section tunnel according to the different surface dip angles.关键词
大断面隧道/三台阶法/数值模拟/洞周位移/台阶长度/地表倾角Key words
large section highway tunnel/method of three steps/numerical simulation/peripheral displacement/step's length/dip angles分类
交通工程
