分叉隧道施工对主隧道扰动的数值模拟

以大连地铁促进路站至春光街站区间45°交叉隧道建设工程为背景,采用有限差分软件FLAC3D模拟0°~90°7种不同横通隧道开挖对主隧道的扰动情况;并对主隧道锐角侧与钝角侧地表沉降进行对比分析,得出不同交叉角度时隧道的变形规律。结果表明:随着横通隧道开挖角度的减少,主隧道锐角侧的变形量逐渐变大,钝角侧的变形量逐渐减少;主隧道锐角侧曲线的波动性较大,钝角侧曲线则相对平缓;主隧道拱顶沉降最大值并非出现在交叉区中点,而是出现在主隧道开挖方向向前一定距离,并偏向横通隧道一侧。

Numerical Analysis of the Deformation Characteristics about Bifurcation Tunnel Construction disturbing the Main Tunnel

Relying on the construction of 45°Cross channel in Dalian subway as the engineering background, the construction of seven kinds of bifurcation tunnels is numerically simulated through FLAC3D Software. The surface settlement at the obtuse and acute angle side of the main tunnel is compared. The deformation laws of different bifurcation angles are obtained. It is shown that the deformation increases at acute angle side and decreases at the obtuse angle side of main tunnel with the decrease of the crossing angle. The deformation of surrounding rock appears relatively large fluctuation at the obtuse angle side of intersection and that is relatively gentle at the acute angle side. The maximum value of the main tunnel vault settlement is not at the midpoint of cross tunnel. It appears in the main tunnel excavation direction forward for a certain distance. It is in the right side of the main tunnel.