摘要
在不同地质条件下浅埋偏压小净距隧道的施工力学效应会有很大不同,尤其在半软半硬岩层中,隧道开挖会破坏软硬岩层交界处软弱围岩的稳定性,其施工力学效应更为特殊。文章采用有限差分软件FLAC3D对15种工况下隧道开挖进行了模拟,对均质硬岩、均质软岩和竖向半软半硬岩中不同净距隧道的拱顶沉降、中岩墙的水平位移、中岩墙最大主应力和围岩塑性区进行了分析。结果表明,均质硬岩隧道拱顶沉降最小,竖向半软半硬岩隧道拱顶沉降和硬岩比较接近,软弱围岩隧道拱顶沉降最大;竖向半软半硬岩隧道中岩柱上部围岩稳定性较差,中部水平位移最大;隧道开挖引起软岩侧洞室上覆盖层围岩稳定性变差,可能引起隧道坍塌。
The mechanical behaviors of shallow bias tunnels with small clear distances in different geological conditions are quite different. In half-soft and half-hard rock especially, rock stability at the interface of the soft and hard rock will be disturbed by tunnelling and is characterized by very special mechanical behaviors. In this paper, tunnel excavations in 15 different conditions are simulated by applying the finite difference software FLAC3D to analyses of crown settlement, middle-wall horizontal displacement, middle-wall maximum principle stress, and the plastic zone of rock for tunnels with different clear distances in homogeneous hard rock, homogeneous soft rock, and half-soft and half-hard rock. The results show that： tunnel crown settlement is minimized in the homogeneous hard rock, similar for the half-soft and half-hard rock, and maximized in soft rock; for the tunnel in the half-soft and half-hard rock, the rock-mass stability is poor at the upper part of the rock pillar, and horizontal displacement reaches a maximum at the middle part; and stability of the overlying rock of the cavern at the soft-rock side is worsened and may result in collapse.
出处
《现代隧道技术》
EI
北大核心
2014年第4期108-112,共5页
Modern Tunnelling Technology
基金
国家自然科学基金(No.51178398)
中央高校基本科研业务费专项资金(SWJTU12CX063)
关键词
小净距隧道
半硬半软岩
围岩塑性区
中岩墙稳定性
Tunnel with a small clear distance
Half-soft and half-hard rock
Rock plastic zone
Stability of the middle pillar
