盾构隧道穿越特殊地质围岩位移向量趋势线变形响应特征

Deformation Response Characteristics of Displacement Vector Trend Line of Shield Tunnel Crossing Special Geology

为减少由于地质因素导致的盾构施工灾害的发生,做到早发现、早预防,利用FLAC3D模拟软硬岩层、断层破碎带、岩层产状、岩溶、球状风化体等多种不良地质体对盾构隧道三维位移的影响,并借鉴国内外学者所发展的隧道三维变形展示方式来呈现隧道开挖地层的反应特性。结果表明:1)盾构由软岩往硬岩掘进时,位移向量趋势线减小;反之,位移向量趋势线增加。2)随着断层破碎带宽度的增加,位移向量趋势线呈现出规律性变化。3)地质界面倾斜时的位移向量角比地质界面垂直时小。4)相邻地层强度差异越大,位移向量趋势线变化越明显。5)岩溶和球状风化体的尺寸越大,位移向量趋势线变化幅度越大。

In order to reduce the occurrence of shield construction disasters caused by geological factors and to achieve early detection and prevention, the influences of soft and hard rock strata, fault and fracture zone, rock strata attitude, karst, spherical weathered body and other adverse geological bodies on the three-dimensional displacement of shield tunnel are simulated by FLAC3D;and the three-dimensional deformation display method developed by domestic and foreign scholars is used to show the response characteristics of tunnel excavation strata. The results show that:(1)When shield tunneling from soft rock to hard rock, the trend line of displacement vector decreases;on the contrary, the trend line of displacement vector increases.(2)With the increase of width of fault and fracture zone, the trend line of displacement vector presents regular changes.(3) The change of alpha angle when the geological interface inclines is earlier than that when the geological interface is vertical.(4)The greater the strength difference between adjacent strata, the more obvious the trend line of displacement vector.(5)The larger the size of karst and spherical weathered bodies, the greater the variation range of displacement vector trend line.