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为探究隧道穿越富水断层破碎带过程中各工况下掌子面安全厚度、涌水量以及水压力的变化特征,以模型试验和数值模拟为主要手段,研究隧道在无地表水补给无注浆、有地表水补给无注浆、有地表水补给有注浆这3种工况下各测量值的变化规律。模型试验以实际工况为基础,设计1个尺寸相似比为1∶80的模型试验系统,其包括渗流系统、控水系统、测量系统和注浆系统4个部分,采用量纲分析法确定各物理力学参数的相似关系,模拟在重力场作用下隧道的涌水特征;数值模拟分析域在X(横向)、Y(竖向)和Z(纵向)方向上的长度分别为240、48、160m,隧道埋深约为80m,普通围岩为Ⅴ级,断层破碎带为Ⅵ级。研究结果表明:地表水补给可显著增加隧道涌水的可能性,模型试验中,有地表水补给较无地表水补给隧道涌水量增加了128.6%,掌子面安全厚度增加了6倍;采用预注水泥浆的方法可在一定范围内改善施工过程中的涌水情况,但不能将涌水量降到正常范围内,还应采取其他必要措施;围岩中的孔隙水压力呈现出以隧道为轴心的降落漏斗分布,涌水量和水压力值突变点即为掌子面临界安全厚度,为保证施工安全,建议无地表水补给无注浆时掌子面安全厚度取0.8~1.6m,有地表水补给无注浆时掌子面安全厚度取2.4~4.8m,有地表水补给有注浆时掌子面安全厚度取1.6~3.2m。
In order to explore the variation characteristics of the safety thickness, water inflow and water pressure under various working conditions during tunneling through the water-rich fault fracture zone, the model tests and numerical simulation are taken as the main measures to study the tunnel without surface grouting , There is surface water supply without grouting, there is surface water supply grouting these three kinds of conditions under the conditions of the measured value changes. Based on the actual working conditions, a model test system with a size-to-similarity ratio of 1:80 was designed. The model test system consisted of four parts: seepage system, water control system, measuring system and grouting system. The dimensional analysis The simulations of the water inflow characteristics of the tunnel under the action of gravity field are carried out by simulating the similarity of the physical and mechanical parameters. The lengths of the numerical simulation analysis field in X (horizontal), Y (vertical) and Z (vertical) directions are 240, 48 and 160 m, The buried depth of the tunnel is about 80m, the general surrounding rock is Grade V, and the fault broken zone is Grade VI. The results show that surface water recharge can significantly increase the probability of tunnel water inflow. In the model test, surface water recharge increases by 128.6% and safety thickness of the palm face increases by 6 times compared with that without surface water replenishment. The mud method can improve the water inflow in the construction process within a certain range, but can not reduce the water inflow within the normal range, and other necessary measures should also be taken; the pore water pressure in the surrounding rock shows the landing with the tunnel as its center Funnel distribution, water inflow and water pressure point of change is the critical thickness of the face of the face, in order to ensure the construction safety, it is recommended that no surface water supply without grouting when the safety of the palm face thickness of 0.8 ~ 1.6m, with surface water supply When grouting, the safe thickness of the face is 2.4 ~ 4.8m, and when the surface water is supplied, the safe thickness of the face is 1.6 ~ 3.2m when grouting.