海底隧道含水断层涌水量分析及突水风险预测方法研究

发布时间：2018-04-21 08:56

  本文选题：海底隧道 + 含水断层　； 参考：《山东大学》2017年硕士论文

【摘要】：海底隧道施工经过断层破碎带等不良地质段时,在开挖卸荷和海水压力的共同作用下,常会引发突涌水等地质灾害,对施工安全造成严重威胁。因此,科学准确地进行隧道涌水量预测和突水风险分析至关重要。本文以青岛胶州湾海底隧道工程为依托,采用理论分析、数值计算等手段对海底隧道穿越含水断层时的涌水量分析方法和突水风险预测方法进行了探讨。(1)本文总结了隧道涌水量预测方法、断层突水致灾机理、隧道突水风险分析方法的国内外研究现状与研究进展,通过对海底隧道安全事故的统计分析得出突涌水是海底隧道最主要的施工风险之一。断层破碎带内裂隙发育、岩体破碎,围岩稳定性差,因此,对海底隧道穿越含水断层时的涌水量预测方法和突水风险分析方法的研究是非常必要的。通过与理论解析法预测的涌水量的对比可知,本文采用的涌水量数值计算预测法有一定可靠性。(2)运用多物理场耦合软件COMSOLMultiphysics对海底隧道含水断层进行了涌水量分析数值模拟,利用Darcy方程和孔隙-裂隙双介质模型,研究了不同覆岩厚度、海水深度、围岩渗透率、裂隙倾角、裂隙间距对涌水量的影响。通过与理论解析法计算的涌水量的对比可知,本文采用的涌水量数值计算预测法有一定可靠性。(3)通过建立断层突水的尖点突变模型,对隧道发生断层活化突水和隔水结构破断突水的机理进行了分析。建立了断层突水风险尖点突变势函数,然后基于平衡曲面方程,运用坐标转换的方法,提出了海底隧道含水断层尖点突变模型突水判据,选取青岛胶州湾海底隧道4条具有较高突水风险的含水断层,计算其突水指标从而预测突水是否发生,同时探讨了该预测模型的优缺点和适用性。(4)运用特菲尔-理想点法和突变级数法,以断层构造特征、物探解译信息、诱发因素等方面为基本出发点,提取了断层两盘岩体的风化程度、断层带渗透系数、断层倾角、断层影响带宽度、纵横波速比、视电阻率值、上覆岩层厚度、海水深度、施工扰动水平等9个影响因素作为突水风险的评价指标,并将断层突水风险分为Ⅰ、Ⅱ、Ⅲ、Ⅳ(极高风险、较高风险、较低风险、极低风险)4个等级,建立了含水断层突水风险预测模型。将该模型运用到胶州湾海底隧道突水风险等级预测中,并与工程实际情况进行验证。
[Abstract]:Under the combined action of excavation unloading and sea water pressure undersea tunnel construction often leads to geological disasters such as water inrush which seriously threatens the safety of construction when it passes through unfavorable geological sections such as fault broken zone etc. The joint action of excavation unloading and sea water pressure often leads to geological disasters such as water inrush. Therefore, it is very important to predict the tunnel water inflow and analyze the water inrush risk scientifically and accurately. Based on the project of Qingdao Jiaozhou Bay Subsea Tunnel, this paper adopts theoretical analysis. Numerical calculation and other methods are used to analyze the water inflow and forecast the water inrush risk when the tunnel passes through the water-bearing fault. In this paper, the prediction method of the tunnel water inflow and the mechanism of water inrush caused by the fault are summarized in this paper. The research status and progress of tunnel water inrush risk analysis method at home and abroad. Through the statistical analysis of the safety accident of submarine tunnel, it is concluded that the sudden water inflow is one of the most important construction risks of undersea tunnel. The fracture in the fracture zone is developed, the rock mass is broken and the stability of the surrounding rock is poor. Therefore, it is necessary to study the water inflow prediction method and the water inrush risk analysis method when the submarine tunnel passes through the water-bearing fault. By comparing with the theoretical analysis method, it can be seen that the numerical calculation and prediction method of water inflow in this paper has certain reliability. (2) numerical simulation of water inflow analysis of underwater tunnel fault is carried out by using multi-physical field coupling software COMSOLMultiphysics. The effects of overburden thickness, sea water depth, surrounding rock permeability, crack dip angle and fissure spacing on water inflow are studied by using Darcy equation and porosity / fissure dual medium model. By comparing with the theoretical analysis method, it can be seen that the numerical calculation and prediction method of the water inflow adopted in this paper has certain reliability. (3) by establishing the cusp catastrophe model of water inrush of faults, The mechanism of fault activated water inrush and water barrier structure breaking and bursting in tunnel is analyzed. The cusp mutation potential function of fault water inrush risk is established. Based on the equilibrium surface equation and the method of coordinate transformation, the water-inrush criterion of water-bearing fault tip catastrophe model is proposed. Four water-bearing faults with high risk of water inrush were selected from Jiaozhou Bay subsea tunnel in Qingdao, and the water inrush indexes were calculated to predict whether water inrush occurred or not. At the same time, the advantages and disadvantages and applicability of the prediction model are discussed. The Tefer-ideal point method and the catastrophe series method are used. The basic starting points are fault structural characteristics, geophysical interpretation information, inducing factors and so on. The weathering degree, permeability coefficient of fault zone, fault dip angle, width of fault influence zone, ratio of longitudinal and transverse wave velocity, apparent resistivity value, overlying strata thickness, depth of sea water are extracted. Nine influencing factors, such as construction disturbance level, are used as evaluation indexes of water inrush risk, and the water inrush risk of fault is divided into four grades: I, II, III, 鈪，

本文编号：1781752