隧道突涌水灾害防突厚度计算方法及适用性评价

Calculation methods of rock thickness for preventing water inrush in tunnelsand their applicability evaluation

将10余种常见的突涌水灾害防突厚度计算方法分类归纳,并与隔水岩体破坏和充填结构失稳两大类突涌水灾害类型对应统一。对于隔水岩体破坏型突涌水,按照力学模型和适用对象的不同将计算公式归类划分为完整岩体型与裂隙岩体型两类,改进了裂隙岩体三区模型的最小安全厚度计算公式,对比了不同工况下各个公式的计算结果,表明适用于完整岩体的三维岩柱剪切模型和适用于裂隙岩体的单裂纹扩展三区模型与工程经验公式一致性较好,具有更好的准确性和适用性。对于充填结构失稳型突涌水,颗粒受力启动适合于作为充填介质渗透失稳开始的标志,流体流态转变可作为失稳发生的临界判别标准。最后,文中对理论分析、数值模拟、模型试验与工程类比等方法的适用条件、判断标准与优缺点做了系统的评价,可为实际工程中监控物理量的选择、临灾状态的识别与灾害预警提供参考。

In this paper,more than ten kinds of common inrush water disaster prevention methods are classified and summarised by comprehensively considering the geological conditions and theoretical analysis models.These prevention methods are further unified with two types of inrush water disasters for water-damage rock mass failure and filling structure instability.For the water-breaking rock mass destruction type water inrush,the calculation formulas are classified according to the mechanical model and its applicable objects,and the minimum safe thickness calculation formula of the single crack extended three-zone model is improved.By comparing the calculation results of each formula under different working conditions,the results show that the three-dimensional(3D)rock-column shear model applicable to the intact rock and the single crack extended three-zone model applicable to the fractured rock mass are consistent with the empirical formula,which proves high accuracy and applicability.In terms of the unstable water inrush type of filling structure,it should be pointed out that the start-up force analysis of particles is suitable for judging the beginning of the seepage instability of the filling media and the fluid flow transition can be used as the critical criterion for the occurrence of seepage failure.Finally,this paper systematically evaluates the applicable conditions,judgment criteria,advantages and disadvantages of theoretical analysis,numerical simulations,model tests and engineering analogy.The results provide guidance and reference for the selection of monitoring objects,identification of disaster status and disaster warning in engineering projects.