基于信息扩散的隧道突水岩层安全厚度概率模型研究

Research on the Probability Model of the Safe Thickness of Water-Inrush Rock Strata in Tunnels Based on Information Diffusion

通过虚功原理和莫尔库伦强度准则建立隧道最小安全岩层厚度力学模型,并推导计算公式,从公式看出最小安全岩层厚度受隧道半径、岩石内摩擦角度、掌子面前溶腔水压和黏聚力等因素影响。针对小样本信息不完备特点,基于信息扩散原理建立岩石力学参数(黏聚力、内摩擦角、弹性模量)和最小安全岩层厚度概率估计模型,以宜万铁路5个隧道的样本数据为基础,获取了岩石力学参数和最小安全厚度概率密度分布函数,并且绘制了图形。依据信息扩散原理建立的隧道最小安全岩层厚度概率模型能很好地利用样本数据信息。建立的最小安全岩层厚度概率模型可以应用到岩溶隧道突涌水灾害的风险评价中,对设计和施工有一定参考价值。

A mechanical model for the minimum safe thickness of rock strata in a tunnel is established by the virtual work principle and the Mohr Coulomb strength criterion,and a calculation formula is derived.From the formula,it can be seen that the minimum safe thickness of rock strata is affected by factors such as the tunnel radius,the internal friction angle of rocks,the water pressure of the solution cavity in front of the tunnel face and cohesive force.For the characteristics of the incomplete information of small samples,a probability estimation model for the mechanical parameters(cohesion,internal friction angle,elastic modulus)of rocks and the minimum safe thickness of rock strata is established based on the principle of information diffusion,and the probability density distribution function of the mechanical parameters and minimum safe thickness of rocks is obtained based on the sample data of the five tunnels of the Yichang-Wanzhou Railway,and a graph is drawn.The probability model of the minimum safe thickness of rock strata in tunnels established based on the principle of information diffusion can effectively utilize sample data information.The established probability model of the minimum safe thickness rock strata can be applied to the risk assessment of sudden water-inrush disasters in karst tunnels,which has certain reference value for design and construction.