基于Hoek-Brown准则的隧道开挖面安全系数模拟

Numerical simulation study on safety factor for a tunnel face subjected to Hoek-Brown criterion

目前,大多数隧道开挖面稳定性研究都是基于线性Mohr-Coloumb破坏准则进行的,而MohrColoumb破坏准则并不能很好地评估松散破碎岩体的强度。针对这一研究现状,利用有限差分软件,模拟盾构隧道在松散破碎围岩中的掘进过程,并通过在模拟过程中采用Hoek-Brown破坏准则,得到隧道开挖面安全系数的数值解。以长沙地铁2号线为工程背景,构建数值模型,计算得到了盾构隧道开挖面安全系数,验证了数值模拟的可靠性。研究结果表明:盾构隧道开挖面安全系数随着开挖面的支护力和Hoek-Brown参数(GSI和m_i)的增加而增加。

At present,the stability of most tunnel faces is based on the linear Mohr-Coloumb failure criterion,and the Mohr-Coloumb failure criterion can t evaluate the strength of the fractured rock mass.In view of this situation,the finite difference software was used to simulate the shield tunnel excavated in loose and fractured rock mass.The Hoek-Brown failure criterion was invoked in the simulation process,and the numerical solution of safety factor for tunnel face is obtained.Taking the Changsha Metro Line 2 as the engineering background,the numerical model was constructed and the safety factor of the tunnel face was calculated.Furthermore,the validity of the numerical simulation was verified.The parameter analysis results show that the safety factor of the tunnel face increases with the increase of supporting force,the rock parameters GSI and mi.