复杂条件下隧道支护体时效可靠性探讨

以Kelvin-Voigt黏弹性模型作为大埋深隧道支护体流变模型,推导了隧道支护体的位移时效方程;提出了支护体时效可靠性的定义,即支护体时效位移曲线(Ur(ti))与位移阀值的交点(A点)到位移收敛值间弧段长(AB)与围岩与支护体发生作用点(O点)与位移收敛点(B点)之间弧段(OB)长的比值,即就是pf=AB/OB。在此基础上,运用自编程序计算了若干工程实例。工程实例表明:支护体的破坏概率与支护体弹性模量(E2)、围岩弹性模量(E1)以及支护厚度比较敏感;随着围岩弹性模量的降低,相同支护强度的支护体破坏率越小。

Time-reliability of tunnel support under complex conditions

The Kelvin-Voigt model was taken as the rhelogical model of large deep tunnel support,and the displacement time-equations of tunnel support were derived.The time-reliability of the tunnel support was defined,i.e.,the ratio of the length of the arc AB and OB.The length of AB was the distance between the intersection A,which was the displacement time–curve(U r(t i)) and the special value of displacement,and the displacement converging valve.The length of OB referred to the distance between the action position O of surrounding rock and the support and the converging valve of displacement.On such a basis,some real projects were calculated using computer programs.The results show that the failure probability of the tunnel support is very sensitive to the elastic modulus of surrounding rock and the tunnel support,and it is also sensitive to the supporting height.The failure probability of the tunnel support with the same supporting strength will reduce when the elasticity of surrounding rocks reduces.