上软下硬地层隧道围岩失稳破坏影响因素研究

采用正交试验与极差分析相结合的方法,对隧道跨度W、埋深h、高跨比λ、隧道开挖方法和掘进尺寸等工程因素对上软下硬地层隧道稳定性的影响作了分析对比。当软硬地层组合不同时,分析研究了在W、h、λ、软硬地层分界结构面位置参数β、上部较软地层物理力学参数Ds和下部较硬地层物理力学参数Dx等地质因素、工程因素共同作用下,上软下硬地层隧道的稳定性。结果表明:W和h是工程因素中影响上软下硬地层隧道稳定性的2个主要因素,其次是λ;当隧道开挖后,自身能够稳定时,W是地质因素、工程因素共同作用下,影响隧道稳定性的主要因素,反之是Ds。

Study on Factor Affected to Instable Failure of Surrounding Rockalong Tunnel with Top Soft and Bottom Hard Stratum

An orthogonal test and range analysis combined method was applied to an analysis comparison on the tunnel span W,the buried depth h,high span ratio λ,tunnel excavation method and tunneling size as well as other engineering factors affected to the stability of the top soft and bottom hard stratum.When the soft and hard strata were differently combined,the paper had an analysis and study on the stability of the tunnel in the top soft and bottom hard strata under the joint role of the W,h,λ,parameter β at the location of the interface structure in the soft and hard strata,the physical mechanics parameter Ds of the top soft strata,the physical mechanics parameter Dx of the bottom hard strata and other geological factors as well as the engineering factors.The results showed that W and h were the two major factors in the engineering factors affected to the stability of the tunnel in the top soft and bottom hard strata and λ was the secondary factor.After the tunnel was excavated,when the tunnel self was stable,W was the major factor affected to the stability of the tunnel under the joint role of the geological factor and engineering factor and whereas W would be Ds.