基于多重判据综合确定的隧道二衬支护时机研究

Study on the second lining support time of tunnel based on multiple criteria

为合理确定隧道二次衬砌支护时机,论文基于隧道变形监测成果,利用位移判据和速率发展趋势判据综合开展了隧道二衬支护时机研究,其中,位移判据是利用极限位移准则确定出位移条件下的二衬支护时机;速率发展趋势判据是利用变形预测和重标极差分析进行隧道变形速率的趋势判断,以评价前述二衬支护时机的合理性。实例分析表明:位移判据能初步确定隧道二衬支护时机,并经速率发展趋势判据评价,得出隧道变形速率趋于减小,变形向稳定方向发展;综合得出Ⅳ级围岩的二衬支护时机为23~25d,Ⅴ级围岩的二衬支护时机为29~32d。

In order to reasonably determine the time of secondary lining support,based on the results of tunnel deformation monitoring,the time of secondary lining support is comprehensively studied by using displacement criterion and rate development trend criterion.The displacement criterion is to determine the time of secondary lining support under displacement condition by using limit displacement criterion;the rate development trend criterion is to judge the trend of tunnel deformation rate by using deformation prediction and rescaled range analysis,so as to evaluate the rationality of the above-mentioned second lining support time.The case study shows that:the displacement criterion can initially determine the second lining support time of the tunnel,and through the evaluation of the rate development trend criterion,it is concluded that the tunnel deformation rate tends to decrease and the deformation tends to be stable;it is also concluded that the second lining support time of grade IV surrounding rock is 23~25 days,and that of grade V surrounding rock is 29~32 days.