隧道安全评估的可靠度分析与工程应用

Reliability Analysis and Engineering Application ofTunnel Safety Assessment

为了提高考虑岩性不均和参数易变情况下的隧道结构安全可靠度,总结了可靠度分析方法特性,归纳出2种隧道可靠度分析方法即概率法及非概率法,前者如矩法和响应面法,后者如鲁棒法。采用概率可靠度方法(矩法)分析了某地铁施工引起的地表沉降问题,并用有限元方法进行了验证;采用非概率可靠度方法(鲁棒分析法)分析了某回风隧道的结构安全问题,并进行了安全评估。结果表明:有限元方法计算得到的最大地表沉降量为14.2 mm,该结果不随沉降量警戒值S_(0)的变化而波动;采用鲁棒方法得到的最大地表沉降量为24.1 mm,失效概率P_(F)=2.13%,P_(F)随着沉降量警戒值S_(0)的增大而减少,隧道支护抗力大于围岩压力,回风隧道设计满足安全要求;在考虑岩性不均及参数易变时,可靠度分析能够更全面地对隧道安全性进行动态评估,具有重要工程应用意义。

In order to improve the safety and reliability of tunnel structure considering uneven lithology and variable parameters,the characteristics of reliability analysis methods were summarized.Two tunnel reliability analysis methods were obtained:probabilistic method and non-probabilistic method.The former was such as moment method and response surface method,and the latter was such as robust method.The probabilistic reliability method(moment method)was used to analyze the surface settlement caused by the construction of a subway,which was verified by the finite element method.The non-probabilistic reliability method(robust method)was used to analyze the structural safety of a return air tunnel,and the safety evaluation was carried out.The results show that the maximum settlement obtained by the finite element method is 14.2 mm,which does not fluctuate with the change of the settlement warning value S_(0);the maximum settlement obtained by the robust method is 24.1 mm,the failure probability P_(F) is equivalent to 2.13%,and P_(F) decreases with the increase of S_(0).The tunnel support resistance is greater than the surrounding rock pressure,and the design of the return air tunnel meets the safety requirements.When the uneven lithology and variable parameters are considered,the reliability analysis can make a more comprehensive dynamic assessment of tunnel safety,which has important engineering application significance.