隧洞变形引起的TBM施工事故综合风险分析

国内采用岩石隧道掘进机(简称TBM)施工的隧洞呈现深埋、超长趋势,变形引起的TBM卡机事故屡见不鲜,为了减少这些事故,可以预先对变形引起的TBM风险事故进行综合评价,因此,在单元风险研究的基础上对综合风险计算及评价准则进行研究。采用概率理论推导了变形引起的TBM风险事故的综合风险概率的计算模型,根据推导的模型可以近似计算出5类后果等级事故发生的概率;采用TBM的卡机时间与纯掘进时间的比值作为分级指标,结合以往TBM施工的统计数据划分工期损失后果等级,再结合风险的概率分级,建立变形综合风险评价准则;采用研究的理论,对工程选取段TBM施工卡机风险进行了两种工况下的计算分析。计算结果表明,施工时若不采取任何措施TBM施工风险比较大,但采用合理的措施之后风险可控制在可接受的范围内。

Comprehensive risk analysis of TBM construction accident induced by tunnel deformations

Now in China the tunnels excavated by TBM become deeper and longer than before; and TBM jamming accidents are very common. In order to reduce these accidents, comprehensive evaluation of TBM risk accident induced by tunnel deformation can be carried out in advance. Therefore, the research on comprehensive risk is started. First, the calculated model of comprehensive risk probability is established by probability theory. According to the derived model, the accident probabilities of different consequence ranks can be calculated. Second, the ratio of jamming time and pure penetrating time is used as graded index. The index combined with the data gathered from previous TBM construction is used to divide consequence ranks of construction time delay. Then the comprehensive risk evaluation criterion for deformation is established. Finally, the jamming risk in certain parts of practical project is analyzed by the theory proposed above in two different construction conditions. It is demonstrated from the calculated conclusion that the construction risk is bigger when no measures are taken; however, the risk can be controlled within the acceptable extent when proper measures are taken.