施工期隧道喷混凝土支护安全性评价

隧道施工中,利用支护位移的监控量测数据及时地进行支护结构的安全性评价是隧道动态设计的关键,对保证隧道结构的安全具有重要意义.在隧道监控量测参数中,由于支护位移测量方便、花费低和可信度高,在工程实践中被广泛采用.本文欲以隧道施工中喷混凝土支护的量测位移为基础来建立一个隧道结构的安全性评价方法.文章给出了支护结构截面失效的功能函数及计算支护内力的计算公式,讨论了基本随机变量的概率特征,叙述了通过测量位移计算可靠指标的步骤.在此基础上进行了实例分析,总结了所提方法的特点,并给出了今后研究工作的建议.本文方法可用于施工期隧道喷混凝土支护的安全性评价,具有较好的理论和实用价值.

Assessment on the Safety of Shotcrete Lining During Tunnel Construction

To a tunnel under construction,a prompt assessment to the safety of the lining through in-situ measured data is of practical importance both for the observational designing of the tunnel and for the construction safety.Among all the parameters measured during tunnel construction,displacement is widely used and thus accepted as a very essential quantity,due to its advantages in convenience,low cost and high credibility.The aim of this paper is to develop a displacement-based method suitable for conducting safety evaluation of the shotcrete lining in the progress of construction of a tunnel.First of all,the performance function at a cross-section is put forward.Next,formulae are listed to calculate the internal forces for a lining segment.Then,the variability of the basic random variables is expatiated.Later on,iterated is the computation process of the reliability index through measured displacements.After that,case studies are conducted.Finally,the nature of the proposed method is observed and some remarks are made on further developments.The proposed method can meet the need of safety evaluation of shotcrete lining during tunnel construction and is also certainly of theoretical and practical significance to some extent.