基于敏感性分析的浅埋偏压隧道支护参数优化

Tunnel-supporting parameter optimization of shallow-buried and unsymmetrically load based on the sensitivity analysis

为得到浅埋偏压隧道合理的初期支护参数,以浙江省某一级公路隧道为工程背景,运用FLAC3D进行模拟计算,结合隧道周边围岩位移变形和支护成本的敏感度分析,对浅埋偏压隧道的锚杆长度、锚杆间距及喷射混凝土厚度进行优化,提出了增加喷射混凝土厚度和非对称施加锚杆的优化措施,并将优化后的隧道支护成本、围岩位移变形及塑性区发展情况与优化前的进行比较,得出优化后的支护措施具有良好的经济性,且能有效控制围岩位移变形和塑性区的发展。研究结果表明:敏感性分析法能在隧道支护参数的优化中得到很好的应用。进行隧道支护参数优化时,应强化喷射混凝土厚度的作用,而弱化锚杆的作用。

In order to obtain reasonable initial supporting parameters of shallow-buried and unsymmetrically load tunnels,the highway tunnel of Zhejiang Province is regarded as a research background,FLAC3D is used to make a simulation calculations. Combined with the results of sensitivity analysis of tunnel surrounding rock displacement and the surrounding support costs, bolt length, bolt spacing and shotcrete thickness of unsymmetrically load tunnels are optimized, optimization measures of increasing the thickness of shotcrete and asymmetric applied bolt are proposed,and the former tunnel supporting costs,surrounding rock displacement and the development of plastic zone are compared with optimized optimization. The optimized supporting measure are economical, which can effectively control the surrounding rock displacement and the development of plastic zone.The result shows that the sensitivity analysis can be well applied in the optimization of tunnel-supporting parameters, and when tunnel supporting parameter is optimized,the role of shotcrete thickness is strengthened,and the role of the anchor is weakened.