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以某隧道V级围岩试验段为工程背景,采用现场测试和数值分析手段,对比支护形式进行基于黏弹塑性的三维变形、受力分析,获取了锚杆、喷射混凝土及钢支撑等初期支护结构的受力特征以及围岩变形规律。分析表明:在云母片岩地层隧道中,大变形主要表现为剪切破坏特征,3种支护形式对围岩的变形都有一定控制作用,但顶部系统锚杆对控制塑性区的影响作用甚微;锚杆及其他初期支护受力最大的区域均位于边墙下部和拱脚位置,提高喷层厚度和钢架刚度能减缓变形速率,但过大的刚度也使得结构内力大大增加。因此,为控制云母片岩隧道过度变形,应增强边墙与锁脚锚杆以提高初期支护成环效应,适当的提高钢架的刚度,必要时提前施作二次衬砌。
Based on the V-stage surrounding rock test section of a tunnel as the engineering background, field tests and numerical analysis methods were used to compare three-dimensional deformation and mechanical analysis based on viscoelasticity and plasticity. The initial stages of bolt, shotcrete and steel support were obtained The bearing characteristics of supporting structure and the deformation law of surrounding rock. The analysis shows that in the mica schist formation tunnel, the large deformation is mainly characterized by shear failure, and the three support forms have certain control effects on the deformation of the surrounding rock. However, the effect of the top system anchor on the control of the plastic zone is negligible The areas where the anchor rod and other initial supports are most stressed are located at the lower part of the side wall and the arch of the arch. Increasing the thickness of the spray layer and the stiffness of the steel frame can slow down the deformation rate. However, the excessive rigidity also causes the internal force of the structure to increase greatly. Therefore, in order to control the over-deformation of mica schist tunnel, the side wall and lock foot anchor should be strengthened to improve the initial support ring forming effect and properly increase the rigidity of the steel frame. If necessary, the secondary lining should be applied in advance.