砂卵石地层盾构始发与到达端头土体加固范围研究

摘要

Based on the theory of the plate strength,mechanical calculation model of soil reinforcement on the end of TBM beginning or arriving,together with the mechanical characteristics of sandy pebble stratum,was simplified to a rectangular plate with four simply supported edges.Based on Levi results about the rectangle plate,the largest shear and tensile stress principle were used to obtain the scope of the reinforce soil.Using MIDAD/GTS software,three-dimensional numerical model was established to analyze the thickness,displacement and strength of reinforced soil.The results show that when the thickness of reinforcement soil is 1 ～ 1.5 times of tunnel diameter,it can meet the safety demand of departure and arrival of TBM.%基于板块强度理论,结合砂卵石地层的受力特点,将盾构始发与到达端头土体加固的力学计算模型简化为四边简支的矩形薄板,根据弹性力学中矩形薄板的莱维解,运用最大剪应力和最大拉应力原理,分析得出端头土体的纵向加固范围;采用MIDAD/GTS有限元分析软件,依托工程实例,建立三维有限元计算模型,对端头土体加固厚度、位移、加固土强度进行分析.研究结果表明:砂卵石地层端头土体纵向加固范围取1.0～1.5倍洞径可以满足盾构始发与到达安全性要求.