PBA工法上导洞施工初期支护变形数值模拟分析

A Numerical Simulation Analysis of Initial Support Deformation during the Construction of Top Heading with PBA Method

依托采用PBA工法施工的某地铁车站工程,针对上导洞开挖阶段初期支护开裂问题,通过采用数值模拟方法得到上导洞开挖阶段不同工况下初期支护的变形量,并建立导洞拱脚水平收敛矩阵及导洞拱顶沉降矩阵,探究开挖阶段不同工况下的初期支护的变形规律。最后,通过对导洞初期支护开裂采用应急处理措施和后续处理措施,并结合现场实测数据分析表明,处理措施能有效控制初期支护结构的变形。

Based on a subway station constructed with PBA method,and aiming at the cracking of the initial support during excavating top heading,the numerical simulation method is used to obtain the initial support deformations under different working conditions during excavating top heading.The horizontal convergence matrix of the top heading arch foot and the settlement matrix of the top heading vault is established to explore the deformation law of initial support under different working conditions during excavating top heading.Finally,the emergency treatment measures and subsequent treatment measures against support cracking are carried out.The field measured data show that the treatment measures can effectively control the initial support deformations during the construction of top heading.