Modeling Ground-Shell Contact Forces in NATM Tunneling,Based on 3D Displacement Measurements
Based on an advanced micromechanics-based nonlinear creep model for shotcrete and thin shell kinematics,measured displacement data are first converted into in-plane stress fields throughout a shotcrete tunnel shell driven according to the New Austrian Tunneling Method (NATM).Subsequently,the partial differential equations for local force equilibrium in the cylindrical coordinate directions are solved for the out-of-plane shell stresses,inclusive of the tractions at the ground-shell interface.Results obtained for a NATM-tunnel driven through clayey ground at moderate depth,show that the maximum shear tractions at the ground-shell interface may even exceed the maximum normal tractions (ground pressure).At the same time,even a young top heading tunnel shell may act as an arching thrust.We regard our method as a further step in the continuous refinement of interpretation displacement measurements stemming from tunnel monitoring systems for the NATM,on a well-defined mechanical basis.This results in two structural models for top heading excavation stages,which might have the potential to support NATM predesign activities in the future.
monitoring micromechanics ground-shell interaction
Shaft Ullah Bernhard Pichler Christian Hellmich
Institute for Mechanics of Materials and Structures Vienna University of Technology(TU Wien)Karlspla Institute for Mechanics of Materials and Structures Vienna University of Technology(TU Wien)Karlspla
国际会议
北京
英文
293-296
2012-10-15（万方平台首次上网日期，不代表论文的发表时间）