Nonlinear analysis of NATM tunnel construction with the boundary element method

Abstract

This paper presents a novel approach to the simulation of NATM tunnel construction using the Boundary Element Method (BEM) as principal numerical method. This new approach has the advantage that only the excavation surface, the possible plastic zones and the tunnel lining have to be discretised. The whole rock mass is represented by the BEM whereas the Finite Element Method (FEM) is used to represent the tunnel lining only. Thus, a general coupling strategy for coupling three-dimensional boundary elements with shell finite elements (shotcrete) and beam finite elements (steel arches) is presented. To achieve realistic results the effect of hydration of the shotcrete and yielding of the steel arches is considered in the excavation process. Furthermore, the nonlinear rock behaviour is modelled more realistically by using a powerful hierarchical constitutive model which considers a large range of rock materials. The combination of these ideas results in higher user-friendliness and efficiency. Some verification tests and practical applications in tunnelling are presented.

Numerische Simulation im Tunnelbau

“…B. elasto-plastische) Materialien und für die Simulation von Teilausbruchssequenzen eingesetzt [161]. …”

Mechanical Analysis of Bolt-Lining Combined Support in Deeply Buried Circular Tunnel

“…Since then, it has been widely used in geotechnical engineering around the world because it can effectively restrict deformation and improve the stress state of surrounding rock. The essence of this method is to mobilize the strength and self-bearing capacity of surrounding rock as much as possible [1][2][3][4][5][6][7]. Shotcrete (lining) and bolts play important roles in the NATM because of their bearing and reinforcement effect [8].…”

Structural Safety Evaluation of Tunnel Based on the Dynamic Monitoring Data during Construction

“…e finite element method (FEM) is an important tool for tunnel research. Based on the theory of elastic-plastic, FEM calculates the stress field and deformation field of rock and soil under certain environmental conditions by solving simultaneous equations of elastic-plastic mechanics, and then the yield criterion of rock and soil is utilized to judge the state of surrounding rock [8][9][10]. is method can be used to solve the problems of elasticity and elastic-plastic in underground engineering; meanwhile, it can evaluate the stability of the whole tunnel structure and surrounding rock and guide the construction of tunnel, which could be widely used in practical engineering.…”