Numerical Analysis of TBM Tunnel Lining Behavior using Shotcrete Constitutive Model

Shotcrete is a fundamental support element for tunnels and underground constructions. Shortly after application, shotcretelinings undergo a high load while the ordinary concrete is not fully hardened yet. Therefore, the time-dependent behaviourof the shotcrete material must consider. Traditional approaches assume a linear elastic behaviour using a hypotheticalyoung modulus to model this time-dependency and creep effects. In this paper, a new constitutive model of shotcrete isapplied to evaluate the time-dependent behaviour of TBM tunnel lining under high in-situ stress state. The Shotcrete modelis based on the framework of Elasto-plasticity and designed to account for non-linear and time-dependent behaviour forconcrete material more realistically. A parametric study of the time-dependent behaviour of the shotcrete lining, using theshotcrete model, is performed. To achieve this, the influence of the lining thickness, tunnel diameter and tunnel depth onthe development of the stresses and displacement of the shotcrete lining with time is investigated. The results showed thatthe development of the lining tensile stress with time at tunnel crown increases by increasing the lining thickness andtunnel depth, whereas it decreases by increasing of the tunnel diameter. At the tunnel sidewall, the lining compressionstress with time increases with the increase of the tunnel depth and diameter, while higher lining thickness decreases thelining compressive stresses. However, the results showed the ability of the shotcrete model to simulate the structuralbehaviour of the shotcrete lining with time.

Keywords:

Shotcrete Model , Shotcrete Lining Stress , Lining Thickness , Tunnel Depth , Numerical Modelling