An Extended Damage Plasticity Model for Shotcrete: Formulation and Comparison with Other Shotcrete Models.

Matthias Neuner,Peter Gamnitzer,Günter Hofstetter

doi:10.3390/ma10010082

Abstract

The aims of the present paper are (i) to briefly review single-field and multi-field shotcrete models proposed in the literature; (ii) to propose the extension of a damage-plasticity model for concrete to shotcrete; and (iii) to evaluate the capabilities of the proposed extended damage-plasticity model for shotcrete by comparing the predicted response with experimental data for shotcrete and with the response predicted by shotcrete models, available in the literature. The results of the evaluation will be used for recommendations concerning the application and further improvements of the investigated shotcrete models and they will serve as a basis for the design of a new lab test program, complementing the existing ones.

Highlights

The use of shotcrete for supporting the surrounding rock or soil of a tunnel is an essential part of the New Austrian Tunneling method (NATM)
The performance of the Shotcrete Damage Plasticity (SCDP) model is evaluated by experimental data from the literature and compared to the performance of the reviewed shotcrete models
The presented numerical results for the Meschke model, the Schädlich model and the SCDP model are obtained at material point level, prescribing the stress in incremental-iterative simulations based on the respective stress update algorithms

Summary

Introduction

The use of shotcrete for supporting the surrounding rock or soil of a tunnel is an essential part of the New Austrian Tunneling method (NATM). For numerical simulations of tunnel advance based on the NATM, in addition to a constitutive model for the rock mass, a constitutive model for shotcrete is required for representing the mechanical behavior of the shotcrete shell. Shotcrete is characterized by continuously developing material properties during hydration, nonlinear stress–strain relations, time-dependent material behavior due to creep and shrinkage and fracture. An early attempt to account for the time-dependent shotcrete behavior in numerical simulations of tunnel advance was proposed in [1]. In this practical approach, a reduced Young’s modulus for shotcrete is used to consider effects such as evolving stiffness and strength during hydration, creep, shrinkage and even effects due to time-dependent loading caused by consecutive excavation steps

Objectives

Results

Conclusion