The Development of the New Advanced Material Model for Numerical Modelling of the Tunnel Excavation in Clays

摘要

This paper describes the development of the new advanced material model for numerical modelling of the tunnel excavation in the clays. The Jardine plastic hardening-softening model (JPHS model) is based on the elasto - plastic theory as in geotechnics widely used Mohr-Coulomb model but it contains some other features, which improves his capabilities and allows the better simulations of the ground behavior. Firstly, the Mohr-Coulomb failure yield criterion is replaced by the William-Warnke failure yield criterion, which eliminates the singular tips from the Mohr-Coulomb surface and has better agreement with the data from the experimental tests. Secondly, the model contains non-associated material description and the plastic flow is controlled by Drucker-Prager potential function. Thirdly, the model has the ability to simulate the non-linear isotropic hardening and softening of the soils. Fourthly, it is capable to increase the stiffness modulus with increasing depth or stress level and finally the model has the possibility to calculate the non-linear stress-strain dependence in a small strain range (0.0001 - 0.1%). To simulate the functionality and practical use of JHPS model, the real project of tunnel in clay is chosen, the numerical analysis is performed and comparison between Mohr-Coulomb, JPHS model and monitoring in-situ data is presented. The results verify that the soil mass behavior modelled by JHPS model corresponds more to the reality.