Publications

@article{Langford2013,

title = {Reliability based approach to tunnel lining design using a modified point estimate method},

author = {JC Langford and MS Diederichs},

url = {https://www.sciencedirect.com/science/article/pii/S1365160912002626},

doi = {https://doi.org/10.1016/j.ijrmms.2012.12.034},

issn = {1365-1609},

year  = {2013},

date = {2013-06-01},

journal = {International Journal of Rock Mechanics and Mining Sciences},

volume = {60},

pages = {263-276},

abstract = {This paper presents a new reliability-based design approach to evaluate the performance of a composite tunnel lining using a modified Rosenblueth Point Estimate Method (PEM), First Order Reliability Method (FORM), Monte Carlo sampling method and finite element analysis. The modified PEM involves the selection of additional evaluation points to provide a more complete assessment of system performance across the range of statistically significant values. To demonstrate this approach, the support performance at the Yacambú-Quibor tunnel in Venezuela was assessed. The general rockmass characteristics and the details of the composite lining system are presented for a segment along the tunnel. Numerical analyses were completed using finite element modeling to determine the behaviour of the lining over the range of possible rockmass and in situ stress conditions. The results of these analyses were then used to determine the reliability index (β) and probability of failure (pf) for a given liner section.},

keywords = {Capacity diagrams, Convergence-confinement method, Reliability based methods, squeezing, Tunnel support, tunnelling},

pubstate = {published},

tppubtype = {article}

}

@article{Vlachopoulos2009,

title = {Improved longitudinal displacement profiles for convergence confinement analysis of deep tunnels},

author = {N Vlachopoulos and MS Diederichs},

doi = {10.1007/s00603-009-0176-4},

year  = {2009},

date = {2009-04-01},

journal = {Rock Mechanics and Rock Engineering},

volume = {42},

number = {2},

pages = {131-146},

abstract = {Convergence-confinement analysis for tunneling is a standard approach for preliminary analysis of anticipated wall deformation and support design in squeezing ground. Whether this analysis is performed using analytical (closed form) solutions or with plane strain numerical models, a longitudinal displacement profile (LDP) is required to relate tunnel wall deformations at successive stages in the analysis to the actual physical location along the tunnel axis. This paper presents a new and robust formulation for the LDP calculation that takes into account the significant influence of ultimate (maximum) plastic radius. Even after all parameters are appropriately normalized, the LDP function varies with the size of the ultimate plastic zone. Larger yield zones take a relatively longer normalized distance to develop, requiring an appropriately calculated LDP. Failure to use the appropriate LDP can result in significant errors in the specification of appropriate installation distance (from the face) for tunnel support systems. Such errors are likely to result in failure of the temporary support. The equations presented here are readily incorporated into analytical solutions and a graphical template is provided for use with numerical modeling.},

keywords = {Convergence-confinement, displacement, ground reaction, squeezing, tunnelling},

pubstate = {published},

tppubtype = {article}

}