Publications

@article{Diederichs2007,

title = {The 2003 Canadian Geotechnical Colloquium: Mechanistic interpretation and practical application of damage and spalling prediction criteria for deep tunnelling},

author = {MS Diederichs},

doi = {10.1139/T07-033},

year  = {2007},

date = {2007-11-08},

journal = {Canadian Geotechnical Journal},

volume = {44},

number = {9},

pages = {1082-1116},

abstract = {Spalling and strain bursting has long been recognized as a mechanism of failure in deep underground mines in hard rock and in deep infrastructure tunnels. The latter is a significant growth industry, particularly in Europe where subalpine base tunnels in excess of 10 m wide and dozens of kilometres long are being driven by tunnel boring machine (TBM) through alpine terrain at depths greater than 2 km. In more massive granitoid or gneissic ground, these tunnels have experienced significant spalling damage. En route to a practical predictive technique for this condition, the author utilizes a number of analytical and micromechanical tools to validate a simple empirical predictive model for tunnel spall initiation. The true nature of damage and of yield, as the result of extensile damage accumulation, in hard rocks is examined using these tools. Based on the resultant conceptual model, the author expands on the empirical damage threshold, using a spalling limit to differentiate stress paths that lead to crack propagation and spalling from those that incur stable microdamage prior to conventional shear failure at higher relative confinements. Finally, the composite and robust in situ yield model is applied to nonlinear modelling for support design.},

keywords = {Crack initiation, Numerical modelling, Rock fracture, spalling, tunnelling, Yield},

pubstate = {published},

tppubtype = {article}

}

@article{Diederichs2003,

title = {Rock fracture and collapse under low confinement conditions},

author = {MS Diederichs},

doi = {10.1007/s00603-003-0015-y},

year  = {2003},

date = {2003-12-01},

journal = {Rock Mechanics and Rock Engineering},

volume = {36},

number = {5},

pages = {339-381},

abstract = {The primary objective of this work was an examination of the complimentary roles of tensile damage and confinement reduction (or stress relaxation) on excavation response of ‘‘hard’’ rockmasses. Tensile damage and relaxation are examined with respect to structurally controlled or gravity driven failure modes as well as to strength controlled or stress driven rockmass damage and yield. In conventional analysis of both structurally controlled and stress driven failure, the effects of tensile damage and tensile resistance as well as the elevated sensitivity to low confinement are typically neglected, leading to erroneous predictions of groundfall potential or rock yield. The important role of these two elements in underground excavation stability in hard rock environments is examined in detail through a review of testing data, case study examination and a number of analytical and numerical analogues including discrete element simulation, statistical theory and fracture mechanics. This rigorous theoretical treatment updates, validates and constrains the current use of semi-empirical design guidelines based on these mechanisms.},

keywords = {discrete elements, Rock fracture, strength, underground stability},

pubstate = {published},

tppubtype = {article}

}