Anisotropic behaviour of stratified rock masses in tunnelling

Fortsakis, P; Nikas, K; Marinos, V; Marinos, P

dc.contributor.author	Fortsakis, P	en
dc.contributor.author	Nikas, K	en
dc.contributor.author	Marinos, V	en
dc.contributor.author	Marinos, P	en
dc.date.accessioned	2014-03-01T02:07:43Z
dc.date.available	2014-03-01T02:07:43Z
dc.date.issued	2012	en
dc.identifier.issn	00137952	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29606
dc.subject	Anisotropy	en
dc.subject	Convergence	en
dc.subject	Rock mass	en
dc.subject	Stratification	en
dc.subject	Tunnel	en
dc.subject	Tunnel behaviour	en
dc.subject.other	Convergence	en
dc.subject.other	Critical failures	en
dc.subject.other	Geomaterials	en
dc.subject.other	Isotropic materials	en
dc.subject.other	Rock mass	en
dc.subject.other	Rock mass elements	en
dc.subject.other	Rock mass properties	en
dc.subject.other	Rock mass structure	en
dc.subject.other	Separate element	en
dc.subject.other	Stratified rock mass	en
dc.subject.other	Surface conditions	en
dc.subject.other	Tunnel excavation	en
dc.subject.other	Tunnel sections	en
dc.subject.other	Anisotropy	en
dc.subject.other	Computer simulation	en
dc.subject.other	Engineering geology	en
dc.subject.other	Numerical analysis	en
dc.subject.other	Rocks	en
dc.subject.other	Thermal stratification	en
dc.subject.other	Tunneling (excavation)	en
dc.subject.other	Tunnels	en
dc.subject.other	Rock mechanics	en
dc.subject.other	anisotropy	en
dc.subject.other	convergence	en
dc.subject.other	discontinuity	en
dc.subject.other	failure mechanism	en
dc.subject.other	numerical model	en
dc.subject.other	rock mass response	en
dc.subject.other	stratification	en
dc.subject.other	tunneling	en
dc.subject.other	uncertainty analysis	en
dc.title	Anisotropic behaviour of stratified rock masses in tunnelling	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.enggeo.2012.05.001	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.enggeo.2012.05.001	en
heal.publicationDate	2012	en
heal.abstract	This paper investigates tunnel excavation through stratified rock masses from the engineering geological behaviour to the rock mass properties quantification and finally to the study of tunnel response, based on numerical analyses results. Initially the spectrum of the engineering geological behaviour of stratified rock masses in tunnelling is delimited and the critical failure mechanisms according to rock mass structure are described. Rock mass simulation as an equivalent isotropic geomaterial through the widely used characterisation systems in most cases cannot lead to a realistic prediction of the distribution and the values of total displacements. In addition, the complete and accurate simulation of all discontinuities networks involves high uncertainty. Therefore in the numerical analyses carried out, based on an already applied approach, the stratification planes, which contain less uncertainty than the secondary discontinuities and affect significantly the behaviour of tunnel, were simulated as separate elements and the rock mass parts between them as an isotropic material. Additionally, using simple rock mechanics principles, an approach for the quantification of the rock mass properties involved in the analyses is described, which tries to obtain the equivalence between the stratified rock mass and the sum of the distinct rock mass elements (stratification planes and internal rock mass). The numerical analyses depict the mechanism of convergence development in stratified rock masses and the differences between isotropic, anisotropic and transversally isotropic approaches are clearly demonstrated. Based on the results of the numerical analyses the incorporation of the stratification planes leads to an increase of the convergence mainly due to the bending of the rock mass strata where the stratification is tangential to the tunnel section. This increase depends on the GSI value of the reference rock mass and the discontinuities surface conditions. © 2012 Elsevier B.V.	en
heal.journalName	Engineering Geology	en
dc.identifier.doi	10.1016/j.enggeo.2012.05.001	en
dc.identifier.volume	141-142	en
dc.identifier.spage	74	en
dc.identifier.epage	83	en