...SLOPE INSTABILITY IN THICKLY BEDDED SANDSTONES. Stephen G. Fityus1, John H. Gibson2 ABSTRACT An important example of slope instability in thickly bedded Carboniferous sandstones in the New England Fold Belt Geology of Eastern New South Wales is described and analysed. The zone of instability...

... & Gas liner Reservoir Characterization orientation plane Gauss instability increment Artificial Intelligence Displacement vector plot separation closing plane elastic-plastic model failure mechanism structural unit compliance matrix MPa ith plane underground cavity deformation...

... head shield instability consequence difficult ground condition ABSTRACT: This paper is to discuss TBM tunnelling in difficult ground conditions, when problems are met which may reduce dramatically the average progress rates and practical consequences may be such as to pose serious questions...

... of renewed instability. Recurrent seasonal activity has been observed, however, in the two areas of the slide in the last few years; this included shallow retrogressive slump-earthflow movements. Of particular concern is the instability of the down-valley part of the toe and of the right flank. These local...

... carried out to examine the interactive effects of sleeved piles on slope stability. In the case of a single pile in a slope with a respectable safety margin, the sleeving technique is shown to be capable of minimising the adverse impact of lateral pile loading on local slope instability compared...

... with or without allowing for differential lateral movements of the slide mass. The results indicated the calculated 3D factors of safety ranged from 1.0 to 1.1, approximately 10 to 15% lower than those of 2D analysis. The 3D analyses appeared to be better in prediction of the instability of the waste fill...

... by the superimposition of rigid calcarenites over clayey silts and clays, creating an environment highly prone to landslide development. The medium-to-high acclivity of the clayey slopes also favour erosional phenomena; when such forms of instability reach the upper slopes, calcarenitic rocks can be involved...

... difficulties and high maintenance costs led to the consideration of alternative systems to reduce the risk of instability at the site. Major landsliding which occurred along other sections of the South Coast Railway, resulted from significant and long duration rainfall events during the La Nina occurrence...

... are discussed and criteria are proposed for their design. A small fast computer program, BEPIL, is introduced; which was developed to facilitate the modelling of typical pillar systems taking into account non-linear pillar behaviour pillar interactions and possible pillar instabilities. Finally, case studies...

... Reservoir Characterization national route ni sandstone worcester section cut face Upstream Oil & Gas joint metre Florence Anchor test anchor rock face instability planar failure structural geology simple block cut 1 cut 3 Surface Rock stabilisation bedding plane South...

... Lithologie und der geologischen Struktur auf die Bohrlochstabilitat der KTB-Vorbohrung a.Natau &G.Borm Department ofRock Mechanics, University of Karlsruhe, FR Germany Th.Rockel KTB Field Laboratory, Windischeschenbach, FR Germany ABSTRACf: In the KTB pilot hole in crystalline rock, mechanical instabilities...

... and suggests corrective actions. A pilot test showed that cooling the mud on an hydrocarbon well was possible and easy. The test also pointed out the importance of the drillstring rotation on downhole temperature. During rotation, hydraulic instabilities increase the heat transfer through the pipe, preventing...

... histories reponed herein serve as a credible database upon which numerical models can be developed or verified in addition to identifying some factors to be considered when drilling deep boreholes in rock. 1. INTRODUCTION Well bore instability, especially in the form of breakouts, has received much...

...Rock at Great Depth, Maury & Fourmaintraux (eds), © 1989 Balkema, Rotterdam. ISBN 90 6191 9754 Instability and stress transformations around underground excavations in highl y stressed anisotropic media Redistribution des contraintes autour des excavations souterraines en milieu anisotrope soumis...

... Wellbore Design displacement sandstone deformation theory wellbore integrity scale effect borehole borehole wall Upstream Oil & Gas surface instability specimen Symposium Reservoir Characterization bifurcation analysis constitutive equation instability Santarelli deep...

... instability deformation rheology Vardoulakis borehole stability Rock at Great Depth, Maury & Fourmaintraux (eds), © 1990 Balkema, Rotterdam. ISBN 90 61919754 General report: Instability problems at great depth drilling boreholes and wells Rapport general: Instabilite de puits durant le forage a grande...

... Reservoir Characterization structural geology reservoir geomechanics criterion wellbore integrity strength shale peak strength Upstream Oil & Gas criteria specimen envelope Wellbore Design pore pressure sandstone investigation elevated temperature instability carboniferous...

... constitutive behaviour elastic-inelastic boundary instability underground excavation Rock at Great Depth, Maury & Fourmaintraux (eds), © t 990 Balkema, Rotterdam. ISBN 90 6t 9t 9754 General report: Deformation, yield, rupture and stability of excavations at depth in rock Rapport general: Deformation...

... equation stress state sand production procedure risne gradient instability reduction permeability flowrate Rock at GreatOepth, Maury & Fourmaintraux (eds), © 1989 Balkema, Rotterdam. ISBN 90 61919754 A procedure for analysing seepage-induced collapse of weakly-cemented formations Methode...

... and a result the domains of unstable motion for the multilayer foundation are found. These unstable motion domains are depending not only on the foundation characteristics but on the parameters of the seismic wave field spectrum, i.e. the domains of the foundation instability for the Particular structure...