| | SLO | ENG | Cookies and privacy

Bigger font | Smaller font

Show document

Title:New trends in rock mass characterisation for designing geotechnical structures
Authors:Ocepek, Drago (Author)
Fakulteta za gradbeništvo, prometno inženirstvo in arhitekturo Univerze v Mariboru (Authorship owner)
Files:.pdf Acta_geotechnica_Slovenica_2005_Ocepek_New_trends_in_rock_mass_characterisation_for_designing_geotechnical_structures.pdf (1,05 MB)
 
URL http://fgserver3.fg.um.si/journal-ags/2005-2/article-4.asp
 
Language:English
Work type:Scientific work (r2)
Typology:1.01 - Original Scientific Article
Organization:FGPA - Faculty of Civil Engineering, Transportation Engineering and Architecture
Abstract:The investigation on designing supporting measures for geotechnical structures consists of the proper selection of the input data for the stress – strain analysis of the excavation process and the selection of retaining measures. In the preliminary phase of investigation the area must be geologically mapped in detail, and discontinuities precisely measured, boreholes and their “in situ” tests listed and samples for laboratory examinations taken. The new method allows rock mass classification for different rock quality, from soft rocks to mixed rock masses, as well as determination of the geological strength index GSI. The limits for using the suggested method are persistent discontinuities in rock mass which lead to translation or rotation failure mechanisms, either in a single plane or as a wedge. In all cases where discontinuities play a significant role, the rock mass structure must be considered and kinematical analyses performed. In other circumstances, a rock may be uniform and reasonably isotropic due to the geometry of discontinuities and their mutual intersections. The value range of GSI is first determined in the beginning of investigation and later in the excavation phase by considering the disturbance factor D, which expresses disturbances caused by excavation methods and rock mass relaxation. The strength and deformability parameters of rocks of different quality are determined by the generalized Hoek-Brown failure criterion and applied to shallow and deep tunnels or slopes. Before the start of excavations work and after establishing the retaining measures, the analysis results are checked by monitoring. New methods include the determination of post peak strength parameters of rock mass after relaxation, and routine measurements. The newest measurement system however allows direct readings of displacements of the rock mass in both the elastic and post-peak states. With back analyses we determine the softening behavior of the rock mass and a possible need for increasing retaining measures. Such a design method enables the optimization of retaining measures and the reduction of investment costs.
Keywords:geological strength index – GSI, simulation of a triaxial large scale »in situ« test, numerical modeling, retaining measures, rock reinforcement, monitoring, back analyses, strain softening, rock mass relaxation
Year of publishing:2005
Number of pages:str. 38-51
Numbering:št. 2, Letn. 2
ISSN:1854-0171
UDC:624.12
ISSN on article:1854-0171
COBISS_ID:1294165 Link is opened in a new window
NUK URN:URN:SI:UM:DK:6M1KIFFV
Copyright:Fakulteta za gradbeništvo, prometno inženirstvo in arhitekturo Univerze v Mariboru
Views:328
Downloads:18
Metadata:XML RDF-CHPDL DC-XML DC-RDF
Categories:Misc.
:
  
Average score:(0 votes)
Your score:Voting is allowed only for logged in users.
Share:AddThis
AddThis uses cookies that require your consent. Edit consent...

Hover the mouse pointer over a document title to show the abstract or click on the title to get all document metadata.

Record is a part of a journal

Title:Acta geotechnica Slovenica
Shortened title:Acta geotech. Slov.
Publisher:Fakulteta za gradbeništvo, prometno inženirstvo in arhitekturo Univerze v Mariboru
ISSN:1854-0171
COBISS.SI-ID:215987712 New window

Secondary language

Language:Slovenian
Title:Novi trendi pri karakterizaciji hribinske mase za projektiranje geotehničnih konstrukcij
Abstract:Pri projektiranju geotehničnih objektov moramo najprej pravilno določiti lastnosti in značilnosti hribinske mase za analize napetostno deformacijskega stanja izkopnih faz z dodajanjem ustreznih podpornih ukrepov. V začetni fazi raziskav je potrebno obravnavano področje podrobno inženirsko geološko kartirati z natančnimi meritvami razpoklinskih sistemov, hkrati pa popisati vrtine in v njih izvesti ustrezne »in situ« preiskave ter odvzeti vzorce za laboratorijske raziskave. Po novejši metodi uporabljamo hribinsko klasifikacijo za razpokane in mešane hribinske mase z določitvijo območja vrednosti geološkega trdnostnega indeksa – GSI, v fazi raziskav za izdelavo projekta in kasneje z določitvijo med samo izvedbo, ob upoštevanju faktorja poškodovanosti hribinske mase D, zaradi načina in kvalitete izkopa ter relaksacije hribinske mase. Če obstajajo v hribinski masi dominantne razpoke, ki lahko povzročijo translacijske, ali rotacijske porušitvene mehanizme, velja omejitev za uporabo obravnavane metode. Posledice so zdrs po eni razpoki (diskontinuiteti/plastovitosti) ali klinast zdrs, ki ga omejujejo presečne ravnine dveh do treh razpoklinskih sistemov. Če v hribinski masi ugotovimo možnost strukturnih porušitev zaradi pomembne vloge razpoklinskih sistemov, je potrebno napraviti kinematične analize. V drugačnih okoliščinah lahko obravnavamo hribinsko maso kot enotno in izotropno. Na podlagi posplošenega Hoekovega in Brownovega porušitvenega kriterija z aplikacijo na plitve ali globoke predore ter brežine določimo trdnostno deformacijske parametre hribinske mase različne kvalitete. Že med izkopom in izvedbo opornih ukrepov preverjamo njihovo uspešnost s pomočjo tehničnega opazovanja. Novejše metode vključujejo poleg običajnih meritev tudi določitev karakteristik hribinske mase po preseženi vrhunski trdnosti in relaksaciji. Novejši merilni sistem omogoča direktno odčitavanje pomikov hribinske mase, tako v stanju elastičnosti, kot v stanju po preseženi vrhunski trdnosti. S povratnimi analizami kasneje ugotavljamo deformacijsko popuščanje hribinske mase in potrebo po morebitnih dodatnih podpornih ukrepih. Tak pristop projektiranja omogoči optimizacijo podpornih ukrepov, kar zniža stroške investicije.
Keywords:geološki trdnostni indeks, triosna preiskava, simulacija, numerično modeliranje, podpore, hribinska masa, povratna analiza, deformacijsko popuščanje


Collection

This document is a part of these collections:
  1. Acta geotechnica Slovenica

Comments

Leave comment

You have to log in to leave a comment.

Comments (0)
0 - 0 / 0
 
There are no comments!

Back
Logos of partners University of Maribor University of Ljubljana University of Primorska University of Nova Gorica