Definisanje parametara čvrstoće na smicanje kod izvođenja kosina u ispucalom stenskom masivu
Shear strength properties of cut slopes excavated in jointed rock mass
Author
Berisavljević, Zoran M.Mentor
Čebašek, Vladimir
Committee members
Gojković, NebojšaRakić, Dragoslav

Šušić, Nenad

Radić, Zoran
Metadata
Show full item recordAbstract
Definisanje parametara čvrstoće na smicanje ispucalih stenskih masa predstavlja jedan
od najzahtevnijih zadataka mehanike stena. Geotehnička istraživanja su uglavnom
ograničena na rezultate laboratorijskih ispitivanja malih makroskopski homogenih
uzoraka, sa kojih se vrši ekstrapolacija rezultata na terensku razmeru. Ispitivanja se
mogu vršiti in situ, ali su i ona ograničena veličinom korišćene aparature i
mikrolokacijom na kojoj se vrše ispitivanja. Pored toga, moguće je vršiti različita
ispitivanja na fizičkim modelima, koja su veoma složena i skupa. Ekstrapolacija
podataka sa malog uzorka na terensku razmeru daje mnogo bolje rezultate u mehanici
tla, gde se materijal sa zadovoljavajućom tačnošću može smatrati kontinualnim i
homogenim. Kod čvrstih stenskih masa, usled prisustva velikog broja pukotina, javlja se
problem diskontinualnosti. Zbog ovoga, rezultati dobijeni na intaktnim uzorcima mogu
biti od ograničene upotrebljivosti ukoliko se ne poznaju karakteristike ispucalosti
stens...ke mase.
Da bi se definisali parametri čvrstoće na smicanje stenske mase potrebno je primeniti
neku od postojećih klasifikacija, koja kombinuje karakteristike ispucalosti i parametre
intaktnih uzoraka. Ovde se posebno ističe GSI sistem, jedina klasifikacija koja je
sastavni deo jednog (Hoek-Brown-ovog) kriterijuma loma. Ona je subjektivna, pa se u
disertaciji daje predlog kvantifikacije GSI dijagrama za fliš preko koeficijenta SCR,
kojim je definisan kvalitet zidova pukotina.
Nakon otvaranja kosina dolazi do promene naponskog stanja i izlaganja stenske mase
dejstvu atmosferskih činilaca. Ovi faktori mogu dovesti do omekšanja, tj. snižavanja
parametara čvrstoće na smicanje u vremenu. Zbog toga, za razmatranje dugoročne
stabilnosti, nije dovoljno definisati parametre samo u trenutku otvaranja kosina, već je
potrebno odrediti ih i u nekom trenutku nakon otvaranja kosina...
Determination of shear strength parameters of jointed rock mass is one of the most
demanding tasks in the field of rock mechanics. Conventional geotechnical
investigations are usually restricted to testing visually homogeneous laboratory prepared
samples of small size. Results are then extrapolated to the field scale. Tests can also be
performed in situ, but then, they are dependent on the size of the equipment and test
location. Besides, it is possible to perform studies on physical models, which are very
complex and expensive. Direct data extrapolation from small laboratory scale to the
field scale is more and less applicable in soil mechanics, whereas material can be
reasonably assumed to behave as homogeneous and continuous. Due to presence of
large number of joints, rock material is considered discontinuous, thus the results
obtained on intact samples could be of limited use unless joint properties are known.
In order to define shear strength properties of jointed rock mass, it is... necessary to apply
some kind of existent classification system which combines intact and joint properties.
The emphasis is here given to GSI system, the only classification which is the part of
one shear strength (Hoek-Brown) criterion. GSI classification is rather descriptive in its
original form, thus an effort is placed on quantifying the GSI chart for flysch by means
of SCR coefficient.
After the excavation, stress state is altered and the slope face is exposed to weathering
process. These factors can lead to slope deterioration and softening i.e. decrease in shear
strength with time. In order to properly consider long-term slope stability it is necessary
to determine shear strength parameters in different time periods after the excavation of
cut.
The purpose of this dissertation is to define shear strength properties of heterogeneous
jointed flysch and braided river deposits (Permian red sediments), with interchanging
siltstone and sandstone lithologies...