Goran Vlastelica

Testing shear strength of soft rock at different stages of laboratory simulated weathering

U radu je opisano određivanje promjene cvrstoce temeljeno na simuliranju procesa rastrosbe u laboratorijskim uvjetima, koristeci uzorke lapora iz flisne formacije s podrucja Dalmacije. Na temelju provedenih ispitivanja zakljuceno je da je predloženi postupak simuliranja rastrosbe u laboratoriju provediv unutar prihvatljivih vremenskih okvira. Zbog uocene promjene parametara posmicne cvrstoce na vrijednosti koje odgovaraju cvrstoci materijala koji se opisuje kao tlo, ponekad je potrebno, zbog raspona velicine opterecenja koje se nanosi u pojedinom tipu uređaja, koristiti i uređaje za tlo.U radu je opisano određivanje promjene čvrstoće temeljeno na simuliranju procesa rastrošbe u laboratorijskim uvjetima, koristeći uzorke lapora iz flišne formacije s područja Dalmacije. Na temelju provedenih ispitivanja zaključeno je da je predloženi postupak simuliranja rastrošbe u laboratoriju provediv unutar prihvatljivih vremenskih okvira. Zbog uočene promjene parametara posmične čvrstoće na vrijednosti koje odgovaraju čvrstoći materijala koji se opisuje kao tlo, ponekad je potrebno, zbog raspona veličine opterećenja koje se nanosi u pojedinom tipu uređaja, koristiti i uređaje za tlo.

Estimation of embankment settlement caused by deterioration of soft rock grains

Embankments made from crushed soft rock grains can be susceptible to additional settlement caused by a deterioration of the grains inside the embankment. This additional settlement is not caused by the change of the stress state inside the embankment and cannot be predicted by standard calculating methods using the embankment modulus of deformability measured after compaction of the embankment. The deterioration of the grains is mainly caused by the weathering process, which, in soft rocks such as marl, is mainly induced by the wetting and drying processes. If marl grains in an embankment are subjected to the wetting and drying process, the result is breakage of the grains, as well as decomposition into soil material. Disintegrated material then fills the macro-pores of the embankment grain structure and gradually causes additional settlement. This process in soft rock material lasts from a few months to a few years. We propose a calculation procedure to estimate the possible value of the additional settlement, based on measured settlements gained from examples of laboratory-weathered samples. The samples were made of crushed marl in laboratory conditions. A test was conducted with a modified oedometer apparatus. In the proposed model, the deformation is calculated based on possible volume changes due to the deterioration of the grains and transport of the detached material into the macro-pores; this is done with the intention of estimating the settlement without measuring the deformation modulus change caused by the weathering.

Mjerenje posmične čvrstoće meke stijene u uvjetima laboratorijski simulirane rastrošbe

U radu je opisano određivanje promjene cvrstoce temeljeno na simuliranju procesa rastrosbe u laboratorijskim uvjetima, koristeci uzorke lapora iz flisne formacije s podrucja Dalmacije. Na temelju provedenih ispitivanja zakljuceno je da je predloženi postupak simuliranja rastrosbe u laboratoriju provediv unutar prihvatljivih vremenskih okvira. Zbog uocene promjene parametara posmicne cvrstoce na vrijednosti koje odgovaraju cvrstoci materijala koji se opisuje kao tlo, ponekad je potrebno, zbog raspona velicine opterecenja koje se nanosi u pojedinom tipu uređaja, koristiti i uređaje za tlo.U radu je opisano određivanje promjene čvrstoće temeljeno na simuliranju procesa rastrošbe u laboratorijskim uvjetima, koristeći uzorke lapora iz flišne formacije s područja Dalmacije. Na temelju provedenih ispitivanja zaključeno je da je predloženi postupak simuliranja rastrošbe u laboratoriju provediv unutar prihvatljivih vremenskih okvira. Zbog uočene promjene parametara posmične čvrstoće na vrijednosti koje odgovaraju čvrstoći materijala koji se opisuje kao tlo, ponekad je potrebno, zbog raspona veličine opterećenja koje se nanosi u pojedinom tipu uređaja, koristiti i uređaje za tlo.

Monitoring of vertical cuts in soft rock mass, defining erosion rates and modelling time- dependent geometrical development of the slope

Usage of Terrestrial Laser Scanners (TLS) is currently the best way of monitoring and detecting changes in slope morphology. In this study Optech ILRIS-3D was used. First scan of slope morphology with ILRIS-3D was made in March 2012 at presented pilot location “Žnjan” and it was repeated in 6 month intervals to this day. Series of observations in man-made cuts at additional 14 pilot sites usingTLS were also made. For the purpose of forecasting and retrograde analysis, the survey was conducted in different time intervals and number of observations. Main goal of this monitoring was to define the average rate of erosion in cuts in this type of material. Also, a proper procedure for establishing future monitoring in this type of materials is introduced, as well as guidelines for selecting minimum and maximum time intervals. Finally, based on the results of monitoring, known mathematical model for development of erosion in cuts is calibrated and the guidelines for its usage are proposed.