Analysis of blasted mass by sieving and image processing

U radu se analizira razlika dobivena pri određivanju granulometrijskog dijagrama odminirane stijenke mase metodom sijanja i obradom slike za situaciju kada se fragmenti međusobno preklapaju. Ukratko je opisana tehnička analiza sijanja i analize slike. Pokazano je da se računalnim programom GoldSize dobivaju bliski rezultati onima koji se dobivaju sijanjem te da se taj program može vrlo uspješno primijeniti za određivanje granulometrijskog dijagrama odminirane stijenske mase.The difference obtained by determining grain size distribution diagram of the blasted rock mass by sieving method and by image processing, in situations when fragments are overlapping, is presented in the paper. The technical analysis of sieving and image processing is described in general terms. The authors demonstrate that results close to sieving results have been obtained by GoldSize program and that this program can successfully be used for determining grading of the blasted rock mass

INVESTIGATION OF ROCKS FOR PROJECTS AT BLASTING IN »KRIŽ« AND »BELSKI DOL« QUARRIES APPLICATION OF THE SHALLOW SEIZMIC REFRACTION METHOD

U eksploatacijskom polju kamenoloma izvršena su terenska istraživnja kompaktnijih i poremećenijih zona dolomita, mjerenja prirodno odvojenih fragmenata u masivu i ispitivanje stijenske mase geofizičkom metodom refrakcijske seizmike. Dobiveni podaci bili su osnova za selektivno projektiranje eksploatacije i miniranje. U kamenolomu »Križ« također su određeni režimi sigurnog miniranja po najbliže stambene objekte.Field investigations of softer and harder dolomite zones, measurements of naturally divided fragments in rock masses and investigations of rock mass by refractional geophysical method in the blasting area of the quarry were carried out. The obtained results provided the basis for selective projects of exploitation and blasting. Safety measures regarding possible damage to adjacent housing estates during blasting were determined

Analysis of blasted mass by sieving and image processing

U radu se analizira razlika dobivena pri određivanju granulometrijskog dijagrama odminirane stijenke mase metodom sijanja i obradom slike za situaciju kada se fragmenti međusobno preklapaju. Ukratko je opisana tehnička analiza sijanja i analize slike. Pokazano je da se računalnim programom GoldSize dobivaju bliski rezultati onima koji se dobivaju sijanjem te da se taj program može vrlo uspješno primijeniti za određivanje granulometrijskog dijagrama odminirane stijenske mase.The difference obtained by determining grain size distribution diagram of the blasted rock mass by sieving method and by image processing, in situations when fragments are overlapping, is presented in the paper. The technical analysis of sieving and image processing is described in general terms. The authors demonstrate that results close to sieving results have been obtained by GoldSize program and that this program can successfully be used for determining grading of the blasted rock mass

AN EXAMPLE OF THE PROTECTION OF A DEEP EXCAVATION IN AN URBAN ENVIRONMENT

The paper presents the design of deep excavation support system in an urban environment. Excavation is carried out in the vicinity of surrounding buildings whose structural stability must be ensured during the execution of the construction works. The 60 cm thick diaphragm wall supported by the two rows (17.00 m and 18.25) of geotechnical anchors was selected as an exca-vation support system. The approximate floor plan dimensions of the diaphragm wall are 81x118 m, and the maximum excava-tion depth is 10.5 m. An additional challenge in designing the diaphragm wall is the presence of groundwater, whose maximum level is observed at a depth of approximately 5.8 m. In order to ensure the execution of construction works in dry conditions, a system of drainage trenches and wells is designed at the bottom of the pit. The diaphragm wall is designed in accordance with Eurocode 7

Estimation of vibro replacement by compression seismic waves

Svrha bonifikacije tla ugradnjom šljunčanih pilota je općenito poboljšanje mehaničkih svojstava u zahtijevanom volumenu. Kontaktne konture pilot-tlo najčešće nisu oštre pa se klasični pojam pilota djelomično gubi, a težište se prenosi na svojstva spregnutog sustava poboljšanog tla. Varijacije volumena i zbijenosti ugrađenog šljunka uzrokuju promjene gustoće i elastičnih svojstava tla prije i poslije zahvata, a dovoljno su distinktivne za njihovo profiliranje kompresijskim P valovima refrakcijskom tomografijom. Zbog toga je analiza mjere poboljšanja tla u ovom radu usmjerena na razlike brzina P valova kroz izvedeno probno i kontrolno polje šljunčanih pilota. Relativni odnos promjene stanja prije i poslije ugradnje može se dobro definirati po položaju i pružanju, dok se vektorom vrijednosti omjera brzina u profilima kvantificira utjecaj poboljšanja po dubini duž čitavog polja. Oblik promjena se dobro poklapa s krivuljama protokola rada vibratora.The purpose of soil improvement by vibro replacement is a general increase in the mechanical properties of soil in the requested volume. Columns-soil contact contours are usually irregular so that the classical concept of a pile is partially lost, and the emphasis switches to the properties of the composite system. Variations of embedded gravel volume and compaction cause significant changes of the soil density and the elastic properties before and after the intervention, and they are sufficiently distinctive for profiling by compression P-wave refraction tomography. Therefore, the analysis of the soil improvement degree is focused on the differences of P-wave velocities of the test pile field and control field. The relative relationship of the condition variations before and after embedding can be well defined by the position and extension, while the velocity ratio vector quantifies the effect of improvement by depth along the whole field. The shape of variations coincides well with the vibrator operation protocol

IN-SITU SOIL TESTING FOR CONSTRUCTION OF PUMPING STATION OF IRRIGATION SYSTEM VAŠKA-KAPINCI

U radu se opisuju dvije metode in-situ ispitivanja tla: statički penetracijski pokus (CPT) i ispitivanje teškom udarnom sondom (DPH). Prikazani su rezultati ispitivanja tla na mjestu izgradnje crpne stanice sustava navodnjavanja Vaška-Kapinci koji su uspoređeni s rezultatima dobivenim istražnim bušenjem. Provedena je usporedba kuta unutarnjeg trenja dobivenog iz korelacija sa CPT i DPH ispitivanjem te je izvedena korelacija između otpora na šiljku qc i broja udaraca N10H.In this paper, two methods of in-situ soil testing are described: Cone Penetration Test (CPT) and Dynamic Probing Heavy (DPH). The results of tests carried out at construction site of pumping station of irrigation system Vaška – Kapinci are represented and compared with borehole data. Comparison of the friction angle derived from correlations with CPT and DPH tests is made and the correlation between cone resistance qc and number of blows N10H is derived

Stability analysis of anchored rock slopes according to Eurocode 7

Osiguravanje stabilnosti stijenske kosine tijekom i nakon iskopa propisivanjem dugoročnih zaštitnih mjera jedna je od čestih zadaća praktičnog geotehničkog inženjerstva i mehanike stijena. U radu je prikazan primjer određivanja optimalnih parametara čvrstoće karbonatne stijenske mase i procjene stabilnosti sidrene stijenske kosine. Kriterij sloma stijenske mase definiran je generaliziranim Hoek-Brownovim kriterijem čvrstoće, pri čemu su korišteni rezultati geotehničkih istražnih radova, kojima je stijenska masa podijeljena u pet različitih geotehničkih zona. Analiza globalne stabilnosti kosine formirane iskopom zasjeka visine do 25 metara provedena je prema pravilima Eurokoda 7, projektni pristup 3. Kod procjene stabilnosti odabrana je mjerodavna klizna ploha. Provedena je analiza nestabilnog bloka za slučaj globalnog sloma i ravninskog klizanja po diskontinuitetu. Pretpostavljeno je pružanje diskontinuiteta u smjeru iskopa. U cilju usporedbe dobivenih rezultata, faktori sigurnosti proračunavani su sa i bez seizmičkih potresnih djelovanja te je provedena kontrola primjenom komercijalnog računalnog programa za analizu stabilnosti kosina.Ensuring the rock slope stability during and after excavation by prescribing long-term protection measures is one of the frequent tasks of practical geotechnical engineering and rock mechanics. The paper presents an example of determining optimal carbonate rock mass strength parameters and assessing the stability of the anchored rock slope. The rock mass failure criterion is defined by the generalized Hoek-Brown\u27s strength criteria, using the results of geotechnical investigations, where the rock mass is divided into five different geotechnical zones. Analysis of global slope stability formed by excavation the cut height up to 25 meters is carried out according to the rules of Eurocode 7, project approach third. For the stability estimation the relevant sliding surface was selected. An analysis of the unstable block in the case of global sloping and flat sliding was performed on discontinuity. It is assumed that discontinuity is provided in the direction of excavation. In order to compare the obtained results, the safety factors were calculated with and without seismic earthquake effects and control was carried out using a commercial computer program for slope stability analysis

INFLUENCE OF SEISMIC BLASTING EFFECT ON NEIGHBOURING STRUCTURES (A COMPARATIVE ANALYSIS)

Prilikom masovnog miniranja u kamenolomu vapnenca »Špica« (Ljubeščica, Hrvatsko Zagorje) mjerene su brzine oscilacije tla na dva mjesta opažanja za više minskih polja. Izložena je komparativna analiza proračuna dozvoljene količine eksplozivnog punjenja za maksimalne i rezultantne oscilacije tla s obzirom na kriterije koji se primjenjuju u svijetu i usporedba dobivenih podataka s njima.The article gives a comparative analysis of allowed explosive quantities at blasting in the limestone quarry »Špica« (Ljubeščica, Hrvatsko Zagorje) executed were precise measurings after mass blasting. The measurings were performed at two observation spots, with three-component geophones and a comparative analysis, considering the criteria in the world are described

SOIL STIFFNESS EVALUATION BASED ON IN-SITU TESTS AND CORRELATIONS BETWEEN vs, NSPT AND N10H

U ovome radu su prikazani rezultati istraživanja tla geofizičkim metodama koje se baziraju na spektralnoj analizi, odnosno disperziji brzine površinskih valova ovisno o frekvenciji. Seizmički presjeci višekanalne analize površinskih valova (Multichannel Analysis of Surface Waves, MASW), odnosno seizmičke sonde spektralne analize površinskih valova (Spectral Analysis of Surface Waves, SASW) uspoređeni su s rezultatima ne-disperzivnih metoda refrakcijske seizmike i bušotinske downhole metode. Radi analize procjene krutosnih svojstava tla izvedenih iz brzine posmičnih valova, provedeni su i standardni geotehnički penetracijski pokusi (Standard Penetration Test, SPT i Dynamic Probe Heavy, DPH). Korelacije brzine posmičnih valova vs i vrijednosti SPT-N i DPH-N pokusa su pokazale visoku pouzdanost procjene krutosti tla iz spektralnih metoda površinskih valova, prema kategorijama Eurokoda 8 (EC8).: In this paper, the results of geophysical surveying methods based on the surface waves are presented. Surface wave velocity dispersion depending on the frequency or spectral analysis was used for subsurface soil properties evaluation. Multichannel analysis of surface waves (MASW) seismic cross sections and spectral analysis of surface waves (SASW) seismic soundings were compared with results of non-dispersive seismic refraction and down-hole methods. In order to analyse the estimated value of soil stiffness derived from the shear wave velocity, geotechnical penetration tests (Standard Penetration Test, SPT and Dynamic Probe Heavy, DPH) were conducted. Statistical correlations of shear wave velocity (vs) and dynamic penetration test blow counts (SPT-N and DPH-N) have revealed high confidence of the estimated soil stiffness based on the surface wave velocity for Eurocode 8 (EC8) ground types

HYDROGEOLOGICAL CONDITIONS OF OCCURRENCE OF CLAY INTERBED WITHIN VARAŽDIN AQUIFER

Varaždinski vodonosnik zauzima krajnji zapadni dio heterogenih kvartarnih naslaga dravske doline. Šljunčani vodonosnik koristi se za potrebe vodoopskrbe većih naselja. Interpretacije strukture naslaga i hidrogeoloških odnosa ovog područja u zadnje vrijeme potaknuta su regionalnim problemima vodoopskrbe i zaštite izvorišta. Istraživanja su naročito usmjerena na glineni proslojak koji dijeli varaždinski vodonosnik na dva izolirana sloja šljunka. Provedena su geofizička mjerenja i izvedene su nove istraživačke bušotine. Ovim su istraživanjima došlo do novih spoznaja te omogućio detaljniji prikaz rasprostiranja glinenog proslojka.Varaždin aquifer is developed in the far western part of the heterogeneous Quaternary deposits in Drava basin. Water captured from this gravel aquifer is used for water supply of major cities. Recent regional problems of water supply and water source protection prompted new interpretations of the structure of deposits and hydrogeological relations in this area. Research has been focused especially on clay interbed that separates Varaždin aquifer in two isolated gravel layers. Geophysical measurements have been carried out followed by drilling of new exploration boreholes. These studies have shown new insights and enabled detailed display of clay interbed within Varaždin aquifer