This paper presents the findings from a study on gravity-induced slope deformations along the northern slope of Mt. Nuria (Rieti-Italy). The slope extends from the village of Pendenza to the San Vittorino plain and hosts the Peschiera River springs, i.e. the most important springs of the Central Apennines (average discharge: about 18 m3/s).
Detailed geological-geomorphological and geomechanical surveys, supported by a site stress-strain monitoring system and laboratory tests, led us to define the main evolutionary features of the studied phenomena. Based on the collected data, a “geological-evolutionary model” was developed with a view to identifying a spatio-temporal correlation between relief forms, jointing of the rock mass and its stress conditions. The geological-evolutionary model was expected to improve numerical simulations and to test our assumptions.
The numerical model also allowed us to simulate changes in the stress-strain conditions of the rock mass and correlate them with jointing, seepage, as well as with site-detected and site-monitored forms and deformations. In particular, significant relations between seepage, tensile stresses within the rock mass, karst solution and collapse of cavities were identified. 相似文献
Hydrographic observations in the eastern Arabian Sea (EAS) during summer monsoon 2002 (during the first phase of the Arabian
Sea Monsoon Experiment (ARMEX)) include two approximately fortnight-long CTD time series. A barrier layer was observed occasionally
during the two time series. These ephemeral barrier layers were caused byin situ rainfall, and by advection of low-salinity (high-salinity) waters at the surface (below the surface mixed layer). These barrier
layers were advected away from the source region by the West India Coastal Current and had no discernible effect on the sea
surface temperature. The three high-salinity water masses, the Arabian Sea High Salinity Water (ASHSW), Persian Gulf Water
(PGW), and Red Sea Water (RSW), and the Arabian Sea Salinity Minimum also exhibited intermittency: they appeared and disappeared
during the time series. The concentration of the ASHSW, PGW, and RSW decreased equatorward, and that of the RSW also decreased
offshore. The observations suggest that the RSW is advected equatorward along the continental slope off the Indian west coast. 相似文献
The mineral industry is leading towards a technology driven optimization process. Drilling and blasting are such unit operations in a mine, which can alter the balance sheet of the mine if not planned properly. The development, improvement and utilization of innovative technologies in terms of blast monitoring instruments and explosives technology are important for cost effectiveness and safety of mineral industries.
The ever-growing demand for minerals has compelled the industry to adopt large opencast projects using heavy equipment. This has necessitated use of a few hundred tonnes of explosives in each blast. The bulk delivered fourth generation explosives have solved the problem of explosive loading to a large extent as it provides improved safety in manufacturing, transportation and handling. Bulk delivered emulsion is non-explosive until gasification is complete and a large quantity of explosive can be transported and loaded into blast holes efficiently and with safety. The priming of bulk delivered explosives in Indian mines uses the conventional PETN/TNT-based boosters. The conventional booster possesses safety problems in terms of handling and use, so Indian Explosives Ltd has developed an emulsion-based booster (Powergel Boost).
This paper explores the potential of an emulsion-based booster used as a primer to initiate bulk delivered emulsion explosives used in mines. An attempt has been made at a comparative study between the conventional booster and the emulsion-based booster in terms of the initiation process developed and their capability of developing and maintaining a stable detonation process in the column explosives. The study has been conducted using a continuous velocity of detonation (VOD) measuring instrument, the VODMate two channel system manufactured by Instantel Inc. of Canada. During this study three blasts were monitored. In each blast two holes were selected for study, the first hole was initiated using a conventional booster while the other one used an emulsion-based booster. The findings of the study advocates that the emulsion-based booster is capable of the efficient priming of bulk delivered column explosive with a stable detonation process in the column. 相似文献
This paper addresses size and boundary effects on wave propagation, fracture pattern development and fragmentation in small scale laboratory-size specimens for model blasting. Small block type specimens are centre-line loaded by linear explosive charges and supersonically detonated. Using elastic wave propagation theory and fracture mechanics it is shown that the type of boundary conditions which prevail at the outer boundary of the cylinder control the extension of bore-hole cracking and fragmentation within the body of the cylinder. In the case of a composite block where a cylindrical core of different material is embedded, the level of fracturing and fragmentation is controlled by the separation of the interface which in turn depends on the relative dimensions of the core and the block. The most important parameter is the ratio between the length of the pulse (space-wise or time-wise) and the characteristic dimensions of the models, i.e. in this case the dimensions of the core and the mantel. Stress wave superposition effects occur in the corner sections of the mantel. Theoretical results are in good agreement with recent experimental findings. 相似文献
On Shikoku Island, which is one of the four main islands of Japan, a large number of large-scale crystalline schist landslides have been revealed and are being monitored by an observation system. Seasonal heavy rainfall is the most active meteorological factor that can threaten the stability of this kind of site-specific landslide. In this paper, on the basis of the study of the rainfall-related behavior of a typical crystalline schist landslide, the Zentoku landslide, by analyzing the precisely and continuously observed piezometric and movement data, a method was developed to quantitatively assess the effect of heavy rainfall on a large-scale landslide. The results indicated that heavy rainfall-induced landslide displacement shows good correlation with the variation of groundwater levels. Variations of groundwater level have been simulated with the use of a tank model. The simulation using this model permits the change in water levels for future rainfall events to be predicted. By combining the predicted results with the empirical relation between displacements and water levels, rainfall-induced landslide movement during extreme rainfall events can be estimated in advance. The effect of heavy rainfall on sliding behavior can be quantified in terms of the change in displacement. Thus warning information or advisories for the local residents can be provided. 相似文献