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Slope stability is a present-day matter, with which the authorities of many countries are confronted, due to the risks the landslides imply regarding not only the material aspect, but also the human aspect. In this paper, a study of the Copou East landslides, Iasi Municipality (Romania), was performed. Other researchers have identified on this hill, through investigations over time, prior consequent deluvial landslides over the base rock. In order to estimate the probability for further landslides to occur, a probabilistic method was applied (Monte Carlo simulation), considering a plane sliding surface. Therefore, the Monte Carlo simulation was used based on the infinite slope method for a cross-section profile obtained from 3 wells. The results show that the well located at the upper part of the slope (F 10.1) has a stability factor smaller that 1 (Fs = 0.83), even when water is not present in the penetrated geological formations, suggesting local landslide occurrence. However, a different situation appears for the other two wells, drilled on the middle (F 10.2) and at the base (F 10.3) of the slope. Here, the computations indicate stability (Fs = 4.16 and 2.42, respectively), even at complete flooding of the intercepted geological formations. The authors consider this situation to occur due to the fact that the sliding surface's angle for F10.2 and F10.3 is much smaller than for F 10.1. This conclusion is also confirmed by the results obtained using Monte Carlo simulation for the whole profile. The mean stability factor for this alignment indicates that, considering the present-day conditions, the slope does not slide. This simulation was made without taking into account the anthropic overloading of the slope with buildings. This factor may drastically alter the equilibrium within the slope and cause failure. [ABSTRACT FROM AUTHOR]

Regularly, in Geotechnics domain the superficial deposits from Iasi (Romania) are associated with Quaternary age and bedrock with Sarmatian. There are situations when this rule does not apply, especially when clays are not containing any fauna, just like the case of some samples collected from Palas area, Iasi. This study aims to establish the boundary between the oldest formation and more recent ones, from their geotechnical characteristics. The research was carried out based on the physical and mechanical parameters obtained in the laboratory. The clay samples were collected from geotechnical wells from Palas area, Iasi. The elaboration of this study followed three steps. The first step was to plot the parameters (humidity, plasticity, porosity, compaction and cohesion) inside variation charts, against depth. Then, it could be observed a dependency on depth of these parameters and, based on that, a separation in zones was made. The third step was the determination of the statistic values of the physical and mechanical properties. This was done order to compare the parameters obtained in the previous stage, already separated in zones. Statistical analysis was performed in accordance with STAS 3300-85, for each of the mentioned parameters. The results show that the analysed perimeter from Iasi can be separated, against depth, into two zones with clay having different characteristics: an area with physical and mechanical characteristics less favourable (at the top) and an area with more favourable characteristics, underneath it. The boundary between the two areas is at 10 m below surface. The layers above this boundary are shallow formations. Below the boundary we can find the bedrock formation. Although, it has been observed few clay samples parameters with no clear connection to one of the two formations. Regarding the clay cohesion values, they are not following a certain trend, so no conclusion could be made on it in the both types of deposits. As a final consideration, the separation by age (Sarmatian from Quaternary), using geotechnical parameters, cannot be made clearly in this area. Other methods of separation will be applied in the next projects. The results show that the analysed perimeter from Iasi can be separated, against depth, into two zones with clay having different characteristics: an area with physical and mechanical characteristics less favourable (at the top) and an area with more favourable characteristics, underneath it. The boundary between the two areas is at 10 m below surface. The layers above this boundary are shallow formations. Below the boundary we can find the bedrock formation. Although, it has been observed few clay samples parameters with no clear connection to one of the two formations. Regarding the clay cohesion values, they are not following a certain trend, so no conclusion could be made on it in the both types of deposits. As a final consideration, the separation by age (Sarmatian from Quaternary), using geotechnical parameters, cannot be made clearly in this area. Other methods of separation will be applied in the next projects. [ABSTRACT FROM AUTHOR]