Groundwater is an important source of drinking water, especially for rural population. In the last years, bacteria, nitrate, organic chemicals and other pollutants existing in groundwater have increased public concern about the quality of groundwater. Groundwater provides about 22% of all freshwater withdrawals; 37% of agricultural use (mostly for irrigation); 37% of the public water supply withdrawals; 51% of all drinking water for the total population and 99% of drinking water for the rural population; 46% of domestic and commercial use; 24% of industrial and mining use. The most severe groundwater quality depreciation appeared in the rural built-up area, where the lack of minimum public facilities allows liquid waste to reach directly or indirectly into the groundwater. The paper analyzes the soil and groundwater behaviour in the presence of three of the most significant sources of groundwater contamination due to waste storage works: sewer lines, septic tanks and landfills.

When studying the stability of a slope, the first issue that needs to be clarified is the slip surface, which determines the minimum safety factor. The slopes investigated here are homogenous with three distinct gradients (1:1.5; 1:1; 2:1), two defined heights (H-3 m; H-8 m), and four different soil characteristics (S1—clayey silt, S2—sandy clayey silt, S3—sandy silty clay, S4—clay). The purpose of this paper is to develop a new methodology capable of estimating the safety factor and the shape and centre of the critical slip surface, delivering an improved estimate of slope probability of failure, which can represent a significant component in a more precise risk assessment. This paper compares distinct methods used in the slope stability analysis, examining their hypotheses and effects on the estimated safety factor and the centre and shape of the critical slip surface. The study compares the limit equilibrium results with those determined by the shear strength reduction method using an approach based on the upper-bound limit analysis to compare the predictions extracted from these methods with those from the finite element method (FEM) analysis. The finite element method discretizes the soil mass into finite elements. Hence, it establishes a kinematically admissible velocity field searching for the failure mechanism of the slope. Results for FEM show the influence of the slope geometry and the mesh size and density on the safety factor. In the study, plots of the regression curves of five different critical slip surface shapes, including a circular slip surface (benchmark), show that the shape of the failure surface depends on the shape and material of the slope. Furthermore, they show that the critical slip surface layout can approach a logarithmic spiral, damped sinusoid, parabola, etc.; the slip surface is not always circular. The analysis reveals that none of the approaches can consider all uncertainties concerning the factor of safety and the interpretations of critical slip surfaces.

Dobruja is a historical region shared by Romania and Bulgaria; it is located on the western Black Sea coast, around the Danube River. The main geological, seismic and geotechnical features, as well as natural hazards are presented in this review. A comparative analysis is made between the northern and southern parts of Dobruja. The region has witnessed various kinds of natural hazard over the past decades, and this paper describes the geotechnical characteristics and chronology of two of the more frequently occurring events, namely earthquakes and soil liquefaction. The structural relationships between the different rock formations in Romania and Bulgaria are analyzed, to show the extent to which they influence the dynamics of these events. The stability of foundations on liquefacted sand, silty clay and karsts on which installations such as wind generators, the nuclear power station and breakwaters are built have been examined in the light of the geoenvironmental risks. The similarity in structural, geotechnical and environmental relationships between Romania and Bulgaria engender common risks that could be properly addressed only through collaboration between scientists from both countries.

The objective of this experimental study is to evaluate the effect of treated and untreated Jute fibers on the behavior of concrete members. Fifteen samples of concrete reinforced by JFRP are subjected to a compression test. The main issues investigated are the ultimate load, and the effect of treatment on fiber morphology. It has shown that the treatment of fibers by 2% of Potassium hydroxide during 24h in a liquor ratio of 10:1 decreases the maximum load capacity. On the other hand, the reinforcement of concrete members using untreated Jute Fibers Reinforced Polymer (JFRP) increases the maximum load capacity. As well as the augmentation of the number of layers of fibers fabric increases the maximum load capacity of concrete of 36.6% and 57.3% in the case of C3-JFRP-2L, C3-JFRP-3L respectively.

Computer simulations are challenging in terms of modeling the appropriate behavior of brick masonry structures. These numerical simulations are becoming increasingly difficult due to several design code requirements considered for the technical assessment of brick masonry structures for rehabilitation. In Romania, many brick masonry structures have withstood powerful earthquakes during their lifetime and require rehabilitation works. This paper aims to further assess various simulation challenges regarding the boundary conditions of spandrels and masonry structural behavior. This paper presents a comparative numerical study of two different spandrel-piers scenarios: one considers the link between them as unaffected, and the other attempts to simulate the occurrence of damage by replacing the spandrel’s presence in the initial structure. The proposed model follows the “strong pier–weak spandrel model” and is aimed at practicing engineers. Models are computed with ordinary design software such as Robot Structural Analysis with 2D shells finite elements for masonry walls and, in a more complex manner, software such as Ansys with 3D solid finite elements. Time history analyses are carried out for three distinct accelerograms recorded in Romania. A comparison of the results acquired from these two models is presented and discussed. The purpose of this research is to highlight the importance of proper modeling of unreinforced brick masonry structures to optimize operational and maintenance practices.