Volume 16 (2021): Edizione 1 (March 2021)

Reservoir modeling involves the construction of a computer model for prediction purposes and making decisions regarding the best operation of the reservoir. The environmental consequences of dams and reservoirs are numerous and varied, and includes direct impacts to the physical, chemical and biological properties of reservoirs and environments. This paper dealt with the study of the dissolved oxygen and the BOD concentrations in the inflow streams as well as those in Lake Morii, as well as the effects of phytoplankton, chlorophyll and reaeration rate using simulations in Mike Zero software. The main objectives of this research are to investigate the concentration of dissolved oxygen if they are among the required of water quality standards and how they are dispersed in the lake during a specific time period, as well as reducing concentration the BOD when it reached highest level, especially in summer time The simulations obtained gave us very good results about the dissolved oxygen and BOD concentrations in the reservoir.

This paper aims to develop a high-precision two-dimensional hydrodinamic model of the Danube critical sector extended between Bechet and Corabia (from rkm 678 to rkm 625), using Danish Hydraulic Institute (DHI) Mike 21 software. The Digital Terrain Model (DTM) of the study area was obtained based on LiDAR (Light Detection and Ranging) data, combined with topogeodetic and bathymetric data collected during two field campaigns within the FAST DANUBE Project. Hydrodynamic modeling is mandatory in order to identify environmentally friendly technical solutions to solve the navigability issues on each critical area and to ensure safe conditions for the freight transport along the entire length of the Romanian-Bulgarian common sector of the Danube River.

This article target is to perform a probabilistic analysis of a concrete dam.Brezina weight arch dam situated at El Bayedh in Algeria is chosen as a case study. Ansys code is used for three-dimensional finite element modeling of the dam. Input variables are generated arbitrary by Monte Carlo (MCS) method which is more precise but costly in terms of computing time. Simulation number privileged in this method (MCS method) is in order of 500 simulations chosen based on convergence of results (of responses). Normal and Log-Normal distributions laws are used to generate random variables; young Modulus (E) and density (ρ).

The bandwidth limits are 38.14Hz and 42.15Hz. It represent frequency margin whose resonance risk is very high. This bandwidth has been determined from a determinist study which is a numerical modal analysis using Ansys code.

The obtained results show that the variation coefficient of E and ρ for Brezina concrete weight arch dam hasn’t an impact on the dam security whose resonance risk is almost neglected. Results also confirm that the mean frequency value for the two distribution laws cases (Normal and Log-Normal) stay practically stable. So, we can conclude that the concrete weight arch dam object of the present study is safe for different values of E and ρ.

The main objective of this paper is to apply the correlations to evaluate the risk of soil swelling in the area of the north-west part of Algeria. On this basis, 84 soil samples were collected from laboratories in the region, plus a reading of the main publications on swelling soils in the area of the north-west part of Algeria, and then different types of regressions were applied to this data. The results show that the plasticity index has a high degree of influence on the swelling pressure; the swelling potential and the swelling coefficient compared to the clay content. New empirical relationships were found between the swelling pressure and swelling potential; these correlations are good concordances with the literature. Cubic; quadratic and multiple models of regression seem are in good concordances better adapted compared to simple linear regression models in the presented study.

In this investigation, the dynamics of soil-structure interaction (SSI) in frequency domain is investigated. The spectral element method is devoted to study free vibrations of Euler-Bernoulli beam resting on general elastic restraint at the ends and continuous springs against rotation and translation. Thus, partial differential equation of the motion is derived and upon solving the eigenvalue problem, natural frequencies are tabulated for the first three modes of vibration. Obtained results are regrouped in (1) the modal analysis of beams on elastic transversal or rotational rigidities of the continuum under foundation, (2) the influence of properties of elastic medium on the beam dynamic response (3), and the influence of non classical boundary conditions. In consequence, various results of above phenomena are described and commented.