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Tailings dam disasters are reported almost every year and are triggered by mechanisms, such as overtopping, piping, and others.The failures due to inadequate management cannot be neglected as well. These dams are constructed mostly in a step-by-step constructionmethod that leads to a continuously changing state of vertical loads during construction and may lead to particle breakage and changes instrength. Therefore, a layer of tailings dam today may not be the same tomorrow during the construction phase. To study the effects ofdifferent loads on particle breakage and strength, direct shear tests were performed on remolded tailings samples that were separated intodifferent particle sizes. The tests were performed using different normal stresses that ranged from 50 to 500 kPa. The results indicate that finertailings exhibited slightly more shear resistance than that of coarser tailings irrespective of the deposition method. For normally depositedspecimen, the dilatant and contractant behavior in vertical height was observed when the normal effective stress was less than 300 kPa andgreater than 300 kPa, respectively. Under the vertical deposition method, the finer tailings showed contractant height behavior when subjectedto a normal effective stress of 300 kPa. The friction angle and the cohesion of vertically deposited specimens were slightly higher and slightlylower, respectively, than that of normally deposited ones. The breakage of tailings particles was observed to be proportional to the particle sizeof the tailings. Validerad;2021;Nivå 2;2021-01-01 (johcin)

Iraq is experiencing water-resource shortages which are expected to become more severe in the future. It is believed that rainwater harvesting will be one of the solutions to overcome this problem. In this paper, rainwater harvest modeling techniques were applied to the Sinjar area of northwest Iraq for agricultural purposes. A watershed modeling system (WMS) and linear programming (LP) optimization techniques were applied to maximize the irrigated area, which could be supplied by each selected reservoir for the period 1990–2009. This technique proved to be efficient for solving large-scale water supply problems with multiple parameters and constraints, including the required input data for the model. Two scenarios of operation were considered for each main basin. In the first, each reservoir was operated as a separate unit while, in the second, all reservoirs within the basin were operated as one system. Both scenarios gave encouraging results but Scenario 2 provided better results.

Laboratory freezing tests were performed on laterally confined samples of lightly overconsolidated fine-grained soil exposed to one-dimensional freezing at a constant temperature gradient. Pore-wat...