Geography

Permanent URI for this collection

https://dspace.ysu.am/handle/123456789/29
Geography

Browse

Recent Submissions

Now showing 1 - 2 of 2
  • Item
    Methods for determining shear resistance by a system of cracks and old slip surfaces with the purpose to evaluate the stability of landslides
    (IOP Publishing Ltd., 2022) S G Hayroyan ; H S Hayroyan
    On slopes, landslide displacements mainly occur along bedding boundaries, lithogenetic and tectonic fractures, as well as along existing ancient slip surfaces, which are the weak zones and potential slip surfaces for new landslides. According to experimental studies to determine the shear resistance by the standard and double cut test methods: a) without wetting the sliding surface, and b) by the wetting the sliding surface, we can conclude: when double- cutting the clay soils of a solid, semi-solid and tightplastic consistency, the cohesion is mainly reduced, but the internal friction factor is slightly changed. Double-cut tests of soft-plastic and flow-plastic clay soils have shown the cohesion and the internal friction factors are being changed insignificantly. At the same time, taking into account the fact that under the condition τ > σ tan ϕ the soft-plastic and flowing-plastic clay soils undergo viscous-plastic deformations, we come to the following conclusion. When developing the anti-landslide measures, independent of the consistency of the soils forming the slope, the τf = σ tan ϕ component should be taken as the slip resistance index in the formula for calculating the slip resistance taking into account the condition Cc + Σw = 0.
  • Item
    Heatwaves in Southern Armenia in the context of climate change
    (Elsevier, 2022) Tatevik Safarya ; Hrachuhi Galstya ; Babak Shiri
    The quantitative and qualitative evaluations of long-term trends and spatial distribution of heatwaves (HW) are carried out in Southern Armenia (Syunik province). For this purpose, the daily average maximum air temperature data (Tmax) from four meteorological stations (Sisian, Goris, Kapan, and Meghri) are studied for the 1936–2019 period. The HW catchment algorithm and a new concept of HW (which is called potential HWs [PHWs]) are developed. The presence of trends and their significance for different HW measures are assessed utilizing linear and exponential trends, Sen's slope, and Mann– Kendall (MK) trend test. The results show that HWs become increasingly frequent and intense. Moreover, they have extended duration, as they emerge earlier and fade later in Syunik province. Significant variation trends of HW are observed (e.g., the frequency of HWs increased up to five times), especially after the 1990s in southern and central parts of the province. Contrary to this, relatively weaker or no trends occurred in the northern parts. Our methodological approach successfully determines the HW measures' trends in the province based on the relief features and altitude differences. The outcomes highlight their notable impact on the progression of HW. Overall, this study provides significant insights into understanding HW's variations and their transformation in the mountainous areas.