عنوان مقاله [English]
Negin Park area in the east of Tabriz has an area of about 110 hectares with topography of the hills and valleys. Therefore, during urbanization, the upper part of the hills is cut and is cast in valleys and low lands. Marl layers are also widely spread in this area. The development of fill soils and the presence of marl layers that have a low geotechnical strength and stability are the main challenges in implementing deep excavation projects for building construction in this area. Marl layers are seen in yellow, green and gray colors.
Investigating of the subject, by examining old aerial photographs and geological maps, as well as field studies and visits to deep excavation projects and collecting information on excavations in the region, properly paid. From 3 deep excavation projects has been visited and 25 boreholes information have been collected. The results of the studies are presented as a map of the development of fill and marl soils. About 28% of the area is covered by fill soils with a thickness of more than 2 meters and also about 35% with marly soils. The depth of groundwater in this area varies from 5 to 20 meters. In the dry marl layers, the strength and stability of to deep excavation walls are suitable, but the stability is strongly reduced of the saturation layers, soil nailing and anchors are difficult to use. Due to the type of underground layers, the depth of the groundwater and the depth of excavation, in this area are using various stabilization methods, such as the retaining walls, piles and anchors, soil nailing and anchors with shotcrete. The efficiency of nails and anchores is facing with problems due to creep phenomena.