Subsurface Zoning For Urban Development Under For Different Geological Conditions

Abstract:

The main criteria for assessment of urban territory for sustainability for underground construction occurred at a certain depth of continuous soil and rock strata of permanent thickness high bearing capacity. Distinguishing areas depending on the distribution, depth of occurrence and thickness of such rock strata is the first stage of territory zoning according to the geological conditions favorable for subsurface construction. The hydrogeological conditions, as well as the development of natural and techno natural hazards, are assessed at the next stage. In this paper, the method and technique of compiling the map of subsurface zoning according to the geological conditions is discussed for two cities with difference geological conditions: Moscow (Russia) and Tashkent (Uzbekistan). Vertical zoning of cities subsurface is controlled by three basic levels: up to a depth of 10 m, foundations of the most of the buildings are situated; up to a depth of 20 m, the highway tunnels are located, collectors of deep subsurface communication lines, and foundations of large multi-purpose complexes; up to a depth of 40 m, deep highway tunnels are located, and foundations of individual unique buildings. In Moscow, the mid- and upper Jurassic clay layer and the Carboniferous carbonate-terrigenous complex are the most continuously stretching stratigraphic and lithological rock strata of permanent thickness. The location of modern and buried ancient erosional channels is one of the chief factors controlling the geological conditions in Moscow. The degree of territory favorable for subsurface construction depends on the depth of the thickness of the Jurassic clay horizon. Tashkent city is located in a high seismic zone and therefore the geological conditions of underground space are defined first by the modern tectonic movements and secondly is defined by distribution of loess soils with up to the depth of 70 m. Hydrogeology is important factor for sustainability of constructions.