Research On Engineering Geological Environment And Its Amenities In Northern Liaodong Bay

Modern sedimentation in northern Liaodong Bay is mainly controlled by development process in Liaohe River Delta, distribution and characteristics of superficial strata of which change dramatically with the variety of sedimentary environments. Recent investigation data show that the topsoil in tidal ditches and offshore areas is made up of muck and mucky soil of liquid to liquid-plastic state. Tidal flat sediments are silt, silty sand and sandy silt covering the mucky soil in offshore areas. Strength of the recently deposited sediments is lower than that of the Gaizhou Tidal Flat sediments winnowed by the wave and tidal action.On the statistical and analytical bases of composition and engineering characteristics of the sediments in the four sedimentary units, ie., the recently deposited tidal flat, the Gaizhou Tidal Flat, offshore areas and tidal ditches, it is concluded that size distribution is one of the primary factors controlling the physical and mechanical properties of the sediments, and that sedimentary environment determines size distribution and hence controls engineering characteristics of soil.Major hazardous geological factors in the study area include buried tidal ditches, gas bodies in shallow layers, fast change in eroding and silting of tidal ditches, eroding of mucky soil in superficial layers and structures under the action of waves and tides, silt liquefaction due to vibration of building structures under cyclic loads, etc.In the light of adaptability of movable platforms, stratum structural characteristics and sedimentary characteristics, the thesis divides the study area into four subzones as follows: engineering geological subzone of the recently deposited tidal flat, engineering geological subzone of the Gaizhou Tidal Flat, engineering geological subzone of offshore areas, and engineering geological subzone of tidalditches; and amenity of ocean engineering is discussed in each subzone.