Study On Rheological Property Of Silt Clay And Its Application

With the further acceleration of China’s urbanization, undergroundspace development receive more attention in the urban construction,especially in coastal areas, which leads the number of geotechnicalengineering and related projects into a gradually increasing state. Thesoft soil is widely spread in China’s coastal areas. Proved byengineering practices and researches, the rheological properties of softsoil will have a significant impact on geotechnical engineering, notonly brings technical problems, but also the stability and safety of theunderground structures will take some risks caused by the creepdeformation. Therefore, studies of the rheological properties of soft soiland its impact on engineering construction have important theoreticaland practical significance.Based on the foundation pit engineering of the South East OuterRing Road Station in Ningbo Rail Transit Line1, through experiments,theoretical analysis and numerical simulation, the rheologicalproperties of the silt clay and its impact on pit engineering constructionwere systematically studied in this paper. The main contents of thisresearch are as follows:(1) Drainage consolidation creep tests of soft soil at different depths have been undertaken by the triaxial rheology testing. In orderto get the stress-strain-time relationship of soft soil, creep deformationof soft soil under different stress levels is analyzed through steploading in tests.(2) Aiming to build the stress-strain-time relationship of soft soil inNingbo area, this paper compares experimental and theoretical results.The based theoretical results are based on the well-knownSingh-Mitchell model and the Mesri model. The comparison showsthat the stress-strain relation accords with hyperbolic model, and thestrain-time relation can be modeled with power function. Finally, therheological constitutive model of Ningbo area is put forward.(3) The transient finite element model is generated according to thefoundation pit engineering of the South East Outer Ring Road Stationin Ningbo Rail Transit. Based on the rheological constitutive model,the simulated results of foundation pit engineering is analysed fromdisplacement timeliness. The feasibility of displacement agingcoefficient is proved by contrast the simulated result with the on-sitemonitoring data, and the method is valuable reference for similarengineering in soft soil area.