Research On Prediction Of Settlement Of Reclaimed Soil Foundation

New reclaimed soil foundation has not yet completed the consolidation, with ahigh water content, high compressibility, high void ratio and other engineeringcharacteristics. The actual project, the theoretical formula for calculating thesettlement has great difference from the actual, which led to the repeated reclamationevents. Secondary reclamation often brings huge economic losses to the generalcontractor, and even become a "cost of the disaster." Therefore, settlement calculationof such projects is also increasing attention to the engineers. Finding a convenient andeffective method of settlement calculation has important significance on the prophaseprogramming and design of the actual project.Grey system theory view the foundation settlement as a gray system, withoutregard to the physical characteristics of the soil itself, based on existing monitoringdata will be able to analyze the development and changes in soft clay ground, if themethod can be used to predict observational settlement, which is an effective methodin actual project. In Tianjin, people have accumulated a lot of practical settlementmonitoring data of observational settlement for the past more than ten years, whichhas laid a solid foundation for the application of the use of gray theory.Combining with subsidence monitoring data of reclaimed soil foundationreinforcement engineering, the effect of monitoring sequence length and modelingsequence length on the final settlement and prediction accuracy that are predicted bytwo kinds of models is studied in this paper. We also respectively summarized theselection rules of modeling sequence when used the grey model GM(1,1) andVerhulst to predict the final settlement of foundation and comparative analysis wereused to the grey model GM(1,1) and Verhulst. The results showed that two kinds ofmodels are able to predict the final settlement of foundation and the error can becontrolled within1%.Also we can see the adaptability of gray model GM(1,1) isbetter. Grey system theory was applied to study and analyze the correlation degreeamong the total settlement, natural density, specific gravity, porosity, void ratio,saturation, liquid limit, plastic limit, plasticity index, liquid index, drainage board andreinforced depth so on. The variable number of GM(1,N) model was determined by the measured values and calculations value comparison. Statistical analysis showedthat the traditional vacuum preloading has the maximum value of19.9%and aminimum of1.03%, with an average of9.96%, a standard deviation of5.03%; verticalvacuum preloading has a maximum of14.77percent, the smallest is0.90%, with anaverage of6.56%, a standard deviation of3.47%. Finally, the author proposed thecalculation methods and formulas to determine the elevation of reclamation afterderivation formula, which provides evidence for the calculation of elevation inReclamation Project in coastal area of Tianjin.