Super Soft And Deep Foundation Settlement Prediction Research

Freeway, which is famous for its low-loss of cargo, low traffic cost,capacity of thoroughfare and safety for driving, becomes a primary objectof highway development all over the world. Along with the high-speeddevelopment of economy in China, there will be more large-scale civilengineering appearing in the high earth filling and soft ground area. Theconditions of the high filling soil and soft ground will bring many problemsto the senior highway road bed, the design of embankment, the constructionand the normal use after the completion. Under construction, for example,the overestimate or underestimate of foundation settlement of soft groundor overlook of the factors of underground water or rainfall will lead tomishandling of subgrade construction. Lack of supervision duringconstruction will cause foundation slide due to the foundation damage andalong with severe and uneven ground settlement which cause theunevenness of the road surface. The prediction of subgrade settlement andcertainty of guidepost of stability of settlement are the crucial content ofinformation construction of subgrade. Therefore, there should be a higherstandard as to the post-construction settlement and differential settlement.This thesis will take the west trunk road in Dongguan as researchbackground and do a systematic research on the detection of sedimentationin cross section. Many statistics has been obtained while lots and sequentialobservation conducted during the filling of embankment. Through the dataanalysis combined with calculation, it comes to my thesis:(1) it gives a general research on the status quo, development andsettlement mechanism of the soft ground subgrade and sums up the factorsthat affect the soft ground subgrade settlement.(2) Through sorting and analyzing data, it can guide the constructionorganization on the control of earth filled speed in order to guarantee thenormal construction; scientific judgement of subgrade stability will ensurethe construction safety and stability, and provide statistic support for thesoft ground management.(3) Based on the settlement of field measurement, it builds up greyGM(1,1) model to predict the final settlement of soft foundation andexamine it with posterior-variance-test. It will seek a prediction model fitfor research of characteristics of soft ground with improved grey predictionof3ways combined with minimum mean-square error’s model theorymethod and through the contrast between traditional index method and hyperbola method.(4) Use Mohr-Coulomb model and FLAC software to have a numericalsimulation on the preloading on soft foundation from an observation pointand compare the simulation statistic with settlement supervison statistic. Itindicates that software simulation results tally with the field test monitoringstatistic which proves the model calculation’s accuracy and practicality.