Discussion On Subarea And Statistical Characteristics Of Parameters Of Soft Soil In China

Although there are abundant research achievements on soft soil,with the rapid development of infrastructure construction in China,many projects still involve soft soil.Due to the poor engineering nature of the soft soil and the limited number of boreholes,it is impossible to carry out a thorough survey of each site,and the nature of its exposure may not be representative.It is hoped that through the statistical analysis of soft soil parameters,an evaluation of site parameters can be obtained,and the soft soil parameters can be obtained more accurately.Based on the characteristics of soft soil,on the basis of definition and determination conditions by cnki,vip,such as literature search website to find,a total of associated with soft soil parameters collected nearly all theses papers and journal articles,and combining the fit-out project survey data collected by the books and soft soil mechanics,established the database,using the methods of probability theory,mathematical statistics,regression analysis,grey relational degree and so on,soft soil area in China regular physical and mechanical indexes are studied.The main conclusions are as follows:(1)The zoning principle of soft soil is given.According to the soft soil genesis,regional characteristics and engineering properties,combined with the current research results,think first follow the specifications first partition(Ⅰarea,Ⅱarea,Ⅲarea),on the basis of considering the formation for soft soil is refined.(2)To our countryⅠarea(littoral facies,lacustrine and swamp facies,reclaimed soil,river facies)Ⅱarea(littoral facies,lacustrine facies,delta facies),Ⅲarea(littoral facies,lacustrine facies,delta facies)made evaluation of soft soil variability.Ⅰzone of littoral facies,hunan,reclaimed soil variability similar soft soil,river and marsh phase variation is similar.The variation of fluid-forming soft soils in river facies and marsh facies is higher than that in coastal facies,lacustrine facies and blown fill soils.Ⅱzone coastal variability and lake facies,delta facies high variability is lake littoral facies.Ⅲvariability area of lacustrine delta and littoral facies relatively high.Mechanical parameters,the physical parameter variability overallⅢarea variability thanⅡarea andⅠarea.(3)EstablishedⅠarea,Ⅱarea,Ⅲarea main causes of soft soil parameters range value,mean,standard deviation and standard indexes of upper and lower,gotⅠarea,Ⅱarea,Ⅲarea main cause of soft soil in the probability distribution of skewness,kurtosis,variance and confidence intervals on behalf of the characteristic value and probability distribution form.The soft soil of different origin in each partition mainly obeys lognormal distribution,normal distribution and Laplace distribution.(4)Based on the basic physical meaning and theoretical relation of soil parameters,the correlation analysis of soil physical and mechanical parameters is discussed considering the complexity of geotechnical engineering.The analysis of correlation degree shows that the results of calculation and analysis of correlation degree among physical and mechanical parameters can provide a method for single factor or multi-factor regression analysis among physical and mechanical parameters.(5)Ⅰarea,Ⅱarea,Ⅲarea main causes of soft soil physical indicators,I_Land w,e and w,e andρ,e andρ_d,I_P andρ,I_P and w has carried on the regression analysis,obtained a better fitting relationship between indicators.The linear and nonlinear fitting of a,E_S and w,e,ρwas carried out,and the optimal fitting equation was obtained.There is a good multi-factor fitting relationship between a and w,ρ,e and I_L.As the model factors w,ρ,e and I_L gradually increase,their correlation coefficients will increase.Shear index and physical index single factor fitting relationship is poor,φ_q、c_qand w、ρ、I_L multi-factor fitting effect is better.