Research On Characteristics Of Deformation And Strength Of Fill Mixture Material And Its Application

Soil and rock mixture is good filling material with exellent poreties.Especially in west China,it has a promising prospect for wide used in railway,airport,dam construction projectsBased on some high fill project in southern Gansu province,using unsaturated soil mechanics and modified unsaturated triaxial testing system,this article is study thoroughly the mixture filling material consist of silty clay and sandy mudstone by certain mixing ratio from abovementioned project.54 sets of unsaturated CD tests has been conducted.Then by limit finiate software,choosing a filling slope from southern Gansu,ite model is established.Through analysis and calculation,the safety factors under under different mixing ratios and matric suction have been compared.The main work and accomplishment is listed following.(1)The filling materal's deviators stress peak value increasees with content of silty clay increasing.This trend is more obvious under high neat confining pressrue and high matric suction.Internal friction angle has few changes over the different suction,but it increases over the increasing content of silty clay and its variation range is from 25?-30?.b? increases with the increasing content of silty clay.For the sample with the same mixing ratio,',',bc ? ? of samples with compactness of 0.93 is all greater than the parameters of samples with the compactness of 0.88.Conhesion value increases with increasing suction and their relation appears linear.Also the shear strength fomula that considering the effect of suction is provided and it can predict shear strength under different suction at certain arrange.(2)The stress-strain relation curve can comply with the hyperbolas hypothesis of Duncan-Chang model and its deviators stress peak value increases with neat confining pressure increasing.When the compactness is 0.93,parameter n increases with silty clay content increasing and its increasing scope reaches maximum at low suction(s=50kPa).When the compactness is 0.88,parameter n increases with suction and silty clay content increasing.It reaches the maximum when the suction is 50 kPa and the silty clay content is 30%.Under both two compactness,parameter k decreases with the mixing ratio increasing.Volume buil modulus increases with silty clay content increasing,especially when the matric suction is high(s=100kPa,s=200kPa),the changing trend is more obvious.And under low suction level,B changes little.The relation of model parameters and matric suction is fitted and its curve is provided which can be used to predict model parameters within some range.(3)Slope safety factor increases with matric suction increasing.It also increases with the silty clay content increasing.