Experimental Study On Scaling Effect Of Creep Of Coarse Filler For Airport High Fill

With the continuous development of economy,China has implemented the strategy of great development to the west,and the mountainous southwest area has been developing unprecedentedly.The main characteristics of the construction of the airport in the southwest of China are the high fill,and the packing plays an important carrier role in the high fill project.The main characteristics are many types of rock,huge amount of filling,and some geological conditions are quite complex.Coarse grained soil,as the main filler for airport fill,is directly related to the deformation and stability of fill works.The filler used for filling is usually near the material,so the filler of the filling body often comes from the rock blasting in the field area,and then is used for filling and compaction.With the development of airport construction and filling technology,the maximum particle size of coarse grained material has reached0.4m,0.8m,1m or larger.On the one hand,the above described filler often has problems such as complex and poorly graded rock mass.On the other hand,it is also influenced by the construction level of the filling body.Therefore,uneven settlement often becomes an important problem faced by high fill works.For most of the laboratory equipment conditions(the diameter of the sample is generally in 30cm),the mechanical properties of the original filler can not be effectively studied.Therefore,it is necessary to scale the original packing to study the stability of the field coarse grained filling engineering,and it is particularly important for the deformation prediction of the ground settlement after completion.At present,there are many directions for the study of the scale effect of coarse grain,and there is no definite conclusion on how to simulate the actual gradation in the project through the experimental results of the laboratory scale.This paper studies and discusses the scaling effect of creep of coarse particle packing for airport high fill.Taking limestone as an experimental research object,the basic mechanical properties of limestone are studied by experiment,and three scales of packing gradation are carried out in Longdong burger airport in Guizhou.Three groups of similar gradations with different sizes are formed.The maximum dry density of three graded samples isdetermined by compaction test,and the scale effect is summarized.The relationship between the maximum dry density and the maximum dry density of the three specimens was tested by uniaxial lateral compression test.The three groups of creep test results are selected to describe the relationship between strain time and strain time,and the relationship between maximum particle size and creep deformation is summarized,which provides a speculate reference for the subsequent different grain size creep deformation.The breaking rate of coarse-grained soil in creep is calculated,and the change of the crushing rate in the creep test under different maximum particle sizes is compared.The influence of the maximum particle size in the similar gradation on the breakage is analyzed.The logarithmic form creep equation of the compacted soil under the similar gradation is fitted,and the relationship between the stress and strain of the compacted soil is characterized,and the analysis of the relationship between the stress and the strain of the compacted soil is analyzed.The variation of the creep and deformation parameters and the scale ratio is calculated.Through the Burger creep constitutive model,the relevant parameters in the constitutive model are calculated.Then the rationality and feasibility of the constitutive model are verified by numerical simulation,and the creep deformation mechanism of the specimen under the scale effect is explained from the micro angle.