Study On Resilient Modulus Attenuation Characteristics Of Weathered Phyllite Subgrade Filling

Phyllite belongs to soft rock category,with strong water sensitivity,used as roadbed filling,must consider the adverse effects of water change,roadbed internal moisture content will not only lead phyllite stuffing to particle breakage,but also change the mechanical properties of the roadbed.In view of this,in this paper,analyzes the influence of water content and the content of coarse particles on the subgrade resilient modulus,through the laboratory test and numerical simulation method analysis the attenuation of subgrade resilient modulus,and the attenuation cause pavement structure mechanics character change,the main results are as follows:Through the screening test,analysis of the particle size of phyllite under natural state conditions,the results showed that the natural state phyllite is mostly poor gradation of grain.Through the compaction test,obtain the maximum dry density and the best water content of different grading types of phyllite filler;By the water immersion test and the dry wet cycle test,find in a relatively short period of time or fewer times of above test that phyllite filler disintegrate effects are not very obvious.In this paper,the test model of the subgrade modulus is developed,and the modulus of resilience of the filler with different coarse particle content and moisture content is tested.The test results show that with the increase of the water content,the modulus of resilience of different stone filling rate showed decrease all the way,and finally tends to be stable trend;with the content of coarse particles increases,the resilient modulus of weathered phyllite filler also decreased like above.When the rate of stone about 35%~45%,the modulus of resilience is more stable,can reach 47 MPa value with reasonable water content.By simulated groundwater migration analyze the effects on phyllite filling,the moisture migration experiment of the stone rate 35%,55%,75% and fine grain soil specimen have been carried out,all the way the water migration,monitoring the springback deformation in the setting time,explore the effect of moisture migration about phyllite filling resilient modulus.Results show that: between water migration 5~10 days,the resilient modulus attenuation most,with the consolidation and settlement of water migration under filler,the resilient modulus value will increase slightly.In 25 days beginning to stabilize,after water supplement,the modulus attenuation coefficient of up to 70% above,and with the increase of the content of coarse particles,modulus of resilience the attenuation coefficient decreases,but the attenuation coefficient is about 50%.The numerical simulation method is used to analysis under the condition that subgrade resilient modulus attenuation the pavement structure mechanical properties.The results show that: with the increase of resilient modulus attenuation amplitude of subgrade,road surface subsidence increase regularly,the stress state of pavement structure layer is changing,especially in the grass-roots force is the most significant.The fatigue life of pavement structure is calculated on the basis of the basic force,and the fatigue life of the base layer decreases exponentially with the increase of axial load.