Study On Wetting Deformation Characteristics Of Subgrade Filled With Weathered Phyllite

The eastern An-kang section of the highway from Shi-yan to Tian-shui passes throughdozens of miles where distributing weathered phyllite. Weathered phyllite is belonged to softrock with poor engineering property. Its strength attenuations seriously and produces wettingdeformation when mixing with water, which effects the stability of the subgrade filled withweathered phyllite badly. This article has a study on wetting deformation of the subgradefilled with weathered phyllite, based on laboratory test, field test and finite element method,etl. This article obtains the following research results:(1) The results of grinding slice of electron microscopy test and x-ray diffraction testconfirm that the soft rock in33th contract section is weathered phyllite. Saturatedcompressive strength of weathered phyllite is below5MPa, which can determines thatweathered phyllite is soft rock with poor engineering property. The results of mineralcomposition, disintegrating resistance test and water stability test all show that engineeringproperties and water stability of the weathered phyllite filling material is poor.(2) Subgrade filled with weathered phyllite belongs to subgrade filled with earth-rockmixtures, But the compaction characteristics of weathered phyllite is more complicated thanthat of the common earth-rock mixtures, which relatives to the content of stone andweathering degree of phyllite. The content of stone after hit-solid determines the peak valueof maximum dry density and the change of optimum water content. The content of stone afterhit-solid correspond the peak value of maximum dry density of weathered phyllite at differentweathering degree is about56%.(3) We build field test road and have wetting deformation test, analyze the affect of theamount of water immersion, soaking time and cement improvement to wetting deformationof subgrade filled with weathered phyllite, and reveal the characteristics of wettingdeformation and modulus of resilience attenuation of subgrade filled with weathered phyllite.Analyze the water content change characteristics of in subgrade by monitoring data.(4) We simulate the affect of groundwater and surface water, have a subgrade model testin testing groove, and analyze the change process of modulus of resilience. Based on theinfluencing factors of wetting deformation, analyze mechanism of the wetting deformation in subgrade. And propose the methods of controlling wetting deformation.(5) The article forecasts the consolidation settlement deformation in subgrade filled withweathered phyllite by finite element method, and establishes forecasting model based on thefield wetting deformation test. On the basis, considerring the most unfavorable factors,forecast the plastic deformation of the subgrade filled with weathered phyllite.