| In the seasonal frozen region, because of bad weather, the maximum freezingdepth of road sub-grade can reach one point five to two meters below pavement.Theroad embankment deformation under the function of temperature under and causedroad diseases, such as frost heave and Frothing.The roadbed material propertiesdrastic change in the role of the freeze-thaw cycle, seriously affecting road bearingcapacity, thus seriously affect the way of life and quality. In this paper, according tothe characteristics of the disease in Seasonal Frost Area, to carry out the followingwork:（1）Refer to a large number of relevant literature, provides an overview onSituation and Measures of disease management of seasonally frozen roads. Beendescribed in detail for the fly ash improved soil used in seasonally frozen regionalroad. Describes the main physical mechanical properties and applications in highwayengineering of the fly ash. In recent years. Fly ash has been a lot of applications inseasonally frozen regional road damage prevention. And achieved good results for theseasonal frozen area road diseases.（2）Explains the basic theory of unsaturated soil penetration, penetration testprinciple, the permeability coefficient of the test method and the processing andanalysis on the final experimental data. Permeability coefficient of specimen increaseswith the increase in the number of freeze-thaw cycles. Also found that the structuralintegrity of the specimen has not been thawed, no obvious cracks on the surface. Afterfreeze-thaw of specimens, tiny cracks can be found after careful observation. Showedthat compared to the specimen has not been freeze-thaw. The soil on the surface of thespecimen after freeze-thaw is more prone to damage in penetrant test. The soildestructed is mainly characterized by flake, fly ash soil after freeze-thaw cycles, themicro-cracks in the fly ash soil specimen increases, as well as the permeabilitycoefficient.（3）Introduced the dynamic characteristics parameters of the roadbed under thedynamic load. Obtains the dynamic characteristics of fly ash soil under different freeze-thaw cycle times by dynamic triaxial test. Freeze-thaw cycles can decrease thedynamic strength of fly ash soil. It can be seen that the dynamic strength of fly ashsoil after three to five freeze-thaw cycles is more stable as well as the frost resistanceand durability. When the confining pressure is300kpa, dynamic strength of fly ashsoil is better than the other two cases, stability is the best at this time. Dynamicmodulus of fly ash soil decreases after one freeze-thaw cycle begins to increase afterthe second freeze-thaw cycle, and then decreases. After three to eight timesfreeze-thaw cycle, the change of dynamic modulus with strain is stable.（4）Introduced the basic theory of damage mechanics, including the definitionof the damage variable, the research process of damage mechanics. Derived thedamage function model of permeability coefficient and dynamic strength and dynamicmodulus of the fly ash soil. Considering the influences of freeze-thaw cycles on it.while referring to the dynamic strength and dynamic modulus of fly ash withattenuation model of freeze-thaw cycles established in references[56].Set up thedamage model of the dynamic strength and dynamic modulus of fly ash soil under theinfluence of the freeze-thaw cycle and the coefficient of permeability. And takeadvantage of previous test data to correct damage function model, correction resultsand the actual test data curve are in good agreement. Directly tested DynamicStrength and Dynamic modulus of Seasonal Frost Area is relatively trouble, so that wecan test the permeability coefficient to calculate its dynamic strength and dynamicmodulus. Provide a reference for the design of the road and disease prevention andtreatment in seasonally frozen ground region. |
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