Study On Fatigue Characteristics And Damage Behavior Of Cemented-stabilized Soil Under Cyclic Loading

Fatigue damage has been perplexing the projects fields all the time, for example such numerous projects fields as spaceflight aeronautical engineering, civil engineering, mechanical engineering, etc. All win puzzlement from fatigue problem deeply. It makes the railway bridge lose efficiency to fatigue damage, the existence of the fatigue crack makes the marine oil drilling platform collapse and topple, fatigue damage shape make railway, expressway even non-uniform settlement, leave stability of the roadbed the unsafe hidden danger. So, numerous scholars are devoted to the research of the fatigue problem, get various evaluations out of fatigue damage and predict the method of fatigue damage development.This text monitors the course of fatigue damage online by the way of system analysis the cemented-stabilized soil, It is unanimous basically that the material that the parameter A value of damaging received reacts in the course of fatigue damage the situation and fatigue result of the test, it can describe cemented-stabilized soil and fatigue instantaneous damage course basically. The result of the test has shown the cemented-stabilized soil has bilinear damage accumulation law. Under cyclic load, the cemented-stabilized soil receives the irreversible development of shape in the axial and can be divided into following three stages: namely fatigue crackle stage, crackle slow growth stage and it feeds through to be out of shape to accelerate stage fast. Cemented-stabilized soil fatigue mechanism that destroy can sum up under circulation load cemented-stabilized soil that function cause little production and expansion of crack cause the cemented-stabilized soil to destroy; In the energy view, forming, development and course of destroying of the structure within the cemented-stabilized soil material, it is the transformation course of the energy.Under the cyclic load, that the cement-stabilized soil results in destroying because damage progression fatigue to certain extent, under the stress level lower than the peak value stress, shown as the low stress destruction characteristics, cement-stabilized soil fatigue life is dispersed and relatively great. According to the result of the test, provide the fatigue destruction criterion (S-N curve) of the cement -stabilized soil stress space, have proposed the three parameters exponential function model S=a+bNc and multinomial model S=a+bN+cN2 two kinds of fatigue life models. There are many factors influencing cement-stabilized soil fatigue life, the analysis results show: The higher cyclic load of the stress level, the shorter the fatigue life of the cement-stabilized soil is, longer on the contrary; Cement-stabilized soil time longer, cement ratio greater, and the fatigue life of the cement-stabilized soil will be longer.With increasing of the circulation times, the fatigue damage within the cement-stabilized soil is being accumulated constantly, ultrasonic wave speed reducing thereupon too, combining theory of the damage mechanics, using the damage variable that ultrasonic wave defines rapidly, it is identical that simple damage evolves the law and result of the test, which is used conveniently in the project. The ultrasonic wave of cement-stabilized soil without load is similar to the shape of the spindle, with the increase of the times of fatigue circulation, the ultrasonic wave form become anomaly and the wave form correlation coefficient changes the obvious stage, the variation tendency figure of the wave form correlation coefficient has reflected basically the fatigue damage process of cement-stabilized soil, which is important to predict the fatigue residual life of the cement-stabilized soil. With constant abundant and perfection of the acoustics parameter of cement-stabilized soil, using non-destructive detection to evaluate fatigue damage characteristics of cement-stabilized soil is more hopeful.