| Part of the geogrid will be aging by ultraviolet radiation in the whole usage life cycle,the aging geogrid will have a series of property change,then it will affect service life.Therefore,it is of great significance to carry out the Photooxidation aging test of geogrid.By use of xenon lamp aging test box to complete thermal aging and photooxidation aging tests with different time,the aging resistance of geogrid was evaluated from the aspects of appearance change,weight change and tensile test results.Experimental results show that there is no obvious change in the appearance of geogrid after long time photooxidation aging,but there is aging layer.In the process of test,the geogrid has less mass loss and aging is not directly related to mass loss of geogrid.Photooxidation aging test was conducted under the condition of 70?,It found that the main factor causing the aging of the geogrid is light.The tensile strength and elongation at break of aged geogrid will decrease,the proportion of the decrease is proportional to the accumulated radiation energy.Therefore,the aging degree of geogrid can be predicted by theaccumulated radiation energy of the geogrid in the external environment.In order to evaluate the effect of photooxidation aging on the creep behavior of geogrid,creep tests were carried out on 0h,200 h,500h photooxidation aging geogrid.The conclusions are as follows:the longer the aging time of the geogrid,the larger the strain rate,more prone to fracture under the same load,.The results show that the greater the aging degree of geogrid,the worse the resistance to creep.The strain values of the geogrid with200 h photooxidation aging are similar to that of the original geogrid,and the strain value of the 500 h photooxidation aging geogrid at the same time is obviously larger than that of the original geogrid and 200 h photooxidation aging geogrid.the results show that the strain rate of the geogrid does not increase linearly with the increase of the aging time.Five kinds of functions are used to fit the strain-time curve,and the fitting results are discussed?Friction interface test was carried out by using the large direct shear test,exploring the effects of aging and creep on the geogrid-soil interface characteristics.Test show that creep has some influence on the geogrid-soil interface because of the change of geogrid mesh size and the thickness of rib after creep,but this kind of influence is not obvious and could not be considered in the project. |
PDF Full Text Request