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| Experimental study on dynamic strength properties of compacted loess under wetting-drying cycles |
| WANG Tiehang1，HAO Yanzhou1，WANG Zhao1，CHENG Lei2，LI Jiangle1 |
(1. College of Civil Engineering，Xi¢an University of Architecture and Technology，Xi¢an，Shaanxi 710055，China；2. College of Engineering Management and Real Estate，Henan University of Economics and Law，Zhengzhou，Henan 450046，China)
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Abstract In order to understand the dynamic strength change law of compacted loess caused by wetting-drying cycles，a series of wetting-drying cycles tests，soil dynamic triaxial tests and scanning electron microscope tests were carried out under different wetting-drying cycle paths，and the dynamic strength and microstructure images of compacted loess were obtained. The results indicate that the dynamic strength and dynamic strength index of compacted loess decrease first and then increase with increasing the number of wetting-drying cycles，and that the turning points of the ，cd-n and curves are obviously different due to the influence of the wetting-drying amplitude. The degradation degree of the dynamic strength increases first and then decreases with increasing the number of wetting-drying cycles，and even has a negative value. The critical wetting-drying cycles number nc is the limit of the whole structure damage and the whole structure strengthening of compacted loess，and changes with the wetting-drying amplitude. The macro and micro structure characteristics of samples in the process of wetting-drying cycles indicate that the increasing number of pores in the humidifying process and the cracks on the surface and in the inside of samples during dehumidification lead to the structural damage and strength reduction of compacted loess. The main reasons for structure strengthening and strength increasing are that soil particle structure develops to mosaic structure，pore structure develops to uniform small pore and matrix suction makes soil sample tend to be dense.
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2020, Vol. 39 
