Dynamic Elastic Modulus and Damping Ratio of Lignin-Modified Loess

To effectively improve the poor engineering properties of loess and enhance its seismic performance, the industrial by-product lignin is used as a modified material. Based on lots of dynamic triaxial tests, the dynamic elastic modulus and damping ratio of lignin-modified loess were tested. The effects of lignin content on the dynamic elastic modulus and damping ratio of lignin-modified loess were analyzed. Combined with scanning electron microscopy (SEM) and X-ray diffraction (XRD), the microscopic mechanism of lignin to improve the dynamic properties of loess was studied. The results show that lignin can effectively modify the dynamic deformation of loess under dynamic load. Under the same dynamic stress condition, the dynamic strain of lignin-modified loess is smaller than compacted loess. The dynamic elastic modulus of modified loess with different lignin content are quite different, but both decrease with the increase of dynamic strain. And the dynamic elastic modulus of modified loess is greater than compacted loess. The maximum dynamic elastic modulus of modified loess with a lignin content of 1% are significantly greater than others. Under the same dynamic strain condition, the damping ratio of lignin-modified loess is smaller than compacted loess. Lignin can effectively fill loess pores and cement loess particles. Compared with compacted loess, no new mineral components are generated in the lignin-modified loess. The optimum lignin content of dynamics characteristic of modified loess is present, and the optimum lignin content is 1%.