其被笔者认为产生应力下降的原因可能为一定程度的偏心变形在土样加载到20

It is believed by the author that the reason for the stress drop may be that a certain degree of eccentric deformation occurs after the soil sample is loaded to 20% strain, resulting in a slight decrease in the axial stress, and the peak stress appears accordingly.

It is believed by the author that the cause of stress decrease may be a certain degree of eccentric deformation after the soil sample is loaded to 20% strain, resulting in a slight decrease in axial stress, peak stress accordingly appears.

It is considered that the cause of stress drop may be eccentric deformation to a certain extent, which occurs after the soil sample is loaded to 20% strain, which leads to the slight decrease of axial stress and the appearance of peak stress.