THE METHOD FOR ANALYSIS SOIL SURFACE ROUGHNESS IN THE PINT-SIZED SOIL BIN Xiao Dong Zhang , Jian Qiao Li, Meng Zou, Rui Yang Shi, Yang Wang Abstract Surveying and analyzing the soil surface roughness in the pint-sized soil bin has a practical significance for researching vibration and ride comfort of vehicle models and studying walking mechanisms. For the purposes of studying methods of analyzing the soil surface roughness in the pintsized soil bin and distinguishing from the routine analysis procedure of the soil surface roughness, in this paper, a distance laser sensor (DLS-C15, DIMETIX, Switzerland) was used to measuring the morphology of digital surfaces of six particle sizes of quartz sand (1-2mm, 2-4mm, 4-6mm,6-8mm, 8-16mm, 16-32mm) paved in the pint sized soil bin flatly. The measured data was preprocessed through zero mean normalization and removing trends method. Then, average root mean square height, the peak estimate of space discrete power spectral density (PSD), mean square estimate and its effective value were analyzed. The statistical re-sults show that soil surface roughness has a good correlation with the average quartz particle size. The presented work indicates that the developed method could be used to analyze the soil surface roughness in the pint-sized soil bin quantitatively.