Abstract: In this paper, the application of laser particle size analyzer in the geotechnical grain size distribution analysis was evaluated by the repeatability tests and parallel comparative tests. The grain size distribution tests of 88 sets of quaternary marine and continental interactive sedimentary soil samples from Bohai region and Shanghai region were performed by using the traditional method and the laser particle size analyzer methods, respectively. The principle of the data interception is proposed, and the applicable range of grain size is determined in the application of laser particle size analyzer. The test results show that: 1. The average absolute value of the percentage difference of each group obtained by the two methods is less than 8%. the average absolute value of the maximum grade in the entire samples was 5.88%, which was 0.075~0.005 mm; The lowest average value was 0.19%, which was 0.50~0.25 mm grading group. 2. The comparative study shows that the deviation of the results obtained by the two methods is within the acceptable range. The laser particle sizer method has good repeatability, wide grain size measurement range and high accuracy. The laser particle sizer method can be used replacing the traditional method in the geotechnical grain size distribution analysis. 3. The grain size distribution test of laser particle size analyzer determined by the laser particle size analyzer model and test method. Winner 2009 laser particle size analyzer could be measured range: in wet method, it was 0.00001~2 mm, in dry method, it was 0.00001~2 mm, and the traditional method in theory has no minimum measured particle size.

Key words: particle size distribution analysis, laser particle size analyzer, traditional method, comparative analysis