激光衍射法与比重计沉降法所测粒度参数的对比研究——以海滩泥沙为例

Comparison of the grain size measured by the laser diffract instrument with that by the hydrometer——a case study of beach silts

用比重计沉降法和激光衍射法这两种方法 ,在相同条件下 ,对 6 5个海滩泥沙样品分别进行了粒度分析。结果表明 ,激光衍射法的测试结果相对偏粗 ,二者的差异主要反映在 >9中和 <4这两个粒级范围内 ,上述差异对平均粒径、中值粒径、标准偏差、尖度、偏度等 5个常用粒度参数的影响程度是不同的 ,经过线性相关性分析发现 ,二者的平均粒径和中值粒径的相关系数R较高 ,分别为 0 986 4 ,0 976 3,F显著性检验和分析表明 ,其回归方程是有意义的 ,可作为换算公式使用 。

Grain size is an important index in many fields,particularly in sedimentology.Hydrometer-size-measuring is one of important traditional methods.A lot of grain-size data are the results of hydrometer-size-measuring.However,with the development of laser technology,more and more grain-size data are from laser diffract instrument.In order to use the both series of data correctly,it is very significant to construct the transfer relation between them. In order to construct the transfer relation of these two series of data,sixty-five sediment samples of beach silts were measured by the laser instrument and by the hydrometer under the same condition.The results show that the phi-value of grain-size measured by the laser instrument is smaller than that by the hydrometer.The main difference between them is in two size fractions:greater than 9 and less than 4.There is obvious relativity between them,and the correlation coefficients of average grain size between them is 0.9864,and that of median grain size is 0.9763.We find the conversion formula as follows(phi): Average size(the hydrometer)=0.9235×Average size(the laser instrument)+0.8531 Median size(the hydrometer)=1.0016×Median size(the laser instrument)+0.3156