成昆铁路北段堆积物粒度参数的应用

APPLICATION OF SIZE PARAMETER OF DEPOSITS AT THE NORTHERN SECTION OF CHENGDU-KUNMING RAILWAY

在成昆铁路北段,取样73个,获粒度参数数据355个。选择其中66个样品,对三类堆积物的粒度用矩值法经微型计算机加以处理,平均后得四个粒度参数,即:粒经平均值(?),标准差σ,偏度S_K和峰态K。此外,还点绘出六种粒度参数散点图。以实地考察为基础,某些粒度参数及其散点图就可作为划分泥右流堆积物类型的指标或判据,并能用来确定沉积环境的若干特点。

355 size parameter data were obtained by processing σsize analysis data of samples of deposits with the statistics method and 6 dispersive point diagrams of size parameter were drawn. At the nothern section of Chengdu-Kunming Railway, samples are mainly debris flow de-posits,and secondly the earth body of debris flow in formation area and the river deposits. The size parameters are as follows: size mean value X, standard deviation(error)666, skewness SK and kurtosis K.Size parameter and dispersive point diagrams give a reference for debris flow classification, as well as present the transport form of debris flow and deposit environmental characteristics.The big or small samples of debris flow deposits X values are-2. 94(?) and-3. 57(?) ((?) = -1b d, d is grain size,mm). It may be seen that the grains of debris flow are coarse, the transport capacity is great.σ of viscous and nonviscous debris flow deposits have great differences. The former is 4. 27(?),the latter is 3. 13(?).The samples of debris flow deposits are basically positive skewness,so SK>0.K value of the nonviscous debris flow deposit is 4. 78(?),the distributed curve is narrow and sharp; K value of the viscous debris flow deposit is 3. 34(?), the curve is wide and plane.On the basis of the field investigation,X-σ,SK-σ,K-σ three dispersive point diagrams may classify out the varied debris flow deposits. But the diagrams of X-SK,X-K and SK-K can not do so.