中文摘要：

泥石流物源、流体和堆积物的颗粒分布满足P（D）=CD^-μexp（-D/Dc）,其中参数C,μ和Dc由传统的粒径分布特征决定。μ随细颗粒（特别是粘粒）含量的增大而增大,Dc刻画粒径的范围,且随粗粒含量而增大。蒋家沟泥石流的观测表明,同一场泥石流包含着数十到数百个不同性质、流态和规模的阵流。阵流的涨落和多样性是与流体的颗粒组成密切相关的。一定的颗粒组成对应着一定的饱和颗粒浓度,决定一定的饱和流体状态。阵流的涨落,是在没有达到饱和状态时的随机运动的状态。阵流涨落随Dc增大而趋于平缓;当流体达到饱和态时,阵流达到最大的流深、流速和流量,且与颗分参数（μ,Dc）具有幂函数关系。运用本文的方法,可根据颗分参数来预估泥石流的性质和规模。

英文摘要：

Debris flow body is composed of a wide range of grains and Its grain size distribution（ GSD） is found to satisfy a general expression,P（ D） = CD^-μexp（- D / Dc）. The grain composition can be described by the GSD parameters（ μ,Dc）,with μ representing fine content and Dcdefining a characteristic scale of grain aggregate. It is found that the fluid has a coupled（ μ,Dc） which is distinct from the source materials and deposits. Observations on debris flows in the Jiangjia Gully（ JJG） have revealed great fluctuations; we fourd that the fluctuations are controlled by thair grain composition,and they will approach some steady state when granular concentration were saturated,and then both the flow depth and velocity gained a power-law relationship regardiy μ and Dc. From the method introduced here it is possible to use the GSD parameters of the sedimentary materials to estimate the probably maximal discharge and velocity of a debris flow.