泥石流的宏观沉积构造与形成机理

根据云南东川、甘肃武都、辽宁阜新现代和古代泥石流沉积概括出３类不同泥石流，即稀性泥石流、过渡型泥石流和粘笥泥石流的宏观沉积构造特征。在云南东川和甘肃武都进行现代泥石流暴发和堆积过程实地观测的基础上，对上述３类泥石流沉积构造的形成机理了探讨。初步建立用宏观构造现象组合识别石流类型的模式。

SEDIMENTARY MACROSTRUCTURES OF DEBRIS FLOWS AND THEIR FORMATION MECHANISM

The discussion of sedimentary macrostructures of debris flows and their formation mechanism ns based on the data of the process and deposition of the present and ancient debris-flows in Dongchuan of Yunnan, Wudu of Gansu and Fuxin of Liaoning. Non-cohesive debris flow with a density of 1. 3 - 1. 7 T/m3 follows the hydraulic fluid or granular flow model. In the hydraulic fluid of flood, electrolytic water combines with clay to form pulp transporting solid debris. The sedimentary structures showing fluid processes are stone-line structure, imbricated structure, gravel supporting-superimposed structure. A part of non-cohesive debris flow and transitional be-bris flow (density 1. 7 - 1. 9 T/m3) follow the granular flow model. Debris is subjected to the actions of friction, collision and dispersion, of which dispersion action forces coarse debris moving upward to form inverse graded load, The sedimentary structures showing granular flow include inverse graded bedding, inverse-normal graded bedding, imbricated-vertical structure, and circling linear structure. Cohesive debris flow with a density of 1. 9-2. 3 T/m3 follows the structural two-phase flow (viscoplastic) model. The sedimentary structures showing the processes of cohesive debris flow are inverse graded-chaotic structure, bottom mud-chaotic structure, and out-wedging structure.