多组分流元模型在稀性泥石流堆积分选特征研究中的应用  

Sediment sorting in deposition process of debris flow

作　　者：倪晋仁[1] 廖谦[1] 曲轶众[1] 

机构地区：[1]北京大学环境科学中心

出　　处：《水利学报》2001年第2期16-23,共8页Journal of Hydraulic Engineering

基　　金：国家自然科学基金! (批准号 4962 5 10 1)

摘　　要：基于结构两相流模型和PIC数值计算方法 ,本文探讨了稀性泥石流堆积过程中的泥沙分选特征 .文中的模型可以模拟阵性泥沙流的非稳定特性 ,通过将传统的Euler和Lagrangian方法结合泥沙流运动的整个过程都能够采用多组分流元模型进行很好的描述 .该模型也能够合理描述泥沙分选过程中伴随的冲淤过程 .文中采用 2～ 5°的坡度 ,固相颗粒被分为三组粒径不同的组分 .研究表明 ,泥石流的垂向和横向分选都不明显 ,但是纵向分选较为明显 .河槽坡度和泥石流的密度是影响泥石流分选过程的两个关键因素 .泥沙输移能力越大 ,颗粒分选越不明显 。Based on the conceptual two phase flow and PIC numerical method,the present paper further discussed the sediment sorting characteristics in the deposition process of the debris flow,particularly for the dilute debris flow.The model reviewed can be used for the simulation of natural debris flow of paroxysmal and unsteady characteristics.By combining the conventional Eulerian and Lagrangian methods,the E-L model can be used to describe the whole process of the typical debris flow in greater details through the elements.The present model is also proper for describing the sediment sorting accompanied with erosion and depositional processes.Varying slopes ranged from 2° to 5° were used for the input information of the model.The solid particles were divided into three groups,each corresponding to one average diameter of the particles.Other parameters were taken from the experimental data obtained in previous studies.The emphasis was laid on the sediment sorting process although other processes such as the motion and sedimentation were investigated.The modeling results show that the channel slope and the specific density of debris flow are key factors controlling the sorting process through modifying the sediment transport capacity.The larger the sediment transport capacity of the debris flow,the less solid particles are apparently sorted.The quantitative prediction of the sediment sorting characteristics is of primary importance for understanding of the deposititonal mechanism of debris flow and prevention of the debris flow disasters.

关 键 词：泥石流 堆积 分选 多组分流元模型 

分 类 号：P642.23[天文地球—工程地质学]