富冰碎屑流启动敏感因素及运移特性研究

项目名称： 富冰碎屑流启动敏感因素及运移特性研究

项目编号： No.41272328

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 祁长青

作者单位： 河海大学

项目金额： 76万元

中文摘要： 多年冻土对气候升温非常敏感，全球气候变暖导致寒区碎屑流灾害频发。然而到目前为止，对于寒区碎屑流的启动和运移特性仍然缺乏足够的了解。本项目从青藏高原冰缘区碎屑流源堆积体入手，获得堆积体的基本特征参数，运用数值模型预测其在气候升温条件下的热状态变化；建立室内尺寸模型，模拟斜坡堆积体在气候升温和地表水入渗条件下的破坏过程，评价碎屑流对环境条件的敏感性；制备不同含冰量碎屑流试样，模拟碎屑流的运移过程，建立碎屑流的摩擦系数与运移过程动态物理力学参数的关系；在实验结果的基础上，对现有碎屑流两相耦合力学模型进行扩充，建立考虑地下冰相变和碎屑流强度随过程弱化的富冰碎屑流两相耦合力学模型。对典型富冰碎屑流源区堆积体失稳和运移过程进行预测和模拟，为多年冻土区碎屑流灾害的预防和治理提供参考和建议。

中文关键词： 寒区堆积体；碎屑流；气候响应；降雨入渗；力学特性

英文摘要： Permafrost is sensitive to clime changing. Global climate warming in recent years results in a large number of slope failures in glaciated high mountain area, among which the debris flow is the common and hazardous one. The debris flow process in permafrost region is still poorly understood up to now. The basic structural, physical and mechanical parameters of slope deposits in periglacial region are studied in this project, and the thermal regime and permafrost degradation of these deposits are calculated using the climate response model. Physical scale models are established in laboratory, and the climate and rainfall response experiments of slope deposits are carried out, the initiation and slide processes of the debris flows are recorded and analyzed. The samples with different ice contents are prepared and the dynamic characteristics of the debris flows is studied. The dynamic frictional characteristics of the debris flows are obtained during the experiments. A real two-phase mechanical model for ice-rich debris flows is presented based on the experimental results and the mechanical model of ice-free debris flow. The proposed model can consider the internal mass and momentum exchanges between the phases and the dynamic strength weakening of the material of debris flow. The stability of typical debris flow o

英文关键词： rock-soil deposit in permafrost region；debris flow；climate response；rainfall infiltration；mechanical characteristics