东帕米尔公格尔山地区冰川融水诱发冰碛土形成泥石流的机理研究

Due to high-frequency and severity of glacier debris flow disasters in Kongur Mountain region, eastern Pamir, it impacts the construction and safety of major projects seriously in China-Pakistan economic corridor. However, the research about the glacier debris flow in this region still very sparse, it is necessary to proceed to further study the glacier debris flow. The issue concentrates on the dynamic mechanism of glacier-melting water induced soil failure and debris flow initiation from moraine soil with less clay content and large pore and overhead structure. Firstly, by analyzing the composition and structure of moraine soil in the glacier debris flow prone area, the tested soil parameter used in the debris flow initiation experiment is obtained. Secondly, based on collection and analysis of hydro-meteorological data from Gaizi river along northern slope of Gongur Mountain, the runoff-producing and converging model of glacier melting water in the studying area is proposed, and further the water volume applied to the debris flow initiation experiment is confirmed. Then, the triggering experiment of glacier melting water induced debris flow from glacier deposits in Gaizi river of Gongur Mountain region will be carried out considering the different groups of representative moraine soil and characteristic runoff, and the research emphasis is focused on the variations of runoff, seepage, pore water pressure and water content during the experimentation, the change rule between melting water creep seepage and soil mass strength reduction will be explored, and the influence of seepage erosion on soil mass structure failure also will be discussed. In the end, soil mechanics theory is applied to reveal dynamic mechanism of glacier melting water induced soil failure and debris flow initiation from moraine soil. Achievement of this research will not only contribute to reveal the formation and movement pattern of glacier debris flow in Gongur Mountain region, but also provide theoretical guidance for calculation of motion parameters and confirmation of monitoring and early warning threshold of glacier debris flow, further will offer support for the construction of major projects in China-Pakistan economic corridor.

东帕米尔公格尔山地区冰川泥石流暴发频繁且危害严重，严重影响中巴经济走廊带重大工程建设与安全，然而当前对该区域冰川泥石流的研究非常少，急需进行深入研究。项目研究冰川融水作用下特殊组构冰碛土失稳形成泥石流的动力学机理。通过统计分析区域冰碛土组构特征，确定泥石流启动试验的土体特征指标；通过收集盖孜河流域站点的水文气象资料，建立冰川融水产汇流计算方法，确定泥石流启动试验的坡面径流量；以代表性冰碛土和特征径流的组合开展冰川融水诱发冰碛土形成泥石流的启动试验，研究冰碛土体启动过程中径流、渗流、孔压和含水量变化，探究融水渗流潜蚀与土体强度衰减的变化规律，融水渗透侵蚀对土体结构破坏的影响机制，揭示冰川融水导致冰碛土体失稳产生泥石流的动力学机理。研究成果可为揭示公格尔山地区冰川泥石流形成与运动规律奠定基础，为区域冰川泥石流运动力学参数计算和监测预警阈值确定提供理论指导，为中巴经济走廊带重大工程建设提供支撑。

本课题以青藏高原西北构造结处地势起伏大、冰川分布广泛、盛行西风带和地质构造复杂的地区—东帕米尔公格尔山北坡的中巴公路奥布段为研究区域，以干旱少雨区降雨型泥石流和高寒高海拔区冰川型泥石流起动机理作为核心科学问题，在多学科理论原理指导下开展研究区泥石流分布规律和危险评价，揭示干旱少雨区降雨型泥石流和高寒高海拔区冰雪融水型泥石流起动机理，建立不同类型泥石流减灾防灾关键技术，为区域冰川泥石流运动力学参数计算和监测预警特征阈值的确定提供理论指导，为中巴公路建设和运营过程中防灾减灾提供科技支撑，保障“中巴经济走廊带”的安全畅通。.课题的主要研究成果和关键技术如下：①查清了研究区泥石流类型、分布与破坏特征，建立了泥石流灾害数据库，为区域泥石流灾害研究提供基础数据支撑；②对研究区泥石流灾害进行了危险评价与风险评估，为公路工程和其他工程建设中防灾设计提供了依据；③获得了降雨型泥石流的激发雨型及临界阈值，对干旱少雨区降雨型泥石流监测预警指标确定提供了依据；④查清了冰川分布与类型，建立了冰川融水径流与气温和降雨的动态关系模型，为冰川型泥石流形成过程及预警指标确定提供了参考依据；⑤查清了研究区冰碛土分布，揭示了冰碛土的工程地质特征，建立了冰碛土综合级配表征方法，为冰碛土的路用性能评价提供了基础数据；⑥提出了泥石流地区公路选定线原则和方法，对泥石流地区公路建设具有重要指导意义；⑦通过水槽冲刷试验和水工模型实验研究了降雨型泥石流和冰川型泥石流起动机理和防治对策，为不同类型泥石流的防治方案和治理技术确定提供依据。