本文選題：泥石流啟動試驗 + 冰磧土　； 參考：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：本次研究以發(fā)育在貢嘎山東坡磨西河流域內(nèi)冰磧補給型泥石流為原型,應(yīng)用地質(zhì)學(xué)和水力學(xué)的相關(guān)理論方法,采用野外調(diào)查、室內(nèi)模擬試驗、現(xiàn)場試驗及數(shù)理統(tǒng)計分析等手段,在深入調(diào)查區(qū)域內(nèi)泥石流地形地貌特征、地質(zhì)構(gòu)造特征、水文氣象特征和冰川活動特征的基礎(chǔ)上,完成了對相關(guān)試驗方案的設(shè)計,并先后在四川大學(xué)水力學(xué)與山區(qū)河流開發(fā)保護(hù)國家重點試驗室和貢嘎山東坡磨西河流域內(nèi)開展了冰磧土啟動形成泥石流的室內(nèi)水槽試驗和野外現(xiàn)場試驗。通過理論分析和試驗相結(jié)合,初步查明了高寒山區(qū)冰磧補給型泥石流物源匯集模式及其對泥石流行程的影響,通過對比分析不同試驗條件下冰磧土啟動形成泥石流所需的水力學(xué)參數(shù)特征差異現(xiàn)象,揭示了冰磧土在不同徑流條件作用下啟動行程泥石流的過程機制,深入研究了溝道徑流對冰磧土的入滲、侵蝕及啟動的連續(xù)過程,初步建立了基于泥石流的啟動時間(y)與物源粗化過程持續(xù)時間(x)關(guān)系的數(shù)學(xué)模型,為高寒山區(qū)冰磧補給型泥石流的形成機理認(rèn)識及預(yù)測預(yù)報提供了科學(xué)依據(jù)。研究主要取得了以下一些認(rèn)識:1.冰磧補給型泥石流溝道內(nèi)物源匯集模式:是重力作用匯集、支溝泥石流匯集和凍融作用匯集的綜合,并以后兩種匯集方式為主。凍融作用匯集模式包括3類循環(huán)凍融方式:循環(huán)式凍融匯集、季節(jié)性凍融匯集、坡向式凍融匯集。循環(huán)凍融作用匯集模式維持了溝道內(nèi)冰磧土物源“非粗化層”的特點,使冰磧補給型泥石流具有與一般水力類泥石流不同的啟動機制。2.冰磧補給型泥石流的啟動過程:物源表層粗化過程溝道徑流形成過程粗顆粒啟動過程。溝道徑流形成過程是物源表層遭受深度侵蝕破壞的結(jié)果,為粗顆粒的啟動提供有利條件。粗顆粒啟動標(biāo)志著泥石流啟動,以側(cè)向侵蝕和垂向掏蝕的方式侵蝕物源來不斷增強泥石流流量。3.冰磧土物源的大規(guī)模侵蝕破壞,是作為粗顆粒固體物質(zhì)基底的細(xì)顆粒物質(zhì)被掏空的結(jié)果。徑流在粗顆粒組成的徑流通道內(nèi)匯流后侵蝕能力更強,導(dǎo)致了細(xì)顆粒物質(zhì)優(yōu)先啟動,而未啟動的粗顆粒暴露程度增加并失去基底支撐并隨著持續(xù)徑流沖刷而啟動。4.泥石流對物源的侵蝕過程中流體水深面和侵蝕面在縱截面上一直維持著波狀形態(tài),兩者波峰和波谷的位置并不是固定,卻表現(xiàn)出形態(tài)幾乎一致的協(xié)同變化的特點。對溝床的侵蝕主要集中在滲透強度高的波谷,整個過程表現(xiàn)為“先滲透先侵蝕”的特征。隨著泥石流侵蝕強度的增加,水深面和侵蝕面的波高和波長也加大。5.冰磧補給型泥石流的啟動時間(y)與物源粗化過程持續(xù)時間(x)數(shù)學(xué)關(guān)系模型:y=3.5x。這表明雖然物源顆粒分布情況和泥石流啟動水動力條件不同,但是在某一次特定啟動條件下,泥石流啟動時間始終受物源粗化階段持續(xù)時間的控制,兩者之間存在著一定的函數(shù)關(guān)系。
[Abstract]:In this study, based on the development of moraine recharge debris flow in the Moxi River basin on the east slope of Gongga Mountain, using the relevant theoretical methods of geology and hydraulics, field investigation, indoor simulation test, field test and mathematical statistical analysis, etc. On the basis of in-depth investigation of the landform and geomorphological characteristics, geological structure characteristics, hydrometeorological characteristics and glacier activity characteristics of debris flow in the region, the design of the relevant test scheme has been completed. In the state key laboratory of hydraulics and river development and protection in Sichuan University and in the Moxi River basin on the east slope of Gongga Mountain, the indoor flume test and field test on the initiation of debris flow by moraine soil were carried out. Through the combination of theoretical analysis and experiment, this paper preliminarily found out the collecting model of debris flow source of moraine recharge type in alpine mountainous area and its influence on the debris flow travel. By comparing and analyzing the characteristics of hydraulic parameters of debris flow caused by the initiation of moraine soil under different experimental conditions, this paper reveals the mechanism of the process of starting debris flow under different runoff conditions. The continuous process of infiltration, erosion and start-up of moraine soil by channel runoff is studied in depth. The mathematical model of the relationship between the starting time of debris flow and the duration of material source coarsening process is established preliminarily. It provides a scientific basis for the understanding of formation mechanism and prediction of the recharge debris flow in alpine mountainous areas. The research mainly obtained the following understanding: 1. The collection model of material source in debris flow channel of moraine recharge type is the synthesis of gravity action collection, branch gully debris flow collection and freeze-thawing process collection, and the latter two kinds of collecting modes are the main. There are three types of freezing and thawing patterns: cyclic freezing and thawing, seasonal freezing and thawing, slope freezing and thawing. The circulation freeze-thaw gathering model maintains the characteristics of the "non-coarse layer" of the source of moraine soil in the channel, which makes the recharge debris flow of the moraine have a different starting mechanism from that of the general hydrodynamic debris flow. The starting process of moraine recharge debris flow is: the coarsening process of the surface layer of the material source, the course of channel runoff formation and the starting process of coarse particles. The formation process of channel runoff is the result of deep erosion on the surface of the material source, which provides favorable conditions for the initiation of coarse particles. The start of coarse particles marks the start of debris flow, which increases the debris flow by lateral erosion and vertical erosion. The massive erosion of moraine soil is the result of the hollowing out of fine granular material as the substrate of coarse granular solid material. The erosion ability of runoff in the runoff channel composed of coarse particles is stronger, which leads to the primacy of fine particle material, while the exposure degree of coarse particles that is not started increases and loses the base support and starts up with continuous runoff scouring. In the process of debris flow erosion to the source, the water depth and erosion surface of the fluid always maintain the wave shape on the longitudinal section. The position of the wave peak and trough is not fixed, but they show the characteristics of almost consistent and synergistic change. The erosion of trench bed is mainly concentrated in the trough with high permeability, and the whole process is characterized by "infiltration first and erosion first". With the increase of debris flow erosion intensity, the wave height and wavelength of water depth and erosion surface also increase. The relation between the starting time of moraine recharge debris flow (y) and the duration of material source coarsening process (x) is: y = 3.5x. This indicates that although the distribution of the source particles is different from the hydrodynamic conditions of the debris flow starting, the starting time of the debris flow is always controlled by the duration of the material source coarsening stage under a certain starting condition. There is a certain functional relationship between the two.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：P642.23
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本文編號：2033696