【摘要】：黃土廣泛分布在亞洲、歐洲和北美,主要是一種風成沉積物。因其具有特殊工程性質(zhì),故被劃分為特殊土,我國對黃土的研究主要是在建國以后,大量的工程活動相繼展開,使得黃土研究有了長足的進展。黃土的研究主要都是從結構、垂直節(jié)理、大孔隙、形成歷史條件等方面研究展開的,而國外對于黃土的研究多是從地理與環(huán)境方面出發(fā)的。關于黃土直立性的研究國內(nèi)外的研究資料都較少,本文主要圍繞直立性影響因素展開論述。本文是在翻閱了大量的相關文獻、研究資料和實際野外地質(zhì)觀察發(fā)現(xiàn)的基礎上,通過分析黃土的沉積歷史及氣候、節(jié)理裂隙、孔隙及微結構、粘聚力、基質(zhì)吸力和鹽類等對黃土直立性的影響因素進行了綜合分析,重點論述粘聚力與基質(zhì)吸力對其直立性的影響,通過邊坡、基坑、洞室等具體工程實例進行分析研究。粘聚力與基質(zhì)吸力對黃土直立性的影響,由試驗確立粘聚力與基質(zhì)吸力的變化關系,分析基質(zhì)吸力變化對粘聚力的影響。通過變化不同的基質(zhì)吸力得到具體的粘聚力數(shù)值,運用數(shù)值軟件FLAC3D、理正深基坑等分別對邊坡與窯洞進行數(shù)值分析,得出粘聚力、基質(zhì)吸力對其穩(wěn)定性的影響,最終證明其對直立性的影響。通過對基坑邊坡和洞室進行數(shù)值分析與計算,得出粘聚力和基質(zhì)吸力的增加對基坑邊坡與洞室的穩(wěn)定都是有益的,分析不同的粘聚力和基質(zhì)吸力數(shù)值變化對位移場、應力場的影響來反映數(shù)值變化對工程活動穩(wěn)定性的影響大小。從而指導具體的工程實踐,利用黃土直立性有利特點,使得工程活動更加合理安全經(jīng)濟。
[Abstract]:Loess is widely distributed in Asia, Europe and North America, mainly as a kind of aeolian sediment. Because of its special engineering nature, it is divided into special soil. The study of loess in our country is mainly after the founding of the people's Republic of China, a large number of engineering activities have been carried out one after another, which has made great progress in the study of loess. The study of loess is mainly from the aspects of structure, vertical joints, macropores, formation of historical conditions and so on, while the study of loess abroad is mostly from the aspects of geography and environment. There are few domestic and international research materials on the vertical property of loess, and this paper mainly discusses the influence factors of the vertical property. Based on a large number of related documents, research data and field geological observations, this paper analyzes the sedimentary history and climate of loess, joints and fissures, pores and microstructures, and cohesion. The influence factors of matrix suction and salt on the vertical property of loess are comprehensively analyzed, and the influence of cohesion and matrix suction on the vertical property of loess is discussed in detail. The concrete engineering examples such as slope, foundation pit and cavern are analyzed and studied. The influence of cohesion and matrix suction on the vertical behavior of loess was studied. The relationship between cohesion and matrix suction was established by experiments, and the influence of matrix suction on cohesion was analyzed. The specific cohesion value is obtained by changing the different matrix suction. The numerical analysis of slope and cave is carried out by using numerical software FLAC3D and deep foundation pit, and the influence of cohesion and matrix suction on its stability is obtained. Finally, its influence on the erectivity was proved. Through the numerical analysis and calculation of the slope and cavity of foundation pit, it is concluded that the increase of cohesion and matrix suction is beneficial to the stability of the slope and cavern of foundation pit. The effect of stress field on the stability of engineering activity is reflected by numerical change. So it can guide the concrete engineering practice and make use of the favorable characteristics of loess upright to make the engineering activities more reasonable, safe and economical.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P642.131

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本文編號：2165179