本文關鍵詞： 凍土 青藏高原 短基線集技術 凍土形變 活動層厚度　出處：《中南大學》2014年碩士論文　論文類型：學位論文

【摘要】：凍土是地球五大圈層之一—冰凍圈的重要組成部分。在全球氣候變暖的大背景下,青藏高原多年凍土呈現面積縮小、活動層厚度增大等退化趨勢,這將深刻影響著寒區(qū)生態(tài)環(huán)境、水文環(huán)境、經濟建設、工程建設、人民生活等。大面積、高精度的開展凍土監(jiān)測對于研究全球氣候變化及保障寒區(qū)人民生命財產安全具有重要意義。 傳統(tǒng)SBAS-InSAR技術雖然能夠監(jiān)測凍土形變,但其形變模型并不適合描述凍土形變,且如何利用InSAR技術獲取凍土活動層厚度仍然是一個研究熱點�；诖�,本論文構建顧及氣候因子影響的凍土形變模型獲取凍土形變,并在此基礎上發(fā)展活動層厚度反演算法。本文研究工作和貢獻主要包括： (1)分析土質、地質構造活動等內因和外部氣候因子對凍土形變的影響,建立顧及氣候因子影響的SBAS-InSAR凍土形變模型,提取研究區(qū)域的凍土時間序列形變。研究區(qū)內天然地表下凍土年周期變形量均介于4-5.5cm之間,青藏鐵路沿線、青藏公路沿線年周期形變量介于3-4cm。凍土的形變與氣溫、降水量呈現負相關關系,相關性分別達到了0.61、0.91。 (2)基于本文建立的凍土形變模型,利用SBAS-InSAR技術獲取凍土形變,假設凍土夏季沉降全部由活動層中冰融化成水引起凍土層體積收縮造成,簡化工程上采用的凍土融沉量分層計算模型,逆運算得到凍土融化深度,并進一步推算研究區(qū)多年凍土上限,2007年8月多年凍土上限約為0～223cm,均值處在102～153cm之間,2010年8月約0～364cm,均值處在108～158cm之間。 (3)寧中盆地多年凍土上限整體上從地勢較低的盆地中央向海拔較高的盆地邊緣逐漸減小,2010年8月凍土上限均比2007年8月有所增加,并可推算出該區(qū)域凍土上限以每年1～2cm的速度在增加,預計百年后多年凍土活動層厚度將增加0.9～1.8m。這將對研究區(qū)域的生態(tài)環(huán)境、工程建設產生影響,對青藏鐵路和青藏公路的安全運行也構成一定威脅。
[Abstract]:Permafrost is one of the five major layers of the earth, which is an important part of the cryosphere. Under the background of global warming, the permafrost of the Qinghai-Xizang Plateau tends to decrease in area and increase in thickness of active layer. This will have a profound impact on the ecological environment, hydrological environment, economic construction, engineering construction, people's daily life and so on in cold regions. High precision monitoring of frozen soil is of great significance to the study of global climate change and the safety of people's lives and property in cold regions. Although the traditional SBAS-InSAR technology can monitor the frozen soil deformation, its deformation model is not suitable to describe the frozen soil deformation, and how to obtain the thickness of the frozen soil active layer by using the InSAR technique is still a research hotspot. In this thesis, a frozen soil deformation model considering the influence of climate factors is constructed to obtain the frozen soil deformation, and on this basis, the inversion algorithm of active layer thickness is developed. The research work and contributions in this paper are as follows:. 1) analyzing the influence of internal and external climatic factors, such as soil quality, geological tectonic activity, on frozen soil deformation, and establishing the SBAS-InSAR frozen soil deformation model, which takes into account the influence of climate factors. The time series deformation of frozen soil was extracted from the study area. The annual periodic deformation of frozen soil in the study area was between 4-5.5 cm, along the Qinghai-Tibet Railway and along the Qinghai-Xizang Highway between 3-4cm.The deformation and temperature of permafrost, There was a negative correlation between precipitation and precipitation, respectively. (2) based on the model of frozen soil deformation established in this paper, the SBAS-InSAR technique is used to obtain the frozen soil deformation. It is assumed that the summer settlement of frozen soil is caused by the volume shrinkage of frozen soil caused by the melting of ice in the active layer. The thawing depth of frozen soil is obtained by inverse calculation by simplifying the layered calculation model of thawing settlement of frozen soil. Furthermore, the permafrost upper limit in the study area is estimated to be 0 ~ 223cm in August 2007, with a mean value of 102103cm, and a mean value of 108m ~ 158cm in August 2010. (3) the permafrost upper limit of Ningzhong basin decreases gradually from the center of the basin with lower topography to the basin margin with higher elevation on the whole, and the upper permafrost limit in August 2010 is higher than that in August 2007. It can also be deduced that the upper limit of frozen soil in this area is increasing at the speed of 1 ~ 2 cm per year, and it is expected that the thickness of the active layer of permafrost will increase by 0.9 ~ 1.8 m after 100 years. This will have an impact on the ecological environment and engineering construction of the study area. It also poses a certain threat to the safe operation of the Qinghai-Tibet Railway and the Qinghai-Tibet Highway.
【學位授予單位】：中南大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：P642.14

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本文編號：1507398