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天然沉积饱和有明粘性土的Burland孔隙指数与归一化含水量的关系 被引量:6
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作者 洪振舜 刘志方 +1 位作者 郭海轮 刘松玉 《岩土力学》 EI CAS CSCD 北大核心 2004年第11期1698-1701,共4页
如何评价土结构性对天然沉积饱和土的力学性状的影响是一个非常重要的研究课题。Burland在第30届郎肯讲座论文中导入孔隙指数对各种重塑土的压缩曲线进行归一化,提出固有压缩曲线用于评价天然沉积土的压缩性状。通过对广泛沉积在日本九... 如何评价土结构性对天然沉积饱和土的力学性状的影响是一个非常重要的研究课题。Burland在第30届郎肯讲座论文中导入孔隙指数对各种重塑土的压缩曲线进行归一化,提出固有压缩曲线用于评价天然沉积土的压缩性状。通过对广泛沉积在日本九洲岛的有明粘性土进行试验研究,探讨了灵敏有明粘性土的特征,提出一个比Burland孔隙指数更为简单实用的评价天然沉积土力学性状的指标——归一化含水量,定义为含水量与液限之比。根据大量的试验结果,得出了天然沉积有明粘性土的Burland孔隙指数与归一化含水量的相关关系,提出了对应于归一化含水量的固有压缩曲线。 展开更多
关键词 有明粘性土 固有压缩曲线:液限 归一化含水量 孔隙指数 含水量
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The Relationship Between Vegetation Characteristics and Altitudes in Transitional Permafrost Zone in Xidatan, Qinghai-Tibetan Plateau
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作者 Zhiwei WANG Bentian MO +3 位作者 Leilei DING Puchang WANG Qian WANG Ruixia LU 《Agricultural Science & Technology》 CAS 2016年第6期1462-1467,共6页
Many studies showed that permafrost has profound influence on alpine ecosystem. However, former researches were mainly focused on typical points by temporal scales. There were few studies about the correlation between... Many studies showed that permafrost has profound influence on alpine ecosystem. However, former researches were mainly focused on typical points by temporal scales. There were few studies about the correlation between vegetation characteristics and different altitudes covering a large region in spatial pattern, especially in transitional permafrost(TP). There were continuous permafrost(CP) discontinuous permafrost(DCP) and seasonal frozen ground(SFG) in this study region. The types of permafrost changed from SFG to DCP, and finally become CP as the altitudes of Xidatan increase. In this paper, 112 845 points interpreted by HJ1-B(environment and disaster monitoring and prediction small satellite constellation), vegetation investigation points, thawing layer thickness research sites, ground temperature and water content observation plots were used to examine the spatial pattern of vegetation which were located in different altitudes in Xidatan, a typical TP region, in Qinghai-Tibetan Plateau. Vegetation characteristics, soil moisture content(SMC) and thaw depths were collected in 15 August to 25 August2012. Characteristics of vegetation were mainly represented by fractional vegetation cover(FVC) derived from the normalized difference vegetation index(NDVI), as well as above ground biomass(AGB). In this paper, we analyzed that the distinction of vegetation characteristics in each range through statistics data. These ranges were divided by varied altitudes. For examples, the ranges were divided into 50 m or 100 m. In this study we use a large area plots method to further discuss the relationship between the features of vegetation and the different regions of permafrost based on altitudes shifts in Xidatan. A diagram described the vegetation characteristics variability with rising altitudes in transitional permafrost region was drawn in this paper. Our results illustrated the FVCs first increased in SFG region and then decreased in DCP zone slowly, and in CP region FVCs soared then dropped dramatically. With the altitudes increased, the curve of FVCs indicated a parabolic distribution except a little difference in the first 200 m range. 展开更多
关键词 vegetation Qinghai Plateau transitional alpine Tibetan ecosystem covering normalized biomass
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