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塔里木河下游土地利用动态变化分析 被引量:11
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作者 张超 高敏华 +1 位作者 赵国强 都伟新 《水土保持研究》 CSCD 北大核心 2006年第1期122-125,共4页
利用1990年,1999年TM影像及2002年CBERS影像的4、3、2(RGB)波段合成影像解译结果,运用分类结果比较法求得研究区土地利用/覆盖变化转移矩阵,结合塔里木河下游土地利用/覆盖动态指数进行分析。结果表明.1990-1999年塔里木河下游... 利用1990年,1999年TM影像及2002年CBERS影像的4、3、2(RGB)波段合成影像解译结果,运用分类结果比较法求得研究区土地利用/覆盖变化转移矩阵,结合塔里木河下游土地利用/覆盖动态指数进行分析。结果表明.1990-1999年塔里木河下游大部分土地利用/覆盖动态变化处于一种动态均衡状态,只有耕地、其他林地、湖泊、水库坑塘、农村居民地处于非均衡或极不均衡状态。转入面积远大于转出面积。1999-2002年只有其他林地、河渠处于非均衡状态。从总体分析.塔里木河下游自然植被面积持续减少,沙漠化面积继续增加,生态环境日趋恶化。 展开更多
关键词 塔里木河 影像 土地利用/覆盖变化 转移矩阵 动态变化指数
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Numerical simulation of intelligent compaction for subgrade construction 被引量:9
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作者 MA Yuan LUAN Ying-cheng +1 位作者 ZHANG Wei-guang ZHANG Yu-qing 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第7期2173-2184,共12页
During the compaction of a road subgrade, the mechanical parameters of the soil mass change in real time, but current research assumes that these parameters remain unchanged. In order to address this discrepancy, this... During the compaction of a road subgrade, the mechanical parameters of the soil mass change in real time, but current research assumes that these parameters remain unchanged. In order to address this discrepancy, this paper establishes a relationship between the degree of compaction K and strain ε. The relationship between the compaction degree K and the shear strength of soil(cohesion c and frictional angle φ) was clearly established through indoor experiments. The subroutine UMAT in ABAQUS finite element numerical software was developed to realize an accurate calculation of the subgrade soil compaction quality. This value was compared and analyzed against the assumed compaction value of the model, thereby verifying the accuracy of the intelligent compaction calculation results for subgrade soil. On this basis, orthogonal tests of the influential factors(frequency, amplitude, and quality) for the degree of compaction and sensitivity analysis were carried out. Finally, the ‘acceleration intelligent compaction value’, which is based on the acceleration signal, is proposed for a compaction meter value that indicates poor accuracy. The research results can provide guidance and basis for further research into the accurate control of compaction quality for roadbeds and pavements. 展开更多
关键词 intelligent compaction numerical simulation dynamic change control indicators orthogonal experiment
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