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工程堆积体流速及产沙特征对坡长及砾石作用响应 被引量:1
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作者 李魁 王文龙 李建明 《水土保持学报》 CSCD 北大核心 2023年第5期48-56,102,共10页
随着经济社会的高速发展以及工程建设项目的快速递增,大量生产建设项目扰动地表并破坏原地貌植被,大范围且不平衡的挖填活动使得多余的土石混合堆积,尤其在山区工程建设形成的多余土石混合介质,堆积在沟道和河道上游及边坡,在强降雨条... 随着经济社会的高速发展以及工程建设项目的快速递增,大量生产建设项目扰动地表并破坏原地貌植被,大范围且不平衡的挖填活动使得多余的土石混合堆积,尤其在山区工程建设形成的多余土石混合介质,堆积在沟道和河道上游及边坡,在强降雨条件下易发生严重水土流失,甚至造成滑坡、泥石流等灾害。以人为重塑工程堆积体为研究对象(坡度25°),通过模拟降雨试验,开展极端降雨条件下(降雨强度为2.5 mm/min)不同坡长(3,5,6.5,12 m)及砾石质量分数(0,10%,20%,30%)共同作用对堆积体流速空间分布特征及产沙特性影响的研究。结果表明:(1)坡长12 m时流速在降雨全过程始终处于波动状态,随砾石质量分数增大,波动幅度减小,而坡长3,5,6.5 m下的流速随产流历时呈先递增后趋于稳定的变化趋势。中下坡位平均流速是中上坡位的1.12~1.54倍,随着坡长增大,平均流速递增17.81%~335.94%,含砾石堆积体平均流速较纯土堆积体降低22.88%~54.67%,砾石质量分数比坡长对流速影响更显著。(2)纯土堆积体平均侵蚀速率随坡长显著增大,递增幅度达7.88%~87.67%,而含砾石堆积体随坡长增大在3~5 m呈下降趋势,降低9.10%~28.86%,但随后又显著增大,存在1个临界坡长。坡长为6.5,12 m的堆积体平均侵蚀速率较3 m增大22.33%~122.48%。砾石具有显著降低堆积体坡面侵蚀效果,其减沙效益达到24.99%~59.54%,且砾石对堆积体平均侵蚀速率影响的贡献是坡长的1.13倍。(3)堆积体坡面中上坡位流速对侵蚀速率影响大于中下坡位,平均侵蚀速率与流速之间呈极显著相关,流速可作为平均侵蚀速率的表征参数,其线性拟合关系较好(R^(2)=0.67~0.95)。研究成果进一步深化了土壤侵蚀学科内涵,可为生产建设项目工程堆积体侵蚀预测模型提供数据基础,同时也为阐明工程扰动坡面侵蚀内在机制提供理论依据。 展开更多
关键词 堆积体 砾石质量分数 不同坡长 流速空间分布 侵蚀
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Spatial Distribution Characteristics of Surface Tidal Currents in the Southwest of Taiwan Strait 被引量:1
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作者 SHEN Zhiben WU Xiongbin +3 位作者 LIN Hang CHEN Xiaofeng XU Xing’an LI Lun 《Journal of Ocean University of China》 SCIE CAS 2014年第6期971-978,共8页
This study was conducted on the spatial distribution characteristics of surface tidal currents in the southwestern Taiwan Strait based on the quasi-harmonic analysis of current data obtained by two high frequency surf... This study was conducted on the spatial distribution characteristics of surface tidal currents in the southwestern Taiwan Strait based on the quasi-harmonic analysis of current data obtained by two high frequency surface wave radar(HFSWR) systems. The analysis shows that the tidal current pattern in the southwestern Taiwan Strait is primarily semi-diurnal and influenced significantly by shallow water constituents. The spatial distribution of tidal current ellipses of M2 is probably affected by the interaction between two different systems of tide wave, one from the northern mouth of Taiwan Strait and the other from the Bashi Channel. The directions of the major axes of M2 tidal current ellipses coincide roughly with the axis of the Taiwan Strait. The spatial distribution of the magnitudes of the probable maximum current velocity(PMCS) shows gradual increase of the velocity from northeast to southwest, which is in accordance with the spatial distribution of the measured maximum current velocity(MMCS). The directions of the residual currents are in accordance with the direction of the prevailing monsoon wind at the Taiwan Strait and the direction of the Taiwan warm current during summer. The bathymetry also shows a significant effect on the spatial distribution characteristics of tidal currents. 展开更多
关键词 high frequency surface wave radar quasi-harmonic analysis spatial distribution characteristic surface tidal current Taiwan Strait
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