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桥梁桩基础施工对航道演变影响分析 被引量:4
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作者 李靓亮 《水运工程》 北大核心 2020年第4期162-168,共7页
近年来多座桥梁建设期间工程河段航道发生了明显变化。针对这一问题,以荆岳长江公路大桥桥墩基础施工阶段为例,对比施工前后的实测水文、地形。结果发现桩基施工时搭设的栈桥、水上施工平台引起丁家洲边滩和南阳洲洲头发生较大改变,加... 近年来多座桥梁建设期间工程河段航道发生了明显变化。针对这一问题,以荆岳长江公路大桥桥墩基础施工阶段为例,对比施工前后的实测水文、地形。结果发现桩基施工时搭设的栈桥、水上施工平台引起丁家洲边滩和南阳洲洲头发生较大改变,加速了局部河段航道条件向不利方向发展的趋势,说明桥梁基础施工对航道演变有较大影响。为尽量避免不利影响,在前期跨度研究阶段,应提前考虑可能采用的施工方案对航道的影响。如果通过调整施工方案难以消除或者减小影响,必须优化桥跨和桥墩布置方案。分析成果可为后续桥梁建设管理提供参考借鉴。 展开更多
关键词 跨河桥梁 基础施工 河床演变 航道条件 航道维护
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Extraction of Soil Boron for Predicting Its Availability to Plants
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作者 LIREN-AN U.C.GUPTA 《Pedosphere》 SCIE CAS CSCD 1991年第2期137-144,共8页
Field and greenhouse studies were conducted in Prince Edward Island (P. E.I.) on soybean (Glycine max (L.) Merr.), red clover (Trifolium praten.se L.), alfalfa (Medieagn saliva L.), and rutabaga (Brassica napobrassica... Field and greenhouse studies were conducted in Prince Edward Island (P. E.I.) on soybean (Glycine max (L.) Merr.), red clover (Trifolium praten.se L.), alfalfa (Medieagn saliva L.), and rutabaga (Brassica napobrassica. Mill). Plant B concentrations were compared to soil B extracted by hot-water, 0.05 M HCI, 1.5 M CH3COOH and 0.01 M CaCl2. The r values for extractable soil B vs. plant B were: hot water (0.67). 0.05 M HCl (0.82), 1.5 M CH3COOH (0.78) and hot 0.01 M CaCl2(0.61). Results of soil B from the 0.05 M HCl extracts were generally found to give the best correlation and linear regression among the four extractants tested for predicting the availability of B to the plants. Overall, the 0.05 M HCl proved to be superior to hot water extraction and is recommended for predicting the available B status of the acid soils of P. E. I. The probability of error with 0.05 M HCL is less since it is shaken for a fixed period of time as opposed to subjective error which could be caused in monitoring the boiling time using hot water. 展开更多
关键词 EXTRACTION 0.05 M HCI soil boron
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