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混合土样的采集和制备
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作者 孙鲜凤 《农村科学实验》 1999年第12期25-25,共1页
当混合土样具有最大的代表性,土壤分析结果才能真实地反映土壤状况,才能够谈到为农业生产提供合理配方施肥,才能够达到提高投入产出比的目的,那么怎样采集和制备混合土样,才具有最大的代表性呢? 一、样品的采集 1.采集的原则:
关键词 混合土样 采集 制备 土壤分析
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Joint member angle limits of composite beams and CFT square columns 被引量:2
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作者 LEE Seung-Jo LEE Kang-Guk 《Journal of Central South University》 SCIE EI CAS 2013年第1期199-206,共8页
This work aims to understand the relationship between the member angle limit and the energy ratio for 24 test samples of composite beams and CFT square steel tube columns. This work also compares the formula applicabi... This work aims to understand the relationship between the member angle limit and the energy ratio for 24 test samples of composite beams and CFT square steel tube columns. This work also compares the formula applicability for member angle limit with the previous test result to provide the basic data for the design of composite beam-CFT column. The evaluation of the member angle limit was performed with concrete compressive strength (fC =22.16 MPa, 30.49 MPa), breadth-to-thickness ratio (B/t=25.0, 33.3, 43.5), and axial capacity ratio (N/N0=0, 0.3, 0.4, 0.5) as the main variables of the test samples. For the relationship between the member angle limit (Ru) and the energy ratio (ES/EC ), the test result shows that the energy ratio becomes lower as the axial capacity ratio and the breadth-to-thickness ratio increase. The energy ratio is lower for the Type B test sample compared with that of Types A and C. For the formula suggested by SATO, the test samples are distributed evenly for comparison between test values and the member angle limit; however, other formulas indicate a deviation. Specifically, for the comparison between R u,cal and R u (Test), Maeda's formula shows severe deviation. 展开更多
关键词 square steel tube axial capacity ratio member angle limit breadth-to-thickness ratio
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Performance of Square Lightweight Concrete Specimens Confined by CFRP and GFRP
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作者 A. Vatani Oskouei M. Pirgholi Kivi S. Taghipour Boroujeni 《Journal of Civil Engineering and Architecture》 2010年第5期22-28,共7页
Confinement is an effective method in order to increase concrete strength and its ductility capacity. To improve the structural properties of lightweight concrete, Fiber Reinforced Polymer (FRP) can be used to confi... Confinement is an effective method in order to increase concrete strength and its ductility capacity. To improve the structural properties of lightweight concrete, Fiber Reinforced Polymer (FRP) can be used to confine the concrete. Effect of Fiber Reinforced Polymer on confined lightweight concrete elements is one of the most important research fields. It is generally accepted that the strength and stiffness of confined concrete is higher than unconfined one. In this research, behavior of confined and unconfined concrete specimens under uniaxial loading has been studied. In order to decrease stress concentration corners of specimens were chamfered to a radius of 5 to 25 mm. The Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP) were used to confine lightweight concrete specimens. The stress-strain curve of specimens is compared. 展开更多
关键词 Axial loading CFRP CONFINEMENT GFRP lightweight concrete.
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自燃煤矸石山覆盖材料压缩及压实特性实验 被引量:8
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作者 陈胜华 焦希颖 +2 位作者 胡振琪 高杨 郭陶明 《环境工程学报》 CAS CSCD 北大核心 2013年第11期4540-4546,共7页
自燃煤矸石山表面构建覆盖层,需要具备一定的低渗透性能以有效阻隔空气,防止煤矸石山内部发生自燃。本研究通过室内实验,测定煤矸石山构建覆盖层涉及的碾压材料包括黄土、粉煤灰及掺有粉煤灰的混合土样的界限含水率、一维压缩特性及压... 自燃煤矸石山表面构建覆盖层,需要具备一定的低渗透性能以有效阻隔空气,防止煤矸石山内部发生自燃。本研究通过室内实验,测定煤矸石山构建覆盖层涉及的碾压材料包括黄土、粉煤灰及掺有粉煤灰的混合土样的界限含水率、一维压缩特性及压实特性,揭示和分析7种覆盖材料配方的压缩压实特性,表明覆盖材料通过碾压可有效阻隔空气,起到阻燃作用;将粉煤灰掺入到一般黄土材料中,可减缓混合土样击实曲线的陡峭性,从而降低材料在碾压中对含水率的敏感度。实验旨在为进行煤矸石山覆盖层碾压提供科学的实验数据及设计参数。 展开更多
关键词 自燃煤矸石山 覆盖材料 混合土样 压缩 压实
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