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用激光粒度仪进行粘土的颗粒分析 总被引:1,自引:0,他引:1
为获得细粒土的粒度分布,分别采用Mastersizer 2000激光衍射粒度仪和传统的密度计法测量合肥地区的粘土.根据激光法的测量原理和影响因素,用单因素试验法依次改变仪器的折射率、质量浓度、超声波端位移和时间、泵速,研究这些控制参数对颗粒粒径的影响,并确定了该仪器测量合肥地区粘土的最佳参数.通过比较最佳参数条件下的激... 相似文献
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《工程勘察》2016,(12)
土的粒度组成是土的基本物理属性之一,传统的土的粒度分析方法有移液管法和密度计法,激光法是近年来新兴的粒度分析方法。然而,这三种方法由于其测试原理的差异导致其测试结果存在定性及定量的差异。本文研究选取粉土和粉质黏土两种不同质地土,通过进行室内粒度分析试验,描述了移液管法、密度计法及激光法三种方法测得结果的粒径分布曲线特征,并讨论了三者之间的差异,结果表明:三种粒度分析方法中激光法精密度最高,移液管法次之,密度计法最低;粒径在2~0.1mm范围内时,对于粉质黏土和粉土两种不同质地土,三种测试方法测试结果均无显著差异;粒径小于0.1mm时,移液管法和密度计法对粉质黏土的测试结果没有显著差异,均显著高于激光法,而粉土的测试结果则为移液管法最高、密度计法次之、激光法最低。在测定土的粒度组成时,激光法与移液管法之间可建立相应的转换关系。 相似文献
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土的分类中塑性指数与黏粒含量的关系 总被引:1,自引:0,他引:1
土的分类是根据土的塑性指数(IP)或土的粒径组成而定的,但不同类型土的塑性指数(IP)和粒径组成在对土进行分类时不尽相同。通过黏性土、粉性土的试验结果比较,对土的分类所采用的不同试验方法的不同结果关系进行了分析和探讨,特别提出对10≤IP≤12的低塑性土,以颗粒分析中的黏粒含量定名为宜。 相似文献
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根据二相土的组成特点,研究饱和黏性土热物理性质与其含水量、密度及孔隙比等参数问的关系。在武汉地铁详勘阶段,采取一级阶地黏性土饱和原状土样,利用KD2 Pro Thermal Properties Analyzer热参数分析仪进行热物理性质试验,同时测试土样的含水茸及密度。对试验结果进行回归分析,分析时假设土中水及同体颗粒骨架的热物理性质为定值,且土中水分没有明显的迁移。结果表明:黏性土导热系数随原状土样密度的增加而增加,随孔隙比的增加而降低:比热容随原状土样含水量的增加而增加。结合试验结果及同外的经验公式.给出了便于工程使用的导热系数及比热容计算公式。 相似文献
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通过实地监测,针对不同车间的棉尘颗粒物的浓度及粒径分布特征进行了对比分析,监测结果表明:清花,梳棉及细纱车间的平均总颗粒物浓度分别为3.65 mg/m 3、2.87 mg/m 3、1.75 mg/m 3,均大于棉尘接触限值.由前纺工艺至后纺工艺,总颗粒物浓度呈逐渐减小的趋势,清花车间总颗粒物浓度是细纱车间浓度的2.08... 相似文献
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W. J. Fisk 《Indoor air》2013,23(5):357-368
The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, for example, 7% to 25%. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air. 相似文献
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《Soils and Foundations》2023,63(4):101336
In practice, post-liquefaction strength is largely determined from case histories, but the case history database is limited and there are gaps in the information available in each case. As a result, laboratory tests have continued to play a key role in determining how various factors influence post-liquefaction strength. This paper presents an investigation into how factors such as particle size, particle size distribution, fines content, and compressibility influence post-liquefaction strength in simple shear tests. Eleven particle size distributions of a natural soil and a tailings material, ranging from silt to fine gravel, were studied. The results were compared with case histories.Materials of different geologic origins have meaningfully different post-liquefaction strengths. Particle size and particle size distributions were both found to significantly affect post-liquefaction response as well. Post-liquefaction strengths obtained from simple shear tests agreed well with those back calculated from case histories. Laboratory testing can be utilized to determine how the post-liquefaction strength of a given material may compare to the case history database, and can be used to guide design decisions. This is an important practical finding, given the sparse case history database. 相似文献