N10检验低路堤地基土承载力的研究

充分利用轻便动力触探试验简便、灵活,快速的优点,通过大量的现场试验,针对一般粘性土地区低路堤地基土对轻型动力触探试验指标N10和基床土承载力σ以及N10和静力触探试验结果(综合比贯入阻力Ps)的数值关系的研究,建立了N10和σ以及N10和Ps的相关关系公式,最终确定了利用轻型动力触探试验检验低路堤地基土承载力的标准,确定了相应的土力学指标,为今后在低路堤地基土的勘察中,节约工程成本、缩短勘察周期以及减少工程设计的盲目性,提供了良好的参考依据.     

N10检验低路堤地基土承载力的研究

充分利用轻便动力触探试验简便、灵活,快速的优点,通过大量的现场试验,针对一般粘性土地区低路堤地基土对轻型动力触探试验指标N10和基床土承载力盯以及N10和静力触探试验结果（综合比贯入阻力Ps）的数值关系的研究,建立了N10和盯以及N10和Ps的相关关系公式。最终确定了利用轻型动力触探试验检验低路堤地基土承载力的标准,确定了相应的土力学指标,为今后在低路堤地基土的勘察中,节约工程成本、缩短勘察周期以及减少工程设计的盲目性。提供了良好的参考依据。     

建筑场地地基土承载力的确定

结合具体的工程实践，通过室内土工试验和现场静力触探等实测资料的分析，并根据有关规范与标准，得出该工程地基土承载力的推荐值和相关参数，为有关的基础设计提供了借鉴。     

某建筑场地的划分及其地基承载力的应用研究

根据等效剪切波速值对该建筑场地的各土层进行了划分,在此基础上利用室内土工试验、岩石抗压强度试验和现场静力触探等室内和实测资料进行分析计算,并结合有关规范与标准,得出了徐州市某一黄金地段户部商都地基承载力的推荐值和设计需要的相关参数,这为基础设计提供了十分重要的依据。     

地基土承载力特征值检测方法与取值研究

通过各种地基土承载力特征值检测方法的分析对比研究,阐述了勘察设计前期或基础施工前期特征值的取值过程.根据不同检测方法的试验要点、影响因素和土层性质,讨论了各方法的适用范围,归纳了不同土层与检测方法的匹配性,提出了科学合理的特征值取值思路,为勘察设计、工程施工等工作提供了有益参考.     

轻型动力触探试验推定地基土承载力的数据统计分析方法论述

轻型动力触探的优点是试验设备轻巧、测试速度快、费用较低,对于施工验槽、查明地基局部软弱土层、推定地基土承载力等,均有实用价值,一般作为地基检测的普查手段。本文介绍了用轻型动力触探试验结合平板载荷试验确定承载力特征值,通过工程实例,论述数据统计分析方法在轻型动力触探试验推定地基土承载力中的应用。     

软土区地基承载力的确定

以南京地铁七号线东青石站为例,通过开展现场原位测试及室内直剪固快试验,综合确定了软土层地基承载力特征值。结果表明,规范法与十字板剪切试验经验公式计算的结果偏大,需折减后使用;扁铲侧胀试验经验公式计算结果略偏保守;而标贯试验通过查表法获得的承载力最为准确。     

复合地基承载力静载荷与动力触探检测比较

结合一工程实例比较了复合地基承载力动力触探计算与静载荷试验结果，说明动力触探计算结果有较高的可靠性，在检测中可以得到较为连续的土层承载力变化情况。     

上海地区江滩土天然地基承载力试验研究

结合上海地区黄浦江沿岸江滩土的特征,进行了天然地基承载力试验,对其试验结果与按规范计算的结果进行了对比分析,探讨了江滩土天然地基承载力的计算方法,最后提出埋深较大的载荷试验成果计算天然地基承载力时宜进行深度修正的建议。     

关于N63．5重型动力触探试验与地基承载力及变形模量关系的探讨

该论文从实践的角度阐述了N63．5重型动力触探试验与土的承载力关系,并论述了试验的适用范围及试验成果的解译。     

地基土基床系数研究

地基土基床系数是岩土工程中一个非常重要的参数。通过对现有基床系数的确定方法和影响准确确定地基土基床系数的一些因素的分析,对地基土基床系数确定方法及其选取提出了一些建议。     

Structure of the condensed phase and char of fire-retarded PBT nanocomposites by TGA/ATR in N2

Recently phosphorous-based fire retardants and nanoparticles are promoted as alternatives to halogenated fire retardants to reduce toxicological damage to the environment. To assess the condensed phase during pyrolysis, this study presents thermal (by TGA in nitrogen) and condensed phase analyses of the residue (by FTIR–ATR) of PBT modified by a phosphinate FR and/or nanoparticles (sepiolite). The thermal analysis shows that the nanoparticles do not change the pyrolysis kinetics of PBT whereas the phosphinate FR does. The condensed phase analysis shows that both the phosphinate FR and the nanoparticles change the structure of the char compared to the structure of the char from pure PBT. In contrast to the pure polymer, which leaves a char consisting of oligomeric components of PBT, the fire-retarded polymer (by phosphinate and /or nanoparticles) leaves a char consisting of polycyclic aromatic hydrocarbons (PAH). The PAH structure of the char is expected to make the char stronger and capable to withstand erosion in full-scale fire tests. This observation is verified from the strength analysis of the char residue in intermediate-scale flammability experiments, such as those in the cone calorimeter, where char is formed behind the flames in the absence of oxygen.     

Summer fluxes of atmospheric greenhouse gases N2O, CH4 and CO2 from mangrove soil in South China

The atmospheric fluxes of N₂O, CH₄ and CO₂ from the soil in four mangrove swamps in Shenzhen and Hong Kong, South China were investigated in the summer of 2008. The fluxes ranged from 0.14 to 23.83 μmol m⁻² h⁻¹, 11.9 to 5168.6 μmol m⁻² h⁻¹ and 0.69 to 20.56 mmol m⁻² h⁻¹ for N₂O, CH₄ and CO₂, respectively. Futian mangrove swamp in Shenzhen had the highest greenhouse gas fluxes, followed by Mai Po mangrove in Hong Kong. Sha Kong Tsuen and Yung Shue O mangroves in Hong Kong had similar, low fluxes. The differences in both N₂O and CH₄ fluxes among different tidal positions, the landward, seaward and bare mudflat, in each swamp were insignificant. The N₂O and CO₂ fluxes were positively correlated with the soil organic carbon, total nitrogen, total phosphate, total iron and NH₄⁺-N contents, as well as the soil porosity. However, only soil NH₄⁺-N concentration had significant effects on CH₄ fluxes.     

Emission of N2O and CH4 from a constructed wetland in southeastern Norway

The Skjønhaug constructed wetland (CW) is a free surface water (FSW) wetland polishing chemically treated municipal wastewater in southeastern Norway and consists of three ponds as well as trickling, unsaturated filters with light weight aggregates (LWA). Fluxes of nitrous oxide (N₂O) and methane (CH₄) have been measured during the autumn, winter and summer from all three ponds as well as from the unsaturated filters. Physicochemical parameters of the water have been measured at the same localities. The large temporal and spatial variation of N₂O fluxes was found to cover a range of − 0.49 to 110 mg N₂O–N m^− 2 day⁻¹, while the fluxes of CH₄ was found to cover a range of − 1.2 to 1900 mg m^− 2 day^− 1. Thus, both emission and consumption occurred. Regarding fluxes of N₂O there was a significant difference between the summer, winter and autumn, with the highest emissions occurring during the autumn. The fluxes of CH₄ were, on the other hand, not significantly different with regard to seasons. Both the emissions of N₂O and CH₄ were positively influenced by the amount of total organic carbon (TOC). The measured fluxes of N₂O and CH₄ are in the same range as those reported from other CWs treating wastewater. There was an approximately equal contribution to the global warming potential from N₂O and CH₄.     

低应变检测在桩基检测中的应用分析

近年来很多城市中的建筑物发生质量问题,桩基工程质量的检测就显得尤为重要.在桩基质量检测中,低应变检测技术具有快速高效、经济效益高等优点,但仍存在一些需注意的事项.因此,研究低应变检测在桩基检测中的应用,其中主要包括三大方面:资料的收集、采用和数据的解释.针对低应变法在桩基检测中的发展现状及原理,提出一些需要注意的事项,...     

Indoor and outdoor PM2.5 and PM10 concentrations in the air during a dust storm

Asian dust storms (ADS) originating from the arid deserts of Mongolia and China are a well-known springtime meteorological phenomenon throughout East Asia. The ventilation systems in office utilize air from outside and therefore it is necessary to understand how these dust storms affect the concentrations of PM_2.5 and PM₁₀ in both the indoor and outdoor air. We measured dust storm pollution particles in an office building using a direct-reading instrument (PC-2 Quartz Crystal Microbalance, QCM) that measured particle size and concentration every 10 min for 1 h, three times a day. A three-fold increase in the concentrations of PM_2.5 and PM₁₀ in the indoor and outdoor air was recorded during the dust storms. After adjusting for other covariates, autoregression models indicated that PM_2.5 and PM₁₀ in the indoor air increased significantly (21.7 μg/m³ and 23.0 μg/m³ respectively) during dust storms. The ventilation systems in high-rise buildings utilize air from outside and therefore the indoor concentrations of fine and coarse particles in the air inside the buildings are significantly affected by outside air pollutants, especially during dust storms.     

Ti/SnO2,Ti/SnO2-Sb2O3阳极电催化氧化酸性品红的试验研究

采用热氧化法制备了Ti/SnO2和Ti/SnO2-Sb2 O3电极,以酸性品红为研究对象,对两种电极材料进行了性能比较,考察槽电压、电流密度、电解质浓度对电催化氧化处理系统的影响.结果表明:热氧化法制备出的Ti/SnO2-Sb2 O3电极,其电催化性能明显优于Ti/SnO2电极;以Ti/SnO2-Sb2 O3为阳极,在酸性品红初始浓度为100 mg/L、电极间距为2.5 cm、电流密度为75mA/cm2、电解质浓度取12 g Na2SO4/L时,60 min后酸性品红的去除率达到了95.41％.     

路基强度的快速无损检测、评价与控制研究

在工程实例中路面的破损问题频频发生。路基作为路面的支撑结构,其强度的不足也是造成此类问题的原因。只有做到确保路基路面整体具有良好的使用性能,才能使最终的路基足够结实和耐用。本文对这项技术应该注意的事项进行积极探讨与研究。     

Temporal variation of nitro-polycyclic aromatic hydrocarbons in PM10 and PM2.5 collected in Northern Mexico City

With the aim to determine the presence of individual nitro-PAH contained in particles in the atmosphere of Mexico City, a monitoring campaign for particulate matter (PM₁₀ and PM_2.5) was carried out in Northern Mexico City, from April 2006 to February 2007. The PM₁₀ annual median concentration was 65.2 μg m^− 3 associated to 7.6 μg m^− 3 of solvent-extractable organic matter (SEOM) corresponding to 11.4% of the PM₁₀ concentration and 38.6 μg m^− 3 with 5.9 μg m^− 3 SEOM corresponding to 15.2% for PM_2.5. PM concentration and SEOM varied with the season and the particle size. The quantification of nitro-polycyclic aromatic hydrocarbons (nitro-PAH) was developed through the standards addition method under two schemes: reference standard with and without matrix, the former giving the best results. The recovery percentages varied with the extraction method within the 52 to 97% range depending on each nitro-PAH. The determination of the latter was effected with and without sample purification, also termed fractioning, giving similar results. 8 nitro-PAH were quantified, and their sum ranged from 111 to 819 pg m^− 3 for PM₁₀ and from 58 to 383 pg m^− 3 for PM_2.5, depending on the season. The greatest concentration was for 9-Nitroanthracene in PM₁₀ and PM_2.5, detected during the cold-dry season, with a median (10th-90th percentiles) concentration in 235 pg m^− 3 (66-449 pg m^− 3) for PM₁₀ and 73 pg m^− 3 (18-117 pg m^− 3) for PM_2.5. The correlation among mass concentrations of the nitro-PAH and criteria pollutants was statistically significant for some nitro-PAH with PM₁₀, SEOM in PM₁₀, SEOM in PM_2.5, NO_X, NO₂ and CO, suggesting either sources, primary or secondary origin. The measured concentrations of nitro-PAH were higher than those reported in other countries, but lower than those from Chinese cities. Knowledge of nitro-PAH atmospheric concentrations can aid during the surveillance of diseases (cardiovascular and cancer risk) associated with these exposures.