Quantifying uncertainty of the reference sampling procedure used at Dornach under different soil conditions

The reference sampling procedure, used in the CEEM soil project on a single test area at Dornach, had been applied under different soil conditions in a sampling proficiency test and in the Swiss national soil-monitoring network related to pollution (NABO). Methods of analysis of variance (ANOVA) were used to quantify sampling and analytical uncertainty. The soil sampling procedure and the chemical analysis were considered as two parts of the same measurement process and the so-called 'top-down' approach was used to quantify their combined contribution to the uncertainty. By this approach a systematic error of one sampler or of one laboratory becomes a random error when assessed as part of a multi-sampler or multi-laboratory comparison.     

A soil sampling strategy for mapping trace element concentrations in a test area

A sampling strategy, based on previous knowledge of a test area, was compared with a Reference Sampling in the frame of the EU-funded CEEM project. The aim was a comparison of sampling strategies for the drafting of concentration maps for a set of trace elements (Cd, Pb, Cu and Zn), with three-dimension information that can be used for risk assessment. The main constraint was that only 15 soil samples were to be analysed. The test area (in Dornach, Switzerland) included different soil types and land uses (forest, arable land and permanent grasslands). The sampling strategy proposed defined strata on the basis of land use, then applying a systematic regular sampling within each stratum. A composite sample was formed from each individual sample. In forests, H and Ah horizons were taken separately. In arable lands, a depth within the ploughed layer (0-15 cm) was analysed. In grasslands, samples were taken at two depths (0-10 and 10-20 cm) to provide information on the vertical variability. The comparison of the results obtained with those derived from the Reference Sampling allowed us to estimate if the information obtained from the proposed sampling strategy was sufficiently representative for an assessment of the level of elements considered. It was concluded that recommendations on sampling strategy depend on the interaction pattern of the element. In this case, for mobile trace elements, such as Cd, the information derived from sampling of two soil layers was not as important as that for the rest of metals studied that accumulated in the upper layer. If the H horizons in forests was not considered this led to unreliable predictions of the concentration levels, since the concentrations in H and Ah horizons differed irrespective of whether they were expressed in mg kg(-1) (the H horizon was enriched in those trace elements, except for Cd) and in mg m(-2) (the low bulk density of the H horizon led to a lower trace element level than in Ah horizon). Finally, in undisturbed systems such as grasslands, sampling 0-10 cm instead of 0-20 cm is recommended to prevent dilution of the concentration of trace elements.     

工程试验中抽样的不合理性

任何一项工程都离不开大量的种类品种繁多的建材,对其质量控制必须进行检测和试验,按照一定程序,用科学的方法,以检测结果--数据来最终做出质量合格与否的判定.     

Automatic sampling equipment and bod test nitrification

The influence of automatic sampling equipment on BOD test nitrification in non-nitrified final effluent was evaluated. Samples were tested for BOD, carbonaceous BOD, nitrogenous oxygen demand and concentration of nitrifying bacteria. Biofilms inside the equipment were tested for nitrification potential. A sampler utilizing continuous circulation of final effluent was found to support attached growth of nitrifying bacteria and was associated with relatively high effluent nitrogenous oxygen demand. The effluent nitrogenous oxygen demand and nitrification potential of attached growth were significantly less with a unit that aspirated effluent on an intermittent basis, purging the sample line with air before and after sampling. Peak nitrifier counts in samples from the continuous flow equipment exceeded those in samples from the intermittent flow equipment.     

秦皇岛地区细砂极限端阻力标准值取值探讨

以细砂作桩端持力层的两项工程为例，计算并探讨了细砂极限端阻力标准值的取值问题，提出了秦皇岛地区中密～密实细砂的极限端阻力标准值，建议参考使用本成果时，必须以载荷试验验证。     

A flexible methodology for the characterisation of soils: a case study of the heavy metal status of a site at Dornach

The sampling scheme devised to study the site at Dornach was successful in identifying most of the features and element distributions in the site using only 15 composite samples. The scheme was based on dividing the area into six individual sampling units each of which represented a different combination of land use and soil type. The three-dimensional information was obtained by taking samples at different depths, either on a fixed depth basis for cultivated soils or according to soil horizons for undisturbed soils. In each sampling unit the composite samples were bulked from 12 individual samples. The sampling point for each individual sample was chosen according to a stratified random plan. Key features of the scheme were the flexibility which required the use of experienced personnel and the fact that the sole task of the sampling exercise was to characterise the site with no preconceptions of possible outcomes. The results showed that the high concentrations of Cd in the soil probably resulted from the high concentrations of Cd in the underlying limestone and not primarily from atmospheric inputs. Higher levels of copper were found in soils close to fruit trees probably as a result of using sprays on the trees. The concentrations of Pb and Zn were relatively uniform throughout the site although there was some evidence of increased Zn concentrations with depth analogous to the Cd distributions. The fact that these findings were in agreement with the known characteristics of the site indicates the successful application of the chosen methodology in this study.     

三针式TDR探头测试区域范围分析及试验验证

在时域反射法（TDR）测试系统中,三针式探头作为应用最广泛的探头形式,其测试区域范围的确定是工程应用中一个重要问题。通过对比分析麦克斯韦方程及地下水渗流方程,利用岩土工程中常用的地下水渗流软件（如：Geostudio软件中SEEP/W模块）对一典型的三针式TDR探头测试区域范围进行计算,并设计了专门的试验对计算结果进行验证。结果显示：①地下水渗流分析软件对三针式TDR探头测试区域范围的计算结果与试验结果有较好的一致性；②三针式TDR探头的测试区域近似长半轴为33.0 mm、短半轴为20.7 mm的椭圆,且该区域内50%的电场能量集中在中间探针周围长半轴为10.7 mm、短半轴为8.7 mm的椭圆内,显示出较明显的“趋肤效应”；③介质的电导率对三针式TDR探头测试范围基本无影响。通过该研究,提出了三针式TDR探头测试范围的计算方法,为工程或试验中该种探头的设计提供了指导。     

室内环境污染物现场采样的分析与探讨

现场采样是室内环境污染物检测中的一个重要环节。本文从现场条件、选点、流量校准和采样记录等方面对此进行分析探讨,结合目前检测人员经常出现的一些不规范行为,就如何取得具有代表性的检测数据提出了建议。     

基准水泥的新鲜程度对速凝剂检测结果的影响

通过对五个厂家的速凝剂与不同新鲜程度的基准水泥的检测进行了分析,结果表明:随着基准水泥存放时间的延长,速凝剂的初凝时间和终凝时间均会延长,初凝时间最高延长3 min以上,终凝时间的最高延长10 min 6 s;1 d抗压强度最高降低14.9%,28 d抗压强度比有提高的趋势,最高可达11%。     

目前室内空气苯、TVOC检测中采样现状及分析

目前我国室内空气苯、TVOC检测的采样中,采样体积不准确的现象十分严重,本文就此进行了分析,发表了自己的观点,提出了解决问题的建议。     

泥灰及泥岩地区钻孔压水试验研究

结合工程实例,介绍了在泥灰、泥岩地区做钻孔压水试验的方法及压水试验过程中产生的问题和解决的方法,并提出了在该种地区做压水试验应注意的一些事项,同时得出了各钻孔压水试验的P—Q曲线以及变化规律。     

解读马来西亚槟榔屿乔治市街道景观的文化多样性

马来西亚槟榔屿乔治市是一个在多元文化影响下发展起来的城市，汇聚了马来西亚的三大种族——马来人、华人和印度人。 其历史街区富有文化多样性，为日常交通、商业活动、宗教祭祀活动、各民族日常生活提供空间。但随着乔治市的城市发展，人口 急速增长，街道景观的文化多样性遭到威胁。随着国际事件引发的多元文化保护浪潮，槟榔屿成功登陆世界遗产名录，以及马来西 亚国内政治格局的变化，槟榔屿乔治市历史街区文化多样性保护面临多样的契机和挑战。     

多雨地区路堤填料现场碾压试验研究

针对南方多雨地区公路工程遇到的工期紧张问题,为达到既可保证工程质量,又可加快施工进度的目的,在施工前进行了系统现场碾压试验,为确定合理的填筑控制参数提供了依据.     

十字板剪切试验在软土地区地基处理检测中的应用

结合具体工程实例,阐述了十字板剪切试验在软土地区地基处理检测中的应用,并验证分析了十字板剪切试验回归抗剪强度指标计算方法的适用性,最终得出了一些有意义的结论。     

Airborne viable, non-viable, and allergenic fungi in a rural agricultural area of India: a 2-year study at five outdoor sampling stations

The information on airborne allergenic fungal flora in rural agricultural areas is largely lacking. Adequate information is not available to the bioaerosol researchers regarding the choice of single versus multiple sampling stations for the monitoring of both viable and non-viable airborne fungi. There is no long-term study estimating the ratios of viable and non-viable fungi in the air and earlier studies did not focus on the fractions of airborne allergenic fungi with respect to the total airborne fungal load. To fill these knowledge gaps, volumetric paired assessments of airborne viable and non-viable fungi were performed in five outdoor sampling stations during two consecutive years in a rural agricultural area of India. Samples were collected at 10-day intervals by the Burkard Personal Slide Sampler and the Andersen Two-Stage Viable Sampler. The data on the concentrations of total and individual fungal types from five stations and 2 different years were analyzed and compared by statistical methods. The allergenicity of the prevalent airborne viable fungi was estimated by the skin-prick tests of >100 rural allergy patients using the antigenic fungal extracts from isolates collected with the Andersen sampler. The ranges of total fungal spore concentration were 82-2365 spores per cubic meter of air (spores/m3) in the first sampling year and 156-2022 spores/m3 in the second sampling year. The concentration ranges of viable fungi were 72-1796 colony-forming units per cubic meter of air (CFU/m3) in the first sampling year and 155-1256 CFU/m3 in the second sampling year. No statistically significant difference was observed between the total spore data of the 2 years, however, the data between five stations showed a significant difference (P<0.0001). No statistically significant difference existed between stations and years with respect to the concentration of viable fungi. When the data of individual allergenic fungal concentrations were compared between stations and years, no statistically significant difference was observed in all cases except for Aspergillus japonicus and Rhizopus nigricans, which showed significant difference in case of stations and years, respectively. The ratios between the total fungal spores collected by the Burkard sampler and the viable fungi collected by the Andersen sampler from all sampling stations ranged between 0.29 and 7.61. The antigenic extracts of eight prevalent viable airborne fungi (A. flavus, A. japonicus, A. fumigatus, Alternaria alternata, Cladosporium cladosporioides, Curvularia pallescens, Fusarium roseum, and R. nigricans) demonstrated >60% positive reactions in the skin prick test. These selected allergenic fungi collectively represented 31.7-63.2% of the total airborne viable fungi in different stations. The study concluded that: (i) a rich fungal airspora existed in the rural study area, (ii) to achieve representative information on the total airborne fungal spores of an area, the monitoring in multiple sampling stations is preferable over a single sampling station; for viable fungi, however, one station can be considered, (iii) the percentage of airborne fungal viability is higher in rural agricultural areas, and (iv) approximately 52% of the viable airborne fungi in the rural study area were allergenic.     

从孟加拉试桩工程对比国内外基桩试验的区别

结合孟加拉古拉绍燃气电厂基桩试验的工程概况及试验背景,对比了国内外基桩试验的区别,总结了国内外基桩试验的侧重点,并对国外工程的勘测设计实践提出了思考与总结。     

Theoretical analysis and model test for rainfall-induced shallow landslides in the red-bed area of Sichuan

Heavy rainfall is a key cause of shallow landslides in red-bed terrains with steep topography and residual soils of degradable strength. In this study, laboratory model tests were carried out to examine the characteristics of rainfall infiltration, deformation, and failures of slopes in the red-bed area of Sichuan. The hydrological response and deformation of the slope soil during rainfall are addressed. Based on a modified Green–Ampt infiltration model, ponding along the bedrock surface is incorporated. A physically based model for shallow landslides caused by rainfall is developed. The theoretical analysis and the model test results indicate that the slope failures are related to erosion in the shallow soil layer and rainwater infiltration, particularly along preferential seepage channels. The process of rainfall-induced shallow landslides can be separated into three stages: erosion at the slope toe, tension crack formation at the slope crest, and shallow sliding. When initial underground water level is located at the bedrock surface or the preferential seepage flow quickly reaches the bedrock surface, it is easier for the soil slopes to slide along the bedrock surface than along the wetting front.     

强干旱地区盐渍土高速公路路基沉降与应力测试

盐渍土地区修筑的高等级公路日益增多,对勘察设计、施工提出了更高的要求,在结合盐渍土研究成果和相关经验的基础上,对位于强烈干旱地区的高速公路盐渍土路基,在基底处理、路基填料选用、隔断层设置及路基沉降与应力测试等方面进行了探索。