氯盐渍土土-水特征曲线的试验研究

采用滤纸法和压力板法测定不同含盐量盐渍土的土-水特征曲线（SWCC）,探讨土中含盐量对盐渍土土-水特征曲线的影响。试验结果表明,粉土中含盐量对基质吸力土-水特征曲线的影响不大。采用滤纸法测得的总吸力与基质吸力之间的差值随着土中盐溶液浓度的增加而增加,且该差值要大于相同浓度纯盐溶液的渗透吸力,其原因是由于土颗粒表面对溶液吸附作用引起的,用滤纸法测得的基质吸力土-水特征曲线处于脱湿曲线和吸湿曲线之间。采用蒸汽平衡法测定Whatman 42号滤纸在高吸力阶段的总吸力的率定曲线,使得高吸力时用滤纸法测定吸力更为精确。     

深圳抽水蓄能电站水压致裂法三维地应力测量和分析

由于水压致裂法地应力测量的突出优点已在国内外得到广泛应用,但以往只能测量钻孔横截面上的二维应力状态。近期兴起的水压致裂法三维地应力测量,已在多个工程中得到应用。深圳抽水蓄能电站采用了3个不同方向钻孔测量法和单钻孔测量法进行了三维地应力测量,得到了很好的测量成果。其中单钻孔三维地应力测量,在近水平向和铅垂向两个钻孔中应用。三维地应力测量成果不仅得到了相应钻孔横截面上和原生裂隙面上二维应力实测值的检验,而且得到了同一位置两种不同三维地应力测量方法的相互印证,和同一个钻孔（铅垂向）中套芯应力解除法三维地应力实测值的印证。两种水压致裂法三维地应力测量成果（单钻孔测量法包含了非铅垂向和铅垂向钻孔的两种测量法）非常一致,能够代表该测量区的地应力状态。     

An evaluation of the carbon-14 beta track technique: Implications for solubilities and partition coefficients determined by beta track mapping

The accuracy and precision of absolute C concentrations measured by beta track autoradiography (BTA) have been evaluated by synthesizing ¹⁴CO₂-bearing glasses (0.5–2.0 wt.% CO₂) of albite and diopside composition and comparing the amount of CO₂ introduced into the glass to the amount measured by BTA. Measured CO₂ contents in diopside glass are less than loaded CO₂ contents, but agree within experimental error; measured contents in albite glass are greater than loaded contents by 10–50%, which exceeds experimental error in many cases. Carbon isotope fractionation between calcite and CO₂ vapor is not significant above 1000°C at 0.1 or 3.0 GPa and cannot explain the discrepancies. The discrepancies represent an error in BTA which has not been previously recognized and is apparently related to beta absorption.Based on this study, CO₂ concentrations in albite measured by BTA should be corrected downward by 40%, which would bring such solubilities into better agreement with those determined by infrared spectroscopy. CO₂ solubilities in diopside melts measured by BTA are in agreement with phase equilibria and are accurate to within 20%. Partition coefficients measured by BTA may be subject to analytical errors inherent to autoradiography. Lack of awareness of these potential errors casts doubt on the accuracy of these measurements in many cases.     

汶川地震紫坪铺面板堆石坝地震波输入研究

对国家强震动台网中心紫坪铺面板堆石坝区域台站实测主震记录以及大坝台网实测余震记录进行分析,研究主震与强余震地震动的基本特征。分别选取茂县地办、郫县走石山、成都中和这3组基岩台站实测主震地震动,紫坪铺台站2008年11月6日实测余震地震动以及按水工抗震规范人工生成地震动作为数值计算的地震动输入,对紫坪铺大坝进行三维动力有限元分析,并与实测结果进行对比。研究表明,郫县走石山与成都中和2个远场台站位于断层下盘,其实测地震动的加速度反应谱长周期（0.65 s以后）分量过于丰富,不宜作为断裂带附近紫坪铺大坝的地震动输入;紫坪铺大坝台站实测的余震地震动1 Hz附近（大坝基频）的频率成分相对较少,且持续时间较短,以至于难以激发大坝响应;对比坝顶实测地震动加速度反应谱和数值计算反应谱,建议汶川地震中紫坪铺大坝动力计算时可采用茂县地办台站实测地震动或按抗震设计规范反应谱人工生成地震动。     

A new interpretation of measured ionic diffusion coefficient in compacted bentonite-based materials

Previous model based on free-water properties to interpret the measured diffusion coefficient in compacted bentonite-based materials is demonstrated to be inadequate. A model considering ionic diffusion in clay surface (bound) and interstitial (free) water is presented to interpret the measured diffusion coefficients and to explain the possible reasons for the discrepancies in the data. The measured diffusion coefficient is determined by the predominant diffusion pathway, which depends on the charge of diffusing species, soil fabric, diffusion time and by the starting concentration condition of the method used.     

隧洞工程弹性参数反演的可辨识性及量测优化布置探讨

探讨依据完备的量测信息开展弹性参数反演的可辨识性及量测的优化布置,对于指导岩土工程反演实践具有重要的实用价值。利用平面弹性复变函数方法和一般弹性理论,推导出任意形状隧洞的位移、应力解析表达式,基于隧洞围岩位移、应力的解析解,依据参数可辨识条件和量测优化布置的最灵敏原则,探讨了地下隧洞工程弹性反演参数的可辨识性及测点优化布置,并通过算例进行了验证。研究表明,依据完备的量测信息开展弹性反分析,只要测点布置方式适当、反演参数满足相应的限定条件,可同时惟一辨识出5个参数P、Q、M、E、μ。参数反演的可辨识性受隧洞形状复杂性的影响,随着隧洞复杂性的提高,参数可同时惟一辨识需满足的限制条件大为减少,对测点布置方式的要求也会降低。工程实践中,为避免量测数据的少量误差导致反演计算结果的大幅度波动,测点(线)应根据最灵敏原则优化选择各反演参数的灵敏系数最大的测点(线)组合进行量测布置。     

Particulate matter concentrations in a high-quality rubber-tyred metro system: the case study of Turin in Italy

Particulate matter concentrations measured in railway metro systems are consistently higher than at street level (up to an indoor/outdoor ratio equal to 10), with dangerous effects for passenger health. These concentrations are mainly produced both by the mechanical friction and wear processes at the rail-wheel-brake interfaces and by the re-suspension caused by the turbulence generated by the train transit. The literature abounds in case studies dealing with the elevated concentrations and the analysis of the atomic composition of particulate matter as well as the epidemiological studies regarding the effects on human health. By contrast, the problem of reducing particulate matter concentrations was not much discussed. Starting from these considerations, the aim of this research was to investigate the PM concentrations of a “high-quality” metro system equipped with useful devices for reducing these concentrations: rubber-tyred, platform screen doors, an advanced ventilation system and a variable slope of the longitudinal profile. A measurement campaign was performed in the metro of Turin (Italy). Experimental results show that the indoor concentrations are statistically lower than those measured in outdoors; that particulate matter levels are closely correlated to the train frequency; the particulate matter concentrations measured inside trains are lower than the ones measured at station platform. From these results, it is possible to note that particulate matter concentrations measured in a “high-quality” metro system are significantly lower than the ones measured in “traditional” railways. This result is significant and poses the bases for the definition of useful interventions for retrofitting metro systems.     

农田N_2O通量测定方法分析

采用空气动力学方法、波文比 /能量平衡法及密闭箱法结合气相色谱分析对农田N2 O通量进行了测定。在夏天和秋天观测前的 1～ 2周 ,148和 10 9kgNhm-2 肥料被分别施入夏玉米田和冬小麦田。实验表明 :空气动力学法与波文比 /能量平衡法测定的N2 O通量在冬小麦田较为接近 ,在夏玉米田则相差较大。夏玉米冠层上方温湿梯度的细微变化可导致能量平衡法计算的N2 O通量发生较大离散 ,从而与空气动力学法的计算结果产生较大偏差。观测期间 ,微气象法和密闭箱法测定的农田N2 O日平均通量在夏玉米田分别为 18± 37和 8± 5ngNm-2 ·s-1;在冬小麦田分别为 43± 2 1和 6± 1ngNm-2 ·s-1。微气象法测定的农田N2 O通量高于密闭箱法的观测值 ,由此推测作物冠层可释放N2O ,其机制可能是土壤中生成的N2 O被作物的蒸腾液流输送到大气中。微气象法和密闭箱法测定的N2 O通量间的差异在冬小麦田大于夏玉米田 ,表明冬小麦释放N2 O的量大于夏玉米。这可能是冬小麦根系分布较夏玉米深的缘故。采用密闭箱法观测时 ,箱内气温发生变化 ,半小时内最高可增加10℃ ,因地温变化小 ,其对土壤中N2 O的生成并无显著影响。由于密闭箱法观测忽略或低估了植物释放的N2 O ,且箱内的边界层阻力可能高于箱外 ,其测定的地表N2 O通量偏小。     

井筒及围岩应力,应变观测方法研究

采用最新研制的岩体应力、应变匹配传感器对西安立井煤柱开采引起的井筒附加应力特别是对井筒穿过断层附近产生的附加应力进行了较系统的观测，并对观测结果进行了分析和总结。     

中粗砂地层中顶管顶进力计算分析

以长春市伊通河排水管网改造工程为例,通过现场实测中粗砂地层条件下采用泥水平衡顶管顶进过程中顶进力的变化情况,系统研究了影响顶进力的因素及其变化规律,并对顶进力的计算进行了理论分析,与实际顶进力进行了对比,最后运用Matlab软件对实测数据进行数值分析,得出在该地质条件下的泥水平衡顶管摩阻力和顶进力计算公式。     

Extraction algorithm of mining subsidence information on water area based on support vector machine

Information on subsidence in a water area caused by mining has a great value on the research of the mining subsidence law of a mining area with a high groundwater level in Eastern China. Based on the measured data of the subsidence area without water, the data extraction of subsidence in a water area is studied in this paper, with a support vector machine, as subsidence in such an area is difficult to measure. Research shows that the training sample number and dimension should be strengthened by increasing the measuring times or using the interpolation method to obtain ideal prediction accuracy. The ε-Support Vector Regression model with three parameters optimized by the genetic algorithm or the particle swarm optimization algorithm is suitable to extract subsidence information in a water area caused by mining, and the algorithm is accomplished on Matlab. Data analysis showed that when the water is deeper than 1.8 m and the distance is over 60 m from the measured points, the prediction error of test samples will exceed 10 % out of all measured results, meaning that practicability is relatively poor; while water depth is <0.8 m or the distance is lower than 60 m from the measured points, the prediction error of test samples will be calculated to <5 % of the measured results, the prediction results can be used.     

挡墙水平变位诱发地表沉降的简化解析解

推导了平移模式下的地表沉降理论显式解,在此基础上提出了任意挡墙变位诱发墙后地表沉降的简化计算方法。分别与平移、绕墙趾及绕墙顶等3种变位模式下的弹性有限元数值解进行对比分析,对简化解析方法进行了验证。最后将这一简化解析方法应用于工程案例预测,与软土地基现场实测结果进行对比,发现理论预测的地表沉降曲线与实测值相吻合,且较准确地预测了最大沉降发生的位置,表明了该简化解析方法的实用性。     

氯化铵-乙醇法测定蛭石的阳离子交换容量

采用氯化铵-乙醇法测定了蛭石精矿的阳离子交换容量。实验结果表明:氯化铵-乙醇法测定蛭石精矿的阳离子交换容量时,必须使蛭石充分润湿分散,以利于NH₄⁺与蛭石层间阳离子的充分交换。甲醛法滴定NH₄⁺含量时,必须消除甲酸的影响,并且不加热待滴定液可以获得较准确的测试结果。实验测得蛭石精矿的阳离子交换容量为60.8824×10^-3mol/100 g。     

伽马能谱测量在陆地伽马空气吸收剂量率评价中的应用

2002～200年,国内首次采用就地伽马能谱测量方法在广东珠海市进行了面积性测量,并用该方法定量解释求得的钾、铀、钍含量用Beck公式估算了地表1 m高处的吸收剂量率,同时用塑料闪烁体X-γ吸收剂量率仪在相同测点做了比对测量.2种方法对比结果(514个测点)显示很好的一致性,珠海市区实测吸收剂量率和伽马能谱估算吸收剂量率平均值分别为(145.07±26.5) nGy/h和(162.10±1.51) nGy/h,计算结果与实测结果的相对误差为11.74%.     

一种新的实测地层剖面绘制方法

当前常采用导线法绘制实测地层剖面,但该法常导致常规导线段在总导线方位上确定的地层边界点不是真实的边界,特别是平移导线段在实测地层剖面图上确定的地形线与岩性线之间产生了比较大的夹角。本文针对导线法绘图的这些缺陷,提出了绘制地层剖面的一个新方法——三维投影法：1）常规导线在总导线方位上确定的地层边界点为真实的地层边界位置,且三维投影法绘制的地层剖面图与总导线方位上的图切剖面一致;2）平移导线只在导线平面图中展现,而不出现于地层剖面图中,消除了地形线与岩性线之间存在夹角和平移导线处理的多解性问题。     

Estimation of error in the determination of Al in stone meteorites by indirect γ-ray spectrometry

The error involved in the determination of the Al²⁶ concentration by the method of Rowe and his co-workers was measured and the values they reported should be increased by a factor of 1.36 ± 0.05. The potassium contents of the meteorites measured by Roweet al., are not affected by this error and can be used with confidence.     

Study on permanent ground displacement induced by seismic liquefaction

Permanent ground displacement as induced by seismic liquefaction was measured in the area which was recently hit by an earthquake. The measurement was carried out by comparing two aerophotographs of the area which were taken before and after the tremor. Using the measured data an empirical equation was derived which can calculate the magnitude of the displacement briefly. Furthermore, a finite-element technique was developed in order to predict the magnitude and the direction of the displacement in more precise manners.     

基于BOTDR的基坑变形分布式监测实验研究

在基坑开挖和支护过程中深部土体的水平位移监测是一项十分重要的工作。布里渊光时域反射计（BOTDR）是近年来国际上研发成功的一项新型的分布式光电传感技术。通过该技术,将传感光纤按照一定的工艺粘贴在埋置于土体中的测斜管上,由传感光纤实测的应变分布,可以实现深部土体水平位移的在线监测。通过室内的模型模拟试验,由实测的光纤应变可以准确地得到测斜管上任意一点的水平位移。结合南京市某深基坑进行的现场试验,探讨了基于BOTDR的分布式光纤传感器应用于基坑深部土体水平位移监测的具体施工工艺,验证了该技术在实际工程中应用的可行性。     

Blast overbreak measurement by light sectioning

Summary In this new method for measuring the cross-section of tunnels and other excavations, the opening is outlined by a plane of light projected from a conical mirror. The image is recorded on videotape, enhanced, then measured by microcomputer. The measured profile is compared automatically with the specified profile to give values for overbreak and underbreak.Trials in Mexican tunnels and at an underground mine in Canada have evaluated the technique in relation to traditional mechanical, photographic, and surveying alternatives. Results indicate that the light sectioning method requires less than a minute per profile and no surveying skills. Costs are low, and the measurements are accurate to within a centimetre or two. Using the same photoanalysis technique and software, rock quality can be measured at the same time and place as overbreak, which helps the engineer to decide whether overbreak is caused by geological conditions or by deficiencies in blasting.     

Galvanic interaction between grinding media and arsenopyrite and its effect on flotation: Part II. Effect of grinding on flotation

Arsenopyrite floatability was correlated with the galvanic current, calculated from polarization curves measured during grinding, as well as the amount of oxidized iron, measured by EDTA extraction, in the mill discharge. The adverse influence of galvanic interaction during grinding on arsenopyrite floatability was quantified.