20世纪90年代以来机械防砂技术的新进展

防砂对于出砂油藏有着重要意义，防砂的成功与否直接关系到油气藏是否能够正常开发。随着新科技和新材料的不断发展和完善，机械防砂技术也获得了日新月异的进展。特别是20世纪90年代以来各种新的防砂技术在油田现场应用均取得了良好的效果。论述了20世纪90年代以来机械防砂技术的现状及发展趋势。     

砂土液化中颗粒分析试验试剂用量标准的研究

采用不同剂量的六偏磷酸钠试剂，对GB／T50123—1999《土工试验方法标准》中的密度计法(甲种密度计)做颗粒分析试验的结果进行对比分析^[1]，由此对4％六偏磷酸钠溶液用量与分析结果的关系以及10m1的标准用量进行验证与探讨。     

青海高寒湖沼景观区风成沙对成矿元素迁移的扰动机制的研究

青海高寒湖沼景观区是风成沙沉降区,由于风成沙的干扰,水系沉积物-0目的粒级段多数元素异常大幅度降低,甚至消失.研究表明,风成沙扰动层的元素分维呈现突变特征.根据固定沙丘和流动沙丘优势粒级混合扰动特征,计算了粒级因素系数,试验结果说明粒级因素系数可以较好地描述风成沙混入量特征.用突变理论的折叠突变势函数公式,计算了组分扰动因素系数,计算结果与扫面试验结果非常吻合.高寒湖沼景观区域化探采样介质以-4(或-10)～+40目为宜.     

雅鲁藏布江两岸风成沙覆盖区地球化学找矿方法及效果

依据西藏山南雅鲁藏布江河谷两岸及风成沙覆盖区表生地球化学作用特征，探讨了地球化学勘查方法技术，指出采用沟谷中岩屑地球化学测量在野外1：5万地球化学普查中更便于开展，同时可避免风成沙的干扰，找矿的效果较好。在矿物呈中、粗粒结构岩石分布区采集0．25mm-2．00mm粒级水系沉积物存在异常稀释的情况。认为土壤地球化学测量不适宜于在该区内开展。     

三极断面测深技术在第四系水源地勘探中的应用

介绍了三极断面测深技术在第四系水源地勘探中的应用。钻探验证结果表明，该方法能够准确地圈定第四系地层中的含水体，可为供水水源地选择提供必要的地质资料。     

Field measurement and numerical modelling of aeolian mass flux distributions on a sandy beach

ABSTRACT The vertical and horizontal distributions of aeolian mass flux were measured at Oceano Dunes, California, and these data were used to evaluate a numerical model of saltation. Grain‐size analyses showed that the distributions of the modal sediment size class corresponded closely to those of the total sediment population, and modelling thus focused on replicating the distributions of the mean grain size. Although much previous work has assumed that the mean launch speed of saltating particles varies in proportion to shear velocity, simulations using a constant mean launch speed were found to yield the closest approximations to the mass flux distributions observed in the field. Both exponential and gamma distributions of launch velocity produced realistic simulations, although the latter approach required the inclusion of an additional reptation component to achieve good results. A range of mean launch angles and an equivalent sphere correction were also found to generate comparable results, providing the other input parameters could be varied freely. All the modelling approaches overestimated the proportion of mass flux occurring at the bottom of the vertical distributions, and underestimated the proportion occurring at the upwind end of the horizontal distributions. No theoretical shortcoming that would account for these small, but systematic, discrepancies could be identified, and experimental error thus represents a more plausible explanation. The conclusion that mean grain launch speeds are essentially constant and independent of shear velocity suggests that the additional kinetic energy extracted by grains under more energetic wind conditions is largely transferred to the bed, and that increases in the transport rate are therefore driven primarily by the ejection of additional grains. It is suggested that the kinetic energy of rebounding grains is constrained by the ability of the bed to resist deformation, equivalent to a plastic limit. Hence, grains of larger mass (diameter) rebound from the bed at lower speeds, and follow shorter, lower trajectories, as has been widely observed previously.     

Thermal Ionization Mass Spectrometry （TIMS）－U－Series Ages of Corals from the South China Sea and Holocene High Sea Level

1IntroductionTostudyglobalchangesinthepast (PAGES) ,i.e.,paleo climaticandpaleoenvironmentalchanges,itisnecessarytoestablishahigh resolutionandhigh precisiontimescale .Lateinthe1 980s,Edwardsetal.( 1 987,1 987)developedthethermalionizationmassspectrometry U seriesdatingmethod (TIMS)andtheyusedthismethodtoconducttheprecisedatingofthecharacteristicclimateeventssincethelastinterglacialperiod .Theirscientificpracticearousedgreatinterestofsci entificworkersengagedinQuaternaryenvironment (Peng…     

粘性土-砂井地基单井固结模型的改进

单井固结模型的计算中通常将砂井周围土体简单划分为涂抹区和非涂抹区,不符合实际砂井周围土体的渗透系数分布复杂的事实。本文在Terzaghi固结理论的基础上提出了改进的单井固结模型,以一个待定参数流量系数Cq取代涂抹区和非涂抹区渗透系数来刻画砂井周围土体的横向渗透性特征,使单井固结问题得到高度简化又不失严密性。本文将改进模型用于非完整砂井单井固结的最终沉降量的数值计算,并将计算结果与谢康和改进法以及Hart法的解析解进行了比较,证明了改进模型数值解的可靠性。     

河砂资源过度开采对水环境的破坏暨环境地质问题--以山东大汶河河砂开采为例

河砂既是矿产资源，也是宝贵的环境资源，具有涵养水分、保护环境的作用。河砂资源的过度开采，既引起了河岸坍塌地质灾害，又对沿河水环境特别是地下水环境造成破坏。大汶河河砂开采造成了河岸坍塌、河桥报废。使沿河第四系孔隙水和旧县水源地岩溶地下水水位下降，地下水开采资源减少，水质变差。分析结果表明，大汶河河砂的过度开采，不利于环境保护、不利于长远经济和社会效益，应予取缔或严格限制开采规模。     

Assessment of temporal changes in coastal sand dune environments using the log-hyperbolic grain-size method

Abstract Three cores (<9 m long) recovered from late Holocene coastal sand dunes in Northumberland, north‐eastern England, were examined stratigraphically and dated by the infrared stimulated luminescence (IRSL) method to the time period between the Medieval Warm Period (MWP; ≈ 900–1200 AD) and Little Ice Age (LIA; ≈ 1550–1800 AD). Grain‐size variability and CaCO₃ content were determined at 10‐mm intervals throughout parts of the cores. The sahara computer program was used to plot the log‐hyperbolic distribution (LHD) of grain‐size spectra from different stratigraphic levels and estimate the LHD's statistical components. Core samples plot variously in the depositional and erosional domains of the hyperbolic chi (χ) vs. xi (ξ) shape triangle, which describes components of sediment sorting. Depositional and erosional phases, discriminated within the LHD's shape triangle, cannot readily be resolved from core stratigraphies or correlated between cores. IRSL dates from single cores show a clustering about the period 1430–1540. Between the dated horizons, dunes accreted at ≈ 0·02–0·05 m year^?1, enabling the timing of excursions in χ and ξ to be estimated. These excursions, which can be resolved to the subannual level between the dated horizons, may be related to deposition by episodic storms or storm surges in the North Sea region, which is supported by historical documentary evidence. This innovative use of the LHD method and its derived statistics can be used successfully to describe temporal trends in coastal depositional environments and identify likely storm events in dune sediment records.