孔隙流体对岩体变形局部化的影响及数值模拟研究

本文首先叙述了孔隙流体对固体变形局部化影响的若干研究进展,并利用三维连续体快速拉格朗日分析,模拟了孔隙压力对岩体变形局部化应变场(剪切带)的影响。数值模拟结果表明,孔隙压力对变形局部化应变场有较大影响,随着孔隙压力的增加剪切带趋于不明显,岩体试件倾向于发生拉伸破坏。      

南京地铁稳定性优势面理论分析

以南京地铁为例,运用优势面理论分析方法,对控制城市浅埋隧道稳定性的优势断裂进行了分析。并对土体中具有规模效应的构筑物的稳定性分析发展了一套工程地质层组划分和优势层判定的分析方法。通过对南京地铁场区优势断裂和优势层的分析。确定南京－湖熟断裂和定淮门－彭楼断裂为控制场址区工程地基稳定性的场区优势断裂,并控制着鼓楼岗和小红山地铁隧道的稳定性;地铁隧道在土层中最佳持力层为O3的硬粘土层Ⅲ1,其次为Q3的软粘土层Ⅲ2。敏感层为Q3的软粘土层Ⅱ2和饱和松砂层Ⅱ4,在保证工程的稳定性和经济的可行性情况下,地铁隧道的底部标高以－5－－15m为宜。     

秦岭黄淮平原交界带自然地理特征

The features of physical geography in the transitional region between Qinling Mountains and Huanghuai Plain possess transitional characters evidently in two directions： one is from the western mountain to the eastern plain and the other is from southern subtropical zone to northern temperate zone. Torrential rain, especially strong torrential rain is frequent in the transitional region, and there are many torrential rain centers. A majority of torrential rain is distributed among 100-200 m asl. The winter temperature at 100-400 m asl is higher than that in Huanghuai Plain whose altitude is lower than that of the transitional region, and the highest temperature in January appears at 350-400 m asl.The thickness of warm slope belt in the transitional region varies from 100 m to 250 m asl. The formation of torrential rain and warm slope belt is the result of joint action of atmospheric circulation and local terrain. Frequent torrential rains and warm slope belt had tremendous influences on the soil properties, plant distribution and local climate in the transitional region.     

艾比湖水面近50a变化成因分析

20世纪90年代以来,艾比湖水面面积持续增大,湖区生态环境明显改善,与60、70年代水面面积急剧缩小、湖区生态环境严重恶化形成鲜明对比.针对艾比湖水面面积近50a变化过程,利用入湖径流及有关水文、气象资料,分析河流丰枯变化对入湖径流的影响、农业引水量与降水的关系,研究了艾比湖水面面积近50a变化成因.     

基于多进制小波的SPOT全色影像和多光谱遥感影像融合

基于多进制小波理论,本文研究了ＳＰＯＴ全色影像与多光谱遥感影像数据融合的理论和方法,并在三进制情形,对１０ｍ分辨率ＳＰＯＴ影像和３０ｍ分辨率多光谱影像进行了实验,同时对实验结果进行了分析和讨论。理论和实验表明,基于多进制小波的遥感影像数据融合具有好的效果,并可用于广泛的研究领域。     

Local Similarity Relationships of Non-Dimensional Wind and Temperature Gradient in the Tower-Layer Atmosphere over Beijing City

Micrometeorological data for wind and temperature from a 325 m high tower in Beijing City are analyzed by use of local similarity theory. Non-dimensional wind and temperature gradients, Фm and Фh, are determined by three techniques called, respectively, eddy-correlation, mean profiles and inertia-subrange cospectra (ISC) method for a wide range of atmospheric stratification from unstable to stable conditions. Average dissipation rate Фε of turbulent kinetic energy (TKE) is evaluated from u-spectrum, as a quantity required in the last technique. Ratio of the eddy transfer coefficients. α (= Kh / Km,), is calculated from Фm and Фh estimations. The results from various techniques are compared with each other and with some available empirical results in the tower-layer. It is shown that the empirical relationships determined by mean profiles and ISC methods in the tower-layer turbulence are in agreement with each other and with some other results.     

河南烟区与云南优质烟区气候生态系统的灰色关联分析

运用灰色系统理论分析了河南新老烟区与云南优质烟区气候生态系统的灰色关联性 ,结果表明 ,卢氏烟区气候生态系统与玉溪烟区的相似性优于许昌烟区与玉溪烟区的相似性。因此 ,建议河南优质烟区向豫西丘陵山区转移     

Selection of the wavenumbers k using an optimization method for the inverse Fourier transform in 2.5D electrical modelling

An optimization method is used to select the wavenumbers k for the inverse Fourier transform in 2.5D electrical modelling. The model tests show that with the wavenumbers k selected in this way the inverse Fourier transform performs with satisfactory accuracy.     

全国年度地震重点危险区与地震相关性的统计模拟分析

用统计模拟的方法对1990～1997年全国年度重点危险区与地震的相关性进行了分析．由于统计模拟的方法有效地处理了地震和危险区的时空不均匀性,并且得到经运算105 次的统计模拟随机预报概率,将其与实际预报平均概率比较,得到较为客观的结果．结果表明:① 1990～1997年全国年度重点危险区的实际预报平均概率,比完全平均随机划定预报区的统计模拟平均随机概率高0.03719;② 考虑地震活动背景概率时,实际预报平均概率比危险区加权重的统计模拟平均概率高0.02183;③ 将中国大陆依地震分布不均匀性分为新疆西部地区、西南地区和其它地区３个区时,新疆西部地区的实际预报平均概率大大高出统计模拟平均随机概率,其差值为0.20962．