边坡稳定可靠性的随机有限元分析   总被引：9，自引：2，他引：9  

傅旭东  茜平一  刘祖德 《岩土力学》2001,22(4):413-418

随机有限元法可以处理土性参数的变异性和空间相关性。对二阶摄动随机有限元法的摄动理论和程序进行了研究，提出了偏导矩阵的组集方法，采用正态分布随机变量的正交变换法来提高计算效率。考虑土性参数随机场作用和土性指标之间的互相关性，建立边坡局部抗剪和总体稳定性可靠度的随机有限元分析模型，对某实际土坡进行了可靠度计算，计算结果较为符合实际。  相似文献   

冷家沙三段砂岩成岩序列与孔隙演化   总被引：3，自引：0，他引：3       下载免费PDF全文

谭荣  黄思静  赵霞飞 《沉积与特提斯地质》2001,21(1):44-49

笔者以辽河盆地冷家地区冷94井为例，通过铸体薄片、电镜扫描、能谱 阴极发光等分析和实验手段，对沙三段砂岩的成岩历史、成岩序列与孔隙演化及发展趋势刊物, 出成岩阶段可划分为同生期→早成岩阶段早期→早成岩阶段晚期→晚成岩阶段早期。孔隙演化主要在压实作用，粘土矿物的包膜作用，方解石、白云石的胶结作用，长石溶蚀作用、石英的次生加大和微晶石英的沉淀作用等方面进行了研究，阐述并总结了它们互相之间的内在联系。  相似文献   

探地雷达天线方向特性探讨   总被引：1，自引：0，他引：1  

刘志新  王志勇  岳建华 《物探与化探》2001,25(1):45-49

利用电磁波的传播特点,对元天线、对称振子及其天线阵辐射电磁波的方向性做进一步的探讨,并分析各因素对其辐射方向性的影响。  相似文献   

长清井田环境水文地质特征分析与评价     

吴恩江 《中国煤田地质》2001,13(4):45-46

在分析井田环境水文地质特征的基础上，利用浅层地下水的分析测试资料，依据水环境污染综合评价指数方法对浅层地下水环境质量的现状进行了评价。简要阐述了矿区开发对地下水资源可能造成的影响，矿区开发后地下水环境的一些变化趋势及初步预防措施，为将来矿井设计、建设和生产过程中浅层地下水环境的保护和利用提供了参考资料。  相似文献   

岩土力学数值模拟中力学参数的确定方法   总被引：4，自引：0，他引：4  

兰恒星  伍法权 《世界地质》2001,20(1):66-71

力学参数的选取是进行岩土力学数值模拟的关键，它直接决定了模拟结果的合理性。不同的力学模型需要选取不同的计算参数，经验值在参数的确定过程中具有一定程度的参考价值，几种变形参数和强度参数的现场尺度转化方法解决了室内土工实验参数的现场应用问题，提出了进行力学参数和计算模型合理确定的推断模型的概念，并对推断模型实现的思想和步骤进行了较为详细的讨论。  相似文献   

松辽盆地地热资源的形成与远景评价     

谭世燕  石义强  赵育捷 《世界地质》2001,20(2):155-160,2091

松辽平原在地貌和地质上都是一个盆地。盆地中心区域上地幔隆升形成地幔枕，使本地区成为地壳中的一个热点，具有较高的地热背景。盆地是汇水区，盆地中部地域自然就成为地下热水主要的分布区。松辽盆地地热资源开发远景大有希望。  相似文献   

新全球动力学理论与成矿作用     

胡建卫  王宏君  杨志华  李勇  苏生瑞  周义 《矿物岩石地球化学通报》2001,20(4):337-343

成矿作用的本质是成矿流体子系统在统一地质 成矿场中与其它子系统在远离平衡系统的动态过程中所能达到平衡的程度。成矿物质的来源和矿床的富集部位都受新全球动力学理论 -涡旋甩出说以及由它所决定的抽拉构造和多重岩片的控制。  相似文献   

Broadband synthetic aperture borehole radar interferometry   总被引：1，自引：0，他引：1  

I. Mason  N. Osman  Q. Liu  C. Simmat  M. Li 《Journal of Applied Geophysics》2001,47(3-4)

Trials in mines have established that wideband VHF borehole radars (BHR), working in the 10–100-MHz band, can be used to probe the rockmass between boreholes over ranges from <5 m to as much as 150 m with submeter resolution. There is evidence that ore bodies reflect these radar signals both specularly and diffusely, much as the ground/air interface does when overflown by synthetic aperture radar (SAR). In both SAR and BHR, multiple flight lines, together with diffuse reflections admit the possibility of developing interferometric 3D images of the object. This paper examines the possibility of imaging buried objects in three dimensions by interferometrically combining broadband VHF borehole radar profiles shot in adjacent pairs of boreholes. Broadbanding in BHR has the advantage of releasing the image from 2nπ phase ambiguities, but practically, interferometric borehole radar (InBHR) needs high signal-to-noise ratios (SNR) to avoid noise capture. This means that 3D InBHR is limited to ranges in wavelengths which are less than the rock's attenuation factor Q. Interferometric methods are developed which are capable of mapping ore bodies and other structures in three dimensions. Tangent plane migration methods are developed here in order to reconstruct surfaces that lie in the near-field of sparse interferometric arrays.  相似文献   

Modelling of space weather effects on pipelines   总被引：1，自引：0，他引：1  

Antti Pulkkinen  Risto Pirjola  David Boteler  Ari Viljanen  Igor Yegorov   《Journal of Applied Geophysics》2001,48(4)

The interaction between the solar wind and the Earth's magnetic field produces time varying currents in the ionosphere and magnetosphere. The currents cause variations of the geomagnetic field at the surface of the earth and induce an electric field which drives currents in oil and gas pipelines and other long conductors. Geomagnetically induced currents (GIC) interfere with electrical surveys of pipelines and possibly contribute to pipeline corrosion.In this paper, we introduce a general method which can be used to determine voltage and current profiles for buried pipelines, when the external geoelectric field and the geometry and electromagnetic properties of the pipeline are known. The method is based on the analogy between pipelines and transmission lines, which makes it possible to use the distributed source transmission line (DSTL) theory. The general equations derived for the current and voltage profiles are applied in special cases. A particular attention is paid to the Finnish natural gas pipeline network.This paper, related to a project about GIC in the Finnish pipeline, thus provides a tool for understanding space weather effects on pipelines. Combined with methods of calculating the geoelectric field during magnetic storms, the results are applicable to forecasting of geomagnetically induced currents and voltages on pipelines in the future.  相似文献   

Onset voltages of atmospheric corona discharges on coniferous trees     

L. Aubrecht  J. Koller  Z. Stanek 《Journal of Atmospheric and Solar》2001,63(18)

In this article, the phenomenon of generation of corona discharges on the tops of trees and plants is described. In the first part of the text, the conditions for generation of this electric field which leads to formation of corona discharge and transfer of electric charge between atmosphere and Earth, are discussed. Experimental results of the onset voltage and its dependence on the discharge parameters are presented. The coincidence between released species from corona burning point and surrounding atmosphere is also discussed. Equation for the calculation of critical intensity of the electric field and onset voltage in dependence on radius of the tip are also discussed and compared with experimental data and equations for current–voltage characteristics are described. The attempt to explain differences between theory and measured data is proposed.  相似文献