Soil properties and performance of landmine detection by metal detector and ground-penetrating radar — Soil characterisation and its verification by a field test     

Kazunori Takahashi  Holger Preetz  Jan Igel   《Journal of Applied Geophysics》2011,73(4):368-377

Metal detectors have commonly been used for landmine detection, and ground-penetrating radar (GPR) is about to be deployed for this purpose. These devices are influenced by the magnetic and electric properties of soil, since both employ electromagnetic techniques. Various soil properties and their spatial distributions were measured and determined with geophysical methods in four soil types where a test of metal detectors and GPR systems took place. By analysing the soil properties, these four soils were classified based on the expected influence of each detection technique and predicted soil difficulty. This classification was compared to the detection performance of the detectors and a clear correlation between the predicted soil difficulty and performance was observed. The detection performance of the metal detector and target identification performance of the GPR systems degraded in soils that were expected to be problematic. Therefore, this study demonstrated that the metal detector and GPR performance for landmine detection can be assessed qualitatively by geophysical analyses.  相似文献   

冲击载荷作用下准脆性材料Ⅱ型裂纹扩展研究   总被引：1，自引：0，他引：1  

袁琳  徐涛  赵高峰  杨岳峰  陈庚 《岩土力学》2011,32(10):3155-3162

冲击载荷作用下准脆性材料的动态断裂一直是关注的热点问题,Ⅱ型裂纹试样受冲击剪切时其裂纹扩展方向同材料力学性质和冲击速度等密切相关。应用岩石动态破裂过程动态分析系统软件,对单边平行双裂缝试样开展了冲击载荷作用下的裂纹动态扩展数值模拟,分别研究了不同材料力学性质、材料均质度、入射应力脉冲幅值和历时对II型裂纹动态扩展的影响。数值模拟结果表明,纯II型裂纹在动荷载作用下的扩展,不仅受到剪切损伤,而且还存在拉伸损伤;准脆性材料的非均匀性导致了主裂缝周围产生大量微裂纹的破坏,影响裂缝的分岔和内部的应力值;应力幅值和应力脉冲历时分别超过某一定值时,主裂缝将出现分叉现象,试样的破坏程度加剧,其研究结果对于深入揭示准脆性材料在动荷载作用下II型裂纹扩展的规律及准脆性材料的损伤断裂机制具有重要的参考价值。  相似文献   

变差函数在储层评价及开发中的应用:以杨家坝油田为例     

李武广  杨胜来  邵先杰  李敏  石磊  单宇 《地质科技情报》2011,30(4):83-87

目前江苏省杨家坝油田已进入高含水阶段且非均质性严重.为了满足油田开发后期的需要,并进一步改善油田开发效果,达到提高原油采收率的目的,需要精细描述单砂体储层的平面非均质性,研究平面非均质性对油田开发效果的影响.利用杨家坝油田的渗透率数据计算了不同层(重点按照沉积微相类型)变差函数的变程.通过变程反映变量的影响范围,对不同...  相似文献   

盐城海岸带表层土壤重金属的空间分布及其影响因素研究   总被引：2，自引：0，他引：2       下载免费PDF全文

方淑波  贾晓波  王玉  张新生  安树青  郑正  杨晓英 《海洋科学》2011,35(5):82-88

以盐城海岸带为研究对象,分析了Cr,Cu,Fe,Mn,Ni,V,Zn,Co,Cd 9种重金属元素在二维空间分布的异质性,以及沿着经纬度方向的梯度变化,并通过主成分分析和元素区域背景值的分析,探讨重金属元素的可能来源.结果表明:自陆向海存在着逐渐减少的格局梯度,而在区域的北部分布着重金属元素的峰值;二维分析的结果表明,重...  相似文献   

碎屑岩储层渗透率分布分维计算及其意义   总被引：4，自引：1，他引：4       下载免费PDF全文

陈程 《地质论评》1995,41(1):15-19

碎屑岩储层渗透率分布非均性是直接影响油气开采效果的客观因素。笔者认为储层渗透率分布具有分形特征，其分维值介于２与３之间，实例研究表明，分维能描述透率分布的非均匀性，其值随非均匀程度增加而增加。分维还能反映沉积能量分布和成岩作用对渗透率分布的影响。分维将是一个研究碎屑岩层渗透率分布的数学和成因特征的重要参数。研究分维与石油工程参数的关系具有现实意义。  相似文献   

石油储层地球化学的原理及应用   总被引：2，自引：0，他引：2  

黄海平  卢松年 《地学前缘》1995,2(4):206-212

储层地球化学是一门新兴的地学边缘学科，近几年，它已成为评价储层含油特征的重要手段，其核心内容是研究储层流体的非均质性。储层中石油组成的变化除由生物降解和水洗引起外，油源岩相和成熟度的变化同样能造成石油组成的非均质性。识别储层流体的非均质性不仅是重建油气聚集史的基础，而且还能为石油开发提供重要信息。这样能降低勘探目标的风险和油田开发费用。储层流体特征的旧纳依赖于油气、岩心抽提物的地化分析，其研究成果在勘探早期到油田生产结束过程中都能得到应用。  相似文献   

储层地质模型建立步骤   总被引：7，自引：0，他引：7  

贾爱林 《地学前缘》1995,2(4):221-225

本文系统介绍了单砂体模型、单井模型、二维模型和三维模型的建立步骤，是目前较为普及和实用的一种建模过程。文章对每种模型的关键点、参数选取和方法都作了概要的叙述，这一方法和步骤特别是对油田开发早期的模型建立具有很好的实用性。  相似文献   

The underdetermined Earth     

B. L. N. Kennett 《Journal of Earth System Science》1995,104(4):539-553

In the endeavour to achieve the goal of understanding the structure of the Earth in three dimensions, the limitations of the seismological probe for Earth structure have to be recognised. In geo-seismology there are high quality observations of a wide range of information on the seismic wavefield but only at a limited number of observation points around the globe. In contrast for the Sun, the other body for which seismological techniques have been routinely applied, there is the equivalent of a very high concentration of seismometers on one-hemisphere but very limited data quality. The restriction imposed by data quality is easily recognised but the restrictions imposed by the limited sampling of the globe are more subtle and have to be borne in mind in the interpretation of any images of seismic structure. A wide range of studies has demonstrated the presence of heterogeneity in Earth-structure on a wide range of scales from planet-wide variations in the degree 2 spherical harmonics to the intensity of variations on the micro-scale in intensely deformed rock belts. Whatever scale of structure is being examined, the potential influence of other classes of heterogeneity has to be recognised and so an effort made to minimise the transfer of information from different scales which may contaminate the picture. An important class of questions which must be faced in the development of threedimensional models is the nature of the reference model (or group of models) from which the model is to be derived, and also whether it is likely that limitations in the starting state will map into final images of structure. Further, are the various classes of data being used, compatible within the class of models which is being imposed?  相似文献   

Approximations for surface-wave propagation in laterally varying media   总被引：3，自引：0，他引：3  

B. L. N. Kennett 《Geophysical Journal International》1995,122(2):470-478

  相似文献   

On lateral viscosity contrast in the mantle and the rheology of low-frequency geodynamics   总被引：2，自引：0，他引：2  

Erik R. Ivins  Charles G. Sammis 《Geophysical Journal International》1995,123(2):305-322

  相似文献