瞬态瑞雷波法在工程检测中的应用研究   总被引：2，自引：0，他引：2  

童立元  方磊 《水文地质工程地质》1999,26(6):52-56

本文简要介绍了瞬态瑞雷波法的工作原理,野外观测及数据采集系统,并总结出了资料处理解释流程图,同时从工程实践出发,探讨了该项新技术应用于高速公路建设中的优点,存在问题及未来发展趋势。  相似文献   

柴达木盆地西部新生界异常高压:分布、成因及对油气运移的控制作用   总被引：10，自引：6，他引：10  

郭泽清  刘卫红  钟建华  杨和山  饶孟余  肖红平 《地质科学》2005,40(3):376-389

如同世界上其它新生代沉积盆地那样,柴达木盆地在一定深度,区域上普遍存在异常高压。异常高压出现在快速沉积的厚层泥质岩中,水热增压效应明显,而且在上新世末至今发生了强烈的以水平挤压为主的构造运动,因此异常高压的形成是由于不均衡压实作用和构造挤压作用所引起的压应力增大以及热液压力引起流体体积的变化。异常高压是油气运聚的一种重要动力来源:在油气运移中,可以使上覆封隔层产生大量微裂缝,油气向上运移到在较低压储集层中,也可以使封闭性断层开启,通过断层进行侧向运移。  相似文献   

强夯振动加速度的量测及现场试验研究   总被引：1，自引：0，他引：1       下载免费PDF全文

李盼盼  王家鼎  谷天峰  刘亚明 《地震工程学报》2018,40(1):166-170

结合延安新区强夯加固地基工程,进行强夯振动加速度测试现场试验。选取填方区场地,结合地形设计监测方案,以测试强夯波沿水平方向和斜坡的传播规律。在选定试验段的某级填方场地上布置多组加速度传感器,运用多个8通道24位高速采集卡记录强夯振动加速度在平面和斜坡的传播和衰减过程,探讨强夯振动波沿水平面和斜坡的传播规律以及能级对振动加速度的影响。结果表明:径向和竖向加速度值均随与夯点距离的增大而减小;在与夯击点距离相同处,强夯振动波沿水平方向传播的径向和竖向加速度值要大于沿斜坡方向;随着能级的增大,强夯产生的夯击波增强,在与夯击点相同距离处产生的径向和竖向加速度均明显增大。  相似文献   

黔西南中晚二叠世大厂层火山热水沉积成矿作用     

杜丽娟  陈军  杨瑞东  黄智龙  郑禄林  高军波  魏怀瑞 《地质论评》2020,66(2):439-456

贵州晴隆大厂锑矿区赋矿地层大厂层为一套以硅化为主的火山碎屑岩沉积建造,因其别具特色的岩石组合、特殊的构造位置,以及含有金、锑、萤石、硫铁矿等矿产资源而备受地学界关注。晴隆大厂锑矿床90%以上的锑矿体和金矿化体均位于大厂层之中,因此,研究大厂层的形成和演化过程及其对锑、金成矿的控制作用或影响机理显得尤为重要。沉积岩相学研究表明,大厂层主要包括火山岩相(火山溢流相、淬碎角砾岩相、沉凝灰岩相、空落集块岩相和熔结凝灰岩相)和热液沉积岩相(热水沉积相、热水喷流相和热水交代相)。中—晚二叠世(约260 Ma)的溢流玄武岩、基性火山喷发和海底热水喷流活动是大厂层的主要物源供给者。元素地球化学研究表明,大厂层在沉积过程的热水喷流沉积作用提供了Sb、As、Au、Ag、Pb等成矿元素,并形成成矿元素的初始"富集体"。综合研究认为,中—晚二叠世的热水喷流沉积活动在时间上与右江盆地印支期低温热液成矿事件(200～250 Ma)在时空上基本一致,为印支期成矿事件在右江盆地北缘的响应。  相似文献   

TWO-PHASE OIL MIGRATION IN COMPACTING SEDIMENTARY BASINS MODELLED BY THE FINITE ELEMENT METHOD     

Magnus Wangen 《国际地质力学数值与分析法杂志》1997,21(2):91-120

The upstream-weighted finite element method with lumped mass matrix is applied to the modelling of oil migration in compacting sedimentary basins. An implicit formulation is made in Lagrangian co-ordinates of a pressure, saturation and a temperature equation, which is based on immiscible two-phase flow of oil and water. The formulation accounts for the compaction of the sediments, the generation of oil from solid organic material (kerogen), the eventual pore space generated by kerogen breakdown, and the density variations of the fluids which may set up thermal convection. The model is validated by comparison with results from a one-dimensional (1D) fractional flow-based migration model. A 2D case example showing oil expulsion from source rocks, and the filling of a trap is presented. The mass balance of the model is easily checked because all oil in the basin originates from breakdown of kerogen. Compared with other alternatives, the simple upstream-weighted finite element method is suggested as a possible first choice for a numerical method for the modelling of oil migration in compacting sedimentary basins. It easily deals with the complex geometry of a basin, it yields reasonably good results, is simple to implement, and the same implementation applies to all spatial dimensions. © 1997 by John Wiley & Sons, Ltd.  相似文献   

多边形断层系及其研究现状     

余一欣  汤良杰  宋纯利 《世界地质》2005,24(2):149-153

多边形断层为一类非构造断层,主要分布于深水环境下的细粒沉积物中。它的形成与沉积物的早期压实作用和流体排出作用有关。多边形断层系的识别主要通过时间切片分析和地震剖面解释等手段进行。研究表明,多边形断层系发育一般要经历3个阶段,即超压封存箱的形成、密度反转和多期水力压裂作用。对多边形断层系的研究有助于泥岩压实、油气运移、泥岩中流体活动状态以及对深水砂体分布和几何形态特征的分析等。由于我国还未发现有多边形断层系的存在,希望本文的介绍能为我国开展此类断层研究时有所帮助。  相似文献   

凸轮型冲击旋压钻头成孔机理研究          下载免费PDF全文

博坤  孙思远  张永光 《探矿工程》2020,47(11):77-82

挤密钻头是潜孔锤冲击挤密钻进技术的关键所在,其结构形式直接影响着钻进效率、成孔质量和应用效果。应用非线性有限元理论,对动载荷作用下土体的弹塑性和压缩性的变化规律进行了分析。研究发现,常规钻头在冲击挤密钻进过程中产生的桩效应是导致钻进效率降低的主要原因。为了克服桩效应的影响,利用ANSYS/LSDYNA软件对阶梯式钻头和凸轮旋压钻头的钻进过程进行数值模拟分析,并通过实钻试验进行验证。数值模拟分析和试验结果均表明：凸轮旋压钻头能够有效避免钻进过程中土体回弹问题,降低桩效应对钻进效率的影响。试验结果与模拟结果相吻合,表明数值模拟的结果相对可靠。  相似文献   

小型土石坝加密抗液化离心机振动台试验研究     

刘庭伟  李俊超  朱斌  汪玉冰  高玉峰  陈云敏 《岩土力学》2020,41(11):3695-3704

地震作用下土石坝液化易导致坝坡失稳滑移等严重后果,加密法是常用的抗液化手段之一。针对坝趾压重与坝壳翻压两种坝身加密加固方法,开展了离心机振动台试验,分析了不同加密型抗液化处理的小型土石坝坝坡地震响应规律。试验结果表明,由于高水头作用下坝坡底部土体软化,未处理坝坡加速度放大系数沿高程先减小后增大,而加密坝坡加速度放大系数沿高程逐渐增大,且坝坡表面处加速度存在表面放大现象。坝趾压重和坝壳翻压提高了坝身有效应力,降低地震产生的超静孔压比,有效防止土体液化。未处理坝坡在峰值加速度为0.24g地震作用下即发生坝趾液化现象,而加密坝坡在峰值加速度为0.24g和0.45g下均未发生液化。未处理坝坡整体侧向位移大,加密处理后,在峰值加速度为0.24g下坝坡整体表现为竖向位移。坝趾压重区坝趾水平位移明显减小,坝壳翻压区坡顶沉降减小了50%。试验结果验证了坝趾压重和坝壳翻压的抗液化效果,为小型土石坝抗震加固设计提供了参考。  相似文献   

卫星数据和地面观测结合的珠三角地区颗粒物质量浓度统计估算方法     

陈良富  陈水森  钟流举  陶金花  王子峰 《热带地理》2015,35(1):7-12

利用卫星观测的气溶胶光学厚度资料和模式模拟数据,与地面颗粒物观测资料结合,探讨近地面颗粒物质量浓度的估算方法。具体包括：利用区域气侯模式RAMS（Regional Atmospheric Modeling System）模拟的边界层高度对气溶胶光学厚度进行垂直订正,获得近地面颗粒物消光系数;利用模式模拟的相对湿度和颗粒物吸湿增长经验模型对消光系数进行湿度订正,获得近地面颗粒物干消光系数;并基于干消光系数与颗粒物质量浓度地面站点资料建立的统计关系估算获得每个像元的颗粒物质量浓度。利用地面站点观测的颗粒物浓度资料验证表明,基于卫星资料可以获得近地面颗粒物质量浓度,而且细颗粒物质量浓度具有更好的估算精度。  相似文献   

Use of fly ash with no water consumption for cold regions transportation infrastructure     

Gokhan Baykal 《寒旱区科学》2015,7(5):619-625

The construction period in cold regions is very short due to problems related to excavation and use of frozen soils in embankment construction, which leads to excessive deformations upon thawing. Also, handling of compaction water is critical due to freezing temperatures. Coalburning thermal power plants are very common in cold regions to supply electricity. The inorganic part of the pulverized coal after burning produces fly ash, which is available in large volumes. Due to excavation difficulties and the poor engineering behavior of frozen soils in cold regions, the utilization of fly ash when it is readily available must be promoted. Any construction technique which utilizes alternative materials like fly ash and minimizes water consumption has a potential to extend the short construction season and even allow service and maintenance during extreme weather conditions. This paper presents two potential techniques to solve the moisture affinity of silt-sized materials like fly ash. One technique involves in-plant production of fly ash pellets using cold-bonding pelletization to manufacture aggregates of up to 40,000-μm diameter from 15- to 60-μm-diameter fly ash grains. Large disc pelletizers have annual production capacities of up to one million ton at a reasonable cost. The product has adequate strength for embankment construction even when no water is used and no compaction is applied. The second technique is an in situ mixing technique which uses snow instead of compaction water for fly ash. The snow is the main element in this technique to compact the embankment. Water is needed for the hydration reactions to form cementitious minerals in fly ash. The slower the hydration reaction, the greater the crystal growth of cementitious minerals. In the proposed technique, in situ snow is mixed with fly ash and is compacted on-site. The temperature increase due to the hydration reaction of fly ash upon contact with snow crystals provides water for continued long-term hydration, which results in high strength, a high void ratio, light weight, and high thermal insulation capability. The presented techniques have the potential to extend the short construction season in cold regions and will provide fill material, decreasing the need for excavation. Both techniques are well documented under laboratory conditions, the research results have been published, and the techniques are ready for field trials to assess implementability.  相似文献