Simulation of individual particle movement in a gravel streambed

A two‐dimensional simulation model of travel distances of individual particles in a gravel‐bed river is presented. The model is based on a number of rules, which include particle size, entrainment, trajectory, distance of movement and entrapment. Particle interactions are controlled by resistance fields defined about each obstacle and critical elevation defined in the model. Resistance fields, particle dropping and critical elevation rules control particle interactions. The interaction rules cause the particles to develop pebble clusters, stone cells and transverse structures (transverse ribs). The simulated travel distances of individual particles are consistent with reported field results. Individual particle travel distances were simulated using two different models; one without interactions between the individual particles and the stationary bed and one with interactions. The case without interactions demonstrates the random nature of sediment transport, and narrow ranges of travel distances. Wider ranges of travel distances, similar to those for natural situations, were obtained for the cases with interactions. The more intense the interaction between the mobile stones and the stationary ones, the wider the range of distances of travel for a given particle size. Modelling the mean travel distance yielded a result similar to that published previously, which was based on empirical data. Well developed bed‐surface structures were obtained for relatively poorly sorted sediment with intense interactions between particles. Transverse structures developed when relatively large particles were allowed to move. Copyright © 2002 John Wiley & Sons, Ltd.     

湖北省南漳县红星磷矿磷块岩特征与物质组分研究

湖北省南漳县震旦系沉积型红星磷矿矿体P_2O_5平均含量23.91%,矿石自然类型主要为角砾状磷块岩,其次为白云质磷块岩、泥质纹层状和条带状致密块状磷块岩。工业类型主要为钙(镁)质和硅钙(镁)质磷矿,其次为硅质磷矿。矿石矿物为胶状磷灰石和微晶磷灰石,经x-射线衍射物相分析,其种属为含碳氟磷灰石。嵌布粒度以细-中粒为主。脉石矿物主要为白云石、伊利石、高岭石、铁质。经测定当磷块岩磨矿粒度小于0.1mm,其磷酸盐矿物单体解离率可达92.53％,这为确定合理的选矿流程具有实际意义。     

高速公路碎石桩软基加固质量检测方法探讨

该文讨论在软基地区修建高速公路时，用碎石桩进行软基处理效果的检测方法，并对其合理运用提出了建议。     

小松山超基性杂岩体橄榄石的岩组分析

沿贺兰山台褶带北部西缘深大断裂带分布的小松山超基性杂岩体属岩浆结晶分异形成的似层状含铬岩体，岩组分析表明岩体中橄榄石具有高度的定向性。笔者通过研究认为，这种定向性系岩浆上侵过程中的流动分异作用影响造成，反映了小松山岩体系构造动荡环境下的产物。     

大庆徐家围子地区深部致密砂砾岩气层识别

大庆徐家圈子地区深部致密砂砾岩储层的骨架成分除了含有石英、长石外，还含有许多酸性喷发岩，而且各种骨架成分的含量随深度变化比较大；复杂的岩性使得气的影响被岩性的影响所淹没，从而造成常规气层识别方法失效。针对这一问题，应用神经网络方法准确求取地层颗粒密度和泥质含量，然后对中子和密度测井值进行岩性影响校正和泥质影响校正，使得求出的中子和密度孔隙度仅受地层气的影响，最后将得到的中子和密度孔隙度进行对比，应用中子和密度孔隙度的差异识别气层。     

高浓度黏性泥石流堆积层理结构中筛积层和粗化层形成机理的研究

根据高浓度黏性泥石流的观测资料,应用不同类型黏性泥石流的流变特性和流体结构的分类指标-流核比,对高浓度黏性泥石流堆积中的混杂层、筛积层和粗化层理结构进行了成因差异分析。侧重分析了砾石质点在高浓度黏性泥石流蠕动流场中作向上垂直运动的魏森伯效应,并在表面富集形成了筛积层的成因,及其它与粗化层结构的区别。     

含柯石英超高压榴辉岩的早期变形--以苏北东海碱场榴辉岩体为例

以超高压矿物组合的各种后成合晶及冠状体等卸载不平衡结构为参考标志，将含柯石英的超高压榴辉岩的交形序列分成两个部分。后成合晶及冠状体发育之前的变形为早期变形，是在大陆深俯冲和碰撞条件下发育的超高压变质变形组构。后成合晶及冠状体发育之后的变形为晚期变形，是在超高压岩石折返剥露过程中，主要是在角闪岩相甚至绿片岩相条件下发育的。构造上江苏省北部东海县碱场合柯石英榴辉岩体，分为块状榴辉岩和面理化榴辉岩两种类型，分别代表超高压变质岩早期变形的两个构造阶段或世代(D1、D2)。详细描述了它们的矿物组合、中小尺度及显微尺度下的组构特征，讨论了两者的几何关系和区域构造意义，强调指出，只有含柯石英榴辉岩的早期变形组构，才能记录和反映斜向大陆深俯冲及碰撞的动力学过程。     

ADV measurements of velocity distributions in a gravel‐bed flume

Velocity measurements carried out by an acoustic doppler velocimeter (ADV) in a rectangular laboratory ?ume having a gravel bed are presented. The velocity pro?les are measured in six verticals of the channel cross‐section having an increasing distance (from 4 to 38·5 cm) from the ?ume wall. The experimental runs are carried out for ?ve different bed arrangements, characterized by different concentrations of coarser elements, and for the two conditions of small‐ and large‐scale roughness. For both hydraulic conditions, the velocity measurements are ?rst used to test the applicability of the Dean pro?le and of the logarithmic pro?le corrected by a divergence function proposed in this paper. Then, for each value of the depth sediment ratio h/d₈₄, the non‐dimensional friction factor parameter is calculated by integration of the measured velocity distributions in the different verticals of the cross‐section. Finally a semi‐logarithmic ?ow resistance equation is empirically deduced. Copyright © 2003 John Wiley & Sons, Ltd.     

陕西洛南陶湾群三岔口组砾岩研究

陶湾群三岔口组砾岩是一套分布于华北地块南缘的水下碳酸盐岩型重力流沉积，砾岩的形成同商州铁炉子栾川断裂带早期活动性质存在因果关系。通过１∶５万区调填图发现，陶湾群三岔口组砾岩从母岩区到砾岩堆积区之间无断陷作用；沉积基底基本连续；砾岩沉积组构出现有序的横向变化规律，依次为母岩区层状白云岩（α区）、具有垂向张裂隙及流动构造的始滑区白云岩（β区）、具有节状构造的滑移区白云岩（γ区）和砾岩堆积区（δ区）。陶湾群三岔口组砾岩时代厘定为早寒武世晚期至中寒武世，这也是华北地块南缘盆地环境的主形成期，砾岩是在东秦岭洋向华     

长乐-南澳韧性剪切带走滑特征探讨

长乐-南澳韧性剪切带可能是在碰撞造山缝合带基础上发育的,其走滑特性严格受闽台微大陆与闽浙中生代火山弧碰撞过程中碰撞动力学的制约。岩石韧性组构和糜棱岩变形的微构造研究表明,碰撞前期走滑为左行。在早垩世晚期(100-120Ma)的主碰撞期和以伸展作用为主的碰撞后期,该带以右行为主,这种右行走滑一直持续至今。发育韧性剪切带的闽台微大陆(或称平潭-东山带)原始位置可能比现今更靠南,这是属于几百公里的漂移位移而不是剪切位移。