滇西地区九种岩石的P波Q值

本文叙述了以波传播和谱振幅比法测得的滇西地区九种岩石在不同应力状态下(σ_1=σ_2=σ_3=σ)的衰减系数,P波速度及Q值。在σ≤90 MPa时,随压力增加,衰减系数减小,P波速度及Q值增大;在σ≥120 MPa以后,衰减系数、P波速度及Q值变化甚小。其中团山砂岩及砖窑村片麻岩Q值较低。     

成都平原东部地震动小区划研究

场地的区域工程地质条件决定了场地土结构及土动力学参数的区域性差异,对强震地面运动起着重要的控制作用。为了考虑这种控制作用,以便合理地进行成都平原地震动小区划,本文根据一定数量的地震反应分析结果和所处的区域工程地质条件,建立了地貌单元、土层厚度和土层结构等因素与各类地震反应谱和各档峰值加速度的统计直方图。并引入分量分析方法,对原始因素进行正交变换,用产生互不相关的新因素来代替它们。正交变换之后,根据因子得分矩阵建立模糊关系矩阵 R,根据反映新因素重要程度的因子载荷矩阵生成新因素权重矩阵 A,然后采用模糊综合评判方法,判别成都平原东部各点的地面地震动类型,并由判别结果勾划了本区地震动小区划图。     

实验流水地貌学研究的回顾与展望

本文简述了地貌实验研究的概况,罗列了我国主要的地貌实验室、站,叙述了我国30多年来,河型造床试验、边界条件及构造运动对河型发育影响实验,应用河流地貌实验、试验理论和技术方面的进展情况,指出实验研究中存在的问题,在回顾基础上,展望了流水地貌实验研究的未来发展趋势。     

中国东部四个水库震例的诱震环境因素研究

本文通过对我国东部四个诱震水库的地质调查及其资料分析,探讨了水库地震诱发过程中所涉及的诸环境因素。研究表明:水库地震的诱发因素很多,但大体上可归纳成库水渗透条件和发震构造条件两类;这些环境因素只有在它们按一定方式恰当地组合成一个统一体存在于同一库区(段),水库地震才有可能诱发产生。因此,预测水库地震一个很重要的工作就是要查明库区诱发地震的环境因素及其总体组合条件。     

隘高岩体地下水的放射性特征及其找矿效果

本文通过对隘高岩体放射性水化学普查、详查、揭露资料的野外调查和综合分析研究,论述了岩体水化找矿效果好的放射性水文地质条件;研究了水异常的展布特征和控制因素;肯定了岩体的水化找矿效果;给出了水化找矿的标志;进而对放射性水化学普查、详查以及成矿远景预测、水异常点找矿意义的评价提出了看法和建议。     

斧石晶体的微形貌特征,化学成分及形成条件

通过对个旧斧石晶体的微形貌、化学成分及生成条件的研究认为,个旧产出的斧石种类属于铁斧石,它是在fo_2=10~(-21)—10~(-31),中偏高温溶液中生成的.应用晶体人工生成的研完成果表明:斧石晶体表面台阶是溶液中的溶质通过体扩散形成的;而不同密度台阶的叠置则反映了晶体生长过程中的动力学参数的变化.     

鞍本地区鞍山群变质矿物及变质作用

鞍本地区鞍山群变质岩出露区可分为鞍山、辽阳、本溪三个小区。所有的变质岩均属角闪岩相,从西向东,变质程度递增。三个小区最先出现的特征变质矿物分别是铁铝榴石、十字石和夕线石。退化变质作用由西向东递减,在东-西鞍山矿区已退变为绿片岩相,在绿泥片岩中普通角闪石仅作为残留矿物出现在绿泥石的核心。鞍山小岭子矿区有紫苏辉石、红柱石和尖晶石组合,它们是燕山期花岗岩围岩中的接触变质矿物。     

THE "CLIMATE TRANSITION" OF THE LONG TERM VARIATION OF OCEAN CONDITION IN THE NORTHERN PACIFIC AND RESPONSE OF ATMOSPHERIC CIRCULATION IN RECENT 50 YEARS

In this paper, the analysis of net volume of the Kuroshio in PN section of the East China Sea, the calculations of volume transports of the North Equatorial Current (NEC) and North Equatorial Countercurrent (NECC) and the upper layer heat content (0～150 m) in 137°E section during 1967-1992,and the sea surface temperature anomaly (SSTA) in the northern Pacific are illustrated. Meanwhile,the long term variation of subtropical high in northern hemisphere and in the western Pacific, and atmosphere oscillation are also analyzed. By using Mann-Kendall method, the verification shows that the ocean condition and atmospheric circulation system mentioned above all presented "climate transition"during the mid-and late-Stage of 1970's, that is, the volume transports of the Kuroshio, the NEC and the NECC varied from weak to strong; the SSTA changed from the type of La Nina to that of E1 Nino,which were coincident with atmospheric circulation system, i. e. the subtropical high in northern hemisphere and in the western Pacific, and atmospheric oscillation all had the feature of changing from weak to strong, which indicated the response of atmospheric "climate transition" to oceanic "climate transition ".     

斑岩铜(钼-金)矿床的成矿流体

斑岩铜矿是主要的铜资源,是矿床研究和勘查的重要目标。斑岩铜矿按其与板块构造的关系可分为2种:俯冲带斑岩铜矿和碰撞造山带斑岩铜矿,它们在成矿流体方面有很多区别,其中较大的差别是碰撞造山带斑岩铜矿的钾化蚀变带比俯冲带斑岩铜矿的钾化蚀变带强得多,且范围也相对较宽。文章简述了这2种斑岩矿床的主要地质特征,着重从流体包裹体、蚀变作用和稳定同位素研究来探讨斑铜矿床成矿流体的主要特征,包括成矿流体的成分、形成温度和压力,氢、氧、碳和硫稳定同位素组成。这两种类型的斑岩铜矿中主要发育5种包裹体:M熔体包裹体;Ⅰ液体包裹体;Ⅱ气体包裹体;Ⅲ含子矿物的多相包裹体和CO2_H2O包裹体。Ⅱ类和Ⅲ类包裹体常共存,且均一温度相似,表明成矿流体经历了不混溶和沸腾作用。在Ⅲ类含子矿物的包裹体中发现了含金属硫化物(黄铜矿、黄铁矿)和氧化物(赤铁矿、磁铁矿)子矿物。在斑岩金矿和碰撞造山带的斑岩铜矿中出现CO2_H2O包裹体,在斑岩的斑晶和一些早期石英脉的石英中可见到熔体包裹体以及熔体_流体包裹体,它们代表斑岩岩浆的样品,说明斑岩铜矿的形成经历了岩浆和热液阶段。最近的研究表明,斑岩铜矿的初始流体是中等盐度和密度的岩浆流体。这种流体在上升过程中因压力释放而发生沸腾,形成气体包裹体和含子矿物的高盐度包裹体。     

Numerical modelling of seismic slope failure using MPM

The Finite Element Method (FEM) is widely used in the simulation of geotechnical applications. Owing to the limitations of FEM to model problems involving large deformations, many efforts have been made to develop methods free of mesh entanglement. One of these methods is the Material Point Method (MPM) which models the material as Lagrangian particles capable of moving through a background computational mesh in Eulerian manner. Although MPM represents the continuum by material points, solution is performed on the computational mesh. Thus, imposing boundary conditions is not aligned with the material representation. In this paper, a non-zero kinematic condition is introduced where an additional set of particles is incorporated to track the moving boundary. This approach is then applied to simulate the seismic motion resulting in failure of slopes. To validate this simulation procedure, two geotechnical applications are modelled using MPM. The first is to reproduce a shaking table experiment where the results of another numerical method are available. After validating the present numerical scheme for relatively large deformation problem, it is applied to simulate progression of a large-scale landslide during the Chi-Chi earthquake of Taiwan in which excessive material deformation and transportation is taking place.