Pore Water Pressure Buildup Under Cyclic Rotation of Principal Stress and Stability Evaluation of Seabed Deposit

- The cyclic rotation of principal stress direction with a constant amplitude is the characteristics of cyclic stress in seabed deposit induced by travelling waves. Presented in the paper are the results obtained from tests simulating the cyclic stress characteristics, with emphasis laid on the buildup of pore water pressure in soil samples. Regression analysis of test data shows that the pore water pressure can be expressed as the function of the number of cycles of cyclic loading, or as the function of generalized shear strain. Using the results thus obtained, the possibility of failure of seabed deposit under cyclic loading induced by travelling waves can be evaluated. The comparison with the results of conventional cyclic torsional shear tests shows that neglect of the effect of the cyclic rotation of the principal stress direction will result in considerable over-estimation of the stability of seabed deposit.     

Numerical Solution of Membrane Forces for A Free-Free Floating Plate with Large Deflection

1 .IntroductionVerylargefloatingstructures (VLFS)haveattractedconsiderableattentionrecentlyduetoitspo tentialuseintheexploitationofoceanresourcesandintheutilizationofoceanspaces (Cui,2 0 0 2 ) .Owingtoitslargesizeandrelativelysmallthickness ,theinfluenceofelasticdeformationonthehydro dynamicresponseisimportant.Thisisknownashydroelasticity .Threedimensionallinear (Wu ,1 984;PriceandWu ,1 985)andnonlinear (Chenetal.,2 0 0 3)hydroelasticityiswellappliedtotheanalysisofthreedimensionalshipsando…     

Dynamic Risk Analysis of Permanent Deformation of Sea Embankment

For evaluation of the permanent deformation of a sea embankment under stochastic earthquake excitation, a robust dynamic risk analytical method is presented based on conventional permanent deformation analysis and stochastic seismic response analysis. This method can predict not only the mean value of maximum permanent deformation but also the reliability corresponding to different deformation control standards. The earthquake motion is modelled as a stationary Gaussian filtered white noise random process. The predicted average maximum horizontal permanent displacement is in agreement with the conventional result. Further studied are the reliability of permanent deformation due to stochastic wave details at one seismic motion level and the risk of permanent deformation due to stochastic seismic strength, i. e., the maximum acceleration in a long period. Therefore, it is possible to make the optimal design in terms of safety and economy according to the importance of a sea embankment. It is suggested tha     

利用陆面岩石中生成的宇生同位素重建冰川漂砾运动历史的尝试

冰川漂砾的形成年代通常难以直接测定，并且漂砾形成以后是否被再次搬运或者移动过，更是无法知道。本文研究发现，通过测试砾石不同部位的宇生同位素，不仅可以测定砾石形成的时代，而且可以确定砾石再次被搬运或者被翻转的年代，从而恢复砾石运动的历史。本文以石英中生成的宇生同位素^10Be，对青藏高原东南部海子山的冰川漂砾进行了探讨，结果表明该砾石形成于倒数第二次冰期(186～128ka BP之间)，在末次冰期中再次被冰川搬运，使之反转。该方法不局限于^10Be和冰川漂砾，也适用于其他陆面岩石中生成的宇生同位素以及其他成因的石块或者砾石。因此为探讨冰川作用、泥石流活动、重力崩塌等过程提供了一种重要的方法和技术途径。     

阿尔泰可可托海3号伟晶岩脉中的铪质锆石

利用电子探针技术研究了阿尔泰可可托海3号伟晶岩脉中铪质锆石的成分特征。结果表明：细粒花岗岩和正岩浆阶段结构带(Ⅳ带)的锆石相对贫Hf，(HfO2)=3．06％-13．33％，主要属于普通锆石；岩浆-热液过渡阶段结构带(V带和Ⅶ带)锆石相对富}Hf，w(HfO2)=9．06％-35．21％，主要属于铪质锆石，少量具有普通锆石特征；同时本区发现的铪质锆石中HfO2最高含量是目前伟晶岩已报道铪质锆石中HfO2的最高含量。成分特征还显示，边部细粒花岗岩和正岩浆阶段锆石成分变化非常局限，岩浆-热液过渡阶段锆石成分变化巨大。认为锆石中HfO2含量从正岩浆阶段结构带到岩浆-热液过渡结构带的高度富集是挥发份从岩浆中分离出来独立成相的结果，而岩浆-热液过渡结构带锆石中HfO2含量在带内的巨大变化可能与热液流体的富集有关。     

柴达木盆地自然伽玛曲线在古气候及沉积环境研究中的应用

应用自然伽玛测井（GR）曲线反演古气候和古环境的方法在国际上逐渐得到重视并取得了进展，柴达木盆地第四纪应用其反演2.85Ma B.P来的古气候变化也取得了成功。本文以柴达木盆地侏罗系冷科1井和雨33井自然伽玛曲线并结合孢粉等地质资料进行了古气候与沉积环境分析，证明GR曲线是有价值的古气候研究参数。GR值的大小及古气候的干湿变化和沉积水体的深浅变化均有内在联系，GR曲线振幅与频率的变化快慢反映出沉积环境动荡与稳定的相对特征，据此对两口井的沉积环境演变作了具体分析。结合古气候与沉积环境综合分析，GR曲线的异常波动还具有特殊的指相意义。GR值增大-古气候加湿-沉积水体加深的同步表现特征是一般性规律，构造-古地理背景的变动可改变这一对应关系，因而提供了研究古地理演变的信息，进一步丰富了GR曲线研究的地质涵义。说明在侏罗纪古气候和古环境研究上，GR曲线是一有价值的参考指标。     

Possible effect of climate changes on the coastal zone of the Yangtze River Delta

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GPS时间比对机对天文预测图像的时间定标

本文介绍了GPS时间比对机利用GPS时标为基准 ,对天文图像进行时间定标的设计原理、可能出现的各种差错和纠正方法、模拟实验和主要误差分析。时间定标精度为 1 .0 85微秒 ,其均方根为 0 .5 4微秒     

地磁Z分量幅相法临震标志体系

应用连云港台和溧阳台 7a以上的地磁 Z分量日变资料及其间江苏地区 ML 5 .0以上地震 ,提取了线性去倾及二次去倾消除年变的幅相法临震标志体系。分析认为上述标志体系与原有的方法比较 ,具有异常判别受人为因素影响小的优点 ,但须进一步降低虚报率。