High-Pressure Behavior of Copper Carbonate: Data from Malachite

Abstract: In-situ high-pressure energy dispersive X-ray diffraction experiments of malachite have been performed using diamond anvil cell and synchrotron radiation. The highest recorded pressure is up to 17.4 GPa. The experimental results reveal that malachite experienced two phase transitions at 0.7 and 7.8 GPa, and the last one is reversible.     

Determining Pressure with Daughter Minerals in Fluid Inclusion by Raman Spectroscopy: Sphalerite as an Example

Abstract: Raman frequency of some materials, including minerals, molecules and ions, shifts systematically with changing pressure and temperature. This property is often used as a pressure gauge in high pressure experiments with the hydrothermal diamond anvil cell (HDAC). Since the system of fluid inclusion is similar to that of HDAC, it can also be used to determine the internal pressure of fluid inclusions. Sphalerite is a common daughter mineral. In this study, the frequency shift of the 350 cm?1 peak of sphalerite has been studied from 296 to 523 K and from 0.07 to 2.00 GPa using the HDAC. The global slope of the isotherms (?n350/?p)T is 0.0048 in the studied pressure range. No significant variation of the slopes with temperature has been observed. The correlation between the frequency shift of the 350 cm?1 peak of sphalerite and pressure and temperature is constrained as P=208.33(?np)350+3.13T?943.75. This relationship may be used to estimate the internal pressure of the sphalerite-bearing fluid inclusions.     

散体材料桩复合地基极限承载力计算

以土力学及弹塑性理论为基础，分析了散体材料桩的塑性应力分布。推导出了单桩极限承载力和单桩复合地基的极限承载力计算公式。得出了提高桩体材料的内摩擦角和桩周土对桩的径向围限力是提高散体材料桩复合地基承载力的有效途径的结论。给出了工程实例，验证了文中计算公式的实用性。     

Overpressure within upper continental slope sediments from CPTU data,Gulf of Lion,NW Mediterranean Sea

Data from in situ piezocone tests (CPTU) and laboratory analyses are utilized for the interpretation of the stress history of Quaternary sedimentary sequences in the upper continental slope of the Gulf of Lion, northwestern Mediterranean Sea. A CPTU based preconsolidation pressure profile referenced to the current effective stress indicates that the deposit is underconsolidated from 12 meters below the seafloor (mbsf) down to at least 150 mbsf. Excess pore pressure below 12 mbsf is further supported by results from oedometer and dissipation tests. Subseafloor pockmarks and indications of free gas in seismic reflection profiles reveal four main overpressure sources (SI–SIV) with overpressure ratios >0.3 at subseafloor depths coinciding with levels where the dominantly silty-clayey sediment contains increased proportions of sand. We relate the excess pore pressure related to free gas due to gas exsolution processes and sea level variations driven by Pleistocene sea level changes.     

某码头软黏土岸坡破坏机制分析及重建

在某吹填软黏土岸坡上修建码头时发生了较大规模的滑坡,待滑体稳定后采取了一系列的工程措施,实现了码头的重建。详细阐述了岸坡发生滑动的全过程,通过现场勘察和有限元模拟分析了岸坡发生滑动破坏的原因。分别考虑了打桩与交通荷载作用,导致地基土中产生超静孔压,从而对岸坡的稳定性造成影响。分析结果表明,岸坡发生失稳破坏是多种不利工况叠加的结果,其主要原因是在低潮位时的超挖引起的,打桩及交通荷载作用也是造成滑坡的不利因素。在破坏的岸坡上重建码头,采用了振动砂桩加固地基,同时在地表铺碎石垫层作为预压荷载,加速地基土的固结。有限元分析和码头的成功重建表明,使用砂桩加固地基可以同时达到提高地基承载力和加速土体排水固结的目的,对于码头的重建是有效的技术措施。     

饱和黄土孔压增长模式与液化机理试验研究

通过室内饱和原状黄土液化试验研究，探讨了孔压增长规律，并从微观结构角度研究了黄土液化机理。研究结果表明：未湿陷饱和黄土结构是一种介稳结构，在地震作用下，介稳结构遭到破坏，塌发和剪缩共同作用造成黄土较大的收缩体积应变并引起孔隙水压力迅速上升。提出的修正A型曲线方程可以用来拟合孔压曲线，拟合参数β隐含了动应力的大小对孔压增长的贡献，而体应变v则反映了湿陷分量对孔压的影响，两者不同组合决定曲线形态丰满程度。液体机理较为合理地解释了塔吉克和海原黄土在近乎平坦的缓坡上形成的泥流。     

Risk analysis of landslides – A case study

The effects of uncertainty due to the variability of soil parameters on the risk of landsliding in the Himalayan region are investigated using a random field model combined with slope stability analyses. Effects of spatial variability both in horizontal and vertical directions, number of test samples, variations in piezometric level and the influence of earthquake on the reliability of a typical slope in a slide area are investigated. The results show that the reliability of slopes in the slide area is significantly affected by the coefficients of variation of soil parameters, spatial variations of soil parameters, number of test samples and piezometric variations. The results also show that the assumption of isotropic variations to assess slope reliability isconservative. The results of the study are useful in providing guidelines and pointing to remedial measures in the form of sub-surface drainage to improve slope reliability in the area.     

高压喷射注浆技术在白龟山水库顺河坝防渗墙围井试验中的应用

本次围井高喷试验,选用三重管摆喷法处理方案,施工采用两序施工方法.砼墙体连续均匀,孔与孔之间连接较好,其防渗、强度、厚度均能满足设计要求.     

深源地震机理的新认识──反向裂隙断层作用

高温高压实验究表明，地幔矿物相交与深源地震有着密切的关系。在具有放热效应的橄榄石一尖晶石相变过程中形成的反向裂隙（ａｎｔｉｃｒａｃｈ）是诱发深源地震的主要原因；而发生在下地幔的相变作用（例如钛铁矿－钙钛矿相变）因其具有吸热效应的特征，不形成反向裂隙，从而导致深源地震终止于下地幔顶界。     

数据分析法确定嶂山闸闸基渗透压力

闸基渗透压力是影响水闸闸室稳定的关键性因素。当水闸同时受到上下游水位差、基底承压水头、粘性土地基扬压力滞后等多重因素作用时 ,闸基渗透压力的估算就变得比较困难。通过对嶂山闸闸基历年实测渗透压力数据进行统计分析 ,初步揭示其基底渗透压力的变化规律 ,为该闸闸室稳定性分析提供依据。