复合桩基与复合地基

鉴于目前复合桩基、复合地基概念上的混淆,从不同侧面,讲述了复合桩基和复合地基之间的联系和区别。为区分这两种新型的基础形式,进而更合理的利用它们,提供一些有益的参考。     

等积变换近似积分法及其应用 ——三相土固结沉降预测研究

半空间点源问题的结果积分往往不能表达为有限形式，经济上未必可行，且不便于工程应用。如与数值法结合，将区域?适当分割并变换为特定的形式，则可降低积分重数，甚至得到解析解。本文将讨论以解析解为基础辅以数值法的近似积分方法，并将其应用于改进扎列茨基解，进而求解三相土的固结沉降问题，并进行参数敏感性分析，得出渗透系数、泊松比以及模量比对固结沉降均有较大的影响；另外该近似解能够较好的求解三相土固结沉降，具有一定的应用价值。     

激光测绘卫星对不同地表形貌探测能力分析

针对斜坡地形、台阶地形和植被地貌、分界地貌建立了4种基本模型,研究了不同的地表空间起伏和反射率分布对回波信号时空分布特性的影响,并采用蒙特卡罗方法仿真了4种模型下Geiger探测模式星载激光雷达的高程测量精度,发现:地形起伏主要影响回波信号的时间分布特性,统计条件下可以消除测量误差;回波信号空间分布特性变化主要由地貌(反射率)的变化引起,误差较小可以忽略.研究结果表明:激光三维测绘卫星对垂直陡变地形(如城市建筑)、斜坡地形(如山坡)、分界地貌(如水陆分界)和折射率起伏地貌(如植被地貌等)具有良好的探测能力.     

西藏仲巴微地体中新世马莜木富钾埃达克质岩及其内暗色微粒包体的成因

西藏南部的中新世含暗色微粒包体的富钾埃达克质岩被认为是之前的大陆地壳在石榴子石稳定压力下发生部分熔融的熔体与同时期的幔源超钾质火山岩发生岩浆混合或混杂的产物。为检验这一观点,本文对雅鲁藏布江缝合带西段仲巴微地体内的中新世马莜木富钾埃达克质岩及其内的暗色微粒包体开展了岩石学、锆石U-Pb定年、矿物电子探针分析以及全岩主微量元素和Sr-Nd同位素测试等方面的工作。结果显示暗色微粒包体和富钾埃达克质岩具有相似的结晶年龄(～17.5 Ma)、矿物组合(石英+长石+角闪石+黑云母)和矿物成分,但暗色微粒包体比富钾埃达克质岩含更多的角闪石和黑云母,且具有比富钾埃达克质岩低的K₂O和SiO₂以及高的MgO、TiO₂和P₂O₅含量。除此之外,富钾埃达克质岩和暗色微粒包体还表现出相似的全岩Sr-Nd同位素组成：富钾埃达克质岩的(⁸⁷Sr/⁸⁶Sr)_i和ε_Nd(t)值分别为0.70933～0.70950和-8....     

Chemical and Isotopic Characteristics of the Water and Suspended Particulate Materials in the Yangtze River and Their Geological and Environmental Implications

The chemical and isotopic characteristics of the water and suspended particulate materials（SPM） in the Yangtze River were investigated on the samples collected from 25 hydrological monitoring stations in the mainsteam and 13 hydrological monitoring stations in the major tributaries during 2003 to 2007. The water samples show a large variation in both δD（ 30‰ to 112‰） and δ18O（ 3.8‰ to 15.4‰） values. Both δD and δ18O values show a decrease from the river head to the Jinsha Jiang section and then increase downstream to the river mouth. It is found that the oxygen and hydrogen isotopic compositions of the Yangtze water are controlled by meteoric precipitation, evaporation, ice（and snow） melting and dam building. The Yangtze SPM concentrations show a large variation and are well corresponded to the spatial and temporal changes of flow speed, runoff and SPM supply, which are affected by the slope of the river bed, local precipitation rate, weathering intensity, erosion condition and anthropogenic activity. The Yangtze SPM consists of clay minerals, clastic silicate and carbonate minerals, heavy minerals, iron hydroxide and organic compounds. From the upper to lower reaches, the clay and clastic silicate components in SPM increase gradually, but the carbonate components decrease gradually, which may reflect changes of climate and weathering intensity in the drainage area. Compared to those of the upper crust rocks, the Yangtze SPM has lower contents of SiO2, CaO, K2 O and Na2 O and higher contents of TFe2 O3 and trace metals of Co, Ni, Cu, Zn, Pb and Cd. The ΣREE in the Yangtze SPM is also slightly higher than that of the upper crust. From the upper to lower reaches, the CaO and MgO contents in SPM decrease gradually, but the SiO2 content increases gradually, corresponding to the increase of clay minerals and decrease of the carbonates. The δ30SiSPM values（ 1.1‰ to 0.3‰） of the Yangtze SPM are similar to those of the average shale, but lower than those of the granite rocks（ 0.3‰ to 0.3‰）, reflecting the effect of silicon isotope fractionation in silicate weathering process. The δ30SiSPM values of the Yangtze SPM show a decreasing trend from the upper to the middle and lower reaches, responding to the variation of the clay content. The major anions of the river water are HCO 3, SO 4 2, Cl, NO 3, SiO 4 4 and F and the major cations include Ca2＋, Na＋, Mg2＋, K＋ and Sr2＋. The good correlation between HCO3-content and the content of Ca2＋may suggest that carbonate dissolution is the dominate contributor to the total dissolved solid（TDS） of the Yangtze River. Very good correlations are also found among contents of Cl, SO4 2, Na＋, Mg2＋, K＋and Sr2＋, indicating the important contribution of evaporite dissolution to the TDS of the Yangtze River. High TDS contents are generally found in the head water, reflecting a strong effect of evaporation in the Qinghai-Tibet Plateau. A small increase of the TDS is generally observed in the river mouth, indicating the influence of tidal intrusion. The F and NO3 contents show a clear increase trend from the upstream to downstream, reflecting the contribution of pesticides and fertilizers in the Chuan Jiang section and the middle and lower reaches. The DSi shows a decrease trend from the upstream to downstream, reflecting the effect of rice and grass growth along the Chuan Jiang section and the middle and lower reaches. The dissolved Cu, Zn and Cd in the Yangtze water are all higher than those in world large rivers, reflecting the effect of intensive mining activity along the Yangtze drainage area. The Yangtze water generally shows similar REE distribution pattern to the global shale. The δ30SiDiss values of the dissolved silicon vary from 0.5‰ to 3.7‰, which is the highest among those of the rivers studied. The δ30SiDiss values of the water in the Yangtze mainsteam show an increase trend from the upper stream to downstream. Its DSi and δ30SiDiss are influenced by multiple processes, such as weathering process, phytolith growth in plants, evaporation, phytolith dissolution, growth of fresh water diatom, adsorption and desorption of aqueous monosilicic acid on iron oxide, precipitation of silcretes and formation of clays coatings in aquifers, and human activity. The δ34SSO4 values of the Yangtze water range from 1.7‰ to 9.0‰. The SO4 in the Yangtze water are mainly from the SO4 in meteoric water, the dissolved sulfate from evaporite, and oxidation of sulfide in rocks, coal and ore deposits. The sulfate reduction and precipitation process can also affect the sulfur isotope composition of the Yangtze water. The87Sr/86Sr ratios of the Yangtze water range from 0.70823 to 0.71590, with an average value of 0.71084. The87Sr/86Sr ratio and Sr concentration are primary controlled by mixing of various sources with different87Sr/86Sr ratios and Sr contents, including the limestone, evaporite and the silicate rocks. The atmospheric precipitation and anthropogenic inputs can also contribute some Sr to the river. The δ11B values of the dissolved B in the Yangtze water range from 2.0‰ to 18.3‰, which is affected by multifactors, such as silicate weathering, carbonate weathering, evaporite dissolution, atmospheric deposition, and anthropogenic inputs.     

安徽铜陵矿集区燕山期岩浆流体系统时空结构及成矿

通过野外地质调查和同位素年代学研究，结合前人资料，建立起铜陵地区燕山期岩浆流体系统的时空格架及岩浆活动与矿产的关系。将铜陵地区的岩浆流体系统分为两类4个子系统。一类是与燕山期(150～133 Ma)侵入岩有关的铜陵侵入岩岩浆流体系统，受近东西向铜陵一南陵基底断裂控制，依据其活动时间先后和流体活动特征，可进一步划分为早、晚2个流体子系统；另一类是与燕山晚期(122～110 Ma)繁昌盆地火山岩有关的火山岩流体系统，受北东侧凹陷盆地控制，与“宁芜式”玢岩铁矿和金矿关系密切，包括2个子系统。各子系统又包括不同的流体单元，流体单元是填图的基本单位。岩浆岩自身可形成独立矿床，同时，对海西期同生沉积矿床或矿胚层叠加改造，增补铜、金等成矿物质，使层状矿体变富，规模变大，在铜陵地区形成全球特有的大型一超大型矽卡岩型铜矿床。     

四川牦牛坪轻稀土矿床地幔流体特征——铅锶钕和氦氩同位素及稀土元素证据

四川牦牛坪稀土矿床是中国第二大轻稀土矿床。笔者对该矿床进行了较系统的Pb—Sr—Nd同位素、稀有气体同位素地球化学以及稀土元素地球化学研究。稀土元素地球化学特征研究显示,矿区萤石、方解石、氟碳铈矿稀土元素分布模式与区内英碱正长岩相似,表明牦牛坪稀土矿床成矿与英碱正长岩岩浆活动有关以及石英包裹体流体REE曲线平直,Eu与Ce无明显异常,曲线规律性较强,可以认为牦牛坪轻稀土矿床成矿流体稀土元素是深源的。Pb—Sr—Nd同位素组成表明成矿物质来自富集地幔,具深源甚至幔源特征。稀有气体同位素地球化学研究也在一定程度上揭示了牦牛坪轻稀土矿化与地幔过程之间存在着成因关系。     

弧前盆地研究进展综述

综述了弧前盆地的沉降机制,充填序列及主要识别标志,沉降机制分析表明,其沉降速率总体呈下降趋势。沉积充填序列总体表现为一向上变粗,变浅的巨层序,其具体发育规律主要受增生槛高程,充填速率与沉降速率比值控制,特殊的构造部位,弱的变形,变质和富有特色的沉积序列,砂岩碎屑组分是判别化石弧前盆地的主要标志。     

南京市主城区大气颗粒物来源探讨

在2005-05-03——05-27期间,用Anderson九级采样器在南京市两个采样点采集大气气溶胶样品,同时进行了部分排放源的采集。用X射线—荧光光谱仪(XRF)分析得到气样及源样中PM10的化学成分,分析了南京市大气气溶胶的元素质量谱分布,进行了PM10的富集因子分析,并应用化学质量平衡法(CMB)计算各类源对气溶胶PM10的贡献。结果表明,各类污染源对南京市气溶胶PM10的贡献率分别为:建筑尘(35.45%)、煤烟尘(22.13%)、土壤尘(20.27%)、硫酸盐(5.43%)、汽车尘(4.61%)、海盐(1.91%)、冶炼尘(1.69%)、其它源(8.51%)。文中还结合了南京市TSP和PM2.5的来源解析结果,分析了南京市不同粒径气溶胶颗粒物的污染特征。     

安徽铜陵矿集区硅质岩成因及意义

铜陵地区二叠系栖霞组到大隆组(P_1q—P_2d)各层位中硅质岩分布广泛。通过野外地质填图过程中的详细观察和硅质岩常量元素、稀土元素和微量元素的分析,结果表明,这些硅质岩是热水活动间歇式、多次活动的结果。硅质岩构成铜陵地区二叠系主要的矿(源)层或矿胚层(Protore)之一。硅质岩具有低 Fe_2O_3/FeO、SiO_2/Al_2O_3、SiO_2/(K_2O+Na_2O)、SiO_2/MgO、MnO_2/TiO_2 值;低 Co高 Ni,Co/Ni<1,U/Th>1;低 ∑REE,负 Ce异常,重稀土相对富集等热水沉积物的特征,为热水沉积的结果。氧同位素估算的热水古温度为49～249℃(高温部分有后期岩浆的叠加扰动)。硅质岩是铜陵地区二叠系层控矿床的重要找矿标志,对于隐伏矿床的寻找和矿产预测具有重要意义。