淤泥质软土中某深大基坑开挖顺序优化分析

南京某深大基坑位于长江下游岸边,场地地层为典型的二元结构且淤泥质软土广泛分布,承压水位高,基坑场地地质条件十分复杂。基坑邻近一个高层建筑,开挖范围涉及到厚层淤泥质土,且支护结构全部埋设于淤泥质软土中,基坑的开挖顺序直接关系到基坑工程及周围建筑物的安全。基于该基坑最深的部位,这里将基坑的开挖顺序分为：I、先开挖主隧道再开挖匝道;Ⅱ、先开挖匝道再开挖主隧道;Ⅲ、主隧道和匝道同时开挖3种开挖方式,运用FLAC^3D模拟软件对3种工况下基坑支护结构及周围建筑物的变形进行对比分析,得知先开挖主隧道再开挖匝道或先开挖匝道后开挖主隧道对基坑支护结构和周围建筑物的影响最小,应优先选择这两种开挖方式,尽量避免主隧道和匝道同时开挖的开挖方式。该研究可为类似深厚淤泥质土中深大基坑的开挖与设计提供经验。     

Provenance and Evolution of the Guarguariiz Complex, Cordillera Frontal, Argentina

The Guarguardz Complex, basement of the Cordillera Frontal, included in the proposed Chilenia Terrane, consists of metasedimentary rocks deposited in clastic and carbonatic platforms. Turbiditic sequences point out to slope or external platform environments. According to geochemical data, the sedimentary protoliths derived through erosion of a mature cratonic continental basement. Volcanic and subvolcanic rocks with N and E-MORB signature were interbeded in the metasedimentary rocks during basin development. A compressional stage, starting with progressive deformation and metamorphism, followed this extensional stage. Continuing deformation led to the emplacement of slices of oceanic crust, conforming an accretionary prism during Late Devonian. The Guarguardz Complex and equivalent units in western Precordillera and also in the Chilean Coastal Cordillera share common evolutional stages, widely represented along the western Gondwana margin. These evidences imply that Chilenia is not an allochthonous terrane to Gondwana, but a portion of its Early Paleozoic margin. Regional configuration indicates that the Guarguardz Complex and equivalent units represent the accretionary prism of the Famatinian arc (Middle Ordovician-Late Devonian).     

Spectral Maxima In A Perturbed Stable Boundary Layer

Wind velocity data have been collected on Nansen Ice Sheet, Antarctica, close to the base of a steeply sloping glacier along which frequently flow katabatic winds. The aim of this study is to investigate how turbulent energy and momentum flux are perturbed by the flow interaction with topography and by the strong mechanical mixing produced by downslope flows. Spectral and cospectral analyses, performed on the wind velocity components, provide evidence that such a perturbation, at any stability, is restricted to frequencies lower than the inertial subrange. Longitudinal spectra display an energy increment, due to turbulence generated by topography and by mechanical forcing related to the katabatic wind structure. The energy, supplied by the topographic forcing, displaces the turbulent energy maximum toward lower frequencies. In near-neutral stratification the spectral maximum occurs at a reduced frequency, which seems to be consistent with the height of the steepest part of the slope, and seems to shift toward higher frequencies as a linear ,function of the local stability parameter,L_l. The parameterisation of the orographic perturbation by means of a similarity relationship allows us to scale u spectra in the same way as over uniform terrain. The scaled, perturbed spectra collapse onto a unique curve in the mid-frequency as well in the inertial subrange, while maxima are grouped in a cluster. Lateral and vertical velocity spectra exhibit shapes independent of stability, suggesting a topographic perturbation that is predominantly over stability effects.     

Large-ion lithophile element characteristics of an amphibolite facies to granulite facies transition at Gruinard Bay, North-west Scotland

Abstract Lewisian grey gneisses from Gruinard Bay, North-west Scotland retain mineralogical and geochemical evidence for Scourian horn-blende-granulite facies metamorphism, and they may be used to assess current models of elemental depletion at granulite grade. Their 'immobile'major and trace element geochemistry is indistinguishable from that of Lewisian amphibolite and pyroxene-granulite facies counterparts. The K, Rb, Th and U contents of the Gruinard Bay gneisses are depleted relative to amphibolite facies gneisses, but generally the abundances of these elements are above those of comparable pyroxene granulites. U and Th have reached an advanced stage of depletion, but allanite appears to be crucial in maintaining significantly higher U and Th abundances at Gruinard Bay than in pyroxene granulites. K and Rb loss is less extreme, and depends on the stability of the rock-forming minerals: K-feldspar; biotite; and, amphibole. Early removal of K and Rb has resulted in a small rise in K/Rb, but further preferential Rb loss would have been required to generate the characteristically high K/Rb ratios of Lewisian pyroxene granulites.
The residence of U and Th in the accessory minerals of granulite facies gneisses, which are often correlated with the residua of intracrustal partial melting, renders unlikely their extreme incompatibility required by such models. Even if such phases are ignored, high mineral-melt partition coefficients for silicic melts argue against partial fusion as an efficient depletion mechanism. On the other hand, the advanced stage of U and Th depletion reached in Gruinard Bay gneisses, which were still partly hydrous, severely restricts the role played by CO₂-dominated fluids and a hydrous medium is preferred.     

晶须增强体复合材料的性能与应用

晶须增强体复合材料是高技术新型复合材料，是当今材料科学的研究热点。作者评述了几种英型晶须增强体的性质、晶须增强复合材料的机理、晶须增强体复合材料的性能以及应用，我们相信，晶须增强体复合材料必将得到越来越广泛的应用。     

黑龙江跃进山杂岩中砾岩的碎屑锆石年代学及其大地构造意义

黑龙江省饶河县石场一带分布的跃进山杂岩为一套富含晚三叠世化石的海陆交互相沉积地层.砾岩样品中的LA-ICP-MS锆石U-Pb测年结果显示，样品中的碎屑锆石年龄谱具有4组年龄，分别为800 Ma以上、500 Ma、251~284 Ma和219~222 Ma.前三者与佳木斯地块中的热事件年龄完全一致，表明其沉积物源主要来自佳木斯地块；后者为砾岩最小年龄组，大致可将这组最小年龄视为这套砾岩的沉积时代下限，与西侧松辽地块东缘的张广才岭地区广泛分布的210~228 Ma的晚三叠世早期花岗岩基本一致，说明具有最小年龄组的碎屑锆石可能来自松辽地块东部.碎屑锆石年龄及其源区特征表明，在晚三叠世之前，跃进山增生杂岩已经就位在佳木斯地块东缘，并成为佳木斯地块东部大陆边缘的一部分.     

动力地貌过程与分形研究：以元谋盆地为例

文章认为动力地貌过程是个动态系统，处于混沌态，分形无处不在。为更好地进行地貌分形研究，作者引进复变函数和复平面作为计算机分形模拟的理论基础。该研究主要是在元谋盆地进行，作者在广泛野外勘测和室内计算机工作站精密跟踪、分析计算的基础上，提出元谋土林发育过程的复变函数表达式，并对其进行深入细致的分析模拟工作，得出部分形参意义，与地貌实体进行对照比较，结果较为理想。最后，文章反省该研究的缺陷与不足，提出存在的问题和今后的研究方向。     

基于VC的INSAR原始数据读取与处理成像

合成孔径雷达干涉复图像配准之前的原始数据读取和处理生成单视复图像技术是提高InSAR复图像配准精度的重要工作之一。介绍了ERS的数据格式,利用VC 6.0快速编译的特点,给出了一个切实可行的数据读取和处理成像的新方法,并通过对部分ERS1/2 SAR原始数据的处理,试验结果证明了该方法的有效性。     

Confronting hysteresis: Wood based river rehabilitation in highly altered riverine landscapes of south-eastern Australia

This study evaluates an experiment in river rehabilitation which uses large wood to stimulate and emulate natural system processes in an effort to reverse channel degradation, excess sediment transport and habitat simplification that has resulted from two centuries of human induced disturbances, particularly desnagging. The experiment involved the reintroduction of 436 logs (350 t) within 20 engineered log jams (ELJs) over an 1100 m reach. Commencing in 1999, the experiment was set up as a standard BACI design, with a control reach 3 km upstream. In the 5 years since implementing the rehabilitation strategy, the study reach has experienced five floods greater than the mean annual, and a further five events capable of mobilising the gravel bed. Five surveys of channel terrain have been completed since treatment implementation, and the changes to net sediment storage and morphologic diversity assessed in comparison to the control reach. Seven surveys of the fish population in the reach have also been undertaken during the project to measure the ecological response to the introduced wood. The experiment has demonstrated the effectiveness of ELJ technology in achieving engineering and geomorphic goals. To date, the treatment has halted further degradation of the river and increased sediment storage, with the test reach now storing, on average, 40 m³/1000 m² more sediment than in the control. These values, it would appear, represent a new reach-scale dynamic equilibrium storage level over decadal timescales. Additional sediment storage amounts to 3.5 m³/m³ of wood added. At the reach scale this additional storage represents a reduction of just 2% or less of the post-European expansion in channel capacity, suggesting far greater efforts are required than those employed here to reverse the cumulative effects of 180 years of channel erosion and simplification.Pool and bar area in the test reach increased by around 5% and 3.5%, respectively, while the corresponding values in the control were around 1.5% and 1%, respectively. Two indices of morphologic diversity were measured for each bed survey: the standard deviation of 3D residuals of change compared with the baseline survey (SD_iΔ3D); and the standard deviation of thalweg residuals from the line of best fit (SD_iTR). The SD_iΔ3D index shows both reaches increased in complexity through the study with the treatment increasing more than the control (0.37 and 0.29, respectively). The SD_iTR index does not detect clear changes because of the low signal to noise ratio, however, it does suggest the test reach was more complex than the control at the outset. The observed increase in fish abundance after the first 12 months of monitoring, reported previously, is now far less distinct 4 years on — a pattern seemingly reflecting the relatively minor increases in critical pool habitat and habitat diversity over the same period. Although no significant differences were detectable in fish species richness or total abundance from the reach aggregate data after 4 years, analysis of individual structures show them to be high quality habitat for native fish compared to the rest of the reach and the upstream control.These results highlight the challenges river managers face in achieving measurable improvements in the health of aquatic ecosystems in highly altered rivers. Managers must confront hysteresis in a biophysical and institutional sense when attempting to reverse the degradation of rivers. The scale of treatment implemented in this experiment was at the upper end of the spectrum of rehabilitation efforts currently being undertaken in Australia, suggesting that far greater resources and longer timescales are required to achieve the levels of improvement in the diversity of stream habitat expected by the community. The study also highlights problems with the strategy of attempting to meet multiple objectives within a reach scale rehabilitation project. While this treatment successfully met some geomorphic study objectives, maximising the benefits for fish habitat would require a strategy focused primarily on the creation of complex woody habitat within deeper pools, particularly pools immediately below riffles.     

关于一类复算子的平均收敛性

本文考虑了文[1]中提出的复算子R_n(f,z),得到了R_n(f,z)在空间L_p(|z|=1)(0相似文献