地铁车站主体结构渗漏及堵漏

地铁工程建设中，结构渗漏的堵漏工作非常重要，实际施工十分复杂，对整个工程质量有重大影响。该文总结了长期项目施工中的有效经验，并以某车站主体结构工程为例，详细介绍了该车站主体结构自防水设计及施工工艺，对结构渗漏的原因及具体的堵漏施工方法进行了探讨。     

Sedimentological and palaeohydrological responses to tectonics and climate in a small, closed, lacustrine system: Oligocene As Pontes Basin (Spain)

ABSTRACT A small, closed, lacustrine system developed during the restraining overstep stages of the Oligocene As Pontes strike‐slip basin (Spain). The increase in basin accommodation and the headward spread of the drainage, which increased the water input, triggered a change from shallow, holomictic to deeper, meromictic conditions. The lower, shallow, lacustrine assemblage consists of mudstone–carbonate cycles recording lacustrine–palustrine ramp deposition in a saline lake. High Sr content in some early diagenetic calcites suggests that aragonite and calcite made up the primary carbonate muds. Early dolomitization took place together with widespread pedogenic activity. The upper, deep, freshwater, lacustrine assemblage includes bundles of carbonate–clay rhythmites and fine‐grained turbidite beds. Primary calcite and diagenetic siderite make up the carbonate laminae. The Mg content of the primary carbonates records variations in Mg/Ca ratios in lacustrine waters. δ¹⁸O and δ¹³C covariance trends in calcite reinforce closed drainage conditions. δ¹⁸O data indicate that the lake system changed rapidly from short‐lived isotopically light periods (i.e. from seasonal to pluriannual) to longer steady‐state periods of heavier δ¹⁸O (i.e. from pluriannual to millennial). The small δ¹³C changes in the covariant trends were caused by dilute inflow, changing the contributions of dissolved organic carbon in the system and/or internal variations in lacustrine organic productivity and recycling. In both shallow and deep carbonate facies, sulphate reduction and methanogenesis may account, respectively, for the larger negative and positive δ¹³C shifts recorded in the early diagenetic carbonates (calcite, dolomite and siderite). The lacustrine system was very susceptible to high‐frequency, climatically forced water balance variations. These climatic oscillations interfered with the low‐frequency tectonic and morphological changes in the basin catchment. This resulted in the superposition of high‐order depositional, mineralogical and geochemical cycles and rhythms on the lower order lacustrine infill sequence.     

Sedimentation in a fluvially infilling, barrier-bound estuary on a wave-dominated, microtidal coast: the Ouémé River estuary, Benin, west Africa

The Ouémé River estuary is located on the seasonally humid tropical coast of Benin, west Africa. A striking feature of this microtidal estuary is the presence of a large sand barrier bounding a 120 km² circular central basin, Lake Nokoué, that is being infilled by heterogeneous fluvial deposits supplied by a relatively large catchment (50 000 km²). Borehole cores from the lower estuary show basal Pleistocene lowstand alluvial sediments overlain by Holocene transgressive–highstand lagoonal mud and by transgressive to probably early highstand tidal inlet and flood‐tidal delta sand deposited in association with non‐preserved transgressive sand barriers. The change in estuary‐mouth sedimentation from a transgressive barrier‐inlet system to a regressive highstand barrier reflects regional modifications in marine sand supply and in the cross‐barrier tidal flux associated with barrier‐inlet systems. As barrier formation west of the Ouémé River led to an increasingly rectilinear shoreline, the longshore drift cell matured, ensuring voluminous eastward transport of sand from the Volta Delta in Ghana, the major purveyor of sand, to the Ouémé embayment, 200 km east. Concomitantly, the number of tidal inlets, and the tidal flux associated with a hitherto interlinked lagoonal system on this coast, diminished. Complete sealing of Lake Nokoué has produced a large, permanently closed estuary, where tidal intrusion is assured through the interconnected coastal lagoon via an inlet located 60 km east. Since 1885, tides have entered the estuary directly through an artificial outlet cut across the sand barrier. Although precluding the seaward loss of fluvial sediments, permanent estuary‐mouth closure has especially deprived the highstand estuary of marine sand, a potentially important component in estuarine infill on wave‐dominated coasts. In spite of a significant fluvial sediment supply, estuarine infill has been moderate, because of the size of the central basin. Estuarine closure has resulted in two co‐existing highstand sediment suites, with limited admixture, the marine‐derived, estuary‐mouth barrier and upland‐derived back‐barrier sediments. This situation differs from that of mature barrier estuaries characterized by active fluvial‐marine sediment mixing and facies interfingering.     

Compositional Kriging: A Spatial Interpolation Method for Compositional Data

Compositional data are very common in the earth sciences. Nevertheless, little attention has been paid to the spatial interpolation of these data sets. Most interpolators do not necessarily satisfy the constant sum and nonnegativity constraints of compositional data, nor take spatial structure into account. Therefore, compositional kriging is introduced as a straightforward extension of ordinary kriging that complies with these constraints. In two case studies, the performance of compositional kriging is compared with that of the additive logratio-transform. In the first case study, compositional kriging yielded significantly more accurate predictions than the additive logratio-transform, while in the second case study the performances were comparable.     

中国城市经济区划分的初步研究

本文建立了城市经济区划分的理论与方法——d△系和R_d链法,应用33个指标对全国434个城市进行了综合实力的R型因子分析评价,并进行了不同层次d系的划分和Ⅰ、Ⅱ、Ⅲ级d△系和R_d链组建,提出了我国两大经济发展地带、三条经济开发轴线、九大城市经济区和33个Ⅱ级城市经济区的城市经济区区划体系设想。     

Variations in the carbon isotope composition and production yield of various pyrolysis products under open and closed system conditions

Production rates and carbon isotopic compositions of various pyrolysis products were investigated for three sediments from the Williston Basin under open and closed pyrolysis conditions in the temperature range of 300–600°C.Both parameters do not show any significant differences for kerogens and carbon dioxides with the analytical procedure. Contrary to open system pyrolysis, however, decreasing yields of pyrolysates and higher amounts of gaseous hydrocarbons (C_2–4 compounds) at temperatures of 500 and 600°C, point to their decomposition to give ultimately methane.Moreover, these pyrolysis products display distinct carbon isotopic variations under open and closed pyrolysis conditions. They are due to a kinetic isotope effect, i.e. the preferential cleavage of ¹²C-¹²C over ¹³C-¹²C bonds, but the extent of the shift in isotopic composition seems to depend primarily on the reservoir size and the type of source material.     

Chemical alteration of volcanic glasses and related control by secondary minerals: Experimental studies

A detailed experimental mineralogical and geochemical study on hydrothermal alteration processes of volcanic glasses with a different chemical composition and leucites sampled in the Roman Comagmatic Region was carried out. 2g samples of different grain sizes and 50 ml of deionized water or seawater were sealed in bronze Teflon-lined autoclaves and placed in a rotating sample-holder at 200°C. The internal pressure was 16.2 bars. At arbitrary intervals, the pressure vessel was quenched to room temperature and both solids and solutions were separated by filtration. The solids were used to identify possible alteration products by means of X-ray powder diffraction, SEM and microprobe analyses. In all deionized water systems the contact solution reached pH basic values, but in the various systems the consumption of H⁺ ions occurred in different ways. This is probably linked to different concentrations of released cations. In seawater systems, however, pH values initially fell sharply but subsequently increased slightly. After 2 days, cation concentrations were clearly buffered by reaction products in all solutions. These were mainly zeolites and clay minerals. The following crystallization sequences in all glass/deionized water experiments were observed: the first reaction product was represented by phillipsite, followed by analcime and illite in the alkali-trachytic run; chabasite and analcime in the phonolitic-tephritic run; analcime and finally feldspar in shoshonitic and trachytic runs. Phillipsite and smectite crystallized together only in the basaltic run. In leucite/deionized water systems, however, the first reaction phase was illite, followed by analcime and then phillipsite. The reaction products in glass/seawater systems were smectite and anydrite. The chemical composition of synthetic zeolites was clearly controlled by the chemistry of initial glasses. These synthetic zeolites are like the natural ones in volcaniclastic products from central and southern Italy. This suggests that extensive zeolitization processes of these volcaniclastic rocks may occur through interaction of volcanic glasses with fluids at a very low salinity and a temperature close to 200°C.     

基于本体的地理空间信息集成框架与实现

论述了地理本体的基本概念、结构,介绍了地理本体的建模方法,提出了基于地理本体的空间数据集成框架,包括构建地理本体、数据预处理、概念映射、数据映射和数据抽取与转换5个步骤;设计了基于本体的空间数据集成方案,以数字地形图数据、海图数据向标准本体的集成为例对方案进行验证试验,并取得了初步成果。     

台湾海峡架桥铺路的层析技术问题的初步分析

关于在台湾海峡架桥和修筑隧道的问题从1987年至2002年在福省召开过三次"台湾海峡两岸地质地震和架桥与修筑隧道的研讨会",以后陆续出版了相应的论文和论文集,提出了"台湾海峡架桥和修筑隧道的可行性研究",和"台湾海峡隧道工程设计总建议"等[1-4],论述了修建该工程的可行性等问题.提出平潭岛可作为海峡北线的端点,探讨了如何具体建桥和相关工程的问题.近年来地球层析技术的发展,可对台湾海峡隧道工程的工程地质问题,海港的开发和沿海陆地的充分利用等,做出探测台湾海峡地下地层三维成像细结构和地球物理场的空间分布,作为台湾海峡架桥铺路工程基本设计的必要依据.为了让大中小轮船在台湾海峡顺利通航,利用现代的科技研讨台湾海峡两岸连接的最佳方案.为了架成大型的高桥和修建堤坝式的地基,必须用地震层析和应力波等方法探测桥梁和堤坝地基的结构和地层的坚实程度,以便决定桥墩深入海底的深度,和设计坚固而又经济的桥墩与堤坝的基础.参考开采海底石油平台施工和荷兰填海造田的工程经验,以双边海堤与大型高桥及活动的船闸相结合,从平潭岛东至台湾新竹西海岸,在124千米距离上架设4-6段桥梁和5-7段堤坝型的路基,既让大中小船舶照常航行,海洋生物照常游动,又可在其上通车,以缩短两岸距离,适应中国大陆和台湾经济快速发展的需要,争取和平沟通的愿望.由于架桥铺路的工程费用较修筑隧道的投资低得多,在福建近海地带局部填海造地,充分利用海洋资源和建筑深水码头,可得到较大的经济补偿,在现阶段较易实施.本文初步分析了有关的地球层析和工业CT技术的作用问题.     

Kepler's problem in constant curvature spaces

In this article the generalization of the motion of a particle in a central field to the case of a constant curvature space is investigated. We found out that orbits on a constant curvature surface are closed in two cases: when the potential satisfies Iaplace-Beltrami equation and can be regarded as an analogue of the potential of the gravitational interaction, and in the case when the potential is the generalization of the potential of an elastic spring. Also the full integrability of the generalized two-centre problem on a constant curvature surface is discovered and it is shown that integrability remains even if elastic forces are added.