城市地面沉降研究进展及其发展趋势

地面沉降是城市主要地质灾害之一。随着中国城市化进程的加快，地面沉降规模扩大，危害加剧，本文简述了国内外地面沉降概况，对地面沉降的成因、危害、机制、数学模拟、监测、防治等方面的研究进展进行了综合论述，并指出，建设工程性地面沉降，孔隙水运移机制、地下水和地面沉降模型耦合、地面沉降生态-经济-社会影响评估、地下水采灌优化设计、地面沉降系统防治、地面变形高精度监测、城市化建设与地面沉降的相互关系等，是今后城市地面沉降研究的主要方向。     

鞍山市区地面沉降的机理分析

鞍山市区地面沉降是近年发现由于抽取地下水引产地面沉降地区，结合区内的环境工程地质及地质条件，通过研究1987～1994年间的分布特征及其演化趋势，初步认为鞍山市区地面沉降除了主要起因于过量开采地下水导致水位持续快速降低外，新构造运动、第四系结构与地面沉降也有密切关系。     

从天津市控制地面沉降的实践看水资源统一管理的必要性

本文通过天津市多年控制地面沉降工作的实践,总结分析了导致地面沉降的主要原因是地下水严重超采,而控制地面沉降的首要措施是实现水资源统一管理,使地表水、地下水联合运用,解决地下水超采区的替代水源。     

开采地下水引起的地面沉降

开采地下水引起的地面沉降 由于地下发生变化引起地表高程降低形成了地面沉降。人类活动引起的地面沉降主要是：开采地下水，从地下储集层开采石油和天燃气。石灰岩含水层的溶解（灰岩坑），地下矿井的塌陷；有机土壤排水，干土壤的起初变湿（渗水压实作用）。美国每个州都有地面沉降发生（图1）。     

地下水位与环境岩土工程：第四讲地下水位波动与地面沉降

简要讨论了地下水与区域性地面沉降之间的关系，主要论未固结松散含水层中抽汲地下水引起地面沉降的机制及其研究方法。介绍几类代表性的预测井点降水引起的地面沉降的计算模型。     

我国地面沉降现状及防治对策研究

文章以长江三角洲、华北平原及汾渭地堑地区为重点提出开展全国地面沉降防治的建议。地面沉降主要是由于不合理开采地下水引发的一种区域性的缓变地质灾害，成灾慢，但损失大，不易治理。同时，在上述三大地区由于地面沉降还伴发了地裂缝灾害。粗略统计，1949年以来，我国地面沉降造成的损失累计高达4500—5000亿元，其中，年均总损失为90～100亿元，年均直接损失8～10亿元。文章建议：利用10～15a时间，综合研究第四系结构、含水层结构及地下水环境、基底地形与断块构造特征，建立三维可视化数字平台；查明全国地面沉降灾害分布状况和演化规律，开展地灾风险评估及地质环境安全功能区划；建成全国地面沉降现代化监测控制网络；开展地面沉降防治，严格控制地下水开采，实施以控制地面沉降为目标的含水层修复等减灾工程。文章总结了禁采或限采地下水、优化地下水开采层位、浅层地下水开发利用、地下水人工回灌与含水层修复等地面沉降防治经验。     

太原市地面沉降初探

本文通过分析太原市地质、水文地质条件，地下水开采状况及地面沉降特点，对太原市地面沉降的原因，现象进行了初步探讨。指出太原市地面沉降主要由于过量开采地下水引起，并就此提出了控制太原市地面沉降的措施。     

开采浅层地下水对地面沉降影响的探讨

苏锡常地区由于长期过量开采深层地下水，已诱发了严重的地面沉降灾害。为此，江苏省政府下达了在2005年全面禁采深层地下水的文件。为解决用水问题，许多专家、学者建议开采利用浅层地下水。在苏锡常地区开采浅层地下水是否会同样诱发严重的地面沉降问题，是目前争议的焦点。文章详述了苏锡常地区水文地质条件及地面沉降现状，确定了地面沉降的各种影响因素，分析对比了浅层地下水与深层地下水在开采条件下所能引起的地面沉降量，说明采用合理的开采工艺开发利用浅层地下水不会诱发严重的地面沉降。     

天津地面沉降区地下水资源超采和涵养恢复阈值的讨论

天津市地面沉降属于典型的水资源短缺型地面沉降,发育范围广,沉降程度高,灾害损失大,有效防治天津市地面沉降的主要手段是严格控制地下水资源超采、涵养恢复地下水含水系统。从地下水流动系统和地面沉降的发育特点出发,综合分析讨论,认为天津沉降区整体上地下水已经超采,仅研究小区域地下水是否超采,存在“以小论大”的误区,宜以水文地质单元为单位来开展超采情况评价,地下水资源实现有效涵养恢复的阈值是要求地下水位恢复至地面沉降临界水位以上。     

城市环境岩土工程的地下水灾害问题

随着城市建设的发展，人类在域市的岩土工程活动越来越频繁，由此产生一系列环境岩土工程问题。其中，由人类的工程活动引发的地下水灾害问题日趋显著，已经引起国内外专家的高度重视。地面沉降范围不断扩展，地下水永喷逐年下降，是当前城市环境岩土工程中日益突出的地下水灾害中最广泛、最严重的两大问题。它们已严重威胁着域市的可持续发展及居民的正常生活。文章概述了地面沉降及地下水水质污染现状，对抽汲地下水引起的地面沉降、建设工程性地面沉降的机理以及城市建设中可能引起的地下水点污染问题等进行了分析，针对地面沉降和地下水污染提出了相应的预防与治理措施，以实现地下水资源的可持续利用，保证城市经济及社会的可持续发展。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861