成都二绕K51+400～700滑坡稳定性分析及处治

成都第二绕城高速K51+400~700段以开挖路堑方式通过,在2013年06~07月间的多次连续强降雨后,路堑边坡发生沿基岩滑动的推移式滑坡变形。通过现场调查及地质分析,确定了降雨、前缘减载作用为本次滑动的重要因素,并提出了坡体后缘减载、前缘抗滑桩及挡土墙支挡、地表截排水的综合治理措施,为今后线路工程路堑边坡滑坡治理提供一定的参考意义。     

基于反演法的牵引式滑坡治理设计及施工

国道213线K193＋060～190滑坡系由公路路堑开挖引起的牵引式滑坡。由于滑坡已经滑动,用勘探提供的滑动面力学参数计算的滑坡推力与实际滑坡状态不符。为此,设计滑动面力学参数时应由滑动后清方减载前的坡体极限平衡法确定,即反算法。同时介绍了主要工程治理措施及施工技术。     

向家坡滑坡综合治理研究

针对渝黔高速公路路堑边坡向家坡滑坡综合治理工程实例,首先通过对该边坡前期滑动及不成功治理过程介绍,结合地表位移监测和详细的地质勘探,准确地判断了路堑边坡滑坡病害性质、滑坡机例,总结了前期治理失败的原因;然后将滑体与前期支挡工程视为桩土复合体进行了稳定性分析;最后制定了临时防治与永久根治相结合的多途径的综合治理方案。成功的实践表明,这是一种既安全可靠、又经济合理的路堑边坡滑坡综合整治措施。     

路堑边坡平面滑动演化过程及远程滑动机制的模拟与分析

永宁高速公路K117滑坡路段原为在泥质粉砂岩单斜地层内开挖2级形成的路堑边坡,开挖后产生典型平面滑动,在中部滑床形成长约25m的滑动槽,产生最远达35m的远程滑距,其成因机制复杂。本文在对滑坡基本特征及孕育过程开展详细调查研究的基础上,采用节理有限单元法对该滑坡经路堑开挖导致高位坍滑、刷方变更后触发高速远程滑塌、滑塌后壁残留滑体牵引松动,以及对其实施卸载、支挡回填及锚固的治理过程开展数值模拟,再现了该滑坡孕育发展全过程及其稳定性演化规律;分析了该边坡破坏的平面滑动机构及滑动面的物理力学特征,论述了该类滑坡启动高速远程滑动的开挖松弛致滑机理和裂隙充水致滑机理,最后提出了预测及治理该类滑坡的6点建议。研究表明,在单斜地层开挖路堑,使顺倾向软弱结构面临空暴露时,可能诱发边坡整体卸荷松弛,产生较大的不平衡滑坡推力,而卸荷松动产生的张裂隙导致滑坡对降雨入渗十分敏感,不平衡力和裂隙水压力的共同作用可迅速剪断滑面,伴随势能向动能的转化,产生高速远程滑动。     

北沿江高速K19+020～K19+164段滑坡稳定性分析与评价

北沿江高速为新建高速公路,K19＋020～K19＋164段由于土方开挖形成了高而陡的碎石土质边坡,2012年11月由于连续降雨,K19＋020～K19＋164段右侧出现滑坡。滑坡的治理要求对其进行稳定性分析与评价,为滑坡治理设计提供岩土工程参数。     

对路堑顺向滑坡分段治理方案的探讨--以贵州省关岭至兴仁二级公路K105+300～510段边坡治理工程为例

通过贵州关岭至兴仁二级公路K105 300～510段路堑边坡治理工程设计、施工与工程监理的观察，结合工程特性，对不同坡度的顺向滑坡，按滑坡形成的地质地貌条件及物理力学性质的差异，采取不同区段的治理方案，并取得较好的效果。     

降雨对花岗岩风化层路堑边坡滑动模式影响

降雨引起路堑边坡的浅层局部滑动是工程中常见的现象,但其内在原因的研究尚不充分。为此,以福建省云平高速云霄段花岗岩风化层中的某两级路堑边坡为例,采用饱和和非饱和土抗剪强度理论,按照强度折减有限元方法分析了该边坡在一般工况、地下水渗流工况和降雨入渗工况下的滑动模式。结果表明:一般工况下该边坡滑动模式为深层整体滑动;地下水渗流作用可使边坡由深层滑动模式向浅层滑动模式转化;长时小或中等降雨作用下坡体内出现三道滑动面,且一级边坡内滑动面最先贯通,滑坡模式由深层整体滑动向浅层局部滑动演化。短时强降雨作用下仅在一级边坡内出现贯通的滑动面,即由整体滑动模式完全转变为浅层局部滑动模式。降雨工况越不利表现越为明显,与实际滑坡现象相吻合,且安全系数不满足规范要求,从而从理论上验证了该路堑边坡发生浅层局部滑动的必然性。此外,为避免花岗岩风化层路堑边坡在降雨入渗下发生浅层局部滑动,对假设的不同放坡方案进行了数值模拟分析。结果表明,适当放缓坡率可使一级边坡内不出现滑动面,滑坡模式仍为较深位置的整体滑动,且安全系数可得到有效提高,使其满足规范要求。因此,实践中,采用文中方法对设计的类似地层中的路堑边坡事先进行降雨入渗影响下的模拟分析极为必要。将使放坡坡率更为科学合理,可在确保边坡整体稳定性的同时,极大降低其发生浅层局部滑动的可能性。     

复杂路堑高边坡病害治理效果模糊层次评价

双永高速公路K227滑坡由于地形高陡、地质复杂、环境敏感、施工困难等因素成为典型的复杂超高路堑边坡和项目建设及运营养护的关注焦点。为评价该边坡病害治理效果,在长期参与其治理过程的实践、思考、评价和监控基础上,从地形条件、地质条件、环境条件、应力调整和变形控制等方面构建复杂路堑高边坡安全评价指标体系、特征状态量化标准和各评价指标权值。结合模糊综合评判法、专家权威系数修正和最大隶属度原则,建立复杂路堑高边坡安全评估的模糊层次评价模型和评估方法,并与极限平衡法和有限元法计算成果、以及治理前后的现场变形迹象调查和持续性变形监测结果对比分析,对K227滑坡病害治理效果进行综合评判,并证明其是评价复杂路堑高边坡病害治理效果的有效方法。     

金丽温高速公路K81高边坡变形动态数值分析

对金丽温高速公路K81高边坡进行接触大变形有限元动态数值分析.结果表明,路堑边坡开挖,导致滑面的法向应力减小、抗滑力下降,是引起古滑坡复活的根本原因.研究结果也说明了接触大变形有限元分析方法可以较好地分析潜在滑面的力学作用,是研究滑坡的滑动机理的有效方法.     

湖南醴潭公路土质滑坡变形破坏特征分析

公路土质滑坡在其滑动变形破坏的过程中,具有一定的潜伏性,不易被识别。对于该类滑坡稳定性的评价与治理,应结合其滑动变形破坏机理及规律,查明滑坡滑动的关键影响因素,以便因地制宜地进行防治。结合醴潭公路K53+960—K54+020段的具体工程边坡实例,分别运用传统的剩余推力法和数值模拟技术,分析了该边坡在自然状态、降雨及地震条件下的稳定性及变形机理,深入分析了导致该边坡变形破坏的成因,认为降雨及地震对公路土质滑坡均具有较大的诱发作用。通过对比分析,传统计算方法和数值模拟结果相符合,印证了数值模拟技术在工程应用中的可视性和实用性。     

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.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

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.     

Late Wuchiapingian (Late Dzhulfian,early Late Permian) limestone olistolites within the Tertiary flysch of Glypia Unit (Mount Parnon,central–eastern Peloponnesus,Greece)

Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931.     

PALEONTOLOGY

正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.)     

GEOCHEMICAL EXPLORATION

正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.)     

MICROPALAEONTOLOGY

正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.)     

PETROLOGY

正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus.,     

ENVIRONMENTAL GEOLOGY

正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an