Integrated analysis of a coupled mechanism for the failure processes of pile-reinforced slopes

A series of centrifuge model tests was conducted to investigate the failure mechanism of pile-reinforced slopes under self-weight loading and vertical loading conditions. An integrated analysis method was proposed based on the image-based measurement results of the displacement of the slope in the tests. The failure process of a pile-reinforced slope was quantified based on the measured deformation process over the entire slope, which was shown to depend primarily on the loading conditions. The deformation localisation was discovered in the slope during loading and was effectively described using a newly introduced index, the Diversity Factor of Displacement (DFD). The deformation localisation of the slope developed and caused the progressive formation of the slip surface. At the same time, a local failure at a point on the slip surface resulted in new deformation localisation, and the influence expanded with the centre of the failure point and waned with increasing distance from the failure point. The deformation localisation process and the deformation-failure process of the piles interacted as both cause and effect and developed alternately. The failure mechanism of the pile-reinforced slopes was used to explain the effects of several influencing factors on the bearing capacity of the reinforced slope, such as the pile spacing, pile location, and gradient of the slope.     

遥感技术在大狐狸山地区1：50000矿产远景调查中的应用

以内蒙古自治区西部阿拉善盟额济纳旗大狐狸山地区1：5万矿产远景调查为例,论述了遥感技术在1：5万矿产远景调查中的应用和具体工作方法。研究结果表明,在1：5万矿产远景调查中充分利用遥感技术,进行线性构造、环形构造、地质体的信息提取,利用主成分分析法有效提取矿化蚀变信息,在RGMAP数字平台,将工作区的标准影像图与其它数据源进行叠加整合,多轮回遥感地质解译成图,结合地质、物探、化探工作成果,快速有效地指导了地面找矿工作,对合理圈定找矿预测靶区起到了重要作用。     

Analysis of the organic matter of oil shales by nuclear magnetic resonance

¹³C NMR spectroscopy was applied in the investigation of the structure of the organic matter in oil shales. By using Proton Enhanced Nuclear Induction Spectroscopy, a fair resolution of aliphatic and aromatic carbon signals was achieved. This method provided information on the relative ratio of aliphatic and aromatic carbons within a given set of samples (Aleksinac, Kimmeridge, Colorado, Australian torbanite and Estonian kukersite).     

Proterozoic tectonic evolution and late Svecokarelian plate deformation of the Central Baltic Shield

The continental crust of the Central Baltic Shield evolved by accretion towards the west during the Svecokarelian orogeny 1700–2200 Ma ago. The following features are consistent with a plate tectonic mechanism involving subduction of oceanic crust below an Archean craton in the east: flysch-sediments with serpentinite masses and pillow lavas, linear high-grade metamorphic zones, island-arc type volcanic belts and late tectonic batholiths with porphyry type Cu-Mo deposits.Semi-consolidated new crust was affected by late Svecokarelian deformation (D_n) after 1850 Ma; NNE-trending folds with crenulation cleavage were overprinted on older structures together with associated NW trending ductile transcurrent shear zones that curve the F_n folds into gentle S and Z shapes. The late tectonic batholiths intruded partly at the same time as and partly after the D_n deformation.

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Zusammenfassung Die kontinentale Kruste des zentralen Baltischen Schildes entwickelte sich durch nach Westen gerichtetes Anwachsen während der Svecokarelischen Orogenese vor 1700 bis 2200 Ma. Die folgenden Erscheinungsformen lassen sich mit einem plattentektonischen Mechanismus in Einklang bringen, der Subduktion von ozeanischer Kruste unter einen Archaischen Kraton im Osten einschließt: Flysch-Sedimente mit Serpentinit-Massen und Kissenlaven, lineare hochmetamorphe Zonen, vulkanische Gürtel vom Inselbogen-Typ und spättektonische Batholithe mit porphyrischen Cu-Mo-Lagerstätten.Die halbkonsolidierte neue Kruste wurde durch späte Svecokarelische Deformation (D_n) nach 1850 Ma erfaßt; NNE-orientierte Falten mit Krenulationsschieferung wurden älteren Strukturen aufgeprägt in Verbindung mit NW-streichenden, plastischen Transcurrent-Scherzonen, die die F_n-Falten in sanfte S- und Z-Formen verbiegen. Die spättektonischen Batholithe intrudierten teils während, teils nach der D_n-Deformation.

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Résumé La croûte continentale du Boucher baltique central a évolué par voie d'accrétion vers l'ouest durant l'orogénie svécocarélienne 1700–2200 Ma. Les événements suivants sont en accord avec un mécanisme de tectonique de plaques impliquant la subduction d'une croûte océanique sous un craton archéen à l'est: sédiments flyschoïdes avec masses de serpentinite et de laves en coussins, zones linéaires à haut degré de métamorphisme, ceintures volcaniques du type guirlande d'îles et batholithes tectoniques tardifs avec gisements porphyriques de type Cu-Mo.La nouvelle croûte à semi-consolidée fut affectée par une déformation svécocarélienne tardive (D_n) postérieure à 1850 Ma. Des plis de direction NNE avec clivage de crénulation ont été superposés sur des structures plus anciennes, associés à des zones de cisaillement transcurrentes de direction NW qui ont incurvé les plis F_n suivant des formes en S et Z. Le batholithe tectonique tardif s'est mis en place en partie au même moment que, et en partie après, la déformation D_n.

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Surface current patterns in front of the Venice Lagoon

Surface patterns of the low-frequency current in a 20 × 30 km region in front of the Venice Lagoon were analysed from a 13-month-long HF radar data set. Surface circulation was related to prevalent wind regimes in the area and to the tidal flow through the lagoon inlet. Three different categories of wind-forcing were defined: bora (NE wind), sirocco (SE wind), and finally the category containing all other wind directions and calms (winds lower than 3 m/sec). Mean flow and vorticity spatial distributions were discussed for different wind conditions. The coastal area about 5 km wide is characterized by a flow field with maximum vorticity. Outside the coastal boundary layer the interior flow is part of the Adriatic basin-wide cyclonic circulation. Two counter-rotating vortices of the dimension of about 4–5 km were evidenced in the average flow field in front of the lagoon inlet (Malamocco inlet) in all situations except for the bora. The vortex-pair is probably associated with the tidal flow through the inlet. The bora wind induces a strong southward coastal jet detached from the coast by about 5 km homogenizing the flow and eliminating the dipole. The average coastal flow pattern in calm wind conditions was also analysed as a function of the strong inflow/outflow (currents in the inlet > 0.7 m s⁻¹) from the lagoon inlet. In both cases the vorticity pattern is similar, with the negative vorticity to the left of the inlet and positive to the right looking seaward.     

青藏高原春季土壤湿度与夏季降水的关系

应用SVD方法对1981-2018年青藏高原春季土壤湿度和高原地区夏季降水进行诊断.结果表明:土壤湿度前两个模态累积协方差百分比达到了 61.15％,左右场展开序列的时间相关系数均为0.7 8,反映两场关系的主要特征.土壤湿度场表现出南北相的一致性,而降水场的一致性较差.第一模态说明青藏高原北部春季土壤湿度较大时,对应...     

An original method for characterizing internal waves

This study consisted in the characterization of internal waves in the south of the Strait of Messina (Italy). The observational data consisted in thermistor string profiles from the Coastal Ocean Acoustic Changes at High frequencies (COACH06) sea trial.An empirical orthogonal function analysis is applied to the data. The first two spatial empirical modes represent over 99% of the variability, and their corresponding time-dependent expansion coefficients take higher absolute values during internal wave events. In order to check how the expansion coefficients vary during an internal wave event, their time derivative, called here changing rates, are computed. It shows that each wave of an internal wave train is characterized by a double oscillation of the changing rates. At the front of the wave, both changing rates increase in absolute value with opposite sign, and then decrease to become null at the maximum amplitude of the wave. At the rear of the wave, the changing rates describe another period, again with opposite sign. This double oscillation can be used as a detector of internal waves, but it can also give information on the width of the wave, by measuring the length of the oscillation, as this information may sometimes be hard to read straight out of the data. When plotting the changing rates one versus another, the resulting scatter diagram puts on a butterfly shape that illustrates well this behaviour.     

那曲地区气候变化对该区湖泊面积的影响

利用地面4个测站常规气象资料及中巴地球资源卫星、美国陆地卫星资料,分析了那曲中东部地区湖泊流域近45年各气候要素的变化对20世纪80年代以来湖泊面积变化的影响。在此基础上,建立了湖泊面积的拟合方程。结果表明:湖泊流域的降水量、气温以及地面温度近年来呈上升趋势,而蒸发量、日照时数、最大积雪深度、最大冻土深度逐渐下降。这些要素变化与湖泊面积的增加具有显著的线性关系,根据这些气象要素的累积值建立的回归方程能较好地拟合湖泊面积的变化。     

1960-2004年金沙江径流量特征及其对气候变化的响应

基于金沙江流域内1960-2004年的水文、气象站观测数据,分析了区域内径流量的年际、年代际变化以及气候因素(如降水量、平均气温)对径流变化的影响.结果表明:近40 a来径流量呈现逐渐增加趋势,并且支流雅砻江为金沙江径流量的主要产流区;干流与支流均存在年代间丰枯转移,20世纪60年代、90年代偏丰,70年代偏枯;干流夏...