铁路滑坡动态及滑坡致灾的离散元评估方法

以铁路沿线滑坡的发育及分布规律为依据，采用积分加权评估方法将铁路运输廊道坡体分为稳定坡段、潜在滑坡点、活动滑坡点和消亡滑坡点；进而针对潜在滑坡和活动滑坡提出致灾的离散元评估方法.对铁路沿线滑坡的防治将起到积极的指导意义.     

驱动机制改变对沙堆模型行为特性的影响

慢驱动机制是自组织临界系统(SOC)的基本条件之一,若仅当驱动机制发生改变时,系统的行为特性会呈现何种变化,尚未有人研究.针对这一问题开展了快驱动机制的沙堆模型实验,通过快速倾斜沙堆底板的方式使沙堆从欠临界角快速到达临界角.实验表明,沙堆坡度保持在临界角附近时,落沙量服从幂律分布;随着沙堆坡度逐渐偏离临界角度,落沙量的统计特性将经历对数正态分布-正态分布的转变,不再呈现SOC特性.汶川实震诱发断裂带上盘的崩塌滑坡原型问题是驱动机制改变在自然界中的体现(其隆升速度与滑坡速度之间不存在巨大的时间标度分离).在对汶川地震断裂带上、下盘地区1.5km内的崩塌滑坡规模面积统计分析发现,上盘灾害服从对数正态分布,而下盘不服从对数正态分布.据此,推断汶川地震靠近断裂带上盘附近的崩塌滑坡呈现对数正态分布的规律可能是具普适性意义的现象.     

摩岗岭滑坡成因机理

摩岗岭滑坡位于泸定县境内的大渡河右岸一级支流磨西河口,为18世纪四川西部强震诱发的巨型地震高位滑坡.研究揭示,该滑坡发育于高烈度区的康定杂岩中,河谷走向与区域最大主应力方向垂直,河谷下切过程中斜坡经历了强烈的浅表生卸荷回弹,形成高陡斜坡后,谷坡在河谷应力场(重力场)的长期作用下坡体浅表层沿与缓倾坡外的结构面、走向北北西的陡倾结构面(与坡面走向一致)分别发生滑移和拉裂,当河谷切穿得妥断裂后,断裂带塑性变形,牵动上部坡体表层发生压缩-剪胀错动变形;周期性强震的反复作用,滑移和拉裂成脉动式和累进性式发展,最终使上述两组结构面接近贯通状态,上下游北东和北向侧裂面的切割,为坡体大规模失稳奠定了基本条件.1786年强烈的地震、高位地形放大效应、背坡效应等因素叠加最终触发摩岗岭滑坡的发生.     

重庆城市滑坡及崩塌的发育规律分析

分析了重庆城市滑坡、崩塌与地质构造、岩性、地貌、暴雨和人类活动的关系;总结了重庆城市滑坡、崩塌的发育规律.在此基础上预测了滑坡、崩塌的发展趋势.     

近断层地震动与汶川地震灾区滑坡破坏特征分析

基于对都江堰、彭州、绵竹、绵阳、北川、青川、平武、江油等重灾区和极重灾区的30多个地震滑坡灾害点进行的滑坡灾害现场测绘、灾害信息数字影像采集、地震滑坡灾害评估工作,发现灾区滑坡破坏模式主要以崩塌破坏或者崩塌破坏诱发的崩滑式破坏,而纯粹滑动式破坏较少,同时灾区滑坡破坏特征与近断层地震动效应存在密切联系,近断层地震滑坡与远震滑坡在灾害机理与破坏形式上存在明显区别,有必要在今后研究工作中针对近断层地震动的大脉冲效应、SH波、崩塌破坏特征展开系统研究.     

Ⅶ—Ⅸ度烈度区地震触发崩塌滑坡分布规律

利用"4·20"芦山地震Ⅶ—Ⅸ度烈度区资料翔实的有利条件,研究不同烈度区地震触发崩塌滑坡的整体分布规律,并基于自组织临界状态理论,从物理角度对其机理进行诠释.实震资料表明:Ⅸ度、Ⅷ度、Ⅶ度烈度区,崩塌滑坡面积与发生频率之间的关系均可用幂律描述,且幂指数b值相近,但随地震烈度的降低,崩塌滑坡密度单调减小;元胞自动机模拟表明:当扰动强度按0.5的比率递减时,沙堆模型的动力学特性基本服从同一幂律分布,雪崩密度呈线性关系减小;振动台沙堆模型物理实验也支持了以上结论.说明规模与发生频率之间的幂律关系是Ⅶ—Ⅸ度烈度区地震触发崩塌滑坡的统一分布规律,灾害点密度的不同是体现它们震害强度差异的主要指标.结论可为地震触发山地灾害危险性区划、地震次生灾害风险评估等提供科学依据.     

重庆市清江河流域山洪致灾临界面雨量研究

为研究重庆市清江河流域的山洪致灾临界面雨量,利用FloodArea模型对该流域2014年8月11日的山洪过程进行模拟,采用统计分析方法确定雨-洪关系得到流水坡、龙洞沟、龙嘴和万里学校隐患点在淹没水深分别为0.6,1.2和1.8m下对应的临界面雨量,结果如下:1)FloodArea模拟的花林站最大水深出现时间与实际一致,最大淹没深度与实际相差0.295m,模拟结果与实际情况符合.2)不同隐患点淹没水深与不同小时尺度的累积面雨量的相关性不一样,分别选取2,2,4和6h累积面雨量作为流水坡、龙洞沟、龙嘴和万里学校隐患点的临界面雨量的小时尺度.     

地震荷载作用下海底滑坡特征及其机理

通过多种勘察手段,分析了厦门沪救码头海底滑坡成因及滑坡附近的地形、地层和海洋水动力条件等因素,采用动力有限元法和强度折减法相结合的方法分析海底滑坡在地震荷载作用下的动力响应、海底滑坡动力稳定性的影响因素以及地震荷载与海底滑坡失稳状态之间的关系.结果表明,在地震荷载作用下,软土层之间存在拉应力效应并导致海底滑坡崩塌滑动的危险;动力有限元法和强度折减法相结合并以计算不收敛为判据的方法,适用于分析海底滑坡的地震整体稳定性.当地震作用时,厦门沪救码头海底滑坡的整体稳定安全系数为1.50.     

兰州高阶地斜坡稳定性分析和防治对策——以伏龙坪为例

以黄河南岸Ⅳ级阶地伏龙坪段前缘高陡斜坡为例,在分析坡体结构和灾害点分布特点的基础上,利用FLAC 3D有限差分方法对坡体稳定性进行了定量评价,结果显示,伏龙坪段大部分坡体在自然条件下处于稳定性较差状态,在降水和地震等条件下,发生崩塌、滑坡的可能性很大.根据兰州城市建设用地的现状,提出了在统一规划的基础上,按照轻重缓急的原则对不稳定斜坡进行工程治理,根据边坡高度和坡体结构,选择坡体挡墙或抗滑桩支挡,坡体根据相对高度采用一级或分级的锚索格构加固,辅以截排水工程,在实践中取得良好的效果.在进行城市区斜坡坡体整治时要注意与周边环境的协调性,同时进行坡体绿化,提高城市绿地,达到消除灾害隐患、保障当地经济社会发展.     

“4·20”芦山地震地质灾害遥感快速解译与空间分析

2013年4月20日四川省芦山县发生7.0级地震,地震诱发了大量的崩塌滑坡。利用四川省测绘地理信息局和四川省地质调查院提供的芦山县城、太平镇、宝盛乡、龙门乡、清仁乡、上里镇、思延乡等重灾乡镇的震后高精度航空影像进行了地质灾害体的解译,利用GIS分析了芦山地震诱发的崩塌滑坡的空间分布关系和特征。结果表明崩塌滑坡主要受断层控制,距离发震断层3km范围内分布密度最大;坡度是影响崩滑分布的重要因素,崩滑体主要分布在坡度40°～50°范围内;在海拔高度1～1.5km范围内崩塌滑坡密度最大;距水系400m范围内的崩塌滑坡分布密度最大;白垩系泥岩、砂岩出露的地方容易产生大量崩塌滑坡;崩塌滑坡主要集中分布在Ⅸ烈度区。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.