基于MSC.Marc软件的面板堆石坝加高的可行性研究

以华东某面板堆石坝加高工程为例,利用MSC.Marc软件的二次开发功能,结合FORTRAN接口实现非线性弹性邓肯E-B模型.通过面板坝加高前后堆石体及面板应力和变形的分析,对面板堆石坝加高问题进行可行性研究,并用经验公式验证计算的准确性.计算结果表明:坝体加高后堆石体的应力和变形规律较好,面板部分顺坡向拉应力区域转变为压应力,对坝体更为有利,加高方案安全可行.     

基于BP神经网络的岩土工程预测模型研究

BP神经网络具有自适应机制,通过训练和学习,达到对知识进行分类、模式判别、联想记忆等能力.岩土工程的灾害预测问题可以看作是一个模式识别问题,而岩土工程中变形情况的监测和预测模型的研究是矿山、建筑、水利等工程的一项重要课题,近年来安全监测技术发展有了巨大的飞跃,呈现出"实时"、"远程"、"非接触"的特点.针对BP神经网络预测模型监测在岩土工程方面的应用,应用BP人工神经网络实现了对岩土工程安全监测数据的预测预报,并对预测结果进行了分析,说明了隐含层数对预测结果误差的影响.通过比对,选择了误差最小的较优组合对岩土工程进行预测.     

工程材料本构模型辨识及参数反演新方法

概述了采矿、岩土、土木等工程材料本构模型辨识及物理力学参数的反 分析等研究;针对具体工程材料最佳本构模型的选择（模型辨识）及基物理力学参数确定问题,视工程对象（岩土体）为一复杂系统,施工中实测获得的工程对象随时间的响应（如载荷、变形位移等宏观信息数据）隐式地蕴含着工程材料的本构信息,即工程对象的应力－应变本构关系和模型的物理力学参数。作为系统识别模拟的理想工具,神经网络能够学习模拟到工程材料的本构关系,这样即工程对象体的本构模型和参数识别为一“黑箱”,给定某一应变向量就可得到期望的输出应力向量,而无需写出显式参数的数学表达式,此即基于神经网络的隐式材料本构模型－智能本构模型。     

堆石流变对金钟混凝土面板堆石坝应力变形的影响分析

采用三参数流变模型,运用有限元法对金钟面板堆石坝进行三维流变分析,得到了考虑堆石流变后坝体、面板的应力变形.分析研究了堆石流变对混凝土面板堆石坝坝体、面板应力变形特性的影响.结果表明,考虑堆石的流变效应后,坝体变形有所增加,坝内拉应力区域变大,最大拉、压应力值有所增加;面板的挠度和轴向变形都有所增加,面板的拉应力区域和拉应力值也有所增加,而面板压应力区域有所减少,但最大压应力值却有所增加.     

隐层自构造小波神经网络及其在深基坑支护工程中的应用

在结合小波分析和神经网络(ANN)基础上,提出了一种隐层自构造小波神经网络模型.该模型通过有限的经验数据学习,建立了深基坑支护结构变形量与其影响因素的非线性关系,并将其应用于深基坑支护工程实例当中.研究表明,该网络训练时间不到0.5 s,预测精度高,预测结果可靠,对今后保证深基坑支护工程施工安全具有借鉴意义.     

基于RBF神经网络预测方法的碱渣土工程特性分析

为了缓解纯碱行业生产快速发展与碱渣贮放的矛盾,国内碱厂主要采用贮渣池加高作为解决手段.对待建碱渣坝土样的工程特性进行预测分析,能够为坝体的后续加固加高提供科学依据.碱渣土具有复杂的物理力学性质,应用优化识别预测方法能够更好地揭示数据中各指标间的非线性关系,因此采用RBF神经网络的数据拟合能力,建立碱渣土工程特性的预测模型.通过工程算例的应用效果表明,RBF神经网络具有可调参数少、网络性能稳定和预测精度高等优点,分析了输入样本数目和宽度向量对RBF神经网络预测性能的影响,可为碱渣土工程特性的初步预测分析提供有效的决策依据.     

隐层自构造小波神经网络及其在深基坑支护工程中的应用

在结合小波分析和神经网络（ANN）基础上，提出了一种隐层自构造小波神经网络模型。该模型通过有限的经验数据学习，建立了深基坑支护结构变形量与其影响因素的非线性关系，并将其应用于深基坑支护工程实例当中。研究表明，该网络训练时间不到0．5s，预测精度高，预测结果可靠，对今后保证深基坑支护工程施工安全具有借鉴意义。     

基于神经网络模型的水平井破裂压力预测方法

破裂压力是井身结构设计的基础依据,也是水力压裂设备选型和方案设计的基础参数,通常采用测井解释获取破裂压力剖面,但其存在参数准确获取难、计算过程繁琐、普适性较差、计算精度低等问题,机器学习提供了一种解决这些问题的新方法。为此,以测井数据作为输入参数,采用4种不同的神经网络模型,建立水平井测井数据与破裂压力间的非线性关系,通过测试集预测结果的对比分析,优选出最佳的神经网络模型,并优化模型网络结构和超参数,实现水平井破裂压力的直接预测。研究结果表明：1)破裂压力与井斜角、横波时差和纵波时差表现为极强相关性,与井深、岩性密度和补偿中子表现为强相关性,与井径和自然伽马表现为弱相关性;2)不同组合的测井参数对模型预测结果具有显著影响,最优输入参数为井斜角、横波时差、纵波时差、井深、岩性密度和补偿中子;3)对比多层感知机、深度神经网络、循环神经网络和长短期记忆神经网络(LSTM)模型,发现LSTM模型的预测效果最佳;4)优化了LSTM模型的网络结构及超参数,优化后破裂压力预测的平均绝对百分比误差为0.106%、决定系数为0.996。LSTM模型能够有效构建水平井测井参数与破裂压力之间的非线性关系,可...     

基于PSO-BP神经网络的地铁盾构场地土体参数反演

土体参数赋值与工程实际的差异是导致数值计算结果与工程实际不符的主要原因之一。针对BP神经网络参数反演存在的缺点,依托实测的太原地铁地表沉降数据,利用MATLAB神经网络工具箱结合正交法和数值模拟技术,构建了PSO-BP神经网络,对土体参数进行反演修正,并采用反演修正后的土体参数对下一工况进行了预测分析。分析结果表明:PSO-BP具有较高的计算精度,所建立的神经网络反演结构能够很好地反映地表沉降与土体参数之间的非线性关系,可以为同地区类似工程的土体参数取值提供参考。     

堆石坝混凝土面板施工期裂缝成因及预防方法

针对堆石坝混凝土面板施工期普遍存在开裂的问题，在前人以温度应力为主要研究对象的基础上，考虑了干缩应力，编制了温湿耦合程序并进行验证.从混凝土面板长度，面板两侧横缝约束强度，环境相对湿度和保温保湿措施方面对某堆石坝混凝土面板进行了温度应力、干缩应力以及温湿耦合应力仿真计算，并对计算结果的温度、湿度、应力进行了综合的对比与分析.结果表明，当环境相对湿度为0.3,温湿耦合应力最大值是温度应力最大值的近2.46倍.当环境相对湿度为0.6,相对湿度下降相同的幅度5%,第60天拆模拉应力涨幅为第5天拆模拉应力涨幅的近2.28倍.此外，横缝约束作用将导致面板最大拉应力最大涨幅约为75%.解释了该堆石坝混凝土面板施工期裂缝成因，得出了“半定量”的关系，并提出相关的预防方法，可为类似工程提供参考.     

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.     

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.     

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).     

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.