地下水对岩土工程的影响及勘察现场注意要点分析

现代社会的发展，各项建设活动均在大力的进行中，建筑物的修筑等岩土工程的数量也在不断的增加，逐步成为了极为普遍的工程项目之一。岩土工程包含了较多的环节，其中地下水勘测与评价是其中十分重要的构成部分，由于地下水对于岩土体的影响极大，直接关系到岩土工程的质量及施工进度，因此在进行岩土工程设计、实质的施工中均需要全面的收集并深入的分析地下水的各项数据，保障岩土工程的设计及施工的科学合理性。该文简单的分析了地下水对于岩土工程的主要影响，如地下水位的上升、下降、动水压力作用、侵蚀作用等，并提出了几点勘察现场的注意要点，为开展岩土工程的人员提供一定的参考与借鉴。     

水—岩作用模型及其在水—玄武岩反应研究中的应用

采用线性规划的方法模拟地下水与岩石之间的作用，计算地下水与岩石之间的矿物溶蚀量是水－岩作用研究的一个新方法。本以江苏六合玄武岩地区水－岩作用研究为例讨论了水－岩作用模型的应用，并对其目前仍存在的问题进行了探讨。     

做好水文地质工作的探讨

为提高工程勘察质量,在工程勘察中不仅要求查明与岩土工程有关的水文地质问题,评价地下水对岩土体和建筑物的作用及其影响,更要提出预防及治理措施的建议,为设计和施工提供必要的水文地质资料,以消除或减少地下水对岩土工程的危害。本文分别从工程地质勘察中水文地质评价内容、岩土水理性质以及地下水引起的岩土工程危害三个方面阐述了水文地质问题在工程勘察中的重要性,供同行参考。     

地下水对城市地下空间开发的制约及机理

国土空间资源和城镇化用地需求矛盾日益突出,城市地下空间开发是解决上述矛盾的有效途径.然而,城市地下空间建设及运营过程中将改变地下三相介质(固-液-气)的平衡状态,造成一系列工程、环境及生态问题.地下水是地质体中能量传输和物质迁移的载体,是引起岩土体性质、地下水化学组分及水动力条件变化的关键因素.因此,以地下水为主线,总结并阐述了8种城市地下空间开发及运营过程中可能引发的与地下水相关的工程、环境及生态问题:地下水水压、浮力、地表变形及沉降、特殊岩土体性能劣化、地下结构腐蚀、地震震害、地下水污染及城市热岛效应.由于目前研究地下水与城市地下空间(特别是深部地下空间)相互作用的机理及实际案例很少,导致对地下水系统变化造成的相关问题的机理认识有限.提出了5个方面的研究建议:加强对城市地下空间建设及运营过程中的体系化监测;研究地下水系统变化对岩土体物性影响;研究地下水系统变化对地层中有毒元素由深部向浅部垂向运移机理;研究多场耦合作用下城市地下空间开发与地质环境相互作用及长期影响;研究地下水水位变化对基础抗浮设计的影响.     

工程地质勘察中水文地质问题的影响

为提高工程勘察质量,在工程勘察中不仅要求查明与岩土工程有关的水文地质问题,评价地下水对岩土体和建筑物的作用及其影响,更要提出预防及治理措施的建议,为设计和施工提供必要的水文地质资料,以消除或减少地下水对岩土工程的危害。文章分别从工程地质勘察中水文地质评价内容、岩土水理性质以及地下水引起的岩土工程危害三个方面阐述了水文地质问题在工程勘察中的影响。     

浅议工程地质勘察中水文地质问题的必要性

为提高工程勘察质量,在工程勘察中不仅要求查明与岩土工程有关的水文地质问题,评价地下水对岩土体和建筑物的作用及其影响,更要提出预防及治理措施的建议,为设计和施工提供必要的水文地质资料,以消除或减少地下水对岩土工程的危害.本文分别从工程地质勘察中水文地质评价内容、岩土水理性质以及地下水引起的岩土工程危害三个方面阐述了水文地质问题在工程勘察中的重要性.     

不同类型岩土浸泡水实验分析

为研究降水补给地下水过程中在包气带发生的物质交换及地下水化学演化的特征,在沂源地区采集不同类型的岩土样品11组,按5min和48h的浸泡时间以1∶5的固液比分两组进行了浸泡试验,检测并分析了不同岩土浸泡水中的K+、Na+、Ca2+、Mg2+、Cl-、SO2-4、HCO-3和NO-3等组成及含量变化。结果表明,不同类型岩土样品经浸泡后均有大量物质进入浸泡水中,并随浸泡时间的延长,除个别离子含量减少外,K+、Na+、Cl-、SO2-4等大部分离子均出现不同程度增加。说明在天然降水补给地下水过程中,降水通过对包气带的淋溶作用,使包气带岩土中的大量物质转入水中,水化学性质发生重大变化。由此可认定,地下水的大部分化学组分来源于降水转化为地下水过程中包气带的淋溶作用。     

花岗岩地区地下水溶质的形成机制探讨

通过对可寺省东部花岗岩地区水－土壤－岩石相互作用过程中地质地球化学特征的研究分析,阐明了花岗石地区地下水的水化学特征,并指出花岗岩工区地下水溶质主要来源于土壤与水的相互作用。     

水—岩土化学作用的环境效应

对水－岩土化学作用的环境效应从几个方面进行了实例分析。针对水－岩土化学作用所存在的正负两方面的环境效应,强调指出,在重视研究其负效应的同时,还应更多地通过分析水－岩土化学作用的过程,综合利用地质环境中水－岩土化学作用的规律来达到调控和防治环境地质灾害的目的。分析了水－岩土化学作用环境效应的研究思路及研究方法,并认为这是环境地质研究中值得开拓的新领域。     

南宁市地下水化学场分区特征及其主要影响因素

根据资料对南宁市地下水化学场进行区域划分,并研究了化学类型、组分含量的特征与规律。从工程的角度进行分析后,认为水化学场变化的同时也改变了城市建筑的基础－岩土体的性质,而导致这些改变的主要因素是人为抽水和污染。     

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.