浅谈小净距隧道支护结构设计原则与施工措施

小净距隧道是介于普通分离式隧道与连拱隧道的一种结构形式，由于不受地形条件以及总体线路线型的限制，其较连拱隧道有施工工艺简单、造价较低的特点，愈来愈受到工程界的青眯。但小净距隧中间岩柱体厚度远小于普通分离式隧道，具围岩变形和支护结构受力较为复杂。本文结合小净距隧道转岩的受力，变形特点，对小净距隧道的支护结构设计原则与施工步骤进行了研究。     

浅谈矿山法小净距隧道的设计与施工

小净距隧道是指并行公路隧道间夹岩石厚度较小, 一般小于1.5倍隧道开挖断面宽度的一种特殊隧道结构型式。小净距隧道方案不仅能很好地满足特殊地质及地形条件,而且有利于公路整体线型规划和线型优化,能较好地解决连拱隧道存在的缺点,具有显著的经济、社会、环境效益。本文将简要介绍一下小净距隧道断面设计与结构设计以及施工中开挖、钻爆作业、中间岩柱加固、监控量测等关键技术,进而得出小净距隧道的合理净距,最后,就目前技术法规条件下,对小净距隧道建设过程中应注意的问题提出一些建议。     

浅埋偏压连拱公路隧道修建若干技术问题探讨

我国在高等级会路建设中,遇到隧道时主要采用分离式双洞形式.但在一些特殊的地质和地形条件下,从线形和线桥隧衔接方式等综合考虑,必须采用连拱隧道.连拱隧道具有浅埋、偏压和中长短等基本特征,较好地解决了传统分离式双洞隧道在线形上的限制,故得到了广泛应用.本文主要就浅埋偏压连拱公路隧道修建过程中的若干技术问题进行了探讨,包括偏压产生的机理及其影响因素研究、合理衬砌结构形式、施工方法、进洞技术和支护结构参数等.     

连拱隧道近接重叠既有隧道时的施工性态数值模拟

以具有浅埋、偏压、近距离不对称重叠于下部既有小净距隧道等特征的雅山连拱隧道为工程背景,借助数值模拟手段,分析偏压近接重叠条件下连拱隧道正洞采用"先深后浅"及"先浅后深"两种开挖工序下的施工力学形态.通过比较两工序中连拱隧道围岩和既有小净距隧道衬砌的变形情况、中隔墙变位和受力情况,可知两开挖工序中,连拱隧道围岩变形基本一致,竖向沉降和水平位移值分别以右侧深埋正洞拱顶和浅埋左侧正洞与中导洞相交处为最大,其值分别达到3.19 mm和1.17 mm;浅埋偏压条件下,中隔墙自浇筑成型即处于小偏心受压,但其初始倾斜变位因正洞的开挖而逐步得到拨正;连拱隧道岩体开挖将导致既有小净距隧道内侧拱肩-拱腰区域衬砌出现朝向开挖区的变形,且"先深后浅"工序较"先浅后深"工序偏大0.01~0.02 mm.     

板岩隧道的施工控制与管理探讨

板岩隧道有其自身的特点：易塌方，遏水产生膨胀风化，预注浆加固困难且效果不明显等；同时，板岩节理发育、板岩冲沟地段对隧道建设影响很大。板岩隧道造价高昂，修建小净距和连拱隧道的经验非常少，这些都是制约了板岩隧道向更高层次发展。本文根据近几年板岩隧道施工中成功和失败的经验，对板岩隧道的施工控制和管理经验进行了总结。     

宝天高速公路三座小净距隧道设计与施工

甘肃省宝(鸡)天(水)高速公路上有三座隧道是典型的双线双洞、小净距公路隧道,其双洞轴线间距为20.5~22.9m,本文以这三座隧道为例,介绍小净距隧道设计支护的特点、中夹岩柱加固的方法和施工技术的要点,为同类隧道设计与施工积累一些经验.     

城市地下铁道连拱隧道群施工技术

本文对连拱隧道群施工工法进行探讨。在施工中首次提出了将连拱隧道改为单洞隧道施工技术，并对单一式中墙和分离式中墙结构的技术方案进行了比选，得出了满足结构安全、施工安全和经济效益较好的技术方案，可为今后类似工程的设计和施工提供借鉴和参考。     

连拱隧道和小净距隧道的有限元比较分析

文章采用分析对比的方法,对Ⅴ类围岩下的相同埋深、支护的条件下的小净距隧道和连拱隧道施工全过程,应用ANSYS有限元程序进行模拟研究。根据2种类型隧道的应力、应变和位移,在不同工况下的对比分布规律,证实小净距隧道在位移和应力方面均优于连拱隧道,从而为隧道设计提供参考依据。     

小净距隧道设计荷载的确定

为了提高小净距隧道的设计理论水平,分析了小净距隧道的受力情况.塌落拱的高度一般在3～4 m(隧道宽度15 m),小净距隧道中夹岩墙宽度只有5～7 m,在施工过程中,2个隧道的松动圈会出现重叠,使中夹岩墙产生较大的垂直向下位移,从而增加了塌落拱的跨度,中夹岩墙上部的应力相应增加.基于双塌落拱理论,认为小净距隧道松动压力的计算值应在单个隧道宽度与整个隧道开挖宽度相应的松动压力之间取值,根据中夹岩壁下沉的大小,在双塌落拱压力上乘以0.5～0.8的系数,来确定小净距隧道的荷载,建立了深、浅埋小净距隧道荷载模式.将该方法确定荷载与福州国际机场高速公路鹤上隧道(小净距)的监测数值进行对比,两者有较好的吻合.     

软弱围岩小净距隧道施工技术研究

本文介绍了石鼓隧道掘进端小净距浅埋、偏压软弱围岩段施工方法和工艺,重点阐述了超前管棚进洞、洞身开挖关键技术及其难点,对小净距隧道施工的应用推广提供理论依据和实践经验。     

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.