超细矿粉对水泥土力学性能的影响

目的研究水泥和超细矿粉复掺对水泥土力学性能的影响,比较不同掺量水泥和超细矿粉所引起水泥土无侧限抗压强度变化之间的差异.方法在固化剂掺量10%条件下,分别测试了不同超细矿粉和氢氧化钙掺量下水泥土的无侧限抗压强度,分析水泥掺量对大掺量超细矿粉水泥土的应力-应变曲线;利用扫描电子显微镜分析固化水泥土的微观结构.结果养护龄期7 d时,超细矿粉水泥土无侧限抗压强度随超细矿粉取代率增加呈下降的趋势,但下降幅度逐渐减小;养护龄期14 d和28 d时,随超细矿粉取代率增加,水泥土无侧限抗压强度呈先减小后增大的趋势.当超细矿粉的取代率为80%时,养护7 d时的水泥土无侧限抗压强度下降了29%,而相同超细矿粉取代率的水泥土在14 d和28 d时的无侧限抗压强度分别提高了9.3%和15%.超细矿粉掺入有利于改善水泥土结构的密实性,掺量为80%的水泥土结构表面有絮状胶凝物和针状钙矾石生成.结论水泥土的无侧限抗压强度随水泥掺量的增大和养护龄期的延长而提高;水泥的掺入可以改变水泥土的弹性模量;随水泥掺量增加,水泥土应力峰值增大;超细矿粉可细化水泥土的孔隙,使结构更加密实.     

固化Zn、Cl污染砂土的强度及浸出特性

为研究新型固化剂固化稳定复合Zn、Cl污染砂土的效果,依托某企业搬迁遗留场地修复工程开展现场中试试验,并结合室内无侧限抗压强度试验、pH测试以及毒性浸出等试验,探讨修复土物理力学、浸出等特性与固化剂成分、养护龄期的变化规律,分析比较了不同固化剂的固化稳定化效果.试验结果表明,固化土干密度较污染素土增加,增幅达11%~12%;固化土强度随养护龄期和固化剂掺量增加而增长,其中28 d龄期6%KMP掺量的固化土无侧限抗压强度较未固化土高6.17倍;掺加固化剂会显著提升污染土pH值,其中掺加GGBS-Mg O的固化土各龄期pH值均略大于掺加KMP的固化土;2种固化剂对Zn、Cl离子的稳定效果有所差别,总体而言,2种固化剂均能有效地稳定土壤中的Zn、Cl离子.     

石灰固化海砂海泥混合料作为填料的室内试验研究

为解决沿海地区缺乏填料的问题,将海砂海泥按质量比1.5∶1进行掺合,将混合料作为填筑材料,采用石灰作为固化剂,开展了一系列室内试验,包括无侧限抗压强度试验、直剪试验以及压缩试验。结果表明,固化混合料的无侧限抗压强度随着石灰掺量增加不断提高,掺量5%~7%之间时,强度变化最明显;7 d养护龄期的混合料的强度约为28 d养护龄期的50%左右,强度增长较为缓慢;石灰掺量大于7%之后,其强度增长速率明显减缓,甚至有减小的趋势;石灰掺量低于5%时固化效果不明显,在7%~9%之间时接近低压缩性土。     

电石渣稳定土强度特性影响因素分析

将电石渣稳定土用作道路底基层的填料,对电石渣的资源化利用具有重要意义。本文采用电石渣稳定两种细粒土,进行无侧限抗压强度试验,分析电石渣掺量、压实度、养生温度和龄期四种因素对电石渣稳定土强度性能的影响。结果表明,随着电石渣掺量的增加,两种稳定土的无侧限抗压强度分别在其掺量为9%和5%左右出现峰值,即为最佳电石渣掺量;压实度每增加2%,两种电石渣稳定土的7d无侧限抗压强度分别提高20%和10%以上;随着养生温度升高,两种电石渣稳定土的强度增大,当养生温度由10℃提高到30℃时,其抗压强度可提高50%;电石渣稳定土的无侧限抗压强度随龄期延长而增大,前期(7d～28d)增长速率比后期(60d～180d)快;基于压实度和养生条件,提出了电石渣稳定土无侧限抗压强度的预估模型,具有较好的相关性。为满足低等级道路底基层强度的要求,建议两种电石渣稳定土的压实度应分别大于95%和97%,养生温度应分别大于10℃和20℃。     

电石渣/偏高岭土固化铜污染土的浸泡试验研究

针对电石渣/偏高岭土地聚合物固化铜污染土开展去离子水和盐酸条件下的浸泡试验,研究固化污染土无侧限抗压强度变化规律,分析浸泡条件对固化污染土稳定性的影响。研究结果表明:在未浸泡条件下,固化污染土无侧限抗压强度随着电石渣掺量的增加而增大;当电石渣掺量较低时,固化污染土的应力随应变增加而缓慢增大,无明显峰值;当电石渣质量分数超过9%时,应力随应变增加而较快增大,强度峰值明显;在去离子水和盐酸浸泡条件下,固化污染土的无侧限抗压强度变化趋势基本一致,随着电石渣掺量增加而增大,且明显低于未浸泡固化污染土的无侧限抗压强度;当电石渣质量分数为10%,偏高岭土质量分数为5%时,电石渣/偏高岭土地聚合物对铜污染土具有较强的抗酸稳定性,修复效果良好。     

小剂量石灰稳定土强度特性的试验研究

为了研究小剂量石灰稳定土的强度特性,制备了石灰剂量4%～8%、压实度90%～95%的石灰稳定土试样,经标准养护后,分别进行了7～180 d龄期的无侧限抗压强度试验和劈裂强度试验.试验结果表明:石灰稳定土的强度指标都随压实度增大而增大,且随时间增长而增大,但剂量4%的石灰稳定土的无侧限抗压强度在超过28 d后基本趋于稳定...     

快速固化土工程特性试验

为探究长安大学研制的新型4#粉体固化剂的固化效果,以山西忻州定襄县粉质粘土为研究对象,进行了单掺长安大学新型4#粉体固化剂固化土制备。通过不同掺量与不同龄期固化土试件的浸水和不浸水无侧线抗压强度试验,分析了掺量和龄期对固化土力学特性的影响规律。结果表明:养护前期,固化剂固化土强度增幅随掺量增大而先快后慢,养护后期其强度增幅随掺量增大而先慢后快;低掺量固化剂固化土强度增幅随龄期延长而先快后慢,高掺量固化剂固化土强度增幅随龄期延长而先慢后快。然后在考虑固化剂掺量和龄期对强度影响的基础上,建立了符合该固化土力学特性的强度预测公式,为该固化剂在工程实际运用中开展强度保证理论和试验研究探索。     

钻孔灌注桩泥浆固化工艺及强度特性研究

为研究钻孔灌注桩施工中废弃泥浆的处置方法和工艺,依托徐丰公路快速化改造工程,基于对固化剂材料种类和特点的调研分析,最终优选HAS固化剂对泥浆进行固化处理,设计不同固化剂掺量和养护龄期的试验方案。通过击实试验、无侧限抗压强度试验和承载比CBR试验,得出HAS固化剂最佳掺量为6%,同时根据现场不同龄期的固化土含水率测试结果,提出泥浆固化后至少应闷料7 d以上方可填筑压实的施工建议。     

水泥砂浆固化土抗压强度特性试验

为论证水泥砂浆固化土工程应用的可行性,通过设置不同掺砂量、含水率、砂料粒径和养护龄期条件,对水泥砂浆固化土进行无侧限抗压强度试验.试验结果表明:(a)掺砂可提高水泥砂浆固化土的抗压强度,尤其是早期强度.一定水泥掺入比条件下,当掺砂量处于最优掺砂率(10％左右)时水泥砂浆固化土的强度特性改善幅度最大,掺砂量超过最优掺砂率后水泥砂浆固化土的抗压强度无显著提高.(b)水泥砂浆固化土的抗压强度随原料土含水率的增加而减小,当原料土的含水率较低或养护龄期较短时,水泥砂浆固化土的抗压强度下降幅度均较大,当含水率较高时水泥土掺砂难以达到预期的固化效果.(c)砂料粒径变化对水泥砂浆固化土的抗压强度影响较小,水泥砂浆固化土强度随着粒径的增大略有提高;砂料粒径变化对水泥砂浆固化土变形系数的影响较大,两者近似成正比关系,在实际工程中无需对砂料进行筛分而直接运用即可获得较好的处理效果.(d)水泥砂浆固化土无侧限抗压强度试验的破坏模式多为脆性张裂破坏和塑性剪切破坏.随着养护龄期的延长以及掺砂量的增加,脆性张裂破坏更为显著.     

离子固化淤泥土的强度特征与破坏模式

为了使废弃的淤泥获得工程价值,提高淤泥土的强度,通过对不同掺量的水泥和离子固化剂的配比,研究固化后淤泥在不同龄期下无侧限抗压强度,分析了水泥掺量和离子固化剂掺量对固化土抗压强度的影响,确定了离子固化剂的最佳掺量,得出了淤泥离子固化土的两种破坏形态。结果表明:淤泥固化土的抗压强度与水泥掺量成明显的线性递增关系,当离子固化剂的掺量达到0.02%时抗压强度不再明显的增加,甚至会降低;离子固化剂固化淤泥土有利于提高早期强度;当6%水泥和0.02%离子固化剂掺量时可达到工程要求,可见淤泥离子固化土的研究具有重要的工程意义。     

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)

正~~     

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.