基于midas的地铁车站支护结构内力分析

以某地铁车站基坑为背景,对该基坑开挖过程中支护结构的内力以及周围土体进行了全面分析。基坑采用排桩加内撑支护结构进行支护,考虑了周围土体、围护结构的相互作用,借助有限元软件midas/GTS建立了地铁车站基坑三维有限元分析模型。通过有限元法分析,表明,施工开挖步骤对基坑支护结构的内力以及位移有显著影响,进而总结其变形规律,为地铁车站及类似深基坑设计和施工提供重要的依据。     

深基坑开挖变形的三维数值模拟研究

采用三维快速拉格朗日差分分析方法(Fast Lagranian Analysis of Continua 3D)将南京A、B大厦支护结构(悬臂支护结构、单层支点混合支护结构、钻孔灌注桩连拱支护结构)与一定范围内的土体(长、宽、高)作为一个整体,结合基坑实际开挖降水及施工工序,模拟和反映支护结构体的空间受力特征和变形,周围土体的位移、沉降及其相关关系,并将模拟结果与实测资料进行对比分析,得出了一些有益的结论,为三维数值模拟研究在深基坑工程中的应用作了有益的尝试。     

浅埋偏压隧道进洞方案优化与边坡稳定性分析

浅埋偏压隧道进洞方案与洞口边坡稳定性分析是公路隧道建设中的重要问题,边坡的稳定性对隧道工程建设与运营起着十分重要的作用.以向家坝水电站库区的姚家坝隧道为研究背景,为了避免隧道洞口开挖引起边坡滑动和洞内塌方,提出格构锚杆、抗滑桩、锚喷支护与超前支护等联合支护技术,采用三维有限元法研究隧道施工引起边坡与支护结构的稳定安全状态,并对洞口治理前、后山体边坡以及隧道支护结构的受力、变形与稳定性进行对比分析.研究结果表明:隧道洞口经治理后,边坡土体与支护结构的位移和应力均得到有效控制,且在安全允许范围之内,表明山体边坡稳定,隧道支护结构安全.     

某综合交通枢纽工程超大基坑信息化施工研究

针对B2地块超大基坑,施工跨度较长等特点,该文结合基坑施工过程中信息化安全监测数据,分析了支护结构,地下水,周围土体及环境的变形,保证了施工过程的安全,验证了设计方案经济有效,积累了工程经验,为进一步进行理论研究和改进设计提供了现实数据。在监测过程中,土体、围护桩及地连墙变形处于安全可控状态,支撑及钢筋应力大小适中,坑外水位变化较小,周边土体变形较小,基坑未发生重大不良事故,保障了基坑的安全施工,基坑南侧的高铁正常运营及基坑东侧通江大道正常施工及使用。现场监测数据表明,无锡市交通综合枢纽项目B2地块基坑支护形式经济有效,现场监测方案正确科学,能及时有效监测基坑变形并及提供监测数据,为施工单位提供了准确及时的预警信息,保障了基坑施工安全有序进行。施工过程中监测得到支护结构中深部土体位移、轴力、水位、周边环境变化等重要参数,能有效积累工程经验,为进一步进行理论研究和改进设计提供现实数据。     

巷道组过断层围岩控制技术研究

以深井巷道组过特大型断层(落差大于100m)破碎带为工程背景,采用数值模拟的办法对比分析了正常地层和断层破碎带中巷道组围岩的力学特征以及相互影响;结合断层破碎带围岩的实际情况,建立了"早预测、短进尺、弱爆破、强支护、紧封闭、勤量测、防突水"的断层带施工技术和综合保障体系,形成超前物探、超前加固、微震开挖、分步动态支护等综合配套技术,保证了巷道的施工安全。     

浅谈隧道初期支护施工方案

在隧道施工期间为解决结构稳定和安全问题,初期支护施工方案的确定十分重要。作为永久性承载结构的一部分,常采用超前锚杆、喷射混凝土、注浆小导管等方法。本文从工程实例总结隧道施工初期支护方案,为相关施工提供一定借鉴作用。     

盾构隧道近接下穿既有地铁车站的数值模拟

以北京某盾构法施工的区间隧道下穿附近既有地铁车站工程为背景,在确定了合理的应力释放率并充分考虑了分步开挖及注浆加固区影响的基础上,采用三维有限差分计算软件FLAC3D进行了数值模拟.模型采用地层-结构模型,土体采用摩尔-库仑弹塑性模型.此外,隧道和车站结构采用结构单元模拟,既有车站变形缝采用连接单元模拟.预测盾构隧道施工后既有地铁车站的变形,为邻近既有车站的安全评估工作提供了依据.     

深基坑支护结构与土体共同作用的三维有限元分析

本文对深基坑进行了施工全过程的三维有限元弹塑性分析和模拟,并详细说明了其具体实现方法.有限元分析中分别考虑了支护结构和土体之间的相互作用问题,以及各种开挖方案、降水方案对基坑变形的影响,并对各种关键参数进行了参数敏感性分析和讨论.对比各种分析结果,考虑共同作用和不考虑共同作用基坑变形相差达到10倍,支护结构内力相差达到1 5倍.分析结果说明,对于这类复杂工程,进行考虑结构与土体共同作用的施工全过程三维有限元分析和模拟是完全必要和必须的.     

某地区基坑支护结构设计与数值模拟分析

基坑开挖以及基坑支护是目前基坑工程中需迫切解决的工程难题,当前多采用数值模拟手段对常用支护结构进行对比分析.结合工程实例,运用大型有限元软件Midas/Gts建立模型,对西安某基坑工程的排桩+锚杆和连续墙支护等结构进行了数值分析.计算结果表明:锚杆+排桩支护作用下,桩基的整体位移较大,单根桩身弯曲变形较小;内支撑连续墙支护的情况下,桩基的整体位移较小,没有明显的弯曲变形但出现倾斜现象.根据实际工程情况,最终采用整体刚度较大的连续墙(排桩)加内支撑的支护方案,或直接采用地下施工结构的"逆作法"施工方案.该支护体系能够提供主动的支护力,有效阻挡土体的侧向位移,将基坑开挖导致对周围的影响效应减至最小.通过对常用的基坑支护结构的模拟分析,对实际工程以及类似项目的设计和施工起到一定的指导意义.     

基于Flac3D的土钉支护应力分析

为了进一步探讨土钉支护的作用机理、受力特点,采用Flac3D模拟土钉支护基坑开挖与支护的施工过程,并对土钉、土体在开挖过程中的受力性能进行了模拟和分析.通过对土钉支护基坑模型的土体应力、应力路径和土钉内力分布等力学参数的分析,能更加全面地认识其在开挖阶段的工作性能,对其设计和施工提出了有益的建议.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

A computer generator for randomly layered structures

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

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.