堆积体围岩中隧道洞口段修建技术

主要介绍丹 (东 )本 (溪 )高速公路的张家隧道右线洞口段通过弃渣堆积体围岩的施工技术。施工中采用自钻式锚杆和注浆工艺并获得成功。     

CRTSⅡ型板式无砟轨道施工组织及成本投入分析

CRTSⅡ板式无砟轨道施工技术和工序复杂,工艺要求高,每条客运专线建设都要先选一段先导段,根据施工组织设计开展施工,在总结经验和评审的基础上,为开展全线施工提供条件。此文针对杭长客运专线先导段的具体情况和特点,从计划工期、组织机构、资源配置等方面阐述施工组织设计的内容。并对其施工功效和成本投入进行分析,提出综合折算指标,为保证施工质量和控制工程成本提供测算依据。     

中心城区大跨度大断面隧道爆破施工技术

广深港客运专线深港隧道位于深圳市中心城区,由单洞双线过渡到双洞单线,采用矿山法施工。结合深港隧道工程实践,介绍在中心城区大跨度、大断面爆破施工技术。     

新九燕山隧道主洞与辅助坑道交叉口施工技术

根据包西铁路大断面红黏土隧道新九燕山隧道施工实例,就斜井和大跨度红黏土隧道交叉口施工方案进行选择,并对斜井向正洞施工方法的转化、施工技术措施等进行阐述。     

大断面暗挖车站施工工法优化比选研究

通过对深圳地铁8号线一期工程深外高中站2种大断面暗挖法(即九步开挖的双侧壁法和台阶法)不同的施工工序进行数值模拟模型比选分析,选择能够较好适应车站不同的地质条件,满足安全施工的施工工序,为现场施工提供指导。结合施工监测数据可知,施工过程的拱顶沉降和水平收敛实测值与数值模拟计算所得的结果较为接近,从而验证数值模拟的合理性,以及2种方法施工工序的地质条件适应性。     

城市轨道交通车辆基地室外综合管沟的应用研究

室外管线综合设计是城市轨道交通车辆基地设计的重点和难点,通常室外管线多以直埋的方式敷设于地下,但这种方式在设计、施工、运营维护阶段均存在着一些问题,因此提出了在室外设置综合管沟的方式,尽可能解决目前出现的问题.针对相关问题,提出了设置室外综合管沟的必要性和意义,从入沟管线种类分析、综合管沟管线布置原则、断面设计、特殊节...     

偏压连拱隧道洞口段二次衬砌施工时机探讨

 针对富溪隧道左线出口段在围岩变形尚未稳定的情况下能否进行二次衬砌施工的问题，根据隧道变形监测结果推测衬砌施工后隧道的剩余变形，并据此计算出衬砌结构的内力和安全系数。结果表明，衬砌施工后产生的变形大小对其内力和安全性影响较大。若衬砌结构变形仅为剩余变形的6.5%，其安全性能够得到保障。现场监测结果表明，衬砌施工后内部应力普遍较小，未超过混凝土强度。这说明在围岩变形没有完全趋于稳定的情况下，只要能够保证衬砌施工质量，可以提前施作二衬。     

高中速客专和高低速客货共线铁路不同坡段组合的动力学性能之比较研究

本文运用车辆-轨道耦合动力学新理论,仿真计算了列车以不同速度匹配通过不同类型纵断面时动力学性能的各项指标,并且根据现行铁道机车车辆动力学性能评定规范加以评价。结果表明:在本文设定的不同类型纵断面条件下,如单面坡划为多坡段或凹型坡加设分坡平段或凸型坡加设分坡平段,无论是高中速客车还是高低速客货混跑,采用新设计方案计算得到的指标略大于采用原设计方案得到的相应值,但差异不明显;所有方案下,除个别指标外,安全性指标均未超过合格限值,平稳性指标属优良等级。     

Physical–biological coupling in spore dispersal of kelp forest macroalgae

The physical–biological linkages controlling the dispersal of spores produced by macroalgae that reside in kelp forests are complicated and laced with feedbacks. Here we discuss the fundamental elements of these interactions. Biological considerations include spore swimming and sinking speeds, their periods of viability in the plankton, and the height of spore release above the seafloor, which together determine the durations over which spores can be swept by horizontal currents before they contact the seafloor. Morphologies and material properties of canopy forming kelps may also influence the drag exerted on passing waters by the kelps, the plants' ability to persist in the face of rapid flows, and thereby the degree to which impinging currents are redirected around, or slowed within, kelp forests. Macroalgal life histories, and the size of spore sources as controlled by the dimensions of kelp forests and the density and fecundity of individuals within them, influence effective dispersal distances as well. Physical considerations encompass the mean speed, direction, and timescales of variability of currents relative to spore suspension times, the interaction of surface gravity waves with currents in producing turbulence in the benthic boundary layer, wind-driven surface mixing, water stratification, and shoreline bathymetry and substratum roughness, all of which can affect the interplay of vertical and horizontal transport of macroalgal spores. Intricate within-forest processes may induce attenuation of current speeds and consequent reductions in seabed shear, along with simultaneous production of small-scale turbulence in kelp wakes. Slower mean currents and smaller eddy scales in turn may attenuate vertical mixing within forests, thus extending spore suspension times. Further complexities likely arise due to changes in the relative rates of horizontal and vertical dispersion, modifications to the overall profiles of vertical mixing, and the creation of fine-scale secondary flows around kelp individuals and substratum features. Under conditions of more rapid currents, submergence of the surface canopy and the establishment of skimming flows at the canopy–fluid interface may introduce additional coherent flow structures that alter rates of fluid exchange to and from the forest. Many of these coupled physical–biological processes are just beginning to be examined in a rigorous fashion in kelp forests, but their potential importance is clear.     

软弱围岩大断面隧道环形开挖预留核心土法相关参数研究

结合湖北省境内某隧道项目,采用三维建模模拟环形开挖预留核心土法在不同核心土长度、台阶长度、进尺深度、衬砌施作时间下围岩变形情况,找出环形开挖预留核心土法各因素对围岩稳定性的影响,获得经济合理的开挖参数。总结了施工关键点,为广大工程技术人员提供参考。