热管在冻土路基中应用的数值模拟分析

文章通过对大气-热管-土体耦合传热模型进行分析简化,采用ANSYS有限元分析系统建立了热管路基三维传热模型,并以青藏铁路北麓河地区气候条件和地质条件为背景,对普通路基和热管路基进行了模拟计算与对比分析,得到了两种冻土路基不同时刻的路基温度场变化规律。     

朝阳东大桥钢管混凝土超声波检测技术应用

结合朝阳东大桥主拱钢管混凝土质量检测实际,介绍了钢管混凝土超声波检测的基本原理、前提条件、检测方法等,并据此对管内混凝土的密实程度和均匀性作出分析、判断。     

小导管双液注浆技术在隧道涌水处理中的应用

结合某隧道工程涌水处治的施工实例,从地质条件和原隧道施工的具体情况出发,详细分析涌水产生的原因,对小导管双浆液注浆止水施工的关键技术和工序进行探讨,可为同类病害处治工程提供参考。     

管件液压柔性成形技术及其在汽车制造领域的应用

近年来人们对管件液压柔性成形技术表现出了越来越大的兴趣,此项技术具有诸多的优点,如质量轻、刚度好、装配零件少、后续装配工序少等,特别适合制造复杂变截面管材结构,故在国外该项技术已被广泛地运用到汽车、宇航领域中。为了推广此项技术在我国的研究及应用,在此对此项技术的原理、优点、实用性及在国内外汽车领域方面的应用现状进行了介绍及探讨。     

隧道穿越富水泥岩断层破碎带超前帷幕注浆技术

郑万高铁巴东隧道穿越的三叠系中统巴东组泥岩,具有一定膨胀性,遇水软化,自稳性差,在三峡库区被称为"易滑地层",并且隧道洞身穿过50 m长断层破碎带,采取有效的地层加固措施极为必要。在对泥岩基本地质特性分析的基础上,针对性地提出了超前帷幕注浆方案,并结合洞身超前管棚提高帷幕胶结体的承载能力,最后通过钻孔成像、现场监测等方法对帷幕注浆效果进行评价。实践表明,帷幕注浆后,掌子面围岩加固止水效果良好,有效保证了富水泥岩断层破碎带的稳定性,确保隧道施工安全。     

管道更新掘进机刀盘切削钢筋混凝土管道转矩试验研究

为研究掘进机直接切削钢筋混凝土管道，实现管道原位破除更新的可行性，对新型刀盘切削过程中的参数进行分析。通过力学与数学方法，从条齿滚刀切削钢筋混凝土管道机制入手，研究切削转矩的计算方法；设计刀盘试验，系统研究切削参数的变化规律与影响因素，并提出管道更新掘进施工控制指导参数。研究表明： 1）刀盘全断面切削钢筋混凝土管道时，刀盘转矩与时间呈Boltzmann函数关系。2）刀盘推进速度提高，刀盘转矩呈线性增加；刀盘转速提高，刀盘转矩呈先减小后增大的规律。3）结合刀盘切削参数与切削比能，确定8~12 mm/r为较优贯入度区间。     

京张高铁正盘台隧道立体式多径路排水方案研究

长大富水隧道施工过程中涌水风险高,工期紧张,对排水能力要求高,辅助坑道设置方案及排水方案对隧道施工及运营有着重要影响。根据正盘台隧道的工程特点及涌水涌渣情况,结合排水需求,合理地选择辅助坑道设置方案,采用辅助坑道为正洞,增开工作面,实现"长隧短打",同时充分利用辅助坑道进行可控式排水、洞内储水仓、中心排水管分流等创新设计。多辅助坑道与正洞排水系统一起形成了立体式多径路的排水系统,有效降低了涌水淹井风险,保障了隧道工期,减轻了正洞防排水压力,可为类似工程的排水设计提供参考。     

大直径钢管桩沉桩工艺及桩身垂直度控制

本文通过对单桩沉桩工艺、垂直度测量控制方法的剖析与总结,为后续海上风电场建设中无过渡段大直径钢管桩单桩基础的施工、质控提供实际经验。     

A finite element model for unbonded flexible pipe under combined axisymmetric and bending loads

Flexible pipes are key equipment for offshore oil and gas production systems, conveying fluids between the platform and subsea wells. The structural arrangement of unbonded flexible pipes is quite complex, encompassing several layers with polymeric, metallic and textile materials. Different topologies and a large amount of intricate nonlinear contact interactions between and within their components, especially because of the relative stick-slip mechanism during bending, makes numerical analysis challenging. This paper presents an alternative three-dimensional nonlinear finite element model that describes the response of flexible pipes subjected to combined axisymmetric and bending loads. To simulate the response of a flexible pipe under axial tension or compression combined with uniform curvature, an equivalent thermal loading is employed on the external sheath, which is modelled as an orthotropic thermal expansion material with temperature-independent mechanical properties. To assess the feasibility of the proposed model, the bending moment versus curvature of the finite element solution is compared with experimental results obtained in literature and good agreements are found between them. Detailed finite element results such as contact pressures, armour wire slip displacements and friction, normal and transverse bending stresses are also shown and compared with available analytical models.     

Burst pressure of steel reinforced flexible pipe

The burst pressure of steel reinforced flexible pipe (SRFP) considering plasticity is investigated through experimental, theoretical and numerical methods. The results obtained from the aforementioned methods are in good agreement with each other, which illustrates the accuracy and reliability of the proposed theoretical and numerical models. The mechanical responses of PE layers and the steel strips are studied in detail, and the rationality of the strain uniformity assumption for the steel strip's cross section in the theoretical model is confirmed from its von Mises stress variation along the width at different points in FEM. Some influential parameters of SRFP on the burst pressure are also investigated in order to guide its cross-section design. The theoretical model and the FEM proposed in this paper can not only give an estimation to the safety and reliability of the pipe when it is subjected to internal pressure, but can also provide some reference for improving and optimizing its cross-section design.