不同覆盖层对海底管道受落锚冲击防护有效性的试验研究

海底管道是海上油气工程的重要基础设施。随着港口运输规模的不断扩大和海洋油气工程的快速发展,港口航道区域与海底管道登陆段发生重叠情况不可避免。第三方活动造成的坠落物撞击(如船舶落锚),会威胁航道下方埋设的海底管道的结构安全。为了寻求合理的防护措施,保证海底管道的安全运行,有必要对落锚引起的管道动态响应进行研究。文章采用物理模型实验的方法,对管道上方覆盖的纯块石层、混凝土块层+块石层、混凝土块层+橡胶垫+块石层、柔性防护垫层+块石层等不同防护形式的有效性进行了对比研究。利用光纤布拉格光栅(FBG)传感器实时测量管道表面的动态应变响应,分析其沿管道的轴向变化以及极值分布。通过模型试验确定了相对有效的覆盖层形式及设计厚度,为海底管道的设计和维护提供了重要依据。     

多功能管道内检测器测试平台研制

针对管道内检测技术开发方法存在的不足,设计了一种多功能管道内检测器开发测试平台,提高了管道智能检测技术相关的元件开发测试的效率。按照实验思路设计不同的检测单元,可以实现多种管道智能检测技术相关元器件的测试,操作方便、节省时间和成本。实验表明,该平台能较好地完成MBN检测信号的采集。     

Experimental and theoretical studies on lateral buckling of submarine pipelines

Global buckling of a submarine pipeline during high pressure/high temperature (HP/HT) operation results in a loss of pipeline stability that is similar to a bar in compression; this phenomenon constitutes one of the key factors affecting pipeline integrity and design. To intuitively study the buckling response, a test system was designed that can account for thermal loading and pipe-soil interactions, and this system was used to perform a series of small-scale model tests on the lateral buckling of submarine pipelines with different initial imperfections. Based on the hat-shaped buckling profiles of the test pipelines, a new buckling mode called "hat-shaped buckling" was proposed. In an attempt to study the conditions under which the pipeline exhibits this hat-shaped buckling mode, the changing law of the buckling mode was investigated through finite element analyses of pipelines with different parameters, including the length of the pipeline and the amplitude and wavelength of the initial imperfection. Subsequently, an analytical solution for calculating the buckling amplitude of a pipeline with a hat-shaped buckling profile was proposed. The theoretical solution was compared to the experimental data, which verified the feasibility of the model in calculating pipeline buckling deformation. The experimental data, the buckling mode based on these data and the corresponding analytical model discussed herein may provide a reference for future experimental studies of pipeline buckling.     

基于方法论的综合管廊施工方案比选

综合管廊建设空间广阔,施工方案不仅对工程项目影响大,对国民经济的发展也有一定影响。当前,关于管廊施工方案比选的专门研究较少,且缺失方法论角度的研究,造成方案选择具有局限性。运用辩证唯物主义的基本原理,提出用求同与求异的方法、用矛盾转移转化的规律来选择方案。这种方法具有重要的科学价值,填补了管廊工程研究哲学领域的空白,也为重大工程、复杂工程、创新型工程方案选择提供了有意义的借鉴。运用求同与求异法,得出管廊施工方案要满足规模化社会化生产、供应链整合及结构-工法-装备统一的要求;通过分析环境-结构-土体、结构制-运-安、前期与后期及一次性与重复性投入、工期与结构及工法的矛盾转移、转化的规律,得出了管廊不同施工方案的适用条件。     

Vortex induced vibrations of short side by side cylinders

Staggered cylinders of different diameters is a common configuration in offshore design, including e.g. clamped risers, piggy-back solutions and piping systems. Current design practice is not clearly formulated in relevant design codes such as DNVGL-RP-F105 and DNVGL-RP-C205. Conservatively, it is often assumed that flow acceleration due to a neighboring cylinder causes up to a doubling of the incoming flow velocity depending on incidence angle and difference in cylinder diameter. Doubling the incoming particle velocity compared to free stream would decrease the required support distance by around 30%. Particularly in conditions with significant diameter disparity, flow acceleration effects due to the larger cylinder of the two can thus cause strict requirements to support distances on the smaller. Designers may want to reduce the number of support points due to cost, maintenance requirements and rigid structure availability, particularly in piping system arrangements. Recent research on piggy-back pipeline vortex induced vibrations have complemented traditional understanding of such configurations, allowing for improved design guidelines. In the present study, a detailed meta study of available laboratory and numerical work is performed, and the resulting findings are translated into simple design guidelines for piggy-back and other staggered arrangements. The present paper provides clear recommendations for improvements to the relevant recommended practices.     

海底管道外表面阴极保护系统优化设计

针对海底管道外表面阴极保护系统优化设计,在传统的规范设计基础上,提出基于数值模拟计算的优化设计技术,设计可以完整描述实际工程中海底管道外表面防腐系统状态的大规模样本,基于边界元方法实现4480种管型（32120个数值模型）的大规模数值模拟计算,得到海底管道外表面阴极保护系统大规模优化设计数据库。在对输入、输出参数进行相关性分析的基础上,应用L-M算法和贝叶斯正则化算法实现两级人工神经网络映射关系的训练。数值仿真结果表明,建立的神经网络映射模型精度高达0.05%,收敛性良好,可以为海底管道外表面阴极保护系统优化设计提供先进的技术手段。     

管道外防腐层耐划伤测试仪的研制

研制一种专用于管道外防腐层耐划伤性能的测试仪器,适用于不同管径、不同壁厚和不同防腐层结构.介绍了管道外防腐层耐划伤测试仪的研制过程,详细描述了耐划伤测试仪机械结构、电子电路及系统软件的设计方法,并对测试仪器的可重复性及可靠性与国外设备进行了对比计算.该测试仪在测试平台的稳定性、划针固定和微调结构、配重压力测量和调节、测控电路设计等方面有创新,提高了设备的准确性和稳定性.防腐层的耐划伤测试试验表明：该仪器适用于不同管径、不同壁厚钢质管道的不同防腐层结构的测试,操作简单,维护方便,能够满足防腐涂层耐划伤测试的要求;测试结果较准确,具有可重复性.     

Identification of hydrodynamic forces on a flexible pipe near plane boundary subjected to vortex-induced vibrations

Formally,use of system identification techniques to estimate the forces acting on the beam may give information on hydrodynamic forces due to vortex-induced vibrations(VIVs),but no results from such attempts for submarine pipeline spans have been reported.In this study,a pipe model with a mass ratio(mass/displaced mass) of 2.62 is tested in a current tank.The gap ratios(gap to pipe diameter ratio) at the pipe ends are 2.0,4.0, 6.0 and 8.0.The response of the model is measured using optical fiber strain gauges.A modal approach linked to a finite element method is used to estimate the hydrodynamic forces from measurement.The hydrodynamic force at the dominant response frequency is the major concern,and the lift force and added mass coefficients are calculated.Response calculations are performed using force coefficients from the inverse force analysis and the calculated results are in accordance with the experimental data.     

隧道洞口浅埋偏压段施工性态数值模拟分析

针对渝湘高速公路斑竹林隧道软弱围岩洞口浅埋偏压段施工难题,采用数值模拟手段对施工过程进行计算分析.分析计算结果,得出主要结论:水平方向的围岩变位相对比较大,可能大于隧道围岩竖向位移;右隧道(埋深大)围岩拱顶特征点处竖向位移大于左隧道,围岩位移值最大值达到22.63 mm,发生在开挖时左隧道右边墙处.结合现场监控量测成果分析,证实了数值分析的正确性.基本掌握了山岭隧道洞口浅埋偏压段围岩和衬砌的变形、应力变化特征,认为该类型隧道围岩变位是隧道施工过程中需要控制的关键性因素.     

温州市灵昆街道截污纳管工程设计

温州市灵昆街道污水处理采用小型污水处理系统与污水处理厂处理结合的方案。该文介绍了现状污水处理特点,污水收集和处理方案,重要环节的设计参数及技术要点,以期为类似的农村污水收集和处理的设计提供可借鉴的经验。