Deformation analysis of tunnel excavation below existing pipelines in multi‐layered soils based on displacement controlled coupling numerical method     

Zhiguo Zhang  Maosong Huang  Mengxi Zhang 《国际地质力学数值与分析法杂志》2012,36(11):1440-1460

The effect of tunneling on surrounding environments, especially on existing buried pipelines is a problem that engineers designing and practicing in urban geotechnical environments encounter more frequently than in the past. However, previous studies are usually based on the assumption that the soil is homogeneous. How to reflect soil stratification is the main focus for the problem of tunneling in multi‐layered soils. A displacement controlled coupling numerical method is presented for the displacement analysis of tunnel excavation below existing pipelines in multi‐layered soils. On the basis of the layered soil model, to consider the soil nonhomogeneous characteristic, the finite element method and boundary element method are coupled to simulate the deformation of existing pipelines induced by tunneling. The solutions indicate that good agreements are obtained between the proposed coupling numerical method and the commercial software. The accuracy of the proposed numerical method is better than the two stages method based on the existing closed‐form solutions. Moreover, the results discussed in this paper show that the error obtained by the previous method of weighted average on the basis of homogeneous half space converted from layered soils is not negligible for the obvious difference of elastic parameters among successive layers. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

城市地下管线系统应用平台功能设计     

赵庆伟  王天文  张立伟 《东北测绘》2014,(1):158-160

地下管线系统应用平台设计是在数据库设计、数据库的数据组织结构设计的同时相互参照与相互约束下进行的。应用平台功能实现也是完成系统既定目标重要构成。先进行基于用户类型的系统功能分析,然后完成平台架构及功能模块设计,最后系统集成实现系统应用平台功能。  相似文献   

东方气田海管悬跨段安全评估分析          下载免费PDF全文

姚平  范奉鑫  李中阳  李磊  曹玉龙  刘洋 《海洋科学》2011,35(8):58-62

从工程实际问题出发,利用实际测量资料,通过建立近底床悬跨海管的有限元模型,计算了不同底床形状下海管最大静挠度随海流流速变化的规律,对东方1-1气田某标段海管进行了安全评估．筛选出了危险悬跨段。这一计算结果对海管的防护维护工程实践具有切实的指导意义。  相似文献   

An effective stress analysis of partially embedded offshore pipelines: Vertical penetration and axial walking     

《Computers and Geotechnics》2014

A study on quantifying offshore pipeline resistance during vertical penetration and axial walking is presented, based on coupled pore pressure and displacement finite element analysis with the Modified Cam Clay model. Following the validation of the numerical method against published centrifuge test results and limit analysis solutions, we present the findings of a detailed parametric study on the response of partially-embedded pipelines under vertical and axial movements, employing 2-D plain strain and full 3-D soil–pipeline models. Emphasis is put on practical findings, and on proposing simplified expressions for the estimation of the contact enhancement factor and of the equivalent friction factor, that can be used at least for preliminary design purposes.  相似文献   

地下水运动的热驱动机理   总被引：2，自引：0，他引：2  

高宗军  刘永贵 《地下水》2014,(2):7-9

地下水在下渗过程中,受地温梯度的影响,水温度会逐渐升高,从而相同压力下的密度就会降低。这种由于温度不同所导致的密度差异会引起地下水的运动,将该种机制称之为地下水运动的热驱动机理。基于此种机理,给出地形变化较小的丘陵地区地热水近源补给的模型,解释同一或相近海拔高度上补给区与排泄区（地热水温泉）共存的现象,提出并论证在地势低洼地带得到补给、而在地势较高处出露温泉的可能性。  相似文献   

深海管道轴向定向移动消减方案研究     

刘润  郝心童  李成凤  彭碧瑶 《海洋科学》2020,44(9):112-120

为解决不埋深海管道在温压荷载循环作用下，轴向移动量不断累积的问题，采用数值模拟方法，在论证了钢悬链线立管（steel catenary riser，SCR）张力相比于其他因素对管道轴向移动影响更为显著的基础上，针对一端受到SCR张力作用的短管，分析了不同轴向移动消减方案的作用特点。研究表明，对管道进行锚固能有效约束其轴向移动，且在中部锚固需要的锚固力及管道内产生的有效轴向力均较小；滑动基础可通过释放一定的管道位移量来减少管中的应力累积。因此将中部锚固与端部滑动相结合可优化锚固系统，使锚固力进一步下降54%，管中最大有效轴向压力减小33%，从而最有效地消减轴向移动。  相似文献   

利用深度学习模型智能识别地下排水管道缺陷     

王大成  谭军辉  彭述刚  钟镇声  陈国强  李国桥 《测绘通报》2021,(10):141-145

排水管道健康状况直接影响整个城市的排水效果,CCTV检测作为目前最为常见的排水管道健康状况检测方法,仍存在自动化程度不高、工作效率低下、严重依赖人工经验等问题。为解决以上问题,本文将当前先进的深度学习技术与地下排水管道缺陷检测技术相结合,提出了一种基于深度学习模型的地下排水管道缺陷智能识别技术。同时,将管道缺陷智能识别与管道检测工作流程紧密结合,实现城市排水管道检测报告的快速自动生成等功能,从而大大提高排水管道缺陷的检测效率。  相似文献   

A lateral global buckling failure envelope for a high temperature and high pressure (HT/HP) submarine pipeline     

《Applied Ocean Research》2015

Submarine pipelines are the primary component of an offshore oil transportation system. Under operating conditions, a pipeline is subjected to high temperatures and pressures to improve oil mobility. As a result, additional stress accumulates in pipeline sections, which causes global buckling. For an exposed deep-water pipeline, lateral buckling is the major form of this global buckling. Large lateral displacement causes a very high bending moment which may lead to a local buckling failure in the pipe cross-section. This paper proposes a lateral global buckling failure envelope for deep-water HT/HP pipelines using a numerical simulation analysis. It analyzes the factors influencing the envelope, including the thickness t, diameter D, soil resistance coefficient μ, calculating length L_f, imperfection length L and imperfection amplitude V. Equations to calculate the failure envelope are established to make future post-buckling pipeline failure assessment more convenient. The results show that (1) the limit pressure difference p_max (the failure pressure difference for a post-buckling pipeline when it suffers no difference in temperature) is usually below the burst pressure difference p_b (which is the largest pressure difference a pipeline can bear and is determined from the strength and sectional dimensions of the pipeline) and is approximately 0.62–0.75 times the value of p_b and (2) thickness t has little influence on the normalized envelopes, but affects p_max. The diameter D, soil resistance coefficient μ, and calculating length L_f influence the maximum failure temperature difference T_max (the failure temperature difference for a pipeline suffering no pressure difference). The diameter D also significantly affects the form of the normalized envelope.  相似文献   

地下管线普查成果的质量保证经验     

周志军 《测绘与空间地理信息》2009,32(3):222-224

地下管线普查作为城市建设信息化的一项重点工作正在全国全面展开.主要结合参与重庆市的城市综合地下管线普查的工作实践,谈谈在地下管线普查实施当中对质量保证的经验.  相似文献   

海底管道止屈器形式与设计方法研究概述   总被引：2，自引：1，他引：1  

余建星  马维林  陈飞宇  林秋雅  刘见德 《海洋工程》2013,31(4):100-105

海底管道的屈曲传播特性对于其整体安全性是极其不利的,一旦发生屈曲传播,会使整个海底管道结构发生失效破坏,为了解决屈曲传播问题同时兼顾经济性的考虑,可以在海底管道上安装止屈器。通过对国外已有止屈器资料的广泛深入调研,首先对止屈器的主要形式进行了总结和对比分析,然后对止屈器的设计方法和流程进行了简要总结。为我国深水海底管道铺设过程中止屈器的选择和设计提供有益的参考。  相似文献