浅谈钢带增强波纹管在吹填土地基的应用

人工吹沙填海形成的陆域属于欠固结的砂性地基,土质以中粗砂为主,地基具有地下水位高、地下水腐蚀性强、砂基含水率大、沉降未稳定等特点,采用何种适应性强、便于施工、耐久性好且兼具经济性的排水管道方案是吹填形成陆域基础设施建设的难题之一。文章以钦州保税港区一期雨水管道工程为实例,介绍了钢带增强波纹管使用于在吹填土地基的特点,为该种管材在类似地质环境条件中的推广应用提供参考。     

高真空击密法在吹填土地基处治中的应用

文章针对钦州保税港吹填土地基施工区域的工程地质情况,提出了高真空击密地基处治方法,阐述了该方法的基本原理,并通过试验段相关试验检测,探讨了该方法的加固处治效果。     

油气长输管道管沟开挖技术

结合国内外长输管道施工实际 ,论述了管沟开挖遵循的原则、开挖技术要点、地下水位较高地段及山区地段开挖技术和开挖安全保证措施 ,提出了地形地势允许条件下 ,优先采用通过管沟开挖实现管道的弹性敷设和开挖方案的制定与开挖作业的风险评价相结合的观点     

埋地管道路由定位及外防腐层损伤无损检测

使用某地探仪对地埋地管道埋设位置、走向进行定位，对管道埋深进行测量；对管道露铁点全线检测。现场开挖结果表明：用地探仪及其测试方法对该埋地管道路由测量基本无偏差，对在地面检测到的露铁点现场开挖，准确率基本达100％，从而为该管道的日常管理与维护提供了可靠的依据。     

给水管道在线不开挖敷设与更新技术比较和综述

本文对目前国内外常用的给水管道在线不开挖敷设与更新技术进行了系统地综述。通过对各种技术的比较，阐述了各种技术的适用性、局限性以及相关的技术经济指标。在给水管道敷设与更新的工程中，对于选择在线不开挖技术方案，本文亦提供了较好的建议。     

汽轮机蒸汽管道的吹扫分析

汽轮机投入使用前,必须吹扫蒸汽管道。文中以陕化2×40000Nm^3／h空分装置为例,针对影响吹扫的因素,从吹扫方案的确定、吹扫原则、吹扫合适参数的选择、临时管道强度计算及校核等方面对蒸汽管道的吹扫进行了分析。总结出根据工艺的实际工况选择合适的参数和吹扫方式,提出了要用理论计算对吹扫中临时管道管架设置与强度校核,对今后此类蒸汽管道的吹扫具有借鉴意义。     

吹砂填海区钢板桩支护坑壁柔性波纹管道施工

采用钢板桩支护的方式进行大尺寸柔性波纹管道施工,可避免开挖工程量大、安全隐患多、施工成本高、不利于环境保护等弊端,是吹砂填海地区柔性波纹管道施工技术发展的一个重要方向。文章结合广西钦州保税港区二三期路网工程建设实际,介绍了钢板桩支护坑壁柔性波纹管道施工工艺及其要点,提出了施工中的常见问题与防范措施,并对其技术效益进行了分析。     

SL -2098检漏仪在埋地管线非开挖检测中的应用

文中系统论述了埋地管道外防腐层非开挖检测的重要性和几种前沿技术,对各种技术做出了比较分析,并结合工程实例,提出了采用SL - 2098检漏仪进行埋地管道的非开挖检测的方案.实践证明,检测方案准确可行.     

潮湿多雨山区钢波纹管管涵施工工艺

文章结合工程实例,分析了钢波纹管涵洞在广西丘陵地区潮湿多雨环境下的施工应用问题:根据实际地基承载力条件,通过建立有限元模型计算出管道在路基填筑过程中总的下沉量,在基础开挖时预抬适当的拱度,以保证钢波纹管通道最终线型;为保证钢波纹管四周受力均匀,管道基础用级配碎石换填,管节楔形区部分用粗砂使用水密法回填;为适用南方湿润多雨天气,管节拼缝和螺栓使用防水黏胶防水,管内外镀锌和喷沥青防腐;待管顶覆盖土厚度足够,可以按设计图纸对路基进行冲击夯补强,适用广西山区高填路基施工;洞口翼墙施工时间应根据管顶填土时,管道的实际变形情况,通过分析测量数据最终决定。     

长输在役修复管道热力允许开挖长度的计算方法

开挖长度是热油管道修复过程中的重要参数之一,其值的合理确定对管道开挖修复方案及油田节能起到重要作用.文中从热力学角度,建立运行开挖不停输工况一次性最大允许开挖长度的热力数学模型,并以林源站至太阳升站的输油管道为例,进行了模拟计算,研究了维修季节、计划维修时间及油品出站温度对热力允许开挖长度的影响.结合油田节能降耗要求,给出热油管道开挖维修建议.     

上海青草沙原水工程五号沟泵站深基坑施工风险及其对策

针对上海青草沙原水工程五号沟泵站的工程特点及施工风险,从基坑开挖、降承压水等方面详细分析了该大型地下水工结构的施工技术特点和风险控制对策,可为类似工程提供参考。     

Axial Response of a Compression Pile to Nearby Excavation北大核心CSCD

One of the major concern in the excavation in soft soil areas is the effect of soil movement on adjacent pile foundations. In this paper, three-dimensional finite element models are established to study the axial response of the adjacent pile foundations close to an excavation in soft soil. The results show that, due to the nearby excavation, the axial bearing capacity of a single pile under compression decreases about 13.6%, and considerable additional settlements of a single pile subjected to the working compression load are generated. Therefore, the characteristics of load transfer mechanism between pile shaft and around soil, as well as the tip soil reaction are investigated extensively, which demonstrates that, as expected, the nearby excavation leads to a reduction of ultimate soil friction resistance. Furtherly, the widely employed load transfer method for pile foundation is modified to consider the effects of nearby excavation, which can be employed to predict the axial response of an axially loaded pile foundation beside an excavation. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Study on the Stress and Deformation Behaviors of a Deep and Irregular Foundation Pit as the Shield Launching Shaft in a Sea Reclaimed Cofferdam北大核心CSCD

With the development of the tunnel technology in China, the shield tunnel will become an important way to build the Sea-crossing channel. Taking the current largest diameter Shantou Bay shield tunnel in China as the engineering background, this paper introduces the challenges faced by the construction of the shield launching shaft in the reclamation cofferdam: e.g. deep, irregular excavation, deep silt layer and great influence of the seawater. Based on the practical conditions, a top-down construction technique of large ring beam considering two working conditions of foundation pit excavation and shield launching is proposed. Based on three-dimensional finite element analysis and field measurement, the stress characteristics and soil deformation of foundation pit are studied. The results show that the top-down construction technique of large ring beam can effectively control the deformation of the foundation pit and save construction time. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

浅覆土砂层土压平衡盾构始发掘进对环境的影响分析

盾构始发和到达安全掘进控制技术是困扰盾构隧道施工的主要难题之一。盾构进出洞施工中,面临掌子面失稳、土体坍塌、涌水涌砂、地表沉陷、盾构"抬头及磕头"等诸多施工风险。本文从基坑及隧道的破坏模式,塑性区分布范围出发,通过有限差分法针对易受扰动的浅埋砂层地层盾构始发段进行了研究,为加固区范围大小的选择提供了依据。研究表明,在不采取加固措施时,基坑开挖后隧道始发段的竖向位移、拱底的隆起和最大纵向挤出变形量均过大,显示基坑将发生坍塌等破坏。当盾构始发段主要加固措施为旋喷桩,加固后的土体的物理参数得到了显著的提升。本文在此基础上得出了旋喷桩的合理加固区域。     

加筋土柔性挡墙在公路边坡滑塌处理中的应用

文章结合高速公路边坡防护设计实例,通过不同防护方案比选,介绍了加筋土柔性挡墙的技术要求、施工工艺、作用机理及技术优势,并阐述了加筋土柔性挡墙在公路路堑边坡滑塌处理中的应用情况。     

冻土地区既有隧道上地铁车站深基坑工程实践

结合哈尔滨市地铁1号线龙江街站深基坑工程的特点,详细介绍了在冻土和既有人防隧道段中实施深基坑的设计思路和实践经验,并分析了冻胀力对围护桩的影响。对在冻土地区进行基坑围护设计和施工,以及对基坑内既有构筑物处理方面的设计实践进行了总结。     

Analysis of the Stability of the Shield Tunnel Excavation Face Considering Fluid-Solid Coupling Effect北大核心CSCD

In order to study the impacts of the transient seepage on the stability of tunnel excavation face during the installation of lining segments, the fluid-solid coupling effect based numerical model of the tunnel excavation face was developed by the finite element software PLAXIS. With adoption of the variablecontrolling approach, the influences of the depth/diameter ratio (the ratio of the buried depth to diameter of the tunnel) and the support pressure ratio (the ratio of the face support pressure to water and soil pressures ahead of the excavation face) on the face stability and ground settlement were investigated, respectively. At same time, the failure modes of the excavation face under the fluid-solid coupling analysis were also discussed. The results show that:1) the transient seepage leads to the development of the soil arching at the front of the excavation face, in which the smaller deformation at the excavation face is achieved, and so less support pressure for the face stability is allowed. While for the plastic analysis without taking into account the effect of transient seepage, a higher support pressure is required to maintain the stability of the excavation face; 2) in the fluid-solid coupling analysis, the depth/diameter ratio has less impacts on the stability of the excavation surface, but has larger impacts on the ground settlement. The larger the depth/diameter ratio, the larger the ground surface settlement and the settlement profile; 3) however, with the combination of the decrease of the support pressure and the impact of transient seepage on the settlement of ground surface, the soil arching effect in front of the excavation face is gradually reduced. The deformation zone at the ground surface is then connected with the deformed part ahead of the tunnel face to form a wedge-shaped soil sliding zone. It is also observed that the wedge-shaped body tends to have a larger funnel-shaped failure mode than that in the plastic analysis without considering the transient seepage. The results show that the transient seepage has a great impact on the stability of tunnel excavation face in the soil condition with high permeability ratio. The fluid-solid coupling analysis should be adopted to evaluate the deformation of excavation face and ground settlement. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

埋地管道防腐层破损点检测技术综合应用研究

对防腐层完整性检测尤其是对防腐层破损点的精确定位,及对检出大、中面积破损点开挖修补,是确保土壤跟管道的有效绝缘、提高阴极保护效果的关键。文中分析了常用埋地钢质管道防腐层破损点检测技术特点,结合现场检测实践,综合应用多种技术,能有效检测埋地钢质管道防腐层破损点。根据测量数据可以判断破损点大小以及是否开挖修理,在管道安全运行及检测的经济性之间寻找结合点。     

基坑开挖引起下方运营隧道位移的预测与控制技术研究

针对基坑开挖过程中对下方运营地铁隧道的保护问题,通过基于工程实测的隧道回弹隆起值的监控,对隧道回弹隆起的规律进行了分析研究。在考虑基坑开挖时空效应的基础上,分别对基坑放置时间、开挖方式、分块开挖宽度对隧道回弹变形的影响进行了分析和归纳,得出了隧道位移受基坑放置时间、开挖方式、分块开挖土体宽度的影响的规律。     

公路新旧路基结合部的病害及处治

结合已有的工程经验,总结出路基结合部的主要病害及成因,并从改造方案的选择、基底处理、边坡清理、台阶开挖、路基填料、路堤加筋、路堤的压实度控制、施工工艺等方面提出了处治方法。