应力波在高桩码头基桩中传播数值模拟研究

结合天津港某码头工程的实桩检测资料,对应力波在高桩码头基桩中的传播特点进行数值模拟研究,得出实桩检测时高桩梁板式码头的激振位置和应力波信号接收位置。该研究分析结果,可为进一步探索高桩码头基桩完整性检测的方法提供参考。     

高桩码头基桩完整性检测技术研究

高桩码头在使用过程中基桩容易出现损伤,目前,国内外对于有上部结构的基桩完整性检测方法的研究成果较少。本研究通过有限元数值模拟方法,确定高桩码头基桩现场检测时最佳的击振位置和信号接收位置,并利用小波分析方法对检测信号进行处理,以确定基桩的完整性。并结合已完成的相关研究成果,对高桩码头基桩完整性检测技术进行总结。     

高桩码头基桩完整性检测技术研究综述

高桩码头基桩与单桩最主要的区别是其存在上部结构,上部结构存在对应力波在高桩码头基桩中的传播有明显的三维效应影响。根据国内外基桩完整性检测的研究现状,系统介绍:应力波在普通单桩与高桩码头基桩中的传播特性,以及二者的区别;高桩码头基桩完整性检测亟需解决的问题,即确定最佳的击振位置和信号接收位置;高桩码头基桩完整性检测研究的思路,包括应用有限元数值模拟和小波分析等。     

在役结构基桩完整性检测新技术

在役结构基桩桩顶是嵌固在桩帽或横梁中的,常规的在桩顶敲击与接收的反射波法不再适用.如何评价在役结构基桩的完整性是检测人员棘手的难题.为了解决该难题,提出若干新技术,如桩侧激振法、双速度法、旁孔透射法、单孔折射波法、弯曲渡法、超震波法以及动力荷栽法、桩长增量逼近法.通过在实际工程的成功应用,试图为检测人员找到可行的技术手段.更好地服务于生产实践.     

在役高桩码头桩基完整性无损检测技术研究的进展

一般情况下梁板式高桩码头的基桩顶部需要与上部结构嵌固,传统的单桩完整性检测方法已不能适用于此类基桩完整性的无损检测,在总结国内、外桩基检测研究成果的基础上,重点介绍对动测法和低应变反射波法的改进,主要包括双速度法、横波法、超震波法、纵阻抗剖面分析法等,分析论证在梁板式高桩码头基桩完整性检测中应用高应变法的可行性,以及综...     

小波分析在高桩码头基桩完整性检测中的应用研究

利用反射波法检测高桩码头基桩完整性时,由于基桩存在上部结构,反射波波形会含有干扰信息,变得十分复杂。文章研究了小波分析在高桩码头基桩完整性检测中的应用,利用小波分析消除干扰信号,以减弱梁板等上部结构对基桩检测信号的影响,最后通过具体的工程实例进行了应用验证。     

浅谈基桩完整性无损检测技术的工程应用

反射波法和机械阻抗法作为基桩完整性检测的基本方法。在基桩检测中,两种方法对比使用,可取长补短,有效排除干扰,能够准确、真实地反映基桩质量。     

基桩完整性三种常用检测技术的应用与比较

结合某高速公路试验基桩完整性检测实例，介绍低应变法、跨孔透射法和钻心法等3种常用的基桩完整性检测技术的原理和在实际工程中的应用，并对3种检测技术进行比较，指出相互验证方式。     

四种常用基桩完整性检测方法在工程中的应用

介绍了四种常用基桩完整性检测方法的检测原理。结合两个工程案例,给出了不同基桩完整性检测方法的优缺点,明确了基桩完整性检测的复杂性,认为基桩的完整性检测应结合多种检测方法进行综合分析。     

声波透射法在冲孔灌注桩质量检测中的应用研究

声波透射法是基桩质量检测中的常用方法之一,特别在大直径灌注桩的完整性检测中具有独特优势。本文对声波透射法的基本原理及检测方法进行了简要阐述,就如何获取声学参数及判定基桩完整性进行了分析,并结合工程实例加以分析和说明,对声波透射法检测技术的应用具有一定的参考价值。     

基桩沉桩过程桩身应力控制标准分析与应用

通过对上千根基桩沉桩过程桩身应力的的统计,找出桩身应力的极值分布,总结出一套适合于预应力混凝土桩和钢管桩的沉桩过程桩身应力控制标准。根据该标准,监控沉桩过程桩身应力值,调整沉桩指令,有利于提高沉桩效率,保证桩身质量。研究成果是对现有规范和的丰富并对工程应用有指导作用。     

水泥土双向搅拌桩智能化施工的研究与应用

智能化可以让管理更高效、让工程更有品质,为了解决水泥土双向搅拌桩传统手动施工过程中存在的问题,提出水泥土双向搅拌桩智能化施工工艺。依托白山船闸项目软基处理工程,研发水泥土搅拌桩智能化施工系统,并通过现场试验,对比在不同施工工艺下桩体进行取芯完整率、无侧限抗压强度、标贯试验。结果表明水泥土双向搅拌桩智能化施工更加符合现代软基处理工程的要求,为后续类似工程的施工和监测提供参考。     

在役码头桩基承载力静载试验

传统在役码头的桩基承载力检测需拆除上部结构,使得检测工作量大且工期较长。以某旧码头桩基检测工程为依托,阐述在保持上部结构完整的情况下,快速准确检测桩基承载力的方法。首先通过数值模拟分析上部结构与桩基荷载分担比例,初步确定试验堆载量。同时在码头下部的桩头安装传感器,加载过程中能较精确的测得桩顶的实际荷载。用该方法顺利地对该码头2根桩承载力进行检测,取得了较好的效果。     

轨道板结构在码头改造工程中的应用

阿联酋富吉拉港某码头通用泊位改造成专业散粮泊位并新设装卸船机基础,现有钢板桩码头岸壁后方存在大量抛石棱体,常用的轨道基础支撑结构施工困难,而且桩基施工还会对现有钢板桩结构造成破坏。针对项目特点提出钢筋混凝土筏型轨道板基础结构形式,并通过Axis VM和PLAXIS有限元软件对轨道板结构现有钢板桩码头结构进行核算。该码头改造和装卸船机使用效果良好。     

Corrosion rate measurements in steel sheet pile walls in a marine environment

Corrosion of steel structures in the marine environment is a major problem. The deterioration of this kind of structures is costly and difficult to predict both when designing new structures and when estimating the remaining service life time for existing structures. The aim of this investigation was to find indicative values for the corrosion rate of steel sheet piles on the Swedish west coast. Such corrosion rates (mm/year) can be used both when designing new structures by oversizing the steel thickness and when estimating the bearing capacity of existing sheet pile structures. Earlier investigations on the corrosion rates along the Swedish east coast – with salinity from about 0.2% to 0.8% – are still used today as guidelines for the corrosion rate of all steel structures in the Swedish maritime environment even though the salinity on the west coast can be as high as 3.0%.Steel sheet pile wharfs located in the port of Halmstad on the Swedish west coast were inspected by ultrasonic measurements. Three wharf structures with a total length of about 700 m were inspected. None of the inspected wharfs had or have had cathodic protection. The thickness measurements of the steel sheet pile structures were performed by divers.The age of the three inspected sheet pile structures ranged from 36 to 51 years. The dimensions of the original sheet pile sections are known. One of the quay structures is located along a river. The salinity at all wharfs varied from low values at the surface to approx. 2% at the bottom (also in the river outflow).The measured average corrosion rates were in the same order as the design values in the European code. However, the results indicate increased corrosion rates about 1 m below the mean water surface and at the level of the propellers from the ships berthing the most frequented of the inspected wharfs, 3–6 m below water surface.The tolerances of steel sheet thicknesses – usually in the order of ±6% – are often neglected when investigating the remaining thickness in steel sheet piles. A simple calculation model shows that the sheet pile must be almost 50 years of age before an accurate estimation on the corrosion rate can be made, considering the tolerances, if the true original sheet pile thickness is not known.     

大直径超长PHC桩缺陷类型分析

结合国外某大型工程中应用PDA进行超长大直径PHC桩的高应变检测工程实例,根据高应变初打和复打检测桩身完整性的结果对比,对出现在桩身、桩顶、接桩位置以及桩身下部的缺陷进行分析。对于超长大直径PHC桩的桩身完整性判断提出一些建议和看法:不能完全以桩身完整性系数作为唯一判断标准。     

灌注桩复合缺陷的低应变反射波法检测实例分析

低应变反射波法较易判断桩顶以下首个缺陷,而当灌注桩存在复合缺陷时,因缺陷反射的叠加效应将导致其他缺陷难以识别甚至影响首个缺陷的判断。结合高桩码头灌注桩低应变反射波法检测实例,分析不同类型复合缺陷的反射波曲线特征,研究复合缺陷的识别和检测方法,并提出接桩、拔除外套筒、增加护筒长度及优化泥浆更新方法、凿除桩头等验证及处理措施。     

Design of a novel drilled-and-grouted pile in sand for offshore oil&gas structures

New offshore oil and gas exploration has placed renewed emphasis on developing structures in relatively complex geological conditions. Due to the damaging nature of impact driving, traditional steel piles used to support jacket structures, are not ideally suited to specific soil types, such as carbonate sands. Drilled and grouted piles are commonly used to support structures in these soil conditions. This paper describes a novel drilled pile, which has been developed specifically to provide a cost effective installation process while maintaining the benefits of grouted piles. The installation process negates the need for temporary casing in weak soils and minimizes the number of offshore operations. In this paper, the installation methodology and post-installation performance of a large scale onshore field trial is described. The installation process was successfully demonstrated with a 1.9 m diameter test pile installed in fine sand to 17.7 m depth in under 3 h. The performance of the pile, as measured in a tension static load test, was shown to compare favorably with existing pile design methods.