灌注桩泥浆浸湿范围及周边土体竖向位移试验

根据西安地铁试验段钻孔灌注桩周边土体深层竖向位移监测试验资料及泥浆浸湿对比资料,对黄土地区灌注桩施工过程中土体不同深度位移及泥浆浸湿范围进行了研究,为钻孔灌注桩的工程应用提供了有益的理论依据和参考。     

泥浆配合比方案选择

结合某工程概况,介绍了泥浆配合比材料试验的目的和方法,根据试验结果,对不同地层采用不同的泥浆配合比进行了分析,通过分析筛选,选用合理的泥浆配合比,以防止钻孔桩施工事故的发生,从而提高成孔质量。     

泥浆护壁钻孔灌注桩施工质量控制要点

根据泥浆护壁钻孔灌注桩施工工艺特点和施工规范要求,主要从成孔和成桩两方面对施工质量控制要点进行阐述,以提高泥浆护壁钻孔灌注桩基桩施工质量。     

钻孔桩施工泥浆比重的控制

钻孔灌注桩,其钻孔和灌注混凝土大多在泥浆中完成。以循环泥浆来冷却、润滑钻具,保护孔壁,排出泥碴,密实混凝土等,因此,泥浆质量直接影响成孔和混凝土灌注质量。笔者根据多年施工经验,对泥浆比重控制等问题,作了较全面的介绍。     

砂卵石地层中钻孔灌注桩成孔控制技术

在砂卵石地层采用钻孔灌注桩成孔难度较大.以北京地铁十号线某盾构始发井围护桩施工为例,对在砂卵石地层中影响钻孔桩成孔效率和质量的主要原因进行了分析,并针对设备选型和泥浆护壁两方面对成孔质量控制措施进行了阐述.根据不同的地质条件选择适合的成孔钻具和泥浆参数,保证了成孔质量,提高了施工效率.     

建筑技术开发文摘

建筑技术开发文摘钻孔灌注桩“抬举法”清渣工艺初探根据施工过程中的现场观察，当钻孔深度小于３ｍ时，由于钻头的旋转孔口里的泥浆也跟着旋转，这时较大的岩渣也随着旋转的泥浆排出孔口。当钻孔深度超过３ｍ，孔口的泥浆旋转就停止了，泥浆只是在钻杆附近成束状流出孔口...     

大直径长桩钻孔泥浆制备和控制

大直径长桩钻孔泥浆的制备和控制是关键工艺。通过对滨江大桥桩基施工介绍钻孔灌注桩在复杂的地质情况下的施工技术,特别着重介绍了聚丙烯酰胺(PHP)钻孔泥浆制备、新浆制备、泥浆循环系统以及钻孔过程泥浆指标的控制。     

钻孔灌注桩中泥浆的净化和利用

根据多年从事灌注桩施工的实践经验，分析了泥浆净化的必要性，介绍了两种控制固相含量的方法，并总结了一套在中砂层、粉砂层、松散层钻进时泥浆的净化和管理的方法，从而更好地稳定泥浆性能，改善钻进工作条件，提高钻孔质量和钻孔效率。     

对钻孔灌注桩泥浆作用的探讨

提高泥浆质量是保证钻孔灌注桩质量的一项重要措施。结合某特大桥的施工实际 ,论述了泥浆的作用、泥浆的配制和使用注意事项。阐述了泥浆对钻孔灌注桩质量的影响和正确的施工方法。     

钻孔灌注桩泥浆循环处理方法

结合钻孔灌注桩工程施工实例,从技术、经济、环保等方面比较了泥浆外运处理方案和场内泥浆循环处理方案,指出泥浆循环处理方案节约了钻孔用水,泥浆处理费用和土地资源,具有很好的经济效益和社会效益。     

水上钻孔灌注桩在珠江堤防整治工程中的应用

介绍了珠江堤防水上钻孔灌注桩施工技术,重点介绍水上钻孔平台设计与施工、钻孔泥浆的循环与回收技术。     

某桥钻孔灌注桩质量事故原因分析及处理措施

结合工程实例，从泥浆的比重不足、桩孔周围有动荷载、施工方法不当等方面对泥浆护壁钻孔灌注桩塌孔的原因进行了分析，并从四方面介绍了事故的处理方案及施工技术措施，取得了良好的效果。     

武汉国际会展中心后压浆钻孔灌注桩施工

在武汉国际会展中心后压浆钻孔灌注桩施工过程中,结合工程实际采取针对性的技术措施,克服邻近基坑深井降水引起地下承压水渗流的影响,保证了桩基施工质量。     

宜万铁路马鹿箐隧道水文地质分析及涌水预警

马鹿箐隧道是宜万铁路八座I级风险隧道之一,在DK255＋978发育大型高压富水充填溶腔。泄水洞揭穿该溶腔后,多次出现大规模突水突泥。介绍了马鹿箐隧道水文地质背景、水文专项监测、峰值涌水量预测及水文地质预警等相关情况,可为类似工程的水文地质分析和预警提供参考。     

支盘桩的质量控制

挤扩支盘灌注桩比普通钻孔桩多一道挤扩盘工序,增加了施工人员、机械和工序作业的复杂性,必须对工艺流程严格控制,特别是挤扩支盘时应注意泥浆下降、设备上浮和挤扩压力值,运用网络技术确保支盘桩质量。     

重复爆炸条件下岩石介质破坏效应试验研究

 为了探索精确制导武器对岩石介质中地下防护工程实施重复打击后的毁伤效应问题,进行重复钻孔爆炸和一次性钻孔爆炸对比试验。试验结果显示：在装药总量相等条件下,二次钻孔爆炸所形成的爆坑直径与一次性钻孔爆炸所形成的爆坑直径近似相等,但爆坑深度和破碎区范围却分别是一次性钻孔爆炸的2倍和1.66倍。量测结果显示：试验中二次钻孔爆炸与一次性钻孔爆炸相同测点处峰值应力相差较大,相同测点处二次钻孔爆炸的峰值应力远高于一次性钻孔爆炸的峰值应力。计算结果显示：一次性钻孔爆炸的应力衰减指数为1.933,应力波传播速度约为4 800 m/s。最后根据应力波传播机制推算得出：在装药总量相等条件下二次钻孔爆炸所需防护层厚度是一次性钻孔爆炸所需防护层厚度的1.07倍。     

How rock samples can be representative of in situ condition: A case study of Callovo-Oxfordian claystones

Within the framework of feasibility studies for a reversible, deep geological repository of high- and intermediate-level long-lived radioactive waste (HLW, IL-LLW), the French National Radioactive Waste Management Agency (Andra) is investigating the Callovo-Oxfordian (COx) formation near Bure (northeast part of France) as a potential host rock for the repository. The hydro-mechanical (HM) behaviour is an important issue to design and optimise different components of the disposal such as shaft, ramp, drift, and waste package disposal facilities. Over the past 20 years, a large number of laboratory experiments have been carried out to characterise and understand the HM behaviours of COx claystones. At the beginning, samples came from deep boreholes drilled at the ground surface with oil base mud. From 2000 onwards, with the launch of the construction of the Meuse/Haute-Marne Underground Research Laboratory (MHM URL), most samples have been extracted from a large number of air drilled boreholes in the URL. In parallel, various constitutive models have been developed for modelling. The thermo-hydro-mechanical (THM) behaviours of the COx claystones were investigated under different repository conditions. Core samples are subjected to a complex HM loading path before testing, due to drilling, conditioning and preparation. Various kinds of effects on the characteristics of the claystones are highlighted and discussed, and the procedures for core extraction and packaging as well as a systematic sample preparation protocol are proposed in order to minimise the uncertainties on test results. The representativeness of the test results is also addressed with regard to the in situ rock mass.     

Prevention and treatment technologies of railway tunnel water inrush and mud gushing in China

Water inrush and mud gushing are one of the biggest hazards in tunnel construction. Unfavorable geological sections can be observed in almost all railway tunnels under construction or to be constructed, and vary in extent. Furthermore, due to the different heights of mountains and the lengths of tunnels, the locations of the unfavorable geological sections cannot be fully determined before construction, which increases the risk of water inrush and mud gushing. Based on numerous cases of water inrush and mud gushing in railway tunnels, the paper tries to classify water inrush and mud gushing in railway tunnels in view of the conditions of the surrounding rocks and meteorological factors associated with tunnel excavation. In addition, the causes of water inrush and mud gushing in combination of macroand micromechanisms are summarized, and site-specifc treatment method is put forward. The treatment methods include choosing a method of advance geological forecast according to risk degrees of different sections in the tunnel, determining the items of predictions, and choosing the appropriate methods, i.e. draining-oriented method, blocking-oriented method or draining-and-blocking method. The treatment technologies of railway water inrush and mud gushing are also summarized, including energy relief and pressure relief technology, advance grouting technology, and advance jet grouting technology associated with their key technical features and applicable conditions. The results in terms of treatment methods can provide reference to the prevention and treatment of tunnel water inrush and mud gushing.     

河北沧县深部盐矿勘探孔盐水泥浆技术

在沧县石盐矿普查的施工中,ZK001勘探孔终孔深度3451m,裸眼段长度达2950m,由于大段连续取心钻进,施工时间大幅增加,对泥浆护壁技术提出挑战。根据地层特征在节约成本的前提下,施工中分别使用了淡水泥浆与盐水泥浆,特别是取心过程中,盐水泥浆护壁起到很好的效果。本文主要介绍了淡水泥浆—盐水泥浆转换需要注意的问题和盐水泥浆的特点与应用。通过施工检验,盐水泥浆性能稳定,易于维护,有效控制了地层坍塌、缩径等复杂问题,保证了钻进安全,适合工区应用。     

高适应性聚羧酸减水剂在机制砂混凝土中的应用

介绍了高适应性聚羧酸减水剂在机制砂不同石粉含量、含泥量和细度模数情况下的使用,提出了高适应性聚羧酸减水剂在机制砂中的具体应用.采用高适应性聚羧酸减水剂,并根据多元混合物的处理特点,提高了组合物的适应性,以适应不同的原材料,解决传统减水剂因机制砂石粉含量或含泥量高造成的混凝土需水量不稳定,以及减少了对水泥适应性差的问题....