Study of damage to a high concrete dam subjected to underwater shock waves     

Lu Lu  Xin Li  Jing Zhou 《地震工程与工程振动(英文版)》2014,13(2):337-346

To study the effect of a strong underwater shock wave on a concrete dam, this research aims to improve hammer impact methods in model tests. Six 1:200 scale models were designed and tested under distributed impact loads. A device was deployed for a direct measurement of the impact force at the upstream face of the dams. The model dam bases were anchored to prevent displacement. The experimental results indicate that the top part of the concrete dam is a weak zone, and the impact failure initiates with a fracture on the top of the dam. The peak value of impact stress increases when the second crack appears in the concrete dam from the upstream face to the downstream face. And, the level of the second crack in the dam body is lower as the peak value of impact stress increases. In this study, dynamic analysis was conducted by calculating the results to verify the effectiveness of a device to directly measure the impact force. This method may be used to approximately forecast the damage of concrete dam and may also be useful in other engineering applications.  相似文献   

Magma chamber growth models in the upper crust: A review of the hydraulic and inertial constraints     

Eugenio Aragón  Fernando J.D'Eramo  Lucio P.Pinotti  Manuel Demartis  José María Tubía  Roberto F.Weinberg  Jorge E.Coniglio 《地学前缘(英文版)》2019,10(3):1211-1218

Finite volumes of magma moving in confinement, store hydraulic potential energy for the generation,control and transmission of power. The Pascal's principle in a hydraulic jack arrangement is used to model the vertical and lateral growth of sills. The small input piston of the hydraulic jack is equivalent to the feeder dike, the upper large expansible piston equivalent to the magmatic chamber and the inertial force of the magma in the dike is the input force. This arrangement is particularly relevant to the case of sills expanding with blunt tips, for which rapid fracture propagation is inhibited. Hydraulic models concur with experimental data that show that lateral expansion of magma into a sill is promoted when the vertical ascent of magma through a feeder dike reaches the bottom contact with an overlying, flat rigid-layer. At this point, the magma is forced to decelerate, triggering a pressure wave through the conduit caused by the continued ascent of magma further down(fluid-hammer effect). This pressure wave can provide overpressure enough to trigger the initial hydraulic lateral expansion of magma into an incipient sill, and still have enough input inertial force left to continue feeding the hydraulic system. The lateral expansion underneath the strong impeding layer, causes an area increase and thus, further hydraulic amplification of the input inertial force on the sides and roof of the incipient sill, triggering further expansion in a self-reinforcing process. Initially, the lateral pressure increase is larger than that in the roof allowing the sill to expand. However, expansion eventually increases the total integrated force on the roof allowing its uplift into either a laccolith, if the roof preserves continuity, or into a piston bounded by a circular set of fractures. Hydraulic models for shallow magmatic chambers, also suggest that laccolith-like intrusions require the existence of a self-supported chamber roof. In contrast, if the roof of magmatic chambers loses the self-supporting capacity, lopoliths and calderas should be expected for more or less dense magmas, respectively, owing to the growing influence of the density contrast between the host rock and the magma.  相似文献   

大直径岩溶水井施工技术          下载免费PDF全文

谢常茂 《探矿工程》2009,36(7):21-24

通过广西河池市九圩镇水厂大直径供水井的施工实例,详细介绍了岩溶复杂地层大直径、大涌水钻孔的空气潜孔锤钻进技术、扩孔技术、钻孔护壁技术及施工工艺。  相似文献   

基于LSDYNA的射流式液动锤回程动力 外传机构研究          下载免费PDF全文

张鹏飞  程靖清  葛东  彭枧明 《探矿工程》2019,46(2):71-74,85

设计一种改变冲击应力波在射流式液动锤内传播途径的结构,分析在不同传播途径中应力波衰减程度的改变,基于LSDYNA显式动力学分析方法,对冲锤回程阶段进行仿真分析,探究冲锤回程冲击在液动锤内两种不同传播途径的模型中射流元件受到的应力变化。研究表明,动力外传机构通过避免对缸体上部的刚性碰撞,能大大降低射流元件所受到的冲击应力,并且外传机构的几何参数对应力的衰减也有一定的影响。  相似文献   

液动锤套管起拔器的研制与应用          下载免费PDF全文

孙天  苗晓晓  叶兰肃  刘建福  王建兴  孙秀梅  刘莎莎  王越光 《探矿工程》2017,44(6):6-12

液动锤套管起拔器的原理是利用冲洗液作为动力介质,推动冲击锤产生振动,将机械应力波通过液动锤传至套管,使其松动后拔起。新研制的液动锤套管起拔器减轻了普通蛮力起拔方法对套管的损伤,节约钻探成本。本文介绍了双作用和正作用两种液动锤套管起拔器的起拔原理以及工作方法,并介绍了其在河北省遵化市西山带铁矿区进行野外试验中取得的效果。  相似文献   

贵州碳酸岩地层地热深井空气潜孔锤钻进技术应用研究          下载免费PDF全文

赵华宣  李强  陈涛  陈浩  苏宁  王虎 《探矿工程》2017,44(2):37-42

研究了空气潜孔锤钻井工艺在贵州省碳酸盐岩地层地热深井中的应用,涉及溶隙、裂隙发育,涌水、漏风、掉块、排渣困难等情况频发的碳酸盐岩地层的10～1100 m井段和φ216～406 mm井径的条件,探讨了在这样环境下空气潜孔锤钻进机具设备配置、钻具组合和钻进参数;分析了空气潜孔锤钻进工艺钻进过程中的常见问题并提出了相应的技术措施;总结了深井碳酸盐岩地层复杂井况的空气潜孔锤钻进效率与经济效益。研究结果表明,通过合理的设备机具配置和技术措施,可有效提高贵州省碳酸岩层空气潜孔锤钻进效率,进而大幅度提高贵州地热深井的钻进效率和经济效益。  相似文献   

H型钢桩作灾区地基承载桩具抗震减震性能的优势分析     

王进怀  王卫东  章磊 《国际地震动态》2010,(2):27-30

地基处理好坏是建筑物是否牢固的前提,当前,国内地基处理的方式多种多样,不同的地基处理方式所涵盖的技术含量不尽相同,施工工艺不尽相同,应用领域不尽相同,用高频液压振动锤施工H型钢桩作为中小学校建筑、或其他建筑物的承载桩,可有效防止地震对建筑物地基的影响和对建筑物的破坏,从而能有效地减少人民生命财产损失。  相似文献   

空气潜孔锤钻进是提高钻进效率的有效途径     

刘景辉  谭效林  路庆海  赵联忠 《中国煤炭地质》2009,(3):63-65

空气潜孔锤冲击钻进与常规回转钻进技术相比,是以动载钻头冲击破碎岩石方式取代静载切削岩石的方式;岩石的体积破碎代替了研磨剪切破碎;是目前提高钻进效率的最佳钻进技术之一。在同井同钻机钻进时,其钻效可较常规钻进提高11-18倍;在邻井相同地层、相同技术要求时,其钻效可提高13倍左右;在同一勘探区、相同技术要求时,其钻效可提高9倍左右。通过反复对比论证,认为空气潜孔锤钻进能有效提高钻进效率,较好的体现出其潜在的经济与环保价值。  相似文献   

气动潜孔锤钻进技术   总被引：12，自引：0，他引：12  

殷琨  蒋荣庆 《世界地质》1999,18(2):101-104

研究潜孔锤内部动力过程,优化潜孔锤性能,研制系列适应于不同工况条件及领域的特殊性能潜孔锤,以满足各种钻孔工程需求。将多种先进钻孔工艺方法融于潜孔锤钻进中,形成多工艺潜孔锤钻进行工艺方法,以满足不同施工领域的钻孔施工需求,解决系列钻孔施工难题,推进钻孔技术的进步与发展。  相似文献   

How does anisotropy in bedrock river granitic outcrops influence pothole genesis and development?          下载免费PDF全文

Jose Ortega‐Becerril  Miguel Gomez‐Heras  Rafael Fort  Ellen Wohl 《地球表面变化过程与地形》2017,42(6):956-968

Pothole formation and development may be influenced by joint sets and other heterogeneities within bedrock, as well as by hydraulics. Previous research indicates that most potholes found in rivers of the mountainous Spanish Central System exhibit preferred orientations associated with dominant joints and correlate more strongly with variations in substrate resistance than with hydraulics. Weathering and erosion weaken rock surfaces, which leads to decreased mechanical resistance. We start from the hypothesis that different mechanisms of pothole formation may create around the pothole a distinctive signature in terms of ultrasound pulse velocity and surface hardness. We develop a conceptual model and test it using potholes for which we know the mechanism of formation, demonstrating that the spatial and statistical distributions of dynamical mechanical properties and surface hardness of a pothole may provide insight into its genesis. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献