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201.
Ice cores contain an abundance of information about the Earth's climate in the past, and recovered from shallow drilling down to 300-350 m give sufficient information for reconstructing of the last climatic changes and for monitoring of pollution from human being. Cable-suspended core auger drills use an armored cable with a winch to provide power to the down-hole motor system and to retrieve the down-hole unit. Because of their lightweight, convenient transportation and installation, high penetration rates and low power consumption, core auger drills are widely used for shallow drilling in ice. Nowadays at least 14 types of auger electromechani- cal drills were designed and tested in different foreign and national glaciological laboratories. However, auger options were usually determined by experience, and the main parameters ( helix angle of the fights and rotational speed) are varied in a wide range from drill to drill. If parameters of auger are not chosen properly, poorly en- gineered drills had troubles with low efficiency of cuttings transportation, jam of ice cuttings, repeated fragmen- tation, cutters icing and stop penetration, abnormal power consumption, high rotation torques, and so on. Thus, this paper presents the method of optimization of iee cuttings transportation of cable-suspended core auger drill on the base of the theory of rotary auger. As the result, the optimal helix angle was determined correspond- ing to the rotational speed from the transportation efficiency point of view.  相似文献   
202.
为了满足贵州省遵义县ZK1地热井钻进施工中引进的螺杆钻进工艺对钻井液性能的要求,应对该井复杂的地质条件,综合分析了地层的特征和复杂程度以及螺杆钻进工艺所需的钻井液性能参数,在实验室进行了钻井液配比实验。通过该井的应用实践,表明所采用的钻井液性能良好,适应性强,粘度适中,滤失量合理,形成的泥饼薄而致密,对防止孔壁的缩径垮塌起到了良好作用,减少了孔内事故发生率,对螺杆钻进能够提供足够的动力,完全能够满足螺杆钻进工艺要求,提高了钻进效率。  相似文献   
203.
李奇龙 《探矿工程》2014,41(3):56-58
螺杆钻具钻进因机械钻速高、经济效益明显而在石油、煤田地质等钻探施工中广泛使用,技术也比较成熟,但在地热井钻探施工中还处于摸索试验阶段。就螺杆钻具在地热井钻探中的设备配套、钻进工艺、效益对比等一系列问题进行了阐述,肯定了螺杆钻具在地热井钻探中的钻进效率和经济效益,同时提出了一些需要在今后实践中解决的问题。  相似文献   
204.
针对松散地层自稳能力差,因钻孔掉块、缩径等引起提钻遇卡的问题,设计了PDH-130型新型双向旋冲挤密钻具,利用浮动芯管改变活塞配气行程,实现正向冲击回转挤密钻进及提钻时的反冲击功能。根据现场试验情况,对双向冲击矛结构进行了改进,以满足砂土、砂卵石等复杂地层旋冲挤密钻进施工要求。  相似文献   
205.
侯庆国 《探矿工程》2010,37(8):37-40
螺杆桩是一种承载力高、成本低、施工效率高、无污染的新桩型,新研制的LGZ-25型全液压螺杆桩钻机满足了螺杆桩独特的施工工艺要求。结合实际工程实例,介绍了钻机的结构、技术参数、工作原理以及应用效果。  相似文献   
206.
A methodology for the development of design tools for direct estimation of peak inelastic response in reduced-degree-of-freedom (RDOF) isolation and energy dissipation systems is presented. The suggested procedure is an extension of an earlier method addressing purely hysteretic isolation systems. Herein, the dynamic equation of motion is first normalised to reduce the number of design parameters that significantly affect the response. The sensitivity of normalised response quantities to the amplitude of the ground motion is then investigated through extensive parametric nonlinear dynamic analyses of isolated single-degree-of-freedom (SDOF) systems with linear viscous damping using code-based target spectra. Regression analysis is subsequently employed to develop generalised design equations (GDEs) suitable for design. Further investigations are made to address nonlinear viscous damping and the effect of the transverse component of seismic action in two-degree-of freedom (2DOF) systems under bidirectional excitation, making the procedure applicable to common bridge isolation schemes. GDEs constitute an alternative to equivalent linearisation approaches commonly adopted by codes, informing the selection among alternative isolation and energy dissipations schemes without requiring iterative analysis. The approach is incorporated in the Deformation-Based Design methodology for seismically isolated bridges in a forthcoming paper.  相似文献   
207.
拱坝-地基三维地震响应分析中大多只分析入射地震波在拱坝-地基系统坐标系方向输入时的地震响应,而事实上,垂直入射的剪切波其振动方向是不确定的,地震波动的合理输入对拱坝-地基系统的地震响应分析起着决定性的作用.本文研究了拱坝-地基系统在双向地震波输入时不同振动方向对拱坝-地基系统地震响应的影响.计算结果表明:在双向地震波输入情形时,拱坝位移及应力响应最大值均不是发生在传统方法的横河向或者顺河向,而是与输入地震波相关,所以在研究拱坝-地基三维地震响应时有必要考虑入射地震波振动方向的影响.  相似文献   
208.
LGZ系列全液压多功能桩机拥有可轴向滑移主动钻杆、大扭矩中空式回转动力头和双筒同步卷扬机3项专利技术,具有施工安全、一机多能、传动平稳高效等技术优势。本文介绍了该系列桩机的性能参数、技术特点,及其在螺杆桩、螺旋挤土桩、水泥土搅拌桩、长螺旋钻孔灌注桩、大直径长螺旋钻孔桩等5种工法中的应用。实践证明,LGZ系列全液压多功能桩机可以满足多种桩基工法施工需求,并可扩展到更多工法应用。  相似文献   
209.
针对时序数据中的破年变异常,基于S变换时频方法构建信息提取流程,在提取常规短周期破年变信号(ONA)的同时分析背景年变信号(ANA)的演化过程。在此基础上,基于双向非对称阈值策略,结合R值评分及Molchan图表法构建预测指标确定和效能定量评估方法。新疆库尔勒水平摆倾斜北南测项的实际应用结果显示,该测项的ANA信息对台站周边250 km内6级以上地震具有较好的预测效能,ONA信息对200 km范围内5级以上地震的预测效果相对更优。  相似文献   
210.
Seismic response of a one-storey structure with sliding support to bidirectional (i.e. two horizontal components) earthquake ground motion is investigated. Frictional forces, which are mobilized at the sliding support, are assumed to have ideal Coulomb-friction characteristics. Coupling effects due to circular interaction between the frictional forces are incorporated in the governing equations of motion. Effects of bidirectional interaction of frictional forces on the response are investigated by comparing the response to two-component excitation with the corresponding response produced by the application of single-component excitations in each direction independently. It is observed that the response of the sliding structure is influenced significantly by the bidirectional interaction of frictional forces. Further, it is shown that the design sliding displacement may be underestimated if the bidirectional interaction of frictional forces is neglected and the sliding structures are designed merely on the basis of single-component excitation.  相似文献   
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