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文章主要介绍了ZHDN-SDR 150A 型高频声波钻机设计及其验证测试,为该钻机应用于污染场地调查和治理提供理论依据和技术指导。论文阐述了钻机总体设计思路及主要性能参数指标,系统分析了高频声波动力头、钻机主体、配套钻具结构设计及其技术创新。该钻机在两种不同地层进行了验证测试,各项测试指标均达到设计要求。将验证测试结果与国内外同类钻机对比表明,ZHDN-SDR 150A型钻机主要性能参数与关键装置已处于国内先进和国外并跑水平。该型钻机在振动频率、地层适用性、钻具使用寿命等方面优势显著,但是存在过高温度运行条件下钻进效率降低、智能自动化水平不足的问题,需进一步研发耐高温强硬度新材料和改进远程无线操控系统。 相似文献
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吴刚 《广东海洋大学学报》1990,(2)
在保证轴承安全而经济的运转条件下,轴承装配间隙取最小值,根据流体润滑理论,选择合适的润滑油;对于厚壁轴瓦,在磨合之后应调整到运转间隙。这样就可以充分利用轴承的使用寿命。 相似文献
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Base shear capping buildings with graphite‐lubricated bases for collapse prevention in extreme earthquakes 
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下载免费PDF全文 Francesca Barbagallo Ikumi Hamashima Hongsong Hu Masahiro Kurata Masayoshi Nakashima 《地震工程与结构动力学》2017,46(6):1003-1021
Damage or collapse of buildings vulnerable to seismic forces may cause human casualties, and seismic upgrading of such structures is a practical solution to this deficiency. The study presented here proposes a simple approach to prevent structural collapse by separating the superstructure from its foundation to let the superstructure slide during extreme ground shaking. The sliding mechanism contributes to cap the horizontal force exerted on the superstructure. In such approach, the key is to maintain the friction force between the superstructure and the foundation sufficiently low and stable. This research proposes to realize a controlled sliding mechanism, which acts as a structural fuse, by means of carbon powder lubrication at the bases of the structure's columns. The fundamental behaviour of the proposed structural system, named the base shear capping building, is investigated by shaking table tests and numerical simulation. Both experimental and numerical results showed that graphite lubrication is an efficient and robust lubrication material, maintaining the friction coefficient between the steel column bases and mortar foundation at around 0.16. The sliding at the bases significantly reduced the acceleration transmitted to the superstructure, keeping the base shear coefficient not greater than about 0.40. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Abstract The fractality of fault zones of thickness T for the 248-m-long core from a borehole penetrating the northern segment of the seismic Chelungpu Fault, Taiwan, was analyzed. The frequency curve of T shows that the fractal dimension is normal when T is smaller than a characteristic thickness T c , and it becomes abnormally large when T exceeds T c . The fractal dimensions of size and spatial distributions of T increase as the mean distribution density of T increases, which is inconsistent with the evolution laws for ordinary brittle faults. This discrepancy implies that the thickening rate of T when T is more than T c is not constant, but a decreasing function of fault displacement. The slow thickening rate is related to the elastohydrodynamic lubrication which was effective on the fault when T exceeds T c . This slip instability mechanism can explain the large, fast and smooth slip on the northern segment of the Chelungpu Fault during the 1999 Chi-Chi earthquake. 相似文献
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Abstract The seismic slip that occurred during the 1999 Chi-Chi earthquake in Taiwan showed contrastive behaviors in different regions along the Chelungpu Fault: A large and smooth slip occurred in the north, while a relatively small slip associated with high-frequency seismic wave radiation occurred in the south. The core samples from shallow boreholes at northern (Fengyuan) and southern (Nantou) sites penetrating the seismic Chelungpu Fault were analyzed. The fault zones at the northern site are characterized by soft clayey material associated with clayey injection veins. This suggests that the fault zones were pressurized during ancient seismic slip events, and hence the elastohydrodynamic lubrication occurred effectively. In contrast, the fault rock from the southern site is old pseudotachylyte that has been shattered by repeated ancient seismic slip events. Statistical analysis of many pseudotachylyte fragments reveals that the degree of frictional melting tended to be low. In this case, the seismic slip is restrained by the mechanical barrier of a highly viscous melt layer. These contrastive fault rocks were produced by repeated ancient seismic slip events, but the two corresponding mechanisms of friction are likely to have also occurred during the 1999 Chi-Chi earthquake, thus causing the contrastive slip behaviors in the north and south. 相似文献
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