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Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One of the effective ways to increase the speed of amphibious vehicle is to reduce the overall resistance. In order to research the influence of trim angle on the resistance characteristics, a numerical calculation method is used to research the resistance characteristics of high speed wheeled amphibious vehicle. The numerical results are in good agreement with the experimental results. The research results show that the resistance increases with the increase in speed when the vehicle trim angle is small; it increases first and then tends to be stable with the increase in speed when the vehicle trim angle is bigger. When the speed is low, the trim angle has a small influence on longitudinal resistance ; when the speed is higher, the resistance decreases first and then increases with the increase in trim angle. As speed increases, the vehicle trim angle becomes smaller, but the resistance increases. [ABSTRACT FROM AUTHOR]

Due to the wellbore trajectory changes caused by directional drilling for Well Long 114, the tripping frictional resistance was increased, and it was difficult to draw the BHA out, resulting in the BHA expansion and dropping into the well bottom during back reaming the wellbore. The fish length was 3 205.21 m, and the internal thread swelled and was deformed. Through analyzing the difficulties during accident treatment, the fishing tool was selected and improved . According to the handling program for the accident, the active stuck freeing strength was controlled within the force of thread making position of the fishing tool, and the fish was successfully tripped out finally. The idea and technical treatment can be helpful to the similar type of accident treating. [ABSTRACT FROM AUTHOR]

In order to ensure the reliability of ocean platform isolation structure under severe earthquake to avoid the break of oil tube, the cone shape memory alloy (SMA) restrainer and frictional restrainer are presented. The control effects and restraint effects are analyzed for ocean platform isolation structure subjected to severe earthquake based on control theory. The analysis results show that the cone SMA restrainer can effectively restrain the displacement of isolation layer, and the SMA restrainer is better than the frictional restrainer. Meanwhile, the SMA restrainer has advantages of self-ecentering and multidirectional energy dissipation, and can satisfy the demands of oil extraction technics better. [ABSTRACT FROM AUTHOR]