6 connecting methods between green area and hardstand were presented and propositions were offered.
介绍了园林绿地与硬地铺装之间的6种交接方式,提出了合理利用地形和合理选用材料以协调两者之间的关系。
PDC bits are generally inadaptable for drilling hard formation,especially for the gravel layer with high compressive strength and abrasion.
PDC钻头不适宜钻硬地层,尤其是高强度、高研磨性的砾石层,因为在极其恶劣的工作条件下,PDC齿的冲击破损严重,热磨损及磨料磨损往往同时存在,齿的磨损速度快,钻头的工作寿命急剧缩短。
Improving the drilling rate of hard formation is always a problem in the world.
为了解决提高硬地层钻井速度的钻井难题,以粒子冲击钻井系统的整个工艺流程为依据,论述了粒子冲击钻井技术的优点和缺点,阐述了其破岩机理。
For the research on characters of cemented soil of SMW(soil mixing wall) technology in medium-hard strata is shortage,so the application in medium-hard soil is restrained.
针对SMW工法缺乏对中硬地层的水泥土性能研究,利用首例北京地区在中硬地层中地铁基坑工程采用SMW工法搅拌后的水泥土,进行了三轴压缩试验。