As part of the ongoing 2nd Avenue Subway extension program which will relieve major crowding for subway riders on Manhattan's east side, MTA Capital Construction (MTACC) has contracted with Skanska/Traylor Joint Venture (STJV) to perform mining and structural concrete work for the 86th St Station. The contract's main objective is to excavate and dispose of approximately 160,000 CY of rock from below one of Manhattan's busiest avenues, 2nd Avenue, with measures to mitigate the impact on the public and traffic during the operation. Working in a densely populated urban neighborhood requires special attention to be paid to the methods used for lifting the excavated rock out of the two access shafts, each located in narrow work zones on Second Avenue, and subsequently transferring the material to trucks for disposal off-site. A fine balance must be maintained in order to provide a high production system for the removal of rock to meet schedule constraints, while at the same time addressing public concerns about the impacts of construction on their local environment. The solution developed for this operation is a mechanized mucking system with an overhead gantry crane for shaft hoisting and a separate dumping crane which loads 30 cubic yard dump trailers for off-site disposal. This paper will also describe the use of an innovative approach to ventilation during drilling and blasting operations in order to address the air quality concerns of a highly sensitive and densely populated local community. A special ventilation system was developed to minimize the visible dust and reduce smoke and fumes created by drilling and blasting. This system uses both a dedicated supply air system and exhaust air system at each of the two access shafts for the cavern excavation. The exhaust air system incorporates a wet dust collector using scrubber technology in order to treat the dust laden air created after a blast before discharging it out into the environment.
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机译：作为正在进行的第二大道地铁扩展程序的一部分，将缓解曼哈顿东侧的地铁车手的主要拥挤，MTA Capital Constally（MTACC）已与Skanska / Traylor合资企业（StJV）合同，为第86段进行采矿和结构具体工作圣站。合同的主要目标是从曼哈顿最繁华，第二大道，第二大道挖掘和处理大约160,000岩石，措施减轻了在运营期间对公共和交通的影响。在一个密集的城市邻居中工作需要特别注意用于将挖掘岩石从两个进入轴抬起的方法支付，每个都位于第二大道上的狭窄工作区中，随后将材料转移到卡车以便处理地点。必须保持精细余额，以便为岩石提供高生产制度以达到安排限制，同时解决公众对建设对当地环境影响的关注。为该操作开发的解决方案是用于轴吊装的架空龙门式起重机的机械破碎系统，以及用于卸载30立方码卸载拖车的单独的倾卸起重机。本文还将描述在钻井和爆破操作期间使用创新方法通风，以解决高度敏感和密集的本地社区的空气质量问题。开发了一种特殊的通风系统，以最大限度地减少可见灰尘，减少通过钻孔和爆破产生的烟雾和烟雾。该系统在两个接入轴中使用专用供应空气系统和排气系统，用于洞穴挖掘。排气系统采用湿式集尘器，使用洗涤器技术，以便在爆炸后涂抹在爆破后的粉尘升起的空气。
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