Category: 白皮书论文

Breaking Through Tough Ground in the Himalayas: Nepal's First TBM

Years of hard work and planning have paid off at the Bheri Babai Diversion Multipurpose Project. This 12 km tunnel is not only breaking through a historically difficult mountain range, but it has also managed to break down the notion, to the people of Nepal, that drill and blast is this only way to excavate the extreme conditions in the Himalayas. This paper highlights the first TBM in Nepal and how it is managing to bore at an exceptional advance rate of over 700 m per month, with a high of 1202 m in one month. It examines which design features of the Double Shield TBM are contributing to the great excavation rates, and how the crew’s operational methods have maximized these results.

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Tunneling in Mixed Face Conditions: An Enduring Challenge for EPB TBM Excavation

EPB TBM tunneling in mixed face conditions—partially in both rock and soil—is inherently problematic for even the most experienced crews. Over-excavation, excessive damage to cutter tools and regular cutterhead interventions are major challenges when negotiating mixed face geology. This paper draws from real field experiences, including successful bores in abrasive rock and soil at India’s Chennai and Bangalore metro projects, to determine the optimal operational parameters for TBMs in such conditions. It also addresses reduction of air losses to facilitate cutterhead interventions under hyperbaric conditions when installation of safe-haven grout blocks is not an option due to surface structures.

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7.93 m Open TBM Shotcrete System Improvement and Innovation - Jilin Project, China

In May 2018, a 7.93 m diameter open gripper (Main Beam) TBM completed the 24.3 km long Jilin Lot 3 tunnel under a maximum overburden of 272.9 m. The tunneling operation for the water transfer project, located in northeastern China, achieved a national record of 1,423.5 m in one month despite challenging conditions. This paper presents an improved, innovative shotcrete system for TBM preliminary lining, developed through experience on previous projects. The shotcrete system, along with other structural design elements and a properly developed ground support program, allowed the TBM to bore successfully in variable hard rock and fault zones. The paper discusses how the shotcrete system and structural design increased safety and improved performance in a cost-effective manner. It defines the variables that allowed the TBM to advance at rapid rates and makes recommendations for future types of projects that could benefit from the shotcrete system.

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Overcoming Extreme Tunneling Conditions in Vietnam's Longest Tunnel

Vietnam’s Thuong Kon Tum Hydroelectric project is a 17.4 km headrace tunnel that will be the country’s longest once complete. A section of the tunnel was excavated by a 4.5 m diameter Main Beam TBM in granitic rock up to 250 MPa UCS. Started in 2012, the project’s original contractor left due to non-satisfactory performance. In 2016, the contract to refurbish the TBM and excavate the remaining 10.45 km of tunnel was awarded to a joint venture of Robbins and a local contractor. Robbins was fully responsible for the TBM operation, including supplying operational crews. The crew overcame massive granitic rock, fault zones gushing water at 600 l/s, and difficult conditions. In under two years, the TBM advanced from a standstill at 15 percent project completion to 85 percent complete. This paper addresses the refurbishment of the TBM in the tunnel, the work to streamline operation, and challenges faced.

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Rescuing and Rebuilding TBMs in Adverse Ground Conditions

Modern TBMs deliver high performance with availability rates that are beyond 90%. The TBM design concepts make the machines highly versatile for employment in varying soil and ground conditions. Machines can now withstand extreme loads and impacts in rough underground environments because of the components made for longtime use. Regular maintenance and planned service is the vital element in prolonging a machine’s life and for high performance and availability. A well-serviced machine provides excellent performance as well as active project safety. Proper operation in variable conditions is also key. For instance, a hard rock TBM may run into zones of swelling rock. The most appropriate method to overcoming the swelling rock is to keep going, avoiding any unnecessary stops. Worn disc cutters that have not been maintained in due course are a prominent example of such avoidable stops, which may result in long downtimes and severe damage to the machine. However with modern and advanced techniques to underground tunneling, rescuing and rebuilding TBMs is possible to save the project. This paper discusses methods and tools for modern TBM service and maintenance using present case studies about TBM rebuilds in extreme project conditions.

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Extreme Ingress: Managing High Water Inflows in Hard Rock TBM Tunneling

Managing water inflows is not new to TBM tunneling, but today there are an increasing number of methods and best practices to handle potentially high water inflows efficiently and safely. High volumes of water can be safely contained or managed in hard rock TBM tunneling, but this requires the proper foreknowledge and planning. This paper outlines how machines can be designed ahead of time for expected high water, and how risk can be mitigated during tunneling. It also covers the importance of pre-planning and includes a look into the future of water control methods. Case studies of hard rock tunneling with heavy water inflows are examined, with a focus on New York, USA’s Delaware Aqueduct Repair, the 3.8 km long bypass tunnel below the Hudson River requires excavation through limestone rock at water pressures of up to 20 bar. A unique 6.5 m diameter Single Shield TBM, sealable for high pressure excavation, is boring and lining the tunnel.

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Challenging Mixed Face Tunneling at India's Sleemanabad Carrier Canal

India’s Sleemanabad Carrier Canal is a prime example of just how challenging mixed face conditions can be, although other examples exist. The water transfer tunnel is being bored using a 10 m diameter hybrid-type rock/EPB TBM. However, in 6.5 years of tunneling the machine had only advanced 1,600 m. Commercial issues for the original contractor stalled the project frequently, while ground conditions turned out to be even more difficult than predicted. Low overburden of between 10 and 14 m, combined with mixed face conditions, transition zones and a high water table restricted advance rates. The TBM manufacturer mobilized a team to refurbish the TBM and within a period of 6 weeks a team of 180 people had been deployed to take over all aspects of tunneling and support activities. Production rates improved dramatically as the TBM advanced more than 400 m in four months. This paper discusses the problems faced and the methodology that enabled good advance rates in highly variable mixed face conditions.

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与掘进机采购相关的风险以及行业变革的下一步

掘进机隧道工程领域的风险管理本身就是一项风险业务。地下往往会出现障碍，跨越数英里隧道的复杂项目会增加这些风险。然而，在我们的行业中有管理和降低风险的方法，即通过确保进行彻底的岩土工程研究并制定应急计划。掘进机本身可以在设计时考虑到降低风险，使用扩大机器周围地面可视化的工具，并为承包商提供以最小延迟通过具有挑战性的地面条件的方法。本文从顾问、承包商和设备制造商的角度探讨了隧道掘进的风险。它还试图就如何更好地管理当今隧道行业的风险提出建议。

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在亚特兰大供水项目中用主梁式掘进机在坚硬的磨蚀片麻岩下掘进

佐治亚州亚特兰大市的供水项目是一个优先项目，其中包括一条5.0英里长的隧道，连接查塔胡奇河（Chattahoochee），该河将为该市建立一个应急供水系统。一个直径12.5英尺的主梁掘进机正在以每天高达100英尺的速度开挖该地区最深的隧道，穿过坚硬、磨蚀的片麻岩。本文研究了该项目的具体设计，以及掘进机的性能。根据本工程和该地区以往的工程，得出了该地区极硬地质条件下开挖的掘进机优化设计结论。

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冰川地质下刀盘配置和资源规划的掘进机刀具磨损分析

冰川地质的磨蚀性通常导致隧道掘进机刀具检查和更换需要，这可能需要高压干预，是成本和风险因素。岩土条件、掘进机运行参数和刀具磨损测量的相关性分析是深入了解磨损系统行为的一种行之有效的方法。本文介绍了在西雅图和温哥华，不列颠哥伦比亚省大城市地区的各种掘进机驱动装置对冰川和冰川间沉积物中滚刀和刮刀类型刀具性能的研究结果。作者对刀盘结构、刀具管理策略和监控技术的使用提出了建议。

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