New concept of tunnel boring machine: high performance using water jet and diamond wire as rock cutting technology

Abstract Tunnel boring machines are important tools in underground infrastructure projects. Although being well established equipment, these machinesare based on designsof more than 60 years ago and are characterized by big dimensions, enormous weight and high power consumption. Commercial aspects should be noted too. The model adopted by the TBM industry requires constant replacement of cutter discs and specific labor skills, usually offered by the same manufacturingcompany. In some cases the cost of replacement parts and technical assistance can be higher than the acquisition cost of an entire machine. These aspects are no longer compatible with the concept of sustainability that is an important aspect of currentsociety. While the technical characteristics require a large quantity of steel and several inputs, the adoptedmodel is not competitive. One alternative is looking for new technologies that break the old paradigms and allow the development of high performance concepts with lower social and environmental impact. This studydealswith this opportunity by proposing a high performance tunnel boring machine that makes use of high power water jet and diamond wire to compose a double shield cutter head. It works in two stages. In the fristone, an annular cut is executed by hydrodemolition,and in the second one, the diamond wire station slices the rock core. Only with the action of diamond wire is the rock core separated from the rock mass and the removal process is finished. A smart water jet nozzle movement system is described and non circular tunnels can be executed. The new technologies involved requirea different type of backup system, lighter and smaller. The non-existence of mechanical contact between the equipment and the rock mass at theexcavation front allows low power consumption. The advanced rate and primary excavation cost analyses can also be encountered herein. It shows that it is possible to reach an advanced rate of 174 m/day in soft and porous rock and 0.64 m/day in hard and non porousrock, whereas the NTNU method indicates only 55m/day and 13m/day underrespective conditions. On the other hand, the excavation cost is high for both conditions. One option is to use sand as an abrasive in the water jet process, reducing by half the primary excavation cost. It is reasonable to say that the proposed concept can be considered as an alternative for tunnels in soft rock and high porosity, and needs better performance of the water jet system to become an alternative for hard rock.摘要：隧道掘进机（Tunnel Boring Machine，TBM）是地下基础设施工程中的关键装备。尽管该类设备已得到广泛应用，但其设计理念仍沿袭自60余年前，普遍存在尺寸庞大、自重巨大、能耗偏高的显著缺陷。此外，其商业运营模式亦存在不容忽视的痛点：当前隧道掘进机行业通行的运维模式，要求定期更换刀具盘，且所需的专业操作技能通常仅由原制造厂商提供。在部分场景中，更换备件与技术援助的成本甚至高于整机采购成本。此类特征与当前社会倡导的可持续发展理念已不再适配：该类设备不仅需要消耗大量钢材与各类原材料，其现有运维模式也缺乏市场竞争力。 对此，寻求打破传统范式的新技术，开发兼具高性能与更低社会环境影响的全新设计方案，成为可行的解决路径。本研究针对该需求，提出一款采用高功率水射流与金刚石绳锯组合式双护盾刀盘的高性能隧道掘进机。该设备采用双阶段作业流程：第一阶段通过水力破碎完成环形切口作业；第二阶段由金刚石绳锯工作站切割岩芯，仅依靠金刚石绳锯的作用即可将岩芯与岩体分离，完成掘进出渣作业。本研究还阐述了一种智能化水射流喷头运动系统，可实现非圆形隧道的掘进作业。 该新型技术方案需要配套轻量化、小型化的辅助支撑系统。由于掘进工作面的设备与岩体之间不存在机械接触，因此可实现低能耗运行。本文同时开展了掘进速率与初始开挖成本分析：结果显示，在松软多孔岩体中，该设备可实现174米/天的掘进速率，在坚硬非多孔岩体中则可达0.64米/天；而根据挪威科技大学（NTNU）的传统方法测算，对应工况下的掘进速率仅分别为55米/天与13米/天。另一方面，两种工况下的开挖成本均偏高，不过可通过在水射流工序中添加砂石作为磨料，将初始开挖成本降低50%。综上，本研究提出的新型掘进机方案可作为松软多孔岩体隧道工程的备选方案；若要适配硬岩隧道场景，则需进一步优化水射流系统的性能表现。