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关键词： True triaxial apparatus   Geomechanical model test   Water gushing and mud outburst   Evolution mechanism   Tunnel boring machines tunnels   PHYSICAL MODEL TEST   NUMERICAL-SIMULATION   PREDICTION MODEL   RISK-ASSESSMENT   KARST TUNNELS   CAVERN GROUP   MECHANISM   BEHAVIOR   GRANITE   ZONE  

摘要： To investigate the mechanism of the fault water gushing and mud outburst in TBM tunnels, an automatic true triaxial model test under TBM driving disturbance was carried out based on a water-conveyance tunnel in Xinjiang, China. By monitoring the various physical parameters of different excavation sections, such as seepage pressure, stress, and displacement, the variation laws of surrounding rock information were obtained. The entire disaster process can be categorized into four distinct periods. When the monitoring section, which was far from the water-bearing fault, was exposed, the displacement and stress changed sharply. The displacement of the water-resistant rock mass increased sharply when the water and mud inrush occurred. The peak stress and seepage pressure platform were formed before the water-resistant rock mass failure, and then the stress and seepage pressure changed sharply. Additionally, the results also indicated that the seepage channel was approximately perpendicular to the fault for the water and mud inrush caused by the inclined fault. The research findings will establish a theoretical foundation for the control and prevention of fault water and mud inrush during TBM excavation, providing valuable insights for reducing and controlling the occurrence of water and mud inrush.

关键词： BIM   Thrust force   TBM performance   Numerical analysis   Dynamic prediction   FEEDBACK   DATASET  

摘要： The prediction of Tunnel Boring Machine (TBM) performance typically requires analyzing a significant amount of multi-source heterogeneous data, including information from TBM machinery, geological conditions, logistical information, and operator-machine interactions. Throughout the excavation process, construction sources frequently undergo changes and often interact in complex ways, posing substantial challenges to accurate performance prediction. Building Information Modeling (BIM) has been extensively utilized for integrating data, managing construction, and facilitating dynamic interactions among multiple sources in construction projects. In response to these challenges and opportunities, we have developed a BIM-based multi-model framework designed to integrate and process multi-source heterogeneous data. This framework incorporates multiple Level of Detail (LoD) of TBM machinery, three-dimensional (3D) geological models and numerical analysis models. A non-intrusive TBM-GEO dynamic interaction method is proposed to efficiently analyze adjacent geological information in real time based on the TBM's spatial position. Additionally, a new BIM-to-Thrust analysis method is incorporated to achieve an automated workflow from BIM-based multi-model of shield tunneling to real-time thrust calculations. This method is applicable to both Mixshield and Earth Pressure Balance (EPB) shield projects. To validate this framework, two actual projects involving mixed ground conditions, confined water, and large curved tunnels are presented, and the results show that the efficiency and accuracy has been greatly enhanced in the analysis of shield thrust. The maximum average time for each analysis of these two case studies is approximately seven seconds. Additionally, comparisons with actual engineering data reveal that the average time for each simulation ring is significantly shorter than the average construction time per ring, confirming that the proposed analysis method meets the

关键词： Tunnel boring machine   Cutter wear   Reinforcement learning   Predictive maintenance   WEAR   PREDICTION   MODEL  

摘要： Optimizing the cutter changing process for tunnel boring machines (TBMs) is crucial for minimizing maintenance costs and maximizing excavation efficiency. This paper introduces TunnRL-CC, a computational framework that utilizes reinforcement learning to autonomously determine cutter-changing strategies. TunnRL-CC's realistic simulation models cutter wear under varying rock conditions, including hard rock and blockyness. A reinforcement learning agent is trained to learn optimal cutter-changing policies based on a reward function that balances cutter conditions and operational costs. The agent demonstrates innovative decision-making, adapting to changing excavation conditions. TunnRL-CC's proposed methodology significantly differs from traditional cutter changing practices, which rely heavily on operator experience. Although TunnRL-CC has not been applied in practical projects, its theoretical basis and comprehensive computational experiments demonstrate its capability to significantly improve TBM cutter maintenance procedures.

关键词： Tunnel boring machine   Disc cutter ring   Microstructure characteristic   Mixed fracture   Impact fracture mechanism   PREDICTION MODEL   WEAR   MICROSTRUCTURE   EVOLUTION  

摘要： The fracture of the disc cutting ring significantly impedes the efficiency of TBM. This phenomenon is particularly obvious in geological conditions with high impact loads, such as fracture zones and extremely hard rock areas. In these environments, the incidence of disc cutter ring fracture failure escalates dramatically. To explore the impact fracture failure causes and mechanisms of the disc cutter ring under high impact loads, and to guide the improvement of cutter ring manufacturing process, an in-depth analysis was conducted. The chemical composition, tensile strength, hardness, impact toughness, structure morphology and impact specimen fracture morphology of the cutter ring from a TBM project were measured and analyzed. The results show that the tensile strength point of the disc cutter ring coincides with the fracture point, demonstrating that the ring has an extremely strong brittleness. The impact toughness of the surface of the disc cutter ring is lower than that of the inside, and cracks are easy to start on the surface of the disc cutter ring. According to the microstructure analysis, there are coarse Al-rich inclusions precipitated between grains, accompanied by microcracks and microvoids, which reduce the mechanical properties of the disc cutter ring. Through the fracture morphology analysis, the type of the disc cutter ring impact fracture is a mixture of quasi-cleavage, cleavage and intergranular. When a very high impact load is applied, cracks first nucleate at hard points such as coarse carbides, Al-rich inclusions and voids, and then the main crack propagates in a tortuous manner parallel to the force direction.

关键词： Multi-source seismic geological ahead-prospecting   TBM tunneling   TBM selection   Fractured strata   TBM blockage   ZONES   EXCAVATION  

摘要： The Tunnel Boring Machine has inherent limitations in adapting to adverse geological conditions. When operating in complex strata, encounters with challenging geological formations such as faults and fractured zones can result in tunnel collapses or TBM blockages. This article outlines the successful implementation of a multi-source seismic prospecting strategy designed to achieve advanced prediction of unfavorable geological bodies in a water conveyance project in Northwest China. Due to long-distance broken strata along the construction path, to ensure safety, a single shield TDM replaced the initial open type TBM for the starting section of TBM3-2. With the change in the tunnel environment prompted by the TBM modification, the conventional active source seismic prospecting method previously employed in the open type TBM section became unsuitable. Consequently, we adopted TBM drilling source seismic prospecting technology, refining the arrangement of geophones to capture high-quality seismic signals. Employing this strategy allowed for continuous seismic ahead prospecting across the entire tunnel, providing crucial data to guide safe TBM operation and tunnel support. The multi-source seismic exploration strategy has notably enhanced the TBM's capability to manage complex geological scenarios, such as long-distance fractured zones. This approach has been instrumental in bolstering risk warnings and minimizing TBM blockages, effectively addressing and resolving engineering challenges.

关键词： Disc cutter wear   Three-dimensional numerical   Rock fracture   Cutting force   Rock breaking efficiency   Tunnel Boring Machine (TBM)   TUNNEL BORING MACHINE   MODEL   FRAGMENTATION   PREDICTION   GRANITE   DESIGN   TESTS  

摘要： The inevitable wear and degradation of disc cutters during the rock-crushing process significantly impacts the efficacy, timeline, and cost-effectiveness of tunnel construction. Optimizing cutter arrangements and adjusting suitable excavation parameters are crucial to reducing cutter wear in Tunnel Boring Machine (TBM) operations. This study probes the interaction between disc cutters and rock, employing an enhanced Bonding model to more accurately depict the failure behavior of rock specimens. Numerical simulations of the rock-breaking process using two disc cutters were conducted, focusing on highly influential excavation parameters-penetration depth (3, 5, 7, 9 mm) and cutter arrangements-tip width (14, 17, 20, 23 mm) and cutter spacing (50, 65, 80, 95, 110 mm). These simulations analyzed the impact of various factors on cutter force, wear, specific energy of rock breaking, and crushing unit rock cutter wear. The results show that increased penetration depth leads to higher cutter force and wear, with specific energy and unit wear remaining low when penetration is less than 5 mm. A larger cutter tip width incurs higher forces and wear of the first cutter, but when the tip width exceeds 20 mm, the force and wear of the second cutter will be reduced. Optimal specific energy for rock breaking and unit wear of rock volume were identified within a cutter spacing range of 80 to 95 mm. These findings can facilitate the analysis of how excavation parameters and cutter arrangements affect wear behavior, offering superior construction recommendations.

关键词： Laser-induced groove   Indentation tests   Orthogonal experiment   TBM cutters   Optimal parameter combination   INDENTATION   PERFORATION   EFFICIENCY  

摘要： Tunnel boring machines (TBMs) have been increasingly applied in extreme regions such as "Three highs" (high confining pressure, high rock hardness and high quartz content), researchers have introduced laser technology to the TBM field to improve cutting efficiency. The aim of this study is to investigate the effect of laser power, laser moving speed, blade width, distance between the cutter and laser-induced groove (DCLG), and edge angle on rock breakage after coupling the laser with TBM cutter-head, and obtain the optimal combination of these parameters. Two sets of indentation tests were conducted: one with the assistance of laser-induced grooves (LG) based on a L18(37) orthogonal design table; the other was a controlled trial without the laser. The corrected indentation hardness index (CIHI), specific energy (SE) and penetration force were utilized as performance indicators to comprehensively evaluate the experimental results. Additionally, a new method proposed in this paper allowed for accurate measurement of the volume of rock debris, avoiding the difficulties associated with the traditional weighing method, which requires collecting rock fragments caused by rock bursts. Finally, variance analysis, range analysis, and comprehensive evaluation analysis were performed on the three performance indicators. Results show that LG can greatly reduce the penetration force of the cutter and improve cutting efficiency. The primary and secondary factors affecting the rock breaking performance of a laser-assisted cutter are: blade width, DCLG, laser moving speed, laser power and edge angle, and the optimal combination of rock-breaking parameters: The blade width is equal to 3 mm, the DCLG is equal to 5 mm, the laser moving speed is equal to 2 mm/s, the laser power is equal to 20 W, and the edge angle is equal to 12 degrees.

关键词： Rock-cutting   Soft-hard composite strata   Frictional heat theory   Radial thermal stress   Temperature field   Numerical simulation   TBM   ROCKS   TESTS   SOFT  

摘要： Composite strata consisting of hard and soft rock are common during shield cutter excavation. The friction cutting process generates a large amount of cutting heat, high temperature will produce thermal stresses and thermal expansion in the disc cutter ring, resulting in wear and deformation of the cutter, reducing its rock breaking performance. From the perspective of thermal force change in cutter, This study establishes the theory of frictional heat generation and the theory of thermal stress of elastomer to analyse the frictional heat generation and derive the thermal stress theory of elastomer model in cutter. Numerical simulations were carried out to analyse the thermal-force multi-field coupling process considering the influencing factors such as penetration, cutting time, rock strength, etc. Solve the heat conduction equation and radial temperature field distribution from the heat transfer perspective. The comparative study of theoretical analysis, numerical simulation and experimental values shows that the theoretical and numerical results of thermal stress and temperature field distributions are consistent, which verifies the reasonableness of the theoretical derivation and numerical model.

摘要： 8 月 23 日 至 24 日,2024 年中国大学生机械工程创新创意大赛——"北起院杯"物流技术(起重机)创意赛全国总决赛在大连理工大学顺利举办.本届大赛由中国机械工程学会主办,由大连理工大学、中国机械工程学会物流工程分会、辽宁重大装备制造协同创新中心、辽宁黄海实验室共同承办,由北京起重运输机械设计研究院有限公司独家冠名.

关键词： 复杂地质条件   地铁   盾构施工技术  

摘要： 地铁盾构施工是一种优质的地铁隧道施工技术,可以在保证稳定安全施工的前提下,提升施工效率与质量,而想要更好的完成复杂地质条件下地铁盾构施工,需要注意施工技术的合理分析.基于此,本文分析复杂地质条件下的地铁盾构施工,应该加强地质分析与预报,做好盾构装备制造与选型、管片生产技术控制、盾构掘进与管片拼装技术管控等工作,对施工周围环境进行有效分析,做好各类地层施工的方案规划,确保地铁盾构施工的可行性,保证地铁盾构施工的质量.