TBM adaptability analysis in small radius curve tunneling in Kurkar stratum in Israel

Abstract

For shield tunneling, both alignment and geological conditions not only influence the performance of the tunnel boring machine (TBM) but also relate to the disturbance to the strata. This paper proposes a targeted TBM design for small-radius curved tunnels in the Kurkar stratum and analyzes the adaptability of the TBM. Based on the analysis of the challenges posed by alignment and geological conditions, a targeted design was implemented for the TBM. The adaptability of the TBM is verified through a comprehensive analysis of strata disturbance, variations in boring parameters, tunnel alignment, and cutter wear. The results indicate that to accommodate small-radius curves, the TBM can be adapted by shortening the shield length, setting articulation cylinders, and configuring overcutting tools. To adapt to the Kurkar stratum, foaming agent CLBF 5/M with a ratio of 2.5‰ can be added, along with appropriately increasing the soil chamber pressure. TBM parameters can be set as follows: total thrust 20000-24000 kN, cutterhead rotation speed 1.3-1.4 r/min, TBM advance rate reaching 30-45 mm/min, and cutterhead torque ranging from 2500-3500 kN•m. Double-disc cutters should be avoided in the Kurkar stratum, especially in central regions of cutterhead.