基于盾构掘进参数分析的隧道围岩模糊判别

以重庆主城越江排水隧道工程的地层条件为背景,基于施工现场盾构掘进试验,运用模糊数学方法,对盾构掘进过程中隧道围岩状况判别的理论和方法进行了研究。结合盾构掘进的特点和刀盘切割岩石的基本原理,提出了比推力和比扭矩的概念,建立了不同围岩条件下的比推力(SF)和比扭矩(ST)模糊集合,探讨和揭示了刀盘比推力和比扭矩的关系,刀盘推力、扭矩及切深与地质条件的相关性及与不同围岩状况、盾构掘进状态的对应关系。研究表明,若比推力与比扭矩以较高的水平同步、均匀变化,说明盾构在较硬的均匀地层中掘进;若比推力与比扭矩均较小且同步、均匀变化,说明盾构在较软的均匀地层中掘进;若比推力与比扭矩的变化出现比例异常,则暗示盾构正在穿越断层破碎地段或遇到障碍物或盾构姿态不良等。该方法减少了盾构在此类地层下掘进的盲目性和停机次数,提高了掘进效率和施工安全度,可用于盾构隧道施工围岩状况的适时、定性判别。

Fuzzy identification of surrounding rock conditions based on analysis of shield tunneling data

Considering the stratums surrounding the Chongqing Yangtze River tunnel, using field tests and fuzzy theory, the method to distinguish the surrounding rock conditions for shield tunneling are studied. Conceptions of specific thrust force (SF) and specific torque (ST) are presented, and fuzzy sets of SF and ST are established. The relationships between SF and ST, shield performance and the geology are studied. The results indicate that shield tunneling parameters may be significantly influenced by rock conditions. Synchronous and homogeneous variations of SF and ST at high level indicate that the shield is driving through homogeneous and hard rock; if SF and ST vary synchronously and homogeneously at low level, it is an indication that the shield is driving in homogeneous and soft rock; and if the ratio of SF to ST varies abnormally, the shield may be obstructed by fault or fractured zones or poor shield attitudes. The proposed method may reduce the blindness and increase the efficiency of shield driving.