摘要
回填层作为管片与围岩之间的传力层对管片受力有着重要的影响,而现行护盾式TBM隧道设计方法均忽略了回填层的影响,与工程实际存在一定的差异。研究考虑了护盾式TBM隧道中回填层的实际分布,推导了回填层-围岩等效抗力系数计算公式,并以此建立了TBM隧道管片结构设计模型。研究得出：由于回填层的存在,围岩-回填层的等效抗力系数与围岩抗力系数存在一定的差别,围岩抗力系数的改变程度与围岩、回填层力学参数比有关;回填层在管片背后分布呈＂上厚下薄＂状,使得管片背后围岩-回填层弹性抗力系数分布不同,Ⅱ级围岩回填层-围岩弹性抗力系数呈＂上小下大＂的鸭蛋状,Ⅲ,Ⅳ级围岩近乎圆状,Ⅴ级围岩呈＂上大下小＂的倒鸭蛋状;基于回填层-围岩等效抗力系数的结构设计模型计算出的管片受力结果与现场试验值更加接近,验证了回填层-围岩等效抗力系数计算方法和设计模型的准确性。
As the transmission layer between segments and surrounding rock, the backfill layer has important influence on the mechanical characteristics of segments. However, the current design method for shield TBM neglects the influence of the backfill layer, and has differences from the engineering practice. According to the actual distribution of backfill in shield TBM tunnel, the formula for calculating backfill layer and ground reaction coefficient is deduced, and the design model for segment structures is established. It is concluded that due to the existence of the backfill layer, the equivalent resistance coefficient of the surrounding rock and backfill layer is different from that of the surrounding rock. The change degree of the resistance coefficient is related to the mechanical parameters of the surrounding rock and the backfill. Because the backfill behind the segments is thick at upper part and thin at lower part, the distribution of resistance coefficient is different. The distribution of resistance coefficient in rock grade II is small at upper part and large at lower part like a duck egg. The resistance coefficient in rock is grade III and IV, close to be uniform. The resistance coefficient in rock grade V is large at upper part and small at lower part like an inverted duck egg. The calculated results of the segmental force based on the structural design model for backfill are closer to the field test values, and the proposed method for the equivalent resistance coefficient and the design model are verified.
作者
吴圣智
姜志毅
王明年
刘大刚
董宇苍
WU Sheng-zhi;JIANG Zhi-yi;WANG Ming-nian;LIU Da-gang;DONG Yu-cang(School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China;Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2018年第5期857-863,共7页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51208434)
重庆市应用开发计划重点项目(cstc2014yykf B30003)
关键词
管片
围岩
回填层
抗力系数
结构设计模型
segment
surrounding rock
backfill layer
resistance coefficient
structural design model
