膨胀岩土地层盾构隧道管片结构荷载及内力特征  

Structural Load and Internal Force Characteristics of Shield Tunnel Segment in Expansive Rock and Soil Strata

作　　者：方勇[1] 符亚鹏[1] 齐春[1] 何川[1] 

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,四川成都610031

出　　处：《中国铁道科学》2014年第3期56-63,共8页China Railway Science

基　　金：国家自然科学基金资助项目(51278422);国家科技支撑计划课题(2012BAG05B03);四川省青年科技基金资助项目(2012JQ0021);中央高校专项资金资助项目(SWJTU11ZT33)

摘　　要：选取成都地铁2号线ZCK40+805.8隧道断面为目标断面,在管片上布设土压力盒、水压力计和混凝土应变计,对具有弱膨胀性的强—中风化泥岩地层盾构隧道施工过程中管片结构的荷载及内力特征进行跟踪测试。分析测试数据可知:脱环初期管片结构水压力变化较大,在管片拼装60环后,水压力开始缓慢增加,隧道贯通后的最终水压力低于理论静水压力;管片结构土压力的实测值小于理论值,它反映了注浆层、地层水土压力等因素对结构主体的共同作用;管片结构内力的稳定需要时间较长,最大内力值出现在隧道贯通后。管片结构内力的实测值与理论计算值的对比分析表明,在该地层中应用荷载—结构模型进行管片结构内力分析时,若采用水土合算方法计算荷载,无须考虑地层膨胀力的作用。Target section at ZCK40＋805.8 on Chengdu Metro line 2 was selected to be embedded with soil pressure cells,water pressure gauges and concrete strain gauges.Field test of segment structure load and internal force characteristics was carried out for shield tunnel construction in strong-intermediary weathered mudstone stratum with weak expansibility.Field test results show that the change of water pressure on the segment was greater in early stage after having been pushed out from shield tail.After 60 segment rings had been arranged,water pressure increased slowly.When shield tunnel construction finished,water pressure tested was less than theoretical hydrostatic pressure.Earth pressure tested on the segment was less than theoretical value too,which reflected the combined actions of grouting layer,soil and water pressure on the structure.It took long time for the stability of segment structure internal force and its maximum value came when the construction was finished.The segment structure internal force of analysis was compared with that of field test.The results show that in this kind of stratum,when load-structure model is used to compute the internal force of segment structure,if the earth pressure is estimated by soil-water joint calculation method,the swelling force of the ground may not be considered.

关 键 词：膨胀岩土 盾构隧道 荷载-结构模型 荷载 内力 

分 类 号：U451.4[建筑科学—桥梁与隧道工程]