盾构管片上浮量理论计算模型及上浮控制措施研究

Research on theoretical calculation model of shield segments floating amount and floating control measures

盾构管片上浮会导致管片错台、破损,降低隧道的整体结构强度、防水性能及使用寿命。在建立管片受力模型的基础上,通过分析管片的受力状态建立了管片上浮的理论计算模型。以北京地铁新机场线3号风井至草桥站盾构区间为背景,对该区间管片异常上浮的原因进行了分析,通过改良同步注浆浆液性能有效地控制了管片的上浮量,并对改进前后的浆液特性进行了试验,最后基于浆液试验结果和理论计算模型对管片上浮量进行了计算。研究结果表明:管片上浮量的理论计算结果与实测值较为吻合,本文的理论计算模型具有较好的准确性;管片在脱出盾尾后的短时间内会大量上浮,缩短浆液初凝时间、提高其早期强度是控制管片上浮的有效措施。

The floating of the shield segment will cause the segment to be misaligned and damaged,reducing the overall structural strength,waterproof performance and service life of the tunnel.On the basis of establishing the force model of the segments,by analyzing the force state of the segments,a theoretical calculation model of the segments floating is established.Taking the shield tunneling section ventilation shaft No.3-Caoqiao Station of Beijing Metro’s New Airport Line as the engineering background,the abnormal rise of the segment was analyzed.By improving the performance of the synchronous grouting slurry,the floating amount of the tube segment was effectively controlled.And the slurry characteristics before and after the improvement were tested.Finally,based on the results of the slurry test and the theoretical calculation model,the floating volume of the tube segment was calculated.The results show that the theoretical calculation result of segment floating volume is consistent with the actual measured value.The theoretical calculation model in this paper has good accuracy.The segments float up a lot in a short time after it is released from the shield tail.Shortening the setting time of the slurry and improving its early strength are effective measures to control the floatation of the segments.