多变复合地层盾构隧道施工期管片上浮实测数据分析与量值预测  

Analysis of shield tunnel segment uplift data and uplift value forecast during tunnel construction in variable composite formation

作　　者：舒瑶[1] 周顺华[1] 季昌[1] 徐润泽 黄钟晖 

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海201804 [2]中国铁建大桥工程局集团有限公司,天津300300 [3]南宁轨道交通集团有限责任公司,广西南宁530029

出　　处：《岩石力学与工程学报》2017年第A01期3464-3474,共11页Chinese Journal of Rock Mechanics and Engineering

摘　　要：针对南宁地铁一多变复合地层盾构区间施工期管片上浮问题,对该区间施工期管片上浮实测数据按地层进行分区统计分析,分别得到粉砂–圆砾段、砂层段、泥岩–粉砂质泥岩段及粉质黏土段等典型地层区段上浮量值数学分布特征,而后研究了同步注浆压力、浆液配比及实际出渣量等施工因素对管片上浮的影响规律,并揭示各典型地层段隧道上浮的主要原因;进而在明确了隧道上浮主要影响因素的基础上,利用纵向等效连续梁模型对各典型地层区段管片上浮量值进行预测分析。研究表明:各典型地层区段上浮量值近似服从正态分布,均值主要为30~60 mm,地层特性及隧道埋深对隧道上浮有重要影响,隧道穿越砂层段上浮量值较小,穿越圆砾、泥岩及粉质泥岩等地层较大;同步注浆浆液配比及注浆压力是影响隧道上浮的主要施工因素,另超挖使砂砾石地层受扰失稳也将导致较大上浮,泥岩层中更是因超挖扰动隧道上覆砂砾层,进一步加剧了浆液压力、泥岩膨胀力及"背土"效应对隧道的上挤力等因素对隧道的起浮作用;等效梁模型的上浮量计算结果与现场实测数据具有较好一致性,可利用其与既有现场反馈的实测数据结合预测上浮及检验施工参数的合理性,从而指导盾构施工。Aiming at the problem of shield tunnel segment uplift during tunnel construction in variable composite formation of Nanning Metro, a sectional statistical analysis on the measured uplift data of a metro shield tunnel is performed and the mathematical distribution characteristics of the uplift value for the typical stratigraphic sections of silty sand-gravel, sand, mudstone-silty mudstone and silty clay are obtained respectively. Then the ruler for the main uplift factors such as the grouting pressure, grout proportion and the actual slag discharge is investigated and the cause of segment uplift in the typical stratigraphic sections is revealed. Then based on the known main factors that influence the tunnel uplift, the longitudinal equivalent continuous beam model is applied to predict and analyze the segment uplift. The results show that the uplift value for the typical stratigraphic section follows normal distribution approximately with respective mean mainly in 30- 60 mm. Formation characteristics and tunnel depth have important influence on segment uplift. The uplift value for sand is smaller, while that for silty sand-gravel, mudstone-silty mudstone and silty clay is larger. Synchronous grouting grout proportion and grouting pressure are the main construction factors affecting the tunnel uplift. The stability for sand and gravel stratum is disturbed by over-excavation and large uplift is caused. The overlying gravel is disturbed by over-excavation in mudstones, further exacerbating the influence for the grout pressure, swelling force and squeezing force to tunnel of ＂earth-carrying＂ effect on the segment uplift. The results of the equivalent beam model and the field measured data match well and the suggestion of using the model with existing data feedback from field to predict the value of uplift and test construction parameters and measures so as to guide the determination and adjustment of shield construction in the field is proposed.

关 键 词：隧道工程 管片上浮 多变复合地层 施工参数 同步注浆 

分 类 号：U45[建筑科学—桥梁与隧道工程]