围岩与注浆层共同约束作用下风化地层管片受力研究

Study on Segment Stress in Weathered Stratum Under the Joint Constraint of Surrounding Rock and Grouting Layer

将注浆层视为厚壁圆筒结构,考虑注浆层呈上厚下薄状分布,推导了围岩与注浆层综合抗力系数的计算公式。以青岛地铁2号线海安路站—高雄路站TBM施工为例,通过数值模拟和现场试验分析注浆层与围岩共同约束作用下风化程度不同地层管片受力规律并验证该公式的准确性。结果表明:围岩风化程度不同,注浆层对管片所受地层约束作用的影响也不同,中风化花岗岩地层中注浆层会增强地层对管片的约束作用,微风化花岗岩地层中注浆层则会削弱地层对管片的约束作用;考虑注浆层对约束作用的影响时管片弯矩模拟计算值更接近现场实测值,验证了所推导的计算公式比较准确。为保障隧道支护结构的安全,管片设计时应考虑注浆层对约束作用的影响。

The grouting layer is regarded as a thick-walled cylinder structure.Considering that the grouting layer is thick at the top and thin at the bottom,the calculation formula of the comprehensive resistance coefficient of surrounding rock and grouting layer was deduced.Taking the TBM construction of Hai’an Road Station-Gaoxiong Road Station of Qingdao Metro Line 2 as an example,through numerical simulation and field test,the stress law of segments in different weathered stratum under the joint constraint of grouting layer and surrounding rock was analyzed,and the accuracy of the formula was verified.The results show that the influence of the grouting layer on the stratum constraint of the segment is different with the weathering degree of the surrounding rock.The grouting layer in the moderately weathered granite stratum will enhance the constraint of the stratum on the segment,and the grouting layer in the slightly weathered granite stratum will weaken the constraint of the stratum on the segment.Considering the influence of grouting layer on restraint,the simulated value of segment bending moment is closer to the field measured value,which verifies that the deduced calculation formula is more accurate.In order to ensure the safety of tunnel support structure,the influence of grouting layer on restraint effect should be considered in segment design.