深孔注浆条件下地铁施工地层位移预测研究

以北京地铁7号线工程为研究背景,首先,利用现场实测数据对深孔注浆预加固条件下,地铁暗挖施工引起地表沉降特性及其地层损失率、沉降槽宽度系数进行了反演分析。其次对注浆加固圈厚度、加固圈等效变形模量、洞室开挖面积、开挖面地层加权变形模量、上覆土厚度、上覆土加权变形模量等参数对深孔注浆条件下地层变形的影响情况进行了因素分析,并在此基础上,提出了深孔注浆预加固条件下Peck理论方法关键参数的预测方法。另外,采用室内试验、数值试验以及理论研究相结合的方法,对深孔注浆复合体的变形和强度特性进行了系统分析,提出了注浆加固复合体等效压缩模量的数学模型,建立了注浆复合体数值计算模型参数的确定方法。以上工作可以为获得可靠的地表变形预测提供方法基础,同时可以为深孔注浆设计优化提供借鉴。

Study on Stratum Displacement Prediction Method Inducedby Metro Construction under Deep Hole Grouting Condition

The Beijing Metro Line 7 project was researched. First, by using the field measured data, including the ground subsidence characteristics, the stratum loss rate and the width coefficient of the subway underground construction under the condition of pre-reinforcement by deep-hole grouting were inversely analyzed. Second, the influence factor analysis of grouting reinforcement thickness, equivalent deformation modulus of reinforcement ring, excavation area, weighted deformation modulus of excavation surface stratum, overlying soil thickness, weighted deformation modulus of overlying soil on deformation control under deep-hole grouting were carried out. The prediction method for key parameters of Peck theory under deep hole grouting pre-reinforcement condition was proposed. In addition, the deformation and strength characteristics of deep-hole grouting composite were systematically analyzed using laboratory test, numerical test and theoretical research. The model of equivalent compressive modulus of grouting reinforced composite was presented, and the numerical calculation model parameters valuation scheme of grouting composite was established. The reliable basis for predicting surface deformation and the reference for optimization of deep-hole grouting design can be provided.