废弃岩渣壁后注浆体固结时变性及对地层沉降影响研究——以南京和燕路过江通道盾构隧道工程为例

Time-Varying Consolidation of Grout Prepared by Waste Rock Slag for Grouting Behind Lining and Its Influence on Ground Settlement:A Case Study of Heyan Road Yangtze River-Crossing Shield Tunnel in Nanjing,China

为研究废弃岩渣替换商品砂配制的壁后注浆体(岩渣-硬性浆)固结后性质的时变规律及其对地层沉降的影响,采用自制的固结装置进行固结试验,测定浆体弹性模量等性质的时变规律,并采用FLAC3D数值模拟,研究岩渣-硬性浆对地层沉降的影响规律。结果表明:1)岩渣-硬性浆固结完成后,浆体性质发展迅速,起始弹性模量为1~1.4 MPa,3 d后已达到120~160 MPa,相较于刚固结完成时其内摩擦角增长21.8%,黏聚力增长4~5倍;2)相比于普通硬性浆,使用岩渣-硬性浆进行壁后注浆能够有效降低地层沉降,最终沉降值降幅为20%左右,但浆体的固结性质差异基本不会改变地层沉降横向影响范围;3)对比沉降模拟结果与现场实测数据发现,采用固结试验所得的岩渣-硬性浆时变性参数进行地层沉降模拟,可较为准确地反映岩渣-硬性浆填充引起的地层沉降规律,进一步验证了岩渣-硬性浆对地层沉降的控制效果。

To investigate the time-varying pattern of the properties of grout body(rock slag-hard slurry)prepared by replacing commercial sand with waste rock slag for grouting behind lining and its influence on ground settlement,a consolidation test is conducted using a self-made consolidation device.Thus,the time-varying pattern of properties,such as elastic modulus of slurry,is determined.The FLAC3D finite element numerical simulation is performed for the influence of rock slag-hard slurry on ground settlement.The results reveal the following:(1)Once the consolidation of rock slag-hard slurry is completed,the properties of the slurry undergo rapid development.The initial elastic modulus is in the range of 1-1.4 MPa and reaches 120-160 MPa after 3 d.The internal friction angle and cohesion increase by 21.8%and become 4-5 times compared to corresponding values when the consolidation is completed.(2)Compared with conventional hard slurry,the rock slag-hard slurry used for grouting behind lining effectively reduces ground settlement with a maximum reduction of 20%.The difference in the properties of the slurry after consolidation does not change the lateral influence range of ground settlement.(3)Field measurement data reveal that the simulation results can accurately reflect the ground settlement pattern induced by grouting behind lining using rock slag-hard slurry,confirming the effectiveness of rock slag-hard slurry in controlling ground settlement.