摘要
为研究地铁隧道穿越砂土地层区围岩竖向变形的问题,依托青岛地铁3号线河西-河东区间工程,采用FLAC 3D数值计算软件,选取预留核心土、上下台阶开挖、预注浆等6种工况,分别计算围岩稳定性及变形情况。计算结果表明:开挖前不注浆与注浆加固时,上下台阶预留核心土工况的最大竖向位移较上下台阶工况分别降低18.15%、39.24%;开挖上下台阶与开挖上下台阶预留核心土时,注浆工况的最大竖向位移较不注浆工况分别降低33.56%、50.69%。根据计算结果进行现场预注浆试验,优化选择预注浆、留核心土及上下台阶开挖方案,注浆压力为1.0~1.5 MPa。试验研究表明:注浆加固后围岩的强度指标提高了30%~50%,现场实测拱顶最大沉降为42.90 mm,较好地控制了地铁隧道穿越砂土地层区产生的变形。
In order to study the vertical deformation of crossing the surrounding rock in the sandy layer area of the subway tunnel,relying on the project of the Hexi-Hedong section of Qingdao Metro Line 3,the numerical calculation software FLAC 3D is used to select 6 working conditions,such as reserved core soil,excavation of the upper and lower steps,pre-grouting and so on to calculate the stability and deformation of the surrounding rock respectively.The calculation results show as follows.When there are no grouting and grouting with reinforcement before excavation,the maximum vertical displacement can be reduced respectively by 18.15%and 39.24%under the condition of reserved core soil of upper and lower steps compared with that of upper and lower steps;When excavating the upper and lower steps and the reserved core soil of the upper and lower steps,the maximum vertical displacement under the grouting condition is 33.56%and 50.69%respectively lower than that under no grouting condition.According to the calculation results,the on-site pre-grouting test is carried out,and the selection of the pre-grouting,reserved core soil and excavation scheme of the upper and lower steps is optimized,and the grouting pressure is 1.0~1.5 MPa.The experimental results show that the strength index of the surrounding rock after the grouting reinforcement is increased by 30%to 50%,and the maximum settlement of the vault measured on site is 42.90 mm,which can control the deformation caused by crossing the sandy layer area of the subway tunnel.
作者
闫茂旺
YAN Maowang(Shandong Hi-speed Construction Management Group Co.,Ltd.,Jinan 250000,China)
出处
《山东交通学院学报》
CAS
2020年第4期79-84,共6页
Journal of Shandong Jiaotong University
关键词
砂土地层
地铁隧道
数值模拟
核心土
围岩稳定性
预注浆试验
sandy layer
metro tunnel
numerical simulation
core soil
surrounding rock stability
pre-grouting test
