黄土地区地铁隧道不同湿陷变形方式模型试验系统的研制及应用研究

Development and Application Research of a Model Test of Different Collapsible Deformation Modes of a Metro Tunnel in the Loess Area

为研究不同湿陷变形方式下黄土地区地铁隧道周围土体的沉降量变化规律,研制出一种测量黄土在均匀湿陷、不均匀湿陷时沉降量的模型试验装置。该装置由模型箱、流速控制系统和沉降量测量系统组成。通过室内模型试验对黄土在遇水后的湿陷变形规律进行总结,并对黄土地层在两种不同浸水方式下隧道围岩土体的变形规律进行分析。试验结果表明:不均匀湿陷最终累计沉降量大于均匀湿陷最终累计沉降量,说明不均匀湿陷对地铁结构物的危害更大;两种湿陷变形方式均为隧道中线附近沉降最大,因此,施工时应该重点加强隧道中线的位移监测。通过室内模型试验,分析了均匀与不均匀湿陷对黄土地铁隧道变形影响,研究结果对湿陷性黄土地区地铁隧道建设中施工把控及灾害规避具有重要意义。

In order to study the settlement laws of soil mass around the metro tunnel in loess area with different pat terns of deformations caused by collapse,a model test device,which consists of a model box,a flow rate control sys tem and a settlement measurement system,is developed to measure loess settlements under even and uneven col lapse modes.The collapse induced deformation of loess upon encountering water is summarized by indoor test,and the deformation law of tunnel surrounding rocks in loess area under two different submerging modes is analyzed.The experiment results show that the final accumulated settlements under uneven collapse is greater than that under even collapse,it means the uneven collapse causes more damages to the metro tunnel;the settlements near tunnel center line are the largest under the two types of collapse induced deformations,therefore,the monitoring of dis placement at central line should be emphasized during construction.The influence of even and uneven collapse on the deformation of metro tunnel is analyzed by indoor model test.The research results are of great significance to the construction control and disaster avoidance during the tunnel construction in loess area.