Construction Monitoring Measurement And Analysis On Shallow-covered Slope Section Of Huolangyu Tunnel

The excavation technology of the shallow-buried bias tunnel is still a hotissue in the exploration of tunnel engineering. Based on the constructionmonitoring of the tunnel and the analysis of the finite element, this paper takingthe construction of the Huo Langyu tunnel in the reconstruction project ofMixing road in Beijing as an example, the characteristics of the stress and thedeformation of the surrounding rocks and the support structure weresystematically studied during the excavation of the shallow-buried bias tunnel.Based on the field monitoring and measurement, the change regularities ofthe pressure of the surrounding rock, the stress of the spray concrete, the stressof the steel frame, the axial forces of the anchor and the convergence ofclearance were researched. The results of the monitoring measurement indicatethat under the shallow-buried bias geological conditions, spray concrete and thesteel arch frame are the main stress structures, especially the section steel frame,which plays a major role in the primary support.Combine the results of the field monitoring and measurement, and use thefinite element analysis software MIDAS/GTS, the stress of the surrounding rock structure and the stress of the primary support structure were calculated, thesafety of the surrounding rock structure and the primary support structure weretheoretically comprehensive evaluated. The analysis results show that after thecompletion of tunnel excavation, a clear plastic zone has appeared at the leftarch foot and the right spandrel, at the depth1.5m to2.0m. Therefore, it is verynecessary to strengthen the monitoring and measurement of the surroundingrock structure at the zone during the construction process, and the secondarylining construction should be done in time.The research results for the tunnels which are under the similar geologicalconditions have guiding role for tunnel design, construction and post-monitoring,and the results also have an important reference value to avoid tunnel accidents.