doi:10.3850/GI127

ABSTRACT

The artificial ground freezing combined with jet grouting was used for shield tunnel launching and arriving of Taipei MRT Project in consideration of risk mitigation measurement. A 40 m depth working shaft was constructed under the riverbed and riverbank in Taipei Silt Formation, Ground freezing associated with jet grouting was carried out outside the shaft to form shelters of 6 tunnel eye’s launching and arriving faces. The ground treatment was proven to be successful to prevent the seepage under the great hydraulic gradients. Frozen soil was modeled and analyzed with 2-D FEM numerical approach to solve the highly complex geothermal problems. Real earth temperature, moisture content and freeze pipes geometric layout were taken into consideration and simulated. Temperature field and cooling capacity were predicted for safety and economic issues. Measured temperature data from thermometric pipes were monitored to estimate the frozen range and feed back analysis. The correlation between numerical analysis results and monitoring data are presented on this engineering practice article.

Keywords: Artificial ground freezing; shield tunnel; hydraulic geology; geothermal.

© 2010 by Geotechnical Society of Singapore (GeoSS)