Principle and application of instrumentation for the first MRTA subway project in Bangkok

摘要

The blue line subway of the Metropolitan Rapid Transit Authority (MRTA) is the first subway project in Bangkok. It is about 20km long dual tunnels with 18 subway stations. Construction has been started since mid of 1997. An extensive instrumentation was set up as a safety control not only during construction, but also for the future work. This paper briefly describes the principle and application of instrumentation for the MRTA project. An analysis on data from instrumented load tests was carried out to verify the design of pile capacity and instrumentation results from subway station excavation and tunneling were back analysed to study the soil-structure behavior. The surface ground loss, layering ground deformation and lateral soil displacement during tunneling were recorded and back analyzed by means of FEM method. The lateral movements of subway station walls during basement excavation were also measured and back analyzed. The results of FEM analysis agree with field measurements. This paper proposes the appropriate soil stiffness in terms of strain order for excavations with diaphragm wall in Bangkok subsoils.