LAUSR

Construction of underground tunnel for highway in the urban area is a challenge to overcome many problems such as subsidence of residential houses and commercial buildings, broken of utilities lines, and vibrating and noise due to rock blasting. This paper presents the analysis of stability of 5.6 km long underground tunnel both partially completed tunnel and planed tunnel section, and the cause of tunnel collapse due to sinkhole. Several methods applied to analyze the stability of tunnel by the monitoring the instrumented data; settlement of ground, ground water level, and lateral and vertical displacement of internal face of tunnel. Soil investigation was also conducted to identify the exact soil layer characteristics and strength of soil and rock, and stratification of soil ground. The rock core was obtained and evaluated for the specimens from the 50 m long horizontal pre-boring process. The numerical analysis was carried out for the stability of tunnel in terms of internal displacement of tunnel, shotcrete bending compressive stress, and rock bolt axial force. GPR survey was also conducted for detection of sinkhole along the route of underground highways.