Innovative Construction Methods
doi:10.3850/978-981-07-0188-8_P094
Tunnel Squat due to Surcharge in Soft Soil and Visualization Monitoring Conception with LEDS
Qi Liu1,2, Dongmei Zhang1,2 and Hongwei Huang1,2
1MOE Laboratory of Geotechnical and Underground Engineering,
Tongji University, Shanghai, China
2Department of Geotechnical Engineering, Tongji University,
Shanghai, China
ABSTRACT
Surcharge can cause transverse deformation on shield tunnel in soft soil, which results in a series of problems like joint opening, bolts stress increase, concrete partial crush and juncture leakage. However, it’s hard to monitor the tunnel structure performance like joint opening, bolt stress and concrete stress under operation tunnel, but the measurement of transverse deformation is much easy. In the practice, transverse deformation is always measured to evaluate the effect of surcharge. This study is to investigate the relationship between tunnel transverse deformation and joint opening, bolt stress and concrete local stress development, set up transverse deformation controlling value of each stage according to tunnel structure performance. In order to monitor transverse development real-time, LEDS monitoring system is introduced, the warning value of which is set according to the controlling value of each transverse deformation stage. The development of transverse deformations can be presented by the changing light color of LED. The feasibility of this system has been verified by the laboratory testing.
Keywords: Shield tunnel in soft soil, Transverse deformation, Concrete partial crush, Bolt stress, Juncture open.
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