ABSTRACT
This paper aims to explain about operation control of Earth Pressure Balanced Shield in tunnelling, focus to the principal of soil face pressure maintenance at shield face during shield advancing as correctly in soil mechanics. Determine important of face pressure monitoring and evaluate face stability in real time by empirical method while shield tunneling. Adjusting the other parameters such as screw conveyor speed, shield jack speed and soil excavation volume related to the changing of face pressure by presenting in simple chart and grout filling control correctly. However, to explain factors affect general problems during shield tunneling as type of excavation mode, airlift effect in borehole, amount and position for injected soil conditioning, assessment condition of soil excavation discharged from screw conveyor and grout leakage into shield to improve these procedures before or during tunneling in Bangkok subsoils by case study of MRT Blue Line Extension project, Thailand. This study is guideline in shield tunneling efficiency for another tunnel works and underground project in the future to reduce ground loss which causes minimum building damage on ground.
