Title: Application of Fiber-Reinforced Shotcrete in Repair of Tunnel Linings in Hong Kong

Author(s): A. P.-C. Sze and C. T.-W. Chan

Publication: Symposium Paper

Volume: 193

Issue:

Appears on pages(s): 63-78

Keywords: fiber-reinforced concrete; shotcrete; tunnel lining

DOI: 10.14359/5813

Date: 8/1/2000

Abstract:
The Hong Kong Mass Transit Railway Corporation, carrying a daily patronage of over 2 million, has a prime objective of providing a safe and reliable railway transportation system to the public in Hong Kong. The existing Urban Line System is situated mostly underground through soft, marine deposits and/or rock. The aggressive underground conditions in the coastal regions had resulted in various degrees of deterioration to the tunnel linings in a period less than 10 years from completion. The problem was most serious where precast concrete (PCC) lining was adopted because of the existence of segmental joints. A special method of repair was jointly developed by MTRC and Skanska International Civil Engineering AB. A robotic high pressure water jet system (hydrodemolition) is used to remove the surface delaminated concrete, and the surface repaired with a 75 mm layer of low permeability, fibre (polypropylene) reinforced shotcrete. Repair has to be implemented in the short time window during non traffic-hours each night with absolutely no disruption to the daily traffic.