A computer-aided tunneling system (CATS) aids in planning and building an urban underground reservoir project

Abstract The Hirano River underground stormwater detention reservoir was planned as a first phase of an ambitious municipal plan to prevent flooding in the southeastern district of Osaka, Japan. The reservoir has been under construction since 1981. The concept involved in the design of the reservoir is stormwater detention through temporary storage of rainwater during heavy rainfalls in order to prevent flooding in the vicinity. The underground reservoir is a 1880-m-long tunnel with a storage capacity of 140,000 m 3 and a finished diameter of 10 m. The tunnel is being bored by the world's largest slurry shield (11.22-m boring diameter). This paper is primarily concerned with Phase I tunnel construction, in which the latest computer monitoring and data processing technology CATS (Computer-Aided Tunneling System) was applied to provide complete environmental protection. Some aspects of project planning are also discussed. The Phase I tunnel reservoir construction was completed on schedule, in time to prevent possible flooding of the area by intercepting 29,000 m 3 (approx. 29 million l) of stormwater in 40 min when a heavy rainfall poured down on July 21, 1986.