Tunnel Boring Machine performance in basalts of the Lesotho Formation

✍ Scribed by A. Boniface

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 507 KB
• Volume: 15
• Category: Article
• ISSN: 0886-7798
• DOI: 10.1016/s0886-7798(00)00028-6

✦ Synopsis

The paper reviews the pre-tender estimates and actual performances of three Tunnel Boring Machines (TBMs) used to excavate the 45-kin-long Transfer Tunnel for Phase 1A of the Lesotho Highlands Water Project. The pre-tender estimates were to a large extent based on the results of investigations into the boreability of the basalts of the Lesotho Formation. These investigations included making use of small scale laboratory tests and the prediction model developed by the Norwegian Technical and Natural Sciences University in Trondheim. The pre-tender studies also included full-scale linear cutting tests done at the Colorado School of Mines. The actual performance of the machines exceeded the pre-tender and tender stage predictions.