EXCVATION OF A LARGE CROSS-SECTION TUNNEL IN SOFT GROUND AT LARGE OVERBURDEN

Hida tunnel (10.7km in length) is being constructed in soft ground at the overburden of 250m by means of NATM. Since the initial displacement of the tunnel convergence became large at the excavation of the upper half heading, the temporary invert by shotcreting was applied at the excavations of uppe...

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Bibliographic Details
Published inPROCEEDINGS OF TUNNEL ENGINEERING, JSCE Vol. 12; pp. 327 - 332
Main Authors EBINE, Masakazu, KAWAKITA, Masatsugu, YAMAZAKI, Tetsuya, KOBAYASHI, Shinji, TANI, Takuya
Format Journal Article
LanguageEnglish
Japanese
Published Japan Society of Civil Engineers 2002
公益社団法人 土木学会
Subjects
convergence
large cross-section tunnel
large overburden
NATM
soft ground
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ISSN1884-9091
DOI10.11532/journalte1991.12.327

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Summary:Hida tunnel (10.7km in length) is being constructed in soft ground at the overburden of 250m by means of NATM. Since the initial displacement of the tunnel convergence became large at the excavation of the upper half heading, the temporary invert by shotcreting was applied at the excavations of upper heading and first bench. Nevertheless, it was predicted that the convergence would exceed the prescribed limit by the excavation of the second bench. Hence, each of the second bench and invert were excavated in three divisions, viz. both sides and center, so as to provide the earliest ring closure of the tunnel support with shotcrete. This method successfully enabled us to reduce the convergence down to about 40% of the prescribed criterion.
ISSN:1884-9091
DOI:10.11532/journalte1991.12.327