00422495

open access

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ミソノ タテコウ コウジ ニオケル クッサク ジバン ノ シントウ ハカイ ニタイスル アンテイセイ

Stability for Seepage Failure of Excavated Soil within Misono Shaft

Japanese (日本語)

神戸大学都市安全研究センター研究報告

8

355-360

神戸大学都市安全研究センター

2004-03

2007-04-19

Misono Shaft was reported as an example of a starting shaft constructed for Neyagawa Nanbu Underground River in Osaka with a high ground water level, at the 3rd World Water Forum 2003 in Osaka. Here, we discussed the stability of the seepage failure of excavated soil within Misono Shaft. The analyses of seepage flow and seepage-failure stability revealed that: (1) Seepage flow was concentrated in the soil within the shaft and was directed upward one-dimensionally. (2) If it were not for countermeasures, the excavated soil within the shaft would exceed the critical state for seepage failure and collapse. Chemical grouting of a 3-rn thickness was conducted at the bottom part of the diaphragm wall,the stability of the seepage failure ofthe excavated soil increased, and the construction work was successful. (3) Without the chemical grouting, the penetration depth of the diaphragm wall of 22,2 m must he increased by 16.5 m, i.e., the required depth ofdiaphragm wall would be 38.7 m. (4) Analyses of the seepage-failure stability of soil excavated successfully provides useful suggestions for stability design of other similarly conditioned sites.

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