METHOD OF SAND BOILING-PREVENTIVE CONSTRUCTION IN EXCAVATION WORK OF SHAFT, ETC.

摘要

PROBLEM TO BE SOLVED: To prevent the generation of sand boiling in the excavation works of a shaft, etc., by executing a gravel pile at a site, where the generation of sand boiling is feared, prior to the excavation process of the shaft, etc., and discharging groundwater from the gravel pile as excavation progresses. ;SOLUTION: A landslide protection wall 1 is executed to a sandy ground G, and a columnar pit 15 is drilled at a site, where sand boiling is feared, while being crossed over an excavating batholith 5. Single-sized medium-grain crushed stones 9 are charged and packed into the columnar pit 15, and a gravel pile 20 is formed. The landslide protection wall 1 is fixed in the lateral direction by walings while struts are introduced among the walings, and the shaft is excavated continuously while stabilizing the landslide protection wall 1. Consequently, a groundwater flow 7 inducing sand boiling is ejected to the excavating batholith 5 through the gravel pile 20. The runoff of the grains of soil and sand in the ground G is prevented by the gravel pile 20, and only groundwater is discharged. Accordingly, the generation of sand boiling in the excavation works of the shaft, etc., can be obviated.;COPYRIGHT: (C)1998,JPO