DRAINING METHOD OF SHALLOW SUMP IN PIT EXCAVATION CONSTRUCTION AND TWO TANK TYPE SHALLOW SUMP

摘要

PURPOSE: To solve a defect, in which construction cost is increased owing to the difficulty of the simultaneous execution of drainage construction and cut-off construction, the cause of the delaying of the term of work due to the difficulty of the simultaneous execution of both construction, the generation of the augmentation of the cost of construction due to the usage of an admixture and the burying of a drain pump at the time of a large quantity of spring water according to the status of spring water after a mat foundation is placed when a shallow sump as one tank is used in pit excavation construction. ;CONSTITUTION: An underwater pump 19 is installed into the main tank 3 of a shallow sump 1 divided into two of the main tank 3 and a sub-tank 4, spring water in the main tank 3 is discharged, the underwater pump 19 is transferred into the sub-tank 4, spring water is discharged into the sub-tank 4, the upper section of the main tank 3 is covered with an upper cover 11 and the main tank is hermetically sealed, and water in the sub-tank 4 is drained and the underwater pump 19 is removed. The opening edge of the shallow sump 1 separated into the main tank 3 and the sub-tank 4 is surrounded circumferentially with an upper frame 5, a large number of through-holes 8 are formed in parallel to the sidewall 7 of the main tank 3 and a sand preventive net 9 is stretched on an external surface, the main tank 3 is hermetically sealed with the upper cover 11, and a drain valve 15 is mounted on a partition wall 2 toward the sub-stank 4 side.;COPYRIGHT: (C)1995,JPO