METHOD OF DETERMINING STRENGTH AND LAYER THICKNESS OF IMPROVED LAYER OF BACK FILLING SAND BY CHEMICAL INJECTION AND EXPERIMENT DEVICE USED THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a method of determining the strength and the layer thickness of an improved layer of a back filling sand by chemical injection which can prevent the back filling sand from being sucked by forming the improved layer suitable for a construction site.;SOLUTION: The back filling sand 5 to be improved is collected from the construction site, the concentration of the chemical to be injected is changed, and an improved layer sample S is manufactured under a predetermined restraint pressure. Data on a relation between the concentration of the chemical and a strength q is acquired by using the improved layer sample S. A variable hydraulic pressure P is given to the improved layer sample S until it is ruptured under predetermined conditions while changing the layer thickness h for each chemical concentration to acquire data on the relation between the layer thickness h and the number of times N or a time t at which the improved layer sample is ruptured. Based on data on both relations acquired, the strength q and the layer thickness H (=h) fulfilling the requirement requested at the construction site are selected.;COPYRIGHT: (C)2007,JPO&INPIT