Integrity Test of DCM Treated Soils with a Cross-hole Sonic Logging

J. Ocean Eng. Technol. 2001;15(1):73-78.

시추공간 음파검층법을 이용한 심층혼합 개량지반의 건전도 조사

김진후,조성경

동아대학교 토목·해양공학부,동아대학교 토목·해양공학부

Keywords: Cross-hole sonic logging(CSL), Integrity test, Non-destructive test, Elastic modulus, Compressive strength, Deep cement mixing

핵심용어: 시추공간음파검층, 건전도 조사, 비파괴 시험, 타성계수, 압축강도, 심층 시멘트 혼합처리

Abstract

Soundness evaluation of a structure being constructed under the sea is usually difficult. In this study, a cross-hole sonic logging(CSL) which have been used for non-destructive test of concrete piles is adopted for the integrity test and monitoring of DCM(deep cement mixing) treated soils. Chemical and physical characteristics of raw ground materials are analysed to delineate ground environmental effects on the strength of DCM treated soils. In order to convert cross-hole sonic logging data into compressive strength, correlations between compressive strengths and wave velocities of core samples have been obtained. It is found that there is little effect of ground environment on the strength of the DCM treated soils, and the density distribution of core samples and cross-hole logging data show that a defective zone may exist in the DCM treated soils. With the time lapse, however, the defective zone has been cured and consequently, compressive strength of the DCM treated soils increases and satisfies the design parameter. From this study it can be concluded that the cross-hole sonic logging can be used for the integrity test as well as monitoring the curing stage of the structures, successfully.