다짐지반의 모관흡수력 변화에 따른 탄성계수 평가를 위한 VPPE-BE 시험 시스템 개발

Abstract

The volumetric pressure plate extractor (VPPE) was modified for the measurement of shear wave velocity (Vs) at various levels of matric suction as well as soil water characteristic curve (SWCC). A non-destructive technique with a pair of bender element (BE) was employed in order to measure the Vs and the corresponding maximum shear modulus (Gmax) of unsaturated soil specimens. Three types of soil were collected from different road construction sites in Korea. For all test soils, the variations in Gmax with the various levels of water content and matric suction were investigated using the developed apparatus. Compared with the preceding results from the suction-controlled torsional shear (TS) testing system and in-situ seismic tests, the feasibility for evaluating modulus characteristics of unsaturated compacted soils with the developed VPPE-BE system was assessed. It was confirmed that the newly developed system would be potentially helpful in modeling seasonal variation of modulus.