Abstract
A series of laboratory triaxial tests that simulated fill construction on peaty ground with vacuum consolidation method were performed to examine that optimizing the rate and starting time of the fill loading can control the lateral deformation of the ground. The test results for two different types of peat soils under vacuum pressure, axial stress loading, and both of them revealed the following characteristic deformation behaviors. The lateral strain resulting from the isotropic vacuum pressure loading was significantly smaller than the axial strain because of anisotropy induced by constitution of peat fibers. The lateral strain resulting from the combined loading of the vacuum pressure and axial stress loading is strongly affected by the starting time and, in particular, the rate of the axial stress loading, and therefore can be controlled widely by the loading rate from drawing to inside to swelling to outside. This suggests a possibility of fill loading without lateral deformation on peat ground.