Volume change behavior of saturated compacted GMZ bentonite and slurry during cyclic loading-unloading processes

抄録

In order to investigate the volume change behavior of saturated GMZ bentonite during cyclic loading-unloading processes, oedometer tests with cyclic loading-unloading process were conducted on saturated compacted GMZ bentonite and slurry specimens. A significant hysteretic loop was observed in compression curve of saturated compacted GMZ bentonite during cyclic loading-unloading process. Compression curve of the slurry specimen presented a bilinear shape. Under smaller stresses (<0.5~2MPa), the unloading-reloading loop was insignificant. However, under higher stresses (>0.5~2MPa), the unloading-reloading loop was significant. The unloading-reloading loop could be explained by the competition between the mechanical and physico-chemical effects on the microstructure changes. When stress was higher than 10MPa, compression curve of the slurry gradually closed to and coincided with the compression curve of the compacted bentonite specimen. Therefore, normal consolidation line of GMZ bentonite could be determined based on the overlapped part of the compression curves.