Abstract:The conventional soil direct shear creep apparatus is modified by adding a sealed device to the pressure box,keeping water content of a soil specimen constant during a creep test. Combined dial gauge and micrometer gauge to measure shear displacement,the measure precision of test from 10 μm to 1 μm is improved. Experiments of water content variation of samples both in improved apparatus and conventional device are simultaneously carried out with a period of 30 days with great change in humidity and temperature. Little change is found for the water content of samples in modified apparatus,and the maximum value is only 0.8%,which confirms the good performance of improved apparatus. Keeping other test approximately in the same conditions,the creep behaviors of soils with different water contents are explored by utilizing the modified instrument,and the results show that with the water content increase,soil behaves a changing creep features from linear rheology to nonlinear rheology. The higher the soil water content is,the less the initial shear creep stress is. The bigger ratio of creep strain to instantaneous strain as well as the longer creep steady time show that water content has a visible effect on the creep characteristics of soil,which shows the importance of maintaining humidity of sample for direct shear creep apparatus. The improved apparatus is economical and practical,and it can be used as an effective complementarity to triaxial rheology apparatus of soil.