Development Of A New Type Of Shear Creep Apparatus And Its Application

For the long-term strength of loess slope, that is, the loess body produces shear creep in the form of long-term deformation under the shearing function; the present study achievements can be seen rarely. A lot of reasons account for this occurrence. Because of the defects of the testing instrument itself, no reliable experimental data can be as the basis which limits the related research, and this is a very important reason. This paper takes the defects of the existing testing instrument as the starting point and launches the study.At present, the shear box of domestic shear creep test instrument is relatively small, and from the beginning stage the round shear box applied forms an obvious phenomenon of stress concentration at the edge. During the whole process of shearing, there always exists the problem that the stress is not distributed evenly. Meanwhile, traditional creep apparatus mainly applies vertical and horizontal loads with long lever mechanism, and during the process of loading, once the soil sample deformed, the lever would slant, which would make the vertical pressure produce a non-vertical direction component force. With the increase in load value, the force also increases, resulting in a relatively big deviation of experiment data. While applying the leverage, the loading value is also restricted greatly due to the lever cannot be too long.In order to solve the problems above, a new shear creep test instrument is devised, whose shear box is changed from the original round one with the area of 30cm~2 into the present square one with 10×10=100cm~2, and its vertical stress loading system and horizontal shear loading system all apply the pulley block structure. After the improvement, this new shear creep test instrument could reduce the emergence of stress concentration and the error caused by loading effectively, and it also could satisfy the loading need of practical project.Based on the successful development of this new shear creep test instrument, some research on the creep characteristics of loess has been done. And, the related data of shear creep of loess body which occur in the form of long-term deformation are obtained, which shows that the new shear creep test instrument developed by ourselves has a higher practical value.