RESEARCH ON INFLUENCING FACTORS OF RED SANDSTONE DIS-INTEGRATION DURING DRYING-WETTING CYCLES

Red sandstone is widely distributed in southern China. Due to the low strength,poor cementation and swelling clay minerals,red sandstone is prone to disintegrate under the influence of water,which can easily induce a variety of geological disasters. The static and disturbed disintegration tests are conducted on the slightly swelling red sandstone collected form Zhuzhou area of Hunan Province. The effects of dry temperature,external disturbance,test block mass and drying-wetting cycle on the disintegration characteristic are explored using evaluating indexes,including slake durability index,standard basis entropy,disintegration ratio and fractal dimension. The results show that,under the static disintegration mode,the drying temperature of 60 ℃is more favorable to disintegrate for red sandstone than those of 105 ℃ and 30 ℃. However,under the disturbed disintegration mode,the effect of drying temperature on the disintegration of red sandstone is almost negligible. Furthermore,in the case of constant temperature and test block mass,the external disturbance has a significant effect on the disintegration properties of red sandstone. Then,the test block mass has the influence on the disintegration behaviors of red sandstone.The faster disintegration rate occurs with the larger test block mass. In addition,the influence of drying-wetting cycle on the disintegration of red sandstone is very significant. The disintegration breakage of red sandstone gradually increases with the increasing cycle numbers.