TEST STUDY ON THE CREEP PROPERTIES OF T_2b~2 SILTITE IN DIFFERENT MOISTURE STATES

Aimed at grasping the deformation properties of soft rock in the Three Gorges Reservoir Area,a study on the creep properties of T2 b2 purple siltite in different moisture state was carried out.The fresh T2 b2 siltite for test was collected from Taoshuya tunnel site,and through uniaxial creep test of T2 b2 siltite in four kinds of moisture states,uniaxial strain-time curves of under 5 load levels in different moisture states were got,based on which some basic creep features and laws of the siltite with the changes of stress level and moisture state were presented.The results show that in any moisture state,initial instantaneous strain and strain caused by creep effect increases are both increase with the growth of stress level,and the strain rate in the stable creep stage is transformed from zero to non-zero constant with the growth of stress level;in the condition of being in same stress level and different moisture state,the time for entering the stable creep phase under the same stress level becomes longer with the growth of the water content of rock sample,the instantaneous strain and total strain are also increased with the growth of the water content of rock sample,but the long-term strength of it has a decreasing trend.