干湿循环下炭质泥岩软弱夹层剪切强度及渗透性演化规律研究OA

Aiming at the soft interlayers of carbonized mudstone in the slope of an open-pit mine in Yunnan province,accelerated simulation test under dry-wet cycle indoor,test of direct shear and test of variable head permeability were carried out to study the evolution law of shear strength and permeability of the soft interlayers of carbonized mudstone under the action of dry-wet cycle,and the influence of cycle times on shear strength and permeability coefficient was analyzed.The results show that the dry-wet cycle has a significant effect on the shear strength of weak interlayers of carboniferous mudstone,and the deterioration trend of shear strength is basically the same under different vertical loads.With the increase of the number of dry-wet cycles,the internal friction angle is basically unchanged,but the cohesion decreases significantly,and the cohesion decreases the most when the dry-wet cycle is 1,and the cohesion deterioration rate is faster when the dry-wet cycle is 2～7.When the dry-wet cycle is more than 7,the cohesion change rate of the weak interlayer of carbonaceous mudstone tends to be flat.Finally,the exponential function model between the cohesion and the number of dry and wet cycles was fitted.Permeability coefficient of weak layers in carbonaceous mudstone is positively correlated with dry-wet cycling times.Permeability coefficient changes gently when cycling times are 0～4,increases significantly after 4 cycles,reaches maximum value when cycling times are 7,and then per-meability coefficient basically remains unchanged.The results of the study can provide reference for the prediction of the strength and permeability coefficient of the weak interlayer in similar mine slopes.