Abstract: In order to explore the stability evolution law, under water-rock interaction, of mudstone reservoir bank which has been located in Funing Port areas of Yunnan province, and then based on the rock samples, collected from the first-stage project field, the conventional triaxial compression tests were conducted with different numbers of drying and wetting cycles and the rock shear strength parameters were obtained. After engineering conversion of strength between rock and rock mass, it formulated the time-varying model of probability distribution of mudstone general shear strength parameters by regression analysis. Then combining with the limit equilibrium method and the reliability theory, the time-varying laws of mean safety factor, reliability and reliability safety factor were drawn. The results show that the reliability safety factor, coupling the safety factor and reliability, can analyze the time-variation of mudstone reservoir bank more reasonably, during the water level fluctuation repeatedly. Furthermore, it is nonlinearly that the characteristic of the whole stability of mudstone reservoir bank has changed. Besides, the failure model of the bank slope is gradual that the critical slip surface changes from inside to outside. The time-varying stability analysis methods of mudstone reservoir bank proposed by the paper based on the laboratory experiment can provide an effective approach for stability evolution rule of the reservoir bank, impacted on by the high water soaking and water level periodic fluctuation.

Key words: water-rock interaction, mudstone reservoir bank, shear strength parameters, time-varying, stability, reliability