含夹层软岩剪切流变特性试验研究OACHSSCD

The dam site area of a hydropower station is predominantly composed of stratified soft rock with weak interlayers,which govern the differential settlement and sliding stability of the dam founda-tion.To investigate the shear rheological behavior of soft rock containing weak interlayers,stepwise loading shear creep tests were conducted under varying normal and shear stresses.The Burgers rheo-logical model was adopted to characterize the shear response.The constitutive parameters of the strati-fied soft rock during stepwise loading were identified via the Quasi-Newton optimization algorithm.Based on strain-time curves derived from experimental data,isochronous shear stress-strain clusters were established for distinct stress levels.The results indicate that the long-term internal friction angle of the weak interlayers corresponds to a coefficient of 0.245(90.7％of the instantaneous value),and the long-term cohesive strength is 0.0131 MPa(93.6％of the instantaneous cohesion).These parame-ters provide critical inputs for long-term stability assessment and deformation prediction of the dam foundation.