[Objective]Bedding deep cutting slopes containing weak interlayers are commonly found in slope engi-neering,whose stability is influenced by two key factors:The strength of the sliding zone soil and the reserved thickness of the base(the distance from the base of an excavated slope to the weak interlayer).[Methods]In this research,taking the K42 cutting slope of the Yang-Xuan Expressway as an example,the evolution process of slope deformation was analyzed,especially the characteristics of basal heave deformation.The properties of the deep slid-ing zone soil in the slope were revealed by ring shear tests,which are suitable for studying the shear strength of soil that has experienced large shear displacements.Moreover,the residual strength parameters of the saturated sliding zone soil were applied to analyze the reserved thickness of the base.[Results]The results show that sliding zone soils exhibit obvious strain softening characteristics,which become more evident as the normal stress decreases.As the soil shear strength transitions from peak strength to residual strength,both the cohesion force and internal fric-tion angle decrease,with the cohesion force decreasing to a greater extent than the internal friction angle.The re-sidual cohesion force of sliding zone soil varies slightly with the shear rate,while the relationship between the resid-ual internal friction angle and shear rate varies as a logarithmic function.When the shear rate is less than 2 mm/min,the residual shear strength parameter of sliding zone soil is more sensitive to the shear rate and vice ver-sa.[Conclusion]Furthermore,according to the regression equations of the critical states of slope stability,the re-served thickness of the base under different slope rates was divided into four zones:A(extremely unstable zone),B(unstable zone),C(basically stable zone)and D(stable zone),and based on this,the criterion and early warning model of the reserved thickness of the base for slope excavation were established.
关键词
软弱夹层/深路堑边坡/滑带土/残余强度/基底预留厚度/预警模型
Key words
weak interlayer/deep cutting slope/sliding zone soil/residual strength/reserved thickness of the base/early warning model
维普
万方数据