Rheological Characteristics of Weak Rock Mass and Effects on the Long-Term Stability of Slopes

Abstract

The creep deformation behavior of the northern slope of an open-pit mine is introduced. Direct shear creep tests are then conducted for the samples taken from the northern slope to study the rheological characteristics of the rock mass. The experimental results are analyzed afterwards using an empirical method to develop a rheological model for the rock mass. The proposed rheological model is finally applied to understand the creep behavior of the northern slope, predict the long-term stability, and guide appropriate measures to be taken at suitable times to increase the factor of safety to ensure stability. Through this study, a failure criterion is proposed to predict the long-term stability of the slope based on the rheological characteristics of the rock mass and a critical deformation rate is adopted to determine when appropriate measures should be taken to ensure slope stability. The method has been successfully applied for stability analysis and engineering management of the toppling and slippage of the northern slope of the open-pit mine. This success in application indicates that it is theoretically accurate, practically feasible, and highly cost-effective. Keywords Creep behavior Á Rheological characteristics of the rock mass Á Long-term strength Á Slope stability Á Failure Notation s i Shear stress G(t) Shear modulus t Time c i Shear strain m Shear strain enhancing factor H Tensile strength r ni Normal stress c Cohesion u The angle of friction G 0 = G(0) Instantaneous shear modulus at t = 0 a Constant d Constant s 0 (c i ) Shear stress when r ni = 0, i.e., intercept of the curve s i -r ni in the ordinate axis u(c i ) Inclination angle between the curve s i -r ni and the abscissa axis c i Shear strain _ c Shear strain velocity c f Failure strain, % j Scale coefficient of deformation, usually j = 1.0 g Constant relevant to the plasticity s i Instantaneous shear stress s 0 Instantaneous shear strength s ? Long-term ultimate shear strength F 0 Factor of safety calculated using the instantaneous shear strength

Dynamic Response and Dynamic Failure Mode of a Weak Intercalated Rock Slope Using a Shaking Table

“…Much attention has been paid to the dynamic response characteristics of slopes under earthquake excitation (Wartman et al 2005;Lin and Wang 2006;Aydan et al 2010; Barbero and Barla 2010;Latha and Garaga 2010;Chen et al 2013;Liu et al 2013Liu et al , 2014. However, research on rock slopes with weak intercalated layers is rare (Xu and Yan 2014;Yang et al 2014), especially in terms of comparison between slopes parallel to geological bedding (referred to here as bedding slopes) and slopes that cross-cut geological bedding (counter-bedding slopes). Huang (2012) put forward a conceptual model of bedding slope deformation under strong earthquake influence based on data from the Wenchuan earthquake.…”

“…Huang et al (2013a) studied the failure mechanism of the Guantan landslide, which was triggered by the Wenchuan earthquake, and investigated the dynamic behavior of hard and soft rock slopes using large-scale shaking table tests. Yang et al (2014) investigated the dynamic response characteristics and dynamic failure processes of counterbedding slope under earthquake excitation. The existing research thus provides important guidance for studying the dynamic response characteristics of both bedding and counter-bedding slopes.…”

Shear Creep Properties of Weak Interlayer in Slope Based on Stationary Parameter Fractional Derivative Burgers Model

“…For attenuation creep soil, the shear strain keeps a constant with the increase of time (Fig. 12) if the shear stress t is less than the attenuation shear strength t ¥ (Yang et al, 2013) (i.e., t < t ¥ ), while the shear strain develops continuously with the increase of time until destruction if the shear stress t is more than the attenuation shear strength t ¥ (i.e., t > t ¥ ), indicating that the long-term shear strength, i.e., the attenuation shear strength t ¥ , can be obtained on the basis of the isochronous curve method (Guo et al, 2005;Xie et al, 2014;Zhu & Yu, 2014;Gao et al, 2015;Simsiriwong et al, 2015).…”

“…analyzed the major mode of the soil erosion in karst areas by combining the long-term shear strength of brown clay, which had been obtained by the long-term creep properties study of the brown clay. Yang et al (2013) studied the shear creep properties of attenuation creep soil by the direct shear creep test, and proposed the long-term shear strength of the attenuation creep soil to assess the long-term stability of the northern slope of an open-pit mine in Fushun City, Liaoning Province, China. Zhu & Yu (2014) studied attenuation creep soil by creep test, and the long-term shear strength of the attenuation creep soil was deduced by the creep curves and isochronous curve method.…”

Dynamic Failure Mode and Dynamic Response of High Slope Using Shaking Table Test

“…rough a large-scale shaking table test, Xu et al studied the dynamic response law of a slope [27]. Yang et al investigated the dynamic failure mechanism and dynamic response characteristics of a counter-bedding slope under earthquake excitation [28]. Che et al used a shaking table test to analyze the influence of discontinuous joints on a high and steep slope in an earthquake [29].…”