Time-Varying Effect of Ductile Flexural Toppling Failure on Antidip Layered Rock Slope

Abstract

Ductile flexural toppling failure is a common form of toppling failure, and it is the product of long-term geological history and shows the characteristics of long-term deformation and progressive failure. The creep characteristics of rock mass have been seldom considered in the current research on toppling, especially interlayer creep of rock layers in the process of toppling. Based on the thought of deformation stability analysis, the flexural toppling failure was divided into the following four stages: start-up, rapid deformation, transient stability, and long-term creep stages. Combined with mechanical analysis, the developmental conditions of the start-up, transient stability, and long-term creep development stages are discussed respectively. Finally, several cases were selected to analyze the stage and the stability of the toppling deformation body, as well as to verify the rationality of the mechanical analysis condition. Study results show that the start-up conditions meet Equation 2, the rock layer inclination and slope angle is 0.5π−φ in the transient stability stage, and that angle is the infinite 0.5π in the long-term creep stage. Other external forces (such as water pressure) will intensify the development of ductile flexural toppling failure, so that the angle between the toppled bedding surface and the slope surface increases. It is of great significance to analyze the development stage of the ductile flexural toppling, comprehensively analyze and evaluate the stability of the ductile flexural toppling, reasonably develop and utilize its self-stability ability, and set up support measures.

Mechanical mechanism of rock mass slabbing aggravating toppling failure

“…Moreover, the more serious the rock mass slabbing is, the more severe the toppling flexural stiffness of the rock slab is reduced, and the more easily the rock slab is inclined to topple and bend. Then, the toppling deformation will develop gradually and enter the creeping stage considering the time effect (Cai et al, 2022b).…”

A Case Study for Stability Analysis of Toppling Slope under the Combined Action of Large Suspension Bridge Loads and Hydrodynamic Forces in a Large Reservoir Area

“…They believe that the deep dumping is caused by the rapid cutting of the valley under high ground stress [25]. Cai et al studied the deformation mechanism of the ductile bending toppling mode in toppling deformation, dividing ductile bending toppling into the start-up stage, rapid deformation stage, transient stability stage, and long-term creep stage [26]. Zhang et al proposed a calculating model of limited toppling depth according to the shallow deformation strength by using geological mechanism analysis and the numerical simulation method [27].…”

Development Pattern of Toppling Deformation Slopes in Western China

“…Owing to diverse causes, geological engineering concerns about toppling deformations have gradually become major issues in the field. Until now, most studies on toppling deformations, especially in hydropower projects, have focused on the evolutionary process [13][14][15][16], deformation mechanisms [17][18][19][20][21][22][23][24][25][26][27][28] and development characteristics [29][30][31][32] of single toppling deformation slopes. The development regularity and susceptibility of toppling deformations are rarely studied from the angle of regional geological conditions and geographic position.…”