Aging Stability Analysis of Slope Considering Cumulative Effect of Freeze–Thaw Damage—A Case Study

Abstract

The change of physical and mechanical properties of slope rock mass in open-pit mines in seasonally frozen area under the action of freeze–thaw cycles is one of the main reasons for slope instability. In this paper, taking the mechanical parameters of coal seam and sandstone layer in the Beitashan Pasture Open-Pit Mine in Xinjiang as the research object, considering the combined effect of the frost-heave tensile stress in the crack perpendicular to the crack surface and the three-dimensional confining pressure in the crack, the criterion for cracking of fractured rock mass under freeze-thaw condition is determined by applying the principle of stress superposition and the theory of strain energy density factor, and the theoretical frost-heave stress required for cracking is deduced. On this basis, the sensitivity analysis of the fixed factors and variable factors to the theoretical frost-heave stress was performed, respectively. Finite element analysis was utilized to analyze the slope stability under the attenuation of five groups of different rock mass mechanical properties and to determine the slope angle required for the slope stability. Seven different slope angles of sidewall mining ranging from 36° to 51° are analyzed. The results of finite element analysis show that considering the timeliness difference of rock mass parameters with time, the safety factor of slope is reduced from the original 1.70 to 1.18, and 91,500 tons of coal resources can be recovered every year, with remarkable economic benefits.

Experimental Study of the Multiple Fractalisation of Coal and Rock Failure Subjected to the Coupled Effects of Water, Temperature and Dynamic Loads

“…In Fraclac, the control panel parameters for analysing the cracks were set in the region of interest (ROI). Finally, the box dimension was obtained from the image scanning and the statistics of Equation (5).…”

“…In addition, rock structures in cold regions are often affected by dynamic loads. For example, in open-pit coal mines in high-altitude and water-rich areas, the mechanical properties of coal and rock are deteriorated by low temperatures and water, combined with blasting and mining disturbances, which will have an impact on the macroscopic and microscopic structure of coal and rock, leading to slope geological disasters [4,5]. Therefore, a comprehensive understanding of coal and rock subjected to the coupled effects of water, temperature, and dynamic loads has great theoretical and engineering significance for the safe mining of rock structures in cold regions and for the study of the impacts of dynamic loads on coal and rock during freezing [6].…”

Mechanical Properties and Damage Layer Thickness of Green Concrete under a Low-Temperature Environment

“…The surface damage of the structure is maximally severe, and the inwardly extended damage gradually weakens. Notably, this phenomenon can reflect the characteristics of concrete freezing damage at the macro level [ 22 , 23 ]. In this perspective, the thickness of the damaged concrete layer can optimally describe this feature.…”

Effect of Freeze-Thaw Damage on the Physical, Mechanical, and Acoustic Behavior of Sandstone in Urumqi

“…The geomechanical behavior of rocks under freeze-thaw (F-T) action has drawn considerable attention due to its crucial role in many rock projects in cold regions [1,2]. Since the implementation of the national strategy of "One Belt, One Road", many infrastructure projects such as highways, railroads, and open-pit mines [3] have been built in western China. However, the fact that western China belongs to a seasonal cold region with large temperature fluctuations in winter makes the outcropping rocks prone to F-T damage, so there are difficulties in maintaining rock projects in this region [4].…”