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With open-pit mines excavated, the slopes will be exposed to the natural environment for a long time. Affected by factors like temperature, seepage, mining, freeze-thaw, etc., slope structural integrity and strength will gradually decline as slope exposure time extends. Besides, the development of defect structure within the rocks is closely correl...
Citations
... Jiang et al. (2018) analyzed the sensitivity and influence of various slope design parameters, seismic load and physical and mechanical parameters of rock mass on slope stability under earthquake action. Chang et al. (2018) utilized the control variable method and orthogonal design method to investigate the sensitivity of factors such as internal friction angle and cohesion on slope stability under freeze-thaw failure. Lian and Wu (2021) employed the orthogonal experimental design method to analyze the sensitivity of geometric parameters, such as embedding depth and skeleton width, on the shallow stability of soil slopes reinforced by frame protective structures, and provided a sensitivity sequence for these parameters. ...
This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ARTICLE DETAILS ABSTRACT Article History: The stability of h-type anti-slide pile, a novel slope retaining structure, has received limited research attention in terms. In this study, we conducted a comparative analysis of indoor small-scale tests and established a numerical analysis model for actual engineering scenario. By employing the finite element strength reduction method, the effects of geometric and soil parameters on the stability of h-type anti-slide piles and the failure mode of the slope. The sensitivity factors affecting slope stability are studied by orthogonal analysis. Findings indicate that the sensitivity factors, ranked from high to low, are the internal friction angle (φ), cohesion (c), front and rear pile row distance (B/L 2), and front pile length (L 3 /L 2). These four parameters exhibit a significant correlation with the sensitivity of the safety factor of slope stability. On this basis, the simplified formula for calculating the safety factor of slope stability is derived.
... In recent years, with the development in the mining of mineral resources and the construction of infrastructure, such as open-pit mining, tunnel excavation, and highway and railway construction, have gradually extended to high-cold and high-altitude regions (Chang et al., 2018;Shen et al., 2018;Fan et al., 2020). The rock slopes of open-pit mining are severely affected by cyclic freeze-thaw (F-T) actions (the alternating freezing and thawing of water in rocks) in cold regions (Jamshidi et al., 2013;Huang et al., 2019Huang et al., , 2022. ...
Rocks in cold regions experience freeze–thaw (F–T) cycles, which have a significant impact on their mechanical properties, causing a series of engineering challenges that threaten engineering stability. To investigate the mechanical characteristics and damage evolution of granite under the influence of F–T cycles, the microstructural evolution and macroscopic mechanical properties of granite were analyzed by conducting P-wave velocity tests, computed tomography scanning, and uniaxial compression tests subjected to different F–T cycles. The results revealed the following: 1) the number of F–T cycles and saturated water content significantly impact on the mechanical properties of granite; 2) as the number of F–T cycles increases, the P-wave velocity, peak strength, elastic modulus, and coefficient of frost resistivity of granite gradually decrease, but the F–T damage values increase; 3) when the number of F–T cycles is less than 40 but within a certain range (0–100), the damage variable of granite increases rapidly, but then gradually tends to stabilize; 4) the damage gradually steadily spreads to the central region of the granite sample as the number of F–T cycles increases, and the ends and marginal regions of the granite samples are more susceptible to damage, and 5) three damage variables with different definitions (elastic modulus, density, and porosity) can be used to predict the degree of damage of granite under F–T cycles.
... Mineral exploration in the glacial and permafrost areas in southern Xinjiang has caused serious environmental issues (Zhao et al. 2019) because continuous exploration aggravates glacier melting, expansion of the freeze-thaw (FT) area, and habitat fragmentation. This progressively degrades the structure and integrity of slopes due to large temperature differences between day and night that promote freezing-thawing action, prompting rocks to break down into smaller fragments (Chang et al. 2018). Extensive soil and runoff losses mainly occur during short rainstorms, and solid losses from mining during this soil erosion contain heavy-metal pollutants; these pollutants contaminate soils and farmlands downslope, causing serious environmental damage Xu et al. 2017). ...
This study highlights the influence of freezing-thawing processes on soil erosion in an alpine mine restoration area. Accordingly, a series of simulation experiments were conducted to investigate runoff, sediment, and nutrient losses, and potential influencing factors under freeze-thaw (FT) conditions. Three FT treatments (i.e., 0, 3, and 5 FT cycles), and two soil moisture contents (SMCs; i.e., 10% and 20% SMC on a gravimetric basis) were assessed. The runoff, sediment yield, ammonia nitrogen (AN), nitrate nitrogen (NN), total phosphorus (TP), and dissolved phosphorus (DP) losses from runoff were characterized under different rainfall durations. The fitting results indicated that the runoff rate and sediment rate, AN, NN, TP, and DP concentrations in runoff could be described by exponential functions. FT action increased the total runoff volume and sediment yield by 14.6%–26.0% and 8.8%–35.2%, respectively. The runoff rate and sediment rate increased rapidly with the increment of FT cycles before stabilizing. At 20% SMC, the total runoff volume and sediment yield were significantly higher than those at 10% SMC. The loss curves of AN and NN concentrations varied due to differences in their chemical properties. FT action and high SMC promoted AN and NN losses, whereas the FT cycles had little effect. FT action increased TP and DP losses by 60.2%–220.1% and 48.4%–129.8%, respectively, compared to cases with no FT action; the highest TP and DP losses were recorded at 20% SMC. This study provides a deep understanding of freezing-thawing mechanisms in the soils of alpine mine restoration areas and the influencing factors of these mechanisms on soil erosion, thereby supporting the development of erosion prevention and control measures in alpine mine restoration areas.
... As the slope is exposed to the natural environment and affected by temperature, seepage, mining, freezing, and thawing [2,3], its structural integrity and rock strength will gradually decrease as the time of slope exposure increases [4,5]. The change of the physical and mechanical properties directly affects the long-term sustainable stability of the slope engineering [6]. ...
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.
... e sensitivity analysis of slope is helpful to study the main factors causing the deterioration of slope stability [29][30][31][32]. FLAC3D is used to establish the slope model, and it is found that the freeze-thaw cycle is the sensitive factor of slope stability in the plateau area [33]. Controlling the freeze-thaw cycle is beneficial to the stability of the slope in the plateau area. ...
Based on the strength reduction method, the laws of slope displacement and the changing positions of the sliding surface during the filling process are studied. The model of multistage fill slope is established by the finite element software PLAXIS. The difference is compared between the slope with no reinforcement and with reinforcement under the same working condition. Sensitivity analysis is carried out from two aspects which are internal factors and external factors. The finite element analysis shows that the settlement of the multistage fill slope with no reinforcement is mainly concentrated on the right side of the slope and gradually decreases with the increase of the filling height. The position of the sliding outlet is located at the joint of the first and the second grade of the slope. The effect of the reinforcement on the sliding surface is ideal. It is obvious that the reinforcement can supply the slope with a better position of the sliding surface, which is beneficial to the stability of the slope. The sensitivity analysis shows that unit weight, ratio of slope, and height of each grade are negatively correlated with the safety factor. At the same time, the platform width, cohesion, and internal friction angle are positively correlated with the safety factor. The internal friction angle has the greatest influence on the stability of the slope. Besides, the platform width and the height of each grade should be controlled at about 4 m. The sensitivity analysis provides a reference for the design of the multistage filling slope.
... In fact, the finite element model is a group of unit combinations which are connected only at the nodes, relying only on the nodes to transmit force, and constrained only at the nodes. The basic idea of the finite element model is shown in Fig. 1 (Chang et al. 2018). ...
... Taking the accuracy and efficiency of analysis as the comparative index, the proposed method is compared with Refs. Boyle et al. (2018), Chang et al. (2018) and Deng and Li (2017). The specific experimental research process is as follows. ...
... In order to better reflect the accuracy of the stability analysis results of the proposed method, the stability of slope in Danjiangkou area is analyzed by the proposed method and the methods in Refs. Boyle et al. (2018), Chang et al. (2018), and Deng and Li (2017), and the results are compared with the actual situation. The comparison results are shown in Table 4. ...
In order to overcome the problems of large analysis error and low analysis efficiency in the current analysis method of rock and soil slope stability, a new research method based on strength reduction method is proposed in this paper. On the basis of the finite element analysis method, the finite element model is established, including the establishment of geometric model, preparatory work, and the fast triangle algorithm is used to optimize the mesh constructed by the finite element optimization method, and the mesh quality is tested. Secondly, the strength reduction method is used to analyze the advantages of geotechnical slope stability, and the established finite element model is solved by using the strength reduction method to obtain accurate geotechnical slope stability coefficient and complete the accurate analysis of geotechnical slope stability. The experimental results show that compared with the traditional method, the stability coefficient calculated by this method is closer to the actual data, with lower analysis error and higher analysis efficiency, and the maximum analysis time is only 2.5 s.
Characterization of properties governing the stability of rock slopes is essential for their design and analysis. Importance ranking of these properties can be obtained by the sensitivity indices that quantifies the extent to which different properties influence the stability of the slopes. This helps the designers to divert major lab/in-situ investigation resources to evaluate highly ranked properties. Another usage is to perform the probabilistic stability analysis of slopes efficiently by treating low ranked properties deterministically in the estimation of probability of failure (Pf). In this paper, the importance ranking of rock properties affecting the Pf of rock slopes prone to different failure mechanisms is performed using Local/Global Sensitivity Approaches (L/GSAs) and the accuracy of these approaches were assessed quantitatively. Four slope case studies indicating different structurally and stress-controlled failures were considered, and sensitivity analyses were performed using six different L/GSAs. Accuracy of the approaches was assessed by comparing the importance ranking of properties based on sensitivity approaches to that of the normalized errors, i.e., εi invoked in the Pf by neglecting the uncertainties in these properties. Results indicated the superior accuracy of GSAs as compared to LSAs. Importance ranking was dependent upon the considered slope (failure mechanisms), with some slopes showing higher sensitivities to external parameters and others to inherent rock properties. An important guideline based on the analysis is suggested to consider the properties as deterministic/random variables in the probabilistic analysis. For the slopes with the minimum interaction effects in their sensitivity (planar, wedge and stress-controlled), uncertainties in multiple properties can be neglected based on the allowable error in the Pf. Further, a dependence of εi and corresponding importance ranking was observed on the selected value of property of interest (assumed as deterministic) across its domain in the analysis.
Granitic residual soils are soils formed by the in situ weathering of intrusive granitic rocks and are present in different parts of the world. Due to their large presence, many civil engineering projects are carried out on and within these soils. Therefore, a correct characterization of the slopes is necessary for slope stability studies. This investigation aims to study the influence of the values of geomechanical parameters (specific weight, cohesion, and friction angle) and the geometry of a slope (height and inclination) on slope stability of residual granitic soils in dry and static conditions. To this end, an automatic system was developed for the numerical study of cases using the finite element method with limit analysis. The system allows modeling, through Monte Carlo simulation and different slope configurations. With this system, the safety factors of 5000 cases were obtained. The results of the models were processed through the SAFE toolbox, performing a Regional Sensitivity Analysis (RSA). The results of this research concluded that the order of influence of the factors were: slope angle > slope height > cohesion > friction angle > unit weight (β > H > c > ϕ > γ).
