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Taking the down-slope with weak strata in the south of Fushun west open-pit mine as the reference prototype, numerical simulations of the down-slope with weak strata were conducted through FLAC3D software, which included the simulation of actual ground motion and ground motion input, the boundary conditions of slope model, rock mass parameters, and grid model division. The response rule of down-slope with weak strata under an earthquake was investigated by analyzing the acceleration and velocity of the monitoring points. The results revealed that: (1) The thickness of the weak layer is a critical factor affecting the response characteristics of the slope with a single weak layer under an earthquake, and it has a greater impact on the stability of the slope under earthquake load than the dip angle of a single weak layer. (2) Based on the horizontal velocity of monitoring point 2# at the intersection of the weak layer and the slope surface, it was concluded that the thickness has a significant influence on the velocity in the X direction. (3) The failure response law at the intersection of weak layers and slope changes with an increase in slope height when analyzing the response law of the double weak layer characteristic slope under an earthquake. The acceleration amplitude and velocity change degree of monitoring point 3# with double weak layers are more noticeable than that of monitoring point 2#. The response law of the down-slope under an earthquake is related to the dip angle, thickness, number, and location of weak layers. Therefore, the coupling effect of earthquake and weak layer characteristics on slope stability should be thoroughly considered in the process of slope treatment and protection.

Taking the down-slope with weak strata in the south of Fushun west open-pit mine as the reference prototype, numerical simulations of the down-slope with weak strata were conducted through FLAC3D software, which included the simulation of actual ground motion and ground motion input, the boundary conditions of slope model, rock mass parameters, and grid model division. The response rule of down-slope with weak strata under an earthquake was investigated by analyzing the acceleration and velocity of the monitoring points. The results revealed that: (1) The thickness of the weak layer is a critical factor affecting the response characteristics of the slope with a single weak layer under an earthquake, and it has a greater impact on the stability of the slope under earthquake load than the dip angle of a single weak layer. (2) Based on the horizontal velocity of monitoring point 2# at the intersection of the weak layer and the slope surface, it was concluded that the thickness has a significant influence on the velocity in the X direction. (3) The failure response law at the intersection of weak layers and slope changes with an increase in slope height when analyzing the response law of the double weak layer characteristic slope under an earthquake. The acceleration amplitude and velocity change degree of monitoring point 3# with double weak layers are more noticeable than that of monitoring point 2#. The response law of the down-slope under an earthquake is related to the dip angle, thickness, number, and location of weak layers. Therefore, the coupling effect of earthquake and weak layer characteristics on slope stability should be thoroughly considered in the process of slope treatment and protection. [ABSTRACT FROM AUTHOR]

Fully grouted bolts are widely used to reinforce road cutting slopes because of their low cost and high efficiency. However, there is a lack of research on the anchorage failure mechanism and stability assessment of bolt-supported road cutting dip slopes (BRCDSs). In this work, a progressive failure process of BRCDSs was captured via a triangular block model in the Universal Distinct Element Code (UDEC). A kinematically admissible velocity field of BRCDSs was innovatively established based on their sliding shear failure and the Mohr–Coulomb criterion. As a consequence, a novel method for evaluating the stability of BRCDSs was proposed using the upper bound theorem of limit analysis. The reinforcement effects of BRCDSs with different bolt angles were subsequently evaluated by UDEC simulations, and the obtained slope safety factors and bolt-supporting forces were compared with the results calculated by the proposed method. In addition, the influence of various parameters (bolt angle, bolt diameter, slope angle, and strengths of rock and discontinuity) on the reinforcement effect was investigated. The results obtained using the proposed method showed good agreement with those obtained via UDEC. There is an optimal bolt angle in BRCDSs, at which the bolt generates the largest supporting force and thus promotes the highest safety factor of the slope, and the value of this angle is approximated as the friction angle of the discontinuity. The safety factor of the slope also increases with the increase of bolt diameter, and the variation increasing according to a power function. The method proposed provided a convenient theoretical tool for the stability assessment and reinforcement design of BRCDSs. [ABSTRACT FROM AUTHOR]

Dip slopes are often encountered in deep-cut canyons and engineering projects. Such slopes, when they become unstable, commonly undergo bi-planar failure, and this mode of failure tends to produce the widest-ranging effects. In this work, a novel method is proposed for assessing the potential of a slope to undergo bi-planar failure based on a stress analysis at a key point on the sliding surface, namely, the point at which the two sections of the sliding surface are connected. Discrete-element simulations are first carried out to capture the essence of the penetration process of the bi-planar sliding surface based on displacement results, plastic failure, and principal stress development. Then, the key point on the sliding surface is skillfully selected according to the sliding surface penetration process, and the characteristics of the stress changes leading to slope failure are investigated using the stress analysis method. Subsequently, considering the stress states of this key point both in the overlying rock strata and in the intact rock at the toe of the slope, a novel method is proposed for assessing the stability of the dip slope and predicting the bi-planar failure surface formed. The stability of dip slopes was subsequently analyzed using both numerical and theoretical methods. The results obtained are highly consistent, confirming the feasibility and accuracy of the proposed method. The results also show that the bi-planar failure process is progressive and that the range of the failure is mainly located in the stress reduction zone. Moreover, the critical height of the dip slope remains approximately unchanged as the stratum thickness is changed. However, it decreases as the slope angle increases and increases linearly if the strength of either the rock or joints is increased. Additionally, if the joint strength is low, the dip slope undergoes buckling failure—increasing the joint strength, however, increases the likelihood of the occurrence of bi-planar failure. The proposed method offers a novel approach to assessing and designing dip slopes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The soil water movement of dip/anti-dip karst slopes is revealed by water isotopes. • Precipitation drives the seasonal variations of soil water isotopes. • Preferential flow is dominant in the upper soil layers on dip and anti-dip slopes. • Preferential flow is deeper on anti-dip versus dip karst slopes. • Soil texture and structure regulate the spatial movement of soil water. Exploring temporal and spatial variations in soil water processes is crucial for identifying the ecological water supply capacity of soil and understanding hydrologic cycles within karst catchments. However, the existing body of knowledge related to soil water dynamics across dip and anti-dip slopes in karst landscapes remains limited. To address this gap, this study investigated soil water dynamics in a karst trough valley (KTV) in southwest China, using stable isotopes (δD and δ18O) from eight sampling sites and precipitation data from April 2017 to November 2018. Our findings suggest that seasonal variations in soil water isotopes are primarily influenced by climatic factors, with soil water lagging behind rainwater isotopes by one to four months due to differences in the residence time of precipitation in different soil layers. Spatially, our results reveal the coexistence of diffuse and preferential flows on both dip and anti-dip slopes. Specifically, on the dip slope, preferential flow dominates above 20 cm, while diffuse flow prevails below this depth. In contrast, on the anti-dip slope, preferential flow is prominent above 40 cm depth, while diffuse flow dominates beneath this threshold. These spatial patterns not only impact the ecological water and nutrient supply capacity of soil but they also contribute to distinct patterns in vegetative growth on both slopes. In turn, vegetation growth facilitates preferential flow pathways, establishing a positive feedback loop between soil water movement and vegetative cover. These findings may lead to a deeper understanding of soil water processes on the dip and anti-dip slopes of KTVs and provide crucial insights into the relationship between soil water and vegetative growth in similar karst landforms. [ABSTRACT FROM AUTHOR]