scholarly journals Deformation and Stability Characteristics of Layered Rock Slope Affected by Rainfall Based on Anisotropy of Strength and Hydraulic Conductivity

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3056
Author(s):  
Chengzhi Xia ◽  
Guangyin Lu ◽  
Ziqiang Zhu ◽  
Lianrong Wu ◽  
Liang Zhang ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Factor Of Safety ◽  
Rock Slope ◽  
Horizontal Displacement ◽  
Field Monitoring ◽  
Monitoring Data ◽  
Anisotropy Ratio ◽  
Conductivity Anisotropy ◽  
Layered Rock ◽  
Dip Angle

The strength and hydraulic conductivity anisotropy of rock slopes have a great impact on the slope stability. This study took a layered rock slope in Pulang, Southwestern China as a case study. The strength conversion equations of the seriously weathered rock mass were proposed. Then, considering the anisotropy ratio and anisotropy angle (dip angle of bedding plane) of strength and hydraulic conductivity, the deformation and stability characteristics of rock slope were calculated and compared with field monitoring data. The results showed that the sensitivity analysis of strength and hydraulic conductivity anisotropy could successfully predict the occurrence time, horizontal displacement (HD), and the scope of the rock landslide. When the anisotropy ratio was 0.01 and the dip angle was 30°, the calculated HD and scope of the landslide were consistent with the field monitoring data, which verified the feasibility of the strength conversion equations. The maximum horizontal displacement (MHD) reached the maximum value at the dip angle of 30°, and the MHD reached the minimum value at the dip angle of 60°. When the dip angle was 30°, the overall factor of safety (FS) and the minimum factor of safety (MFS) of the rock slope were the smallest. By assuming that the layered rock slope was homogeneous, the HD and MHD would be underestimated and FS and MFS would be overestimated. The obtained results are likely to provide a theoretical basis for the prediction and monitoring of layered rock landslides.

scholarly journals Sensitivity Analyses of the Seepage and Stability of Layered Rock Slope Based on the Anisotropy of Hydraulic Conductivity: A Case Study in the Pulang Region of Southwestern China

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2314 ◽  
Author(s):  
Chengzhi Xia ◽  
Guangyin Lu ◽  
Dongxin Bai ◽  
Ziqiang Zhu ◽  
Shuai Luo ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Factor Of Safety ◽  
Rock Slope ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Sensitivity Analyses ◽  
Southwestern China ◽  
Anisotropy Ratio ◽  
Rock Slopes ◽  
Layered Rock

In the study of the seepage characteristics of layered rock slope under rainfall conditions, the majority of previous research has considered the hydraulic conduction to be isotropic, or only considered the anisotropy ratio of the hydraulic conductivity, ignoring the anisotropy angle. In the current study, a layered rock slope in the Pulang region was selected as an example. Then, based on the fitting parameters of the Van Genuchten model, pore water pressure sensitivity analyses of the layered rock slope were carried out. The anisotropy ratio and anisotropy angle were used to analyze the sensitivity of the seepage and stability of the layered rock slopes. The results show that as the anisotropy angle of hydraulic conductivity of layered rock slope decreased, the maximum volume water content of surface (MWCS) of layered rock slope gradually increased. Additionally, as the anisotropy ratio decreased and the anisotropy angle increased, the rising heights of the groundwater (RHG) of layered rock slope gradually increased. When the hydraulic conduction of layered rock slope was considered isotropic, the factor of safety (FS) tended to be overestimated. As the anisotropy ratio decreased and the anisotropy angle increased, the factor of safety (FS) of layered rock slope decreased. Prevention should be the objective for rock slopes with larger dip angles in the bedding plane in the Pulang region. This study provides feasible schemes for the evaluation of the seepage and stability of layered rock slopes in Pulang region of southwestern China.

scholarly journals Stability Analysis and Reinforcement of a High-Steep Rock Slope with Faults: Numerical Analysis and Field Monitoring

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Qibing Zhan ◽  
Xinjian Sun ◽  
Cheng Li ◽  
Yawei Zhao ◽  
Xinjie Zhou ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Numerical Analysis ◽  
Rock Slope ◽  
Field Monitoring ◽  
Monitoring Data ◽  
Slope Surface ◽  
Monitoring Point ◽  
Reinforcement Measure ◽  
The Stability ◽  
External Forces

This study presents a stability analysis of a high-steep rock slope with two faults during excavations and evaluates the effectiveness of a proposed reinforcement method using prestressed anchor cables. A 3D finite difference model was established based on the strength reduction method using FLAC3D software. The influence of various fault conditions and the effectiveness of the reinforcement on the slope stability during the excavation process were analyzed and compared to field monitoring data. The numerical analysis and field monitoring results showed that the fault close to the slope surface (f20) was prone to the local instability under external forces caused by the excavation, but a fault further away from the slope surface (f14) had insignificant influence on the stability of the slope. Based on the numerical analysis results, the proposed reinforcement measure can increase the factor of safety (FOS) of the slope by 19.2%. The field monitoring data also showed that the displacement of the monitoring point gradually decreased after the reinforcement, and the deformation of the slope was effectively controlled.

scholarly journals A Sensitivity Analysis of the Anisotropy of Hydraulic Conductivity to the Seepage, Deformation and Stability of Anti-Dipping Layered Rock Slopes: A Case Study of the Pulang Area in Southwestern China

2021 ◽  
Author(s):  
Guangkeng Zhang ◽  
Guangyin Lu ◽  
Chengzhi Xia ◽  
Lianrong Wu ◽  
Zongming Xu ◽  
...  
Keyword(s):  
Anisotropy Ratio ◽  
Rock Slopes ◽  
Safety Factors ◽  
Water Conductivity ◽  
Conductivity Anisotropy ◽  
Layered Rock ◽  
Rock Formations ◽  
Layered Slope ◽  
Unsaturated Seepage

Abstract In this paper, in order to study the influencing effects of anisotropy ratios and anisotropy directions on the seepage, deformations and stability of the anti-dipping layered rock slopes, Geo-studio software was used in this study to carry out this test based on the unsaturated seepage, fluid-solid coupling, and stability theory numerical analysis of carbonaceous slate slopes in Pulang area. The results showed that the maximum surface water content of the layered rock slopes gradually decreased with increases of the water conductivity anisotropy ratio and decreases in the anisotropy angle of the anti-dipping layered rock slopes. In addition, the rainfall infiltration depths in the middle sections of the slopes were observed to be the most affected by the anisotropy ratio and dip angles of the rock formations. Meanwhile, the bottom sections of slopes were the least affected by the anisotropy ratio and the dip angles of the rock formations. In regard to the anti-dipping rock slopes, it was found that the anisotropy ratio and rock layer dip angles should be considered in the deformation and stability analyses. When the seepage of an anti-dipping layered slope was considered to be isotropic, the safety factors often were overestimated. As the anisotropy ratio decreases and the anti-tilt angles of the layered planes increases, the safety factors of the slopes will gradually decrease. This study provided a feasible scheme for evaluating the seepage, deformations and stability of the anti-dipping layered rock slopes in southwest China’s Pulang area.

scholarly journals A Sensitivity Analysis of the Anisotropy of Hydraulic Conductivity to the Seepage, Deformation and Stability of Anti-dipping Layered Rock Slopes: A Case Study of the Pulang Area in Southwestern China

2021 ◽  
Author(s):  
Guangkeng Zhang ◽  
Guangyin Lu ◽  
Chengzhi Xia ◽  
Lianrong Wu ◽  
Zongming Xu ◽  
...  
Keyword(s):  
Anisotropy Ratio ◽  
Rock Slopes ◽  
Safety Factors ◽  
Water Conductivity ◽  
Conductivity Anisotropy ◽  
Layered Rock ◽  
Rock Formations ◽  
Layered Slope ◽  
Unsaturated Seepage

AbstractIn this paper, in order to study the influence of anisotropy ratios and anisotropy directions on the seepage, deformations and stability of the anti-dipping layered rock slopes, Geo-studio software was used in this study for the numerical analysis of carbonaceous slate slopes on the unsaturated seepage, fluid–solid coupling, and stability theory in Pulang area. The results showed that the maximum surface water content of the layered rock slopes gradually decreased with increases of the water conductivity anisotropy ratio and decreases in the anisotropy angle of the anti-dipping layered rock slopes. In addition, the rainfall infiltration depths in the middle sections of the slopes were observed to be the most affected by the anisotropy ratio and dip angles of the rock formations. Meanwhile, the bottom sections of slopes were the least affected by the anisotropy ratio and the dip angles of the rock formations. In regard to the anti-dipping rock slopes, it was found that the anisotropy ratio and rock layer dip angles should be considered in the deformation and stability analyses. When the seepage of an anti-dipping layered slope was considered to be isotropic, the safety factors often were overestimated. As the anisotropy ratio decreases and the anti-dipping angles of the layered planes increases, the safety factors of the slopes will gradually decrease. This study provided a feasible scheme for evaluating the seepage, deformations and stability of the anti-dipping layered rock slopes in southwest China’s Pulang area.

Model Test Study on Influences of Layered Rock Mass Dip Angle on Stability of Deep-Buried Tunnel

2011 ◽  
Vol 90-93 ◽  
pp. 2363-2371
Author(s):  
Bin Wei Xia ◽  
Ke Hu ◽  
Yi Yu Lu ◽  
Dan Li ◽  
Zu Yong Zhou
Keyword(s):  
Rock Mass ◽  
Physical Model ◽  
Model Test ◽  
Physical Models ◽  
Physical Model Test ◽  
Stress Distributions ◽  
Failure Characteristics ◽  
Layered Rock ◽  
Layered Rock Mass ◽  
Dip Angle

Physical models of layered rock mass with different dip angles are built by physical model test in accordance with the bias failure characteristics of surrounding rocks of layered rock mass in Gonghe Tunnel. Bias failure characteristics of surrounding rocks in thin-layered rock mass and influences of layered rock mass dip angle on stability of tunnel are studied. The research results show that failure characteristics of physical models generally coincide with those of surrounding rocks monitored from the tunnel site. The failure regions of surrounding rock perpendicular to the stratification planes are obviously larger than those parallel to. The stress distributions and failure characteristics in the surrounding rocks are similar to each physical model of different dip angles. The stress distributions and failure regions are all elliptic in shape, in which the major axis is in the direction perpendicular to the stratification planes while the minor axis is parallel to them. As a result, obvious bias failure of surrounding rocks has gradually formed. The physical model tests provide reliable basis for theoretical analysis on the failure mechanism of deep-buried layered rock mass.

scholarly journals New insights into the drainage of inundated ice-wedge polygons using fundamental hydrologic principles

2021 ◽  
Author(s):  
Dylan R. Harp ◽  
Vitaly Zlotnik ◽  
Charles J. Abolt ◽  
Brent D. Newman ◽  
Adam L. Atchley ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Aspect Ratio ◽  
Annular Region ◽  
Active Layer Thickness ◽  
Conductivity Anisotropy ◽  
Aspect Ratios ◽  
High Anisotropy ◽  
Vertical Hydraulic Conductivity ◽  
Depth Analysis ◽  
Ice Wedge

Abstract. The pathways and timing of drainage from inundated ice-wedge polygon centers in a warming climate have important implications for carbon flushing, advective heat transport, and transitions from carbon dioxide to methane dominated emissions. This research provides intuition on this process by presenting the first in-depth analysis of drainage from a single polygon based on fundamental hydrogeological principles. We use a recently developed analytical solution to provide a baseline for the effects of polygon aspect ratios (radius to thawed depth) and hydraulic conductivity anisotropy (horizontal to vertical hydraulic conductivity) on drainage pathways and temporal depletion of ponded water heights of inundated ice-wedge polygon centers. By varying the polygon aspect ratio, we evaluate the effect of polygon size (width), inter-annual increases in active layer thickness, and seasonal increases in thaw depth on drainage. One of the primary insights from the model is that most inundated ice-wedge polygon drainage occurs along an annular region of the polygon center near the rims. This implies that inundated polygons are most intensely flushed by drainage in an annular region along their horizontal periphery, with implications for transport of nutrients (such as dissolved organic carbon) and advection of heat towards ice wedge tops. The model indicates that polygons with large aspect ratios and high anisotropy will have the most distributed drainage. Polygons with large aspect ratio and low anisotropy will have their drainage most focused near the their periphery and will drain most slowly. Polygons with small aspect ratio and high anisotropy will drain most quickly. Our results, based on idealized scenarios, provide a baseline for further research considering geometric and hydraulic complexities of ice-wedge polygons.

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