Effect of Tension Crack Formation on External Seismic Stability Analysis of Geosynthetic-Reinforced Soil Slopes
Publication: International Journal of Geomechanics
Volume 24, Issue 6
Abstract
A method to assess the influence of tension cracks on the seismic external stability analysis of geosynthetic-reinforced soil slopes is carried out in the present study. In addition to being subjected to uniform surcharge loading, hydrostatic and hydrodynamic pressures with water on both sides of the c-ϕ soil slope and seismic inertia forces are considered, and the reinforcement length for both sliding and overturning conditions is evaluated by using a two-part wedge mechanism. The analysis is implemented separately by considering and neglecting the effect of the formation of tension cracks, and reinforcement lengths are evaluated for both the slope angles 60° and 70°. It is seen that when the horizontal seismic acceleration coefficient increases from 0 to 0.2 for a 60° slope angle under the direct sliding mode of failure for a particular set of input parameters as shown in Table 3, the required minimum length of the geosynthetic reinforcement increases from 0.59H to 1.30H, and in the overturning mode, it increases from 0.46H to 0.60H, when the analysis is implemented without considering similar tension cracks when tension cracks are considered in the study, for the increases in kh, as mentioned previously, required minimum length of the geosynthetic reinforcement against direct sliding mode of failure increases from 0.80H to 1.67H, and increases from 0.55H to 0.64H for overturning mode of failure. In addition to kh, the influence of the height of water on the downstream side, pore pressure ratio, soil friction angle, cohesion, and surcharge on the length of reinforcement against sliding and overturning modes of failure are presented in this paper in the form of design charts. The results obtained from the present study are compared with the previous literatures and usefulness of the present method in analysis of reinforced soil slopes against direct sliding and overturning modes of failure has been proposed.
Practical Applications
The present research work delves into the external stability analysis of reinforced soil slopes. This analysis evaluates the optimal length of reinforcement necessary to maintain long-term safety and stability against potential failures, such as direct sliding and overturning. While direct sliding is influenced by forces pushing the slope forward, overturning is concerned with rotational risks. Geosynthetic reinforcement for soil slope stability plays a crucial role in stabilizing slopes across various infrastructures: highways, railways, airports, landfills, mining operations such as tailings dams and heap leach pads, urban developments, and erosion control measures along riverbanks and shorelines. Adopting the insights and methodologies of this research can amplify the safety benefits by reducing landslide risks and facilitating the customization of designs according to specific site conditions. This approach paves the way for a more efficient use of resources, ultimately slashing costs and bolstering the long-term reliability of slope performance. Furthermore, the study presents a clear analysis of geosynthetic-reinforced soil slopes, considering soil properties, failure risks, seismic forces, and water effects. This framework, suitable for both experts and novices, bridges academic research with practical engineering, making the latest insights usable and valuable for the engineering community.
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Data Availability Statement
Some or all data, models, or code generated or used during the study are proprietary or confidential in nature and may only be provided with restrictions. The MATLAB code developed to analyze the expression and obtain the results in the present study is confidential.
Notation
The following symbols are used in this paper:
- cn
- Normalized value of cohesion;
- Fd
- Driving forces;
- Fr
- Resisting forces;
- FS
- Factor of safety;
- H
- Height of slope;
- hwd
- Height of water in downstream side;
- hwu
- Height of water in upstream side;
- kh
- Horizontal seismic acceleration coefficient;
- kv
- Vertical seismic acceleration coefficient;
- lds
- Length of the reinforcement against direct sliding;
- Lo
- Normalized length of the reinforcement against overturning;
- lot
- Length of the reinforcement against overturning;
- Ls
- Normalized length of the reinforcement against direct sliding;
- Md
- Moments of driving forces about toe;
- Mr
- Moments of resisting forces about toe;
- Nb
- Normal force at failure plane;
- Pa
- Interwedge force for Wedge A;
- Pb
- Interwedge force for Wedge B;
- Pdyd
- Hydrodynamic pressure in downstream direction;
- Pdyu
- Hydrodynamic pressure in upstream direction;
- Pstd
- Hydrostatic pressure in downstream direction;
- Pstu
- Hydrostatic pressure in upstream direction;
- qn
- Normalized value of surcharge load;
- ru
- Pore pressure ratio;
- Sb
- Shear force acting along failure plane;
- Wa
- Weight of Wedge A;
- Wa2
- Weight of tension cracked zone of Wedge A;
- Wb
- Weight of Wedge B;
- Zc
- Depth of tension crack;
- α
- Backfill inclination.
- β
- Slope angle with the horizontal;
- θ
- Angle of failure plane;
- δ
- Inclination of interwedge force;
- γd
- Dry unit weight of backfill soil;
- γeq
- Equivalent unit weight of backfill soil;
- γsat
- Saturated unit weight of backfill soil;
- γw
- Unit weight of water;
- γwe
- Equivalent unit weight of water on downstream side;
- ϕ
- Soil friction angle;
- Summation of forces in horizontal direction; and
- Summation of forces in vertical direction;
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Published In
International Journal of Geomechanics
Volume 24 • Issue 6 • June 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Apr 6, 2023
Accepted: Dec 27, 2023
Published online: Apr 4, 2024
Published in print: Jun 1, 2024
Discussion open until: Sep 4, 2024
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