scholarly journals Displacement of Pile-Reinforced Slopes with a Weak Layer Subjected to Seismic Loads

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Haizuo Zhou ◽  
Gang Zheng ◽  
Xinyu Yang ◽  
Yu Diao ◽  
Lisen Gong ◽  
...  
Keyword(s):  
Failure Mechanism ◽  
Seismic Stability ◽  
Collapse Mechanism ◽  
Acceleration Coefficient ◽  
Stabilizing Piles ◽  
Weak Layer ◽  
Stability Of Slopes ◽  
Reinforced Slopes ◽  
Critical Yield ◽  
Yield Acceleration

The presence of a weak layer in a slope requires special attention because it has a negative impact on slope stability. However, limited insight into the seismic stability of slopes with a weak layer exists. In this study, the seismic stability of a pile-reinforced slope with a weak thin layer is investigated. Based on the limit analysis theory, a translational failure mechanism for an earth slope is developed. The rotational rigid blocks in the previous rotational-translational failure mechanism are replaced by continuous deformation regions, which consist of a sequence ofnrigid triangles. The predicted static factor of safety and collapse mechanism in two typical examples of slopes with a weak layer compare well with the results obtained from the available literature and by using the Discontinuity Layout Optimization (DLO) technique. The lateral forces provided by the stabilizing piles are evaluated using the theory of plastic deformation. An analytical solution for estimating the critical yield acceleration coefficient for the pile-reinforced slopes is derived. Based on the proposed translational failure mechanism and the corresponding critical yield acceleration coefficient, Newmark’s analytical procedure is employed to evaluate the cumulative displacement. Considering different real earthquake acceleration records as input motion, the effect of stabilizing piles and varying the spacing of piles on the cumulative displacement of slopes with a weak layer is investigated.

scholarly journals Upper-Bound Multi-Rigid-Block Solutions for Seismic Performance of Slopes with a Weak Thin Layer

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Gang Zheng ◽  
Xinyu Yang ◽  
Haizuo Zhou ◽  
Da Ha ◽  
Tianqi Zhang
Keyword(s):  
Thin Layer ◽  
Failure Mechanism ◽  
Seismic Performance ◽  
Upper Bound ◽  
Limit Analysis ◽  
Slope Angle ◽  
Rigid Block ◽  
Acceleration Coefficient ◽  
Critical Yield ◽  
Yield Acceleration

The presence of a weak layer has an adverse influence on the seismic performance of slopes. The upper-bound solution serves as a rigorous method in the stability analysis of geotechnical problems. In this study, a multi-rigid-block solution based on the category of the upper-bound theorem of limit analysis is presented to examine the seismic performance of nonhomogeneous slopes with a weak thin layer. Comparison of the static factors of safety is conducted with various solutions (i.e., limit analysis with a different failure mechanism, limit equilibrium solution, and numerical method), and the results exhibit reasonable consistency. An analytical solution in estimating the critical yield acceleration coefficient is derived, and the influence of slope angle, slope height, and soil strength on the critical yield acceleration coefficient and failure mechanism is analyzed. Subsequently, Newmark’s analytical procedure is employed to evaluate cumulative displacement with various real earthquake acceleration records as input motion. Results show that the strength and geometric parameters have a remarkable influence on the critical yield acceleration coefficient, and the cumulative displacement increases with the increasing slope angle.

scholarly journals Stability of Slopes Reinforced with Truncated Piles

2016 ◽  
Vol 2016 ◽  
pp. 1-16
Author(s):  
Shu-Wei Sun ◽  
Fu Zhao ◽  
Kui Zhang
Keyword(s):  
Slip Surface ◽  
Influential Factors ◽  
Point Of View ◽  
Optimum Ratio ◽  
Weak Layer ◽  
Stability Of Slopes ◽  
Engineering Technique ◽  
Shear Strength Reduction Method ◽  
Practical Engineering ◽  
The Stability

Piles are extensively used as a means of slope stabilization. A novel engineering technique of truncated piles that are unlike traditional piles is introduced in this paper. A simplified numerical method is proposed to analyze the stability of slopes stabilized with truncated piles based on the shear strength reduction method. The influential factors, which include pile diameter, pile spacing, depth of truncation, and existence of a weak layer, are systematically investigated from a practical point of view. The results show that an optimum ratio exists between the depth of truncation and the pile length above a slip surface, below which truncating behavior has no influence on the piled slope stability. This optimum ratio is bigger for slopes stabilized with more flexible piles and piles with larger spacing. Besides, truncated piles are more suitable for slopes with a thin weak layer than homogenous slopes. In practical engineering, the piles could be truncated reasonably while ensuring the reinforcement effect. The truncated part of piles can be filled with the surrounding soil and compacted to reduce costs by using fewer materials.

The Implementation of the Gradual Movement of Sliding Blocks to a New Method for Evaluating the Seismic Stability of Slopes Reinforced by Geotextile

2018 ◽  
Vol 12 (04) ◽  
pp. 1841010
Author(s):  
Tadashi Kawai ◽  
Makoto Ishimaru
Keyword(s):  
Seismic Performance ◽  
Nuclear Power ◽  
Power Plants ◽  
Slope Failure ◽  
Failure Process ◽  
Tohoku Earthquake ◽  
Seismic Stability ◽  
Centrifuge Tests ◽  
Stability Of Slopes ◽  
Design Basis

Evaluating the seismic stability of a rock slope typically involves searching for the minimum value of calculated safety factors (SF) for each supposed sliding block. Because only the transient equilibrium is evaluated, the likelihood of any slope failure can be deemed negligible if all the calculated SFs are greater than unity. However, even if some of the calculated SF are less than unity, it cannot be assumed that the slope will collapse. Recently, in the wake of extremely large earthquakes in Japan, the design earthquake standards for nuclear power plants (NPP) have been extended. After the experience of the 2011 off the Pacific coast of Tohoku Earthquake, the designer is expected to consider beyond design basis earthquakes to determine whether more can reasonably be done to reduce the potential for damage, especially where major consequences may ensue [IAEA (2011). IAEA international fact finding expert mission of the Fukushima dai-ichi NPP accident following the Great East Japan Earthquake and Tsunami, Mission report, IAEA]. With this in mind, the method employed to evaluate the seismic performance of the slope surrounding an NPP needs to be capable of doing more than determining the likelihood of failure: it must also consider the process toward failure in the event of an earthquake beyond the design basis. In this paper, a new evaluation flow which considers the failure process is proposed to evaluate the seismic performance of slopes surrounding an NPP. This is followed by confirming the validity of the concepts in the proposed flow chart by re-evaluating centrifuge tests in past literature and the numerical simulations designed for those tests.

Three-dimensional seismic stability of slopes reinforced by soil nails

2020 ◽  
Vol 127 ◽  
pp. 103768 ◽  
Author(s):  
Tao Yang ◽  
Jin-Feng Zou ◽  
Qiu-Jing Pan
Keyword(s):  
Three Dimensional ◽  
Seismic Stability ◽  
Soil Nails ◽  
Stability Of Slopes

Analysis of a rock slope with internal dilation

1984 ◽  
Vol 21 (4) ◽  
pp. 605-620 ◽  
Author(s):  
C. D. Martin ◽  
P. K. Kaiser
Keyword(s):  
Failure Mechanism ◽  
Rock Slope ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Back Analysis ◽  
Hydroelectric Project ◽  
Limit Equilibrium Methods ◽  
Slide Mass ◽  
Stability Of Slopes

A class of rock slope failures exists in which the mode of failure requires the existence or creation of internal shears to accommodate large internal slide mass distortion. These internal displacements are required to allow motion along the basal slip surface. This paper demonstrates that the more traditional limit equilibrium methods of analysis are often conservative when used to assess the stability of slopes with this failure mechanism. As a result, back analysis may overestimate the available shear resistance. A method of analysis capable of handling this failure mechanism was proposed by S. K. Sarma. A case history from the Revelstoke Hydroelectric Project, British Columbia, is used to demonstrate that these internal shears were required for movement to occur and that passive anchors inside the sliding rock mass can be used to improve the overall slope stability. No attempt is made to evaluate the actual factor of safety of the three-dimensional slide mass. Key words: rock slope, foliation shear, stability analysis, dilation, internal shears, passive anchors.

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