Failure Mechanism of Rock Slopes under Different Seismic Excitation

In earthquake-prone areas, special attention should be paid to the study of the seismic stability of rock slope. Particularly, it becomes much more complicated for the rock slopes with weak structural surfaces. In this study, numerical simulation and the shaking table test are carried out to analyze the influence of seismic excitation and structural surface in different directions on dynamic response of rock slope. Huaping slope with bedding structural surfaces and Lijiang slope with discontinuous structural surfaces besides Jinsha River in Yunnan Province are taken as research objects. The results of numerical simulation and the model test both show that discontinuous structure surface has influence on the propagation characteristics of seismic wavefield. For Huaping slope, the seismic wavefield responses repeatedly between the bedding structural surface and slope surface lead to the increase of the amplification effect. The maximum value of seismic acceleration appears on the empty surface where terrain changes. Horizontal motion plays a leading role in slope failure, and the amplification coefficient of horizontal seismic acceleration is about twice that of vertical seismic acceleration. The failure mode is integral sliding along the bedding structural surface. For Lijiang slope, seismic acceleration field affected by complex structural surface is superimposed repeatedly in local area. The maximum value of seismic acceleration appears in the local area near slope surface. And the dynamic response of slope is controlled by vertical and horizontal motion together. Under the seismic excitation with an intense of 0.336 g in X direction and Z direction, the amplification coefficients of seismic acceleration of Lijiang slope are 3.23 and 3.18, respectively. The vertical motion leads to the cracking of the weak structural surface. Then, Lijiang slope shows the toppling failure mode under the action of horizontal motion.

Download Full-text

Dynamic Response Differences Between Bedding and Counter-Tilt Rock Slopes with Intercalated Weak Layers

Journal of Disaster Research ◽

10.20965/jdr.2016.p0681 ◽

2016 ◽

Vol 11 (4) ◽

pp. 681-690

Author(s):

Song Zhi ◽

◽

Liu Yang ◽

◽

...

Keyword(s):

Dynamic Response ◽

Rock Slope ◽

Surface Displacement ◽

Amplification Coefficient ◽

Rock Slopes ◽

Relative Height ◽

Slope Surface ◽

Weak Layer ◽

Acceleration Amplification ◽

Bedding Rock Slope

Bedding and counter-tilt rock slope with intercalated weak layers are common geological bodies in west China, the dynamic response research will guide the anti-seismic reinforcement of bedding and counter-tilt rock slope with intercalated weak layer effectively. Two test models of bedding rock slope with intercalated weak layer and counter-tilt rock slope with intercalated weak layer, which are in the same size, have been designed and developed. A large scale shaking table test has been performed to analyze the dynamic response difference of bedding and counter-tilt rock slope with intercalated weak layer. The study results show that the acceleration amplification coefficient inside the bedding slope is smaller than that inside the counter-tilt rock slope; at the middle and upper parts of the slope body (relative height > 0.4), the acceleration amplification coefficient at bedding rock slope surface is larger than that of counter-tilt rock slope. At the lower part of the slope (relative height le 0.4), the acceleration amplification coefficient at bedding rock slope surface is close to that of counter-tilt rock slope. The slope surface displacement of both bedding and counter-tilt rock slopes increases with increasing input seismic wave amplitude. The slope surface displacement of the bedding rock is larger than that of counter-tilt rock slope. The seismic stability of counter-tilt rock slope is stronger than bedding rock slope. The dynamic failure form of bedding rock slope mainly includes vertical tension crack at back edge, bedding sliding along intercalated weak layer and rock collapse at slope crest; whereas the dynamic failure form of counter-tilt slope mainly includes intersection of horizontal and vertical cracks on slope surface, extrusion of intercalated weak layer and shattering of slope crest.

Download Full-text

Dynamic Response and Failure Process of a Counter-Bedding Rock Slope under Strong Earthquake Conditions

Symmetry ◽

10.3390/sym14010103 ◽

2022 ◽

Vol 14 (1) ◽

pp. 103

Author(s):

Ming-Zhu Guo ◽

Kun-Sheng Gu ◽

Chen Wang

Keyword(s):

Dynamic Response ◽

Seismic Wave ◽

Rock Slope ◽

Amplification Factor ◽

Failure Process ◽

Slope Surface ◽

Maximum Value ◽

Acceleration Amplification ◽

Weak Intercalated Layer ◽

Bedding Rock Slope

There are massive landslides and potential landslides along the Three Rivers Basin in the Qinghai–Tibet Plateau, which pose a serious threat to the Sichuan–Tibet Railway. A normal shaking table model test was conducted to study the dynamic characteristics and dynamic response of a symmetrical counter-bedding rock slope based on the Zongrong Village landslide. The influences of the dynamic parameters, seismic wave type, and a weak intercalated layer on the slope’s dynamic response were considered. The results showed symmetry between the growth trend of the acceleration amplification factor and other research results. When the input wave amplitude was constant, the acceleration amplification factor increased at first and then decreased as the frequency increased. When the input frequency was near the slope’s natural frequency, the acceleration amplification factor increased at first and then decreased with an increase in the input amplitude and reached the maximum value at 0.3 g. The acceleration amplification factor increased linearly with height in the vertical direction inside the slope but increased slowly at first and then sharply along the slope surface, reaching the maximum value at the slope’s top and exhibiting an obvious “elevation effect”. When sinusoidal waves, Wolong waves, and Maoxian waves with the same amplitude were input, the slope’s amplification effect on the bedrock wave was more obvious. The weak intercalated layer showed the phenomenon of “thin layer amplification” and “thick layer attenuation” in response to the input seismic wave. The slope’s failure process can be roughly divided into three stages: (1) the formation of tensile cracks at the top and shear cracks at the toe; (2) the extension of cracks and the sliding of the slope-surface block; (3) the formation of the main sliding surface.

Download Full-text

Soil-Rock Slope Stability Analysis by Considering the Nonuniformity of Rocks

Mathematical Problems in Engineering ◽

10.1155/2018/3121604 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 6

Author(s):

Shunqing Liu ◽

Xianwen Huang ◽

Aizhao Zhou ◽

Jun Hu ◽

Wei Wang

Keyword(s):

Stability Analysis ◽

Slope Stability ◽

Relative Position ◽

Rock Slope ◽

Slope Stability Analysis ◽

Rock Slope Stability ◽

Rock Slopes ◽

Analysis Method ◽

Slope Surface ◽

The World

Soil-rock slopes are widely distributed around the world, while the commonly adopted method by simplifying it as a uniform media tends to be excessively conservative. In this study, a slope stability analysis method considering the nonuniform characteristics of rocks was proposed. It was found that the distribution, relative position, and shape of rock have significant effect on slope stability. For the influence of distribution, large rocks at the foot of slope have the most significant effect on slope stability while the effect is insignificant when the rocks are on the slope surface. In terms of the relative position of rocks, four plastic expansion modes of bypass, diversion, inclusion, and penetration were put forward through the analysis on the expansion mode of the plastic zone. Moreover, rock shape also has influence on slope stability.

Download Full-text

Observation of the rock slope thermal regime, coupled with crackmeter stability monitoring: initial results from three different sites in Czechia (central Europe)

Geoscientific Instrumentation Methods and Data Systems ◽

10.5194/gi-10-203-2021 ◽

2021 ◽

Vol 10 (2) ◽

pp. 203-218

Author(s):

Ondřej Racek ◽

Jan Blahůt ◽

Filip Hartvich

Keyword(s):

Time Series ◽

Air Temperature ◽

Thermal Regime ◽

Rock Slope ◽

Slope Aspect ◽

Rock Slopes ◽

Slope Surface ◽

Rock Face ◽

Diurnal Temperature ◽

Temperature Cycles

Abstract. This paper describes a newly designed, experimental, and affordable rock slope monitoring system. This system is being used to monitor three rock slopes in Czechia for a period of up to 2 years. The instrumented rock slopes have different lithology (sandstone, limestone, and granite), aspect, and structural and mechanical properties. Induction crackmeters monitor the dynamic of joints, which separate unstable rock blocks from the rock face. This setup works with a repeatability of measurements of 0.05 mm. External destabilising factors (air temperature, precipitation, incoming and outgoing radiation, etc.) are measured by a weather station placed directly within the rock slope. Thermal behaviour in the rock slope surface zone is monitored using a compound temperature probe, placed inside a 3 m deep subhorizontal borehole, which is insulated from external air temperature. Additionally, one thermocouple is placed directly on the rock slope surface. From the time series measured to date (the longest since autumn 2018), we are able to distinguish differences between the annual and diurnal temperature cycles of the monitored sites. From the first data, a greater annual joint dynamic is measured in the case of larger blocks; however, smaller blocks are more responsive to short-term diurnal temperature cycles. Differences in the thermal regime between the sites are also recognisable and are caused mainly by different slope aspect, rock mass thermal conductivity, and colour. These differences will be explained by the statistical analysis of longer time series in the future.

Download Full-text

Assessment of Slope Instability and Risk Analysis of Road Cut Slopes in Lashotor Pass, Iran

Journal of Geological Research ◽

10.1155/2014/763598 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 3

Author(s):

Mohammad Hossein Taherynia ◽

Mojtaba Mohammadi ◽

Rasoul Ajalloeian

Keyword(s):

Rock Mass ◽

Risk Analysis ◽

Rock Slope ◽

Classification Systems ◽

Slope Instability ◽

Rock Slope Stability ◽

Rock Slopes ◽

The Stability ◽

Cut Slopes ◽

Road Cut Slopes

Assessment of the stability of natural and artificial rock slopes is an important topic in the rock mechanics sciences. One of the most widely used methods for this purpose is the classification of the slope rock mass. In the recent decades, several rock slope classification systems are presented by many researchers. Each one of these rock mass classification systems uses different parameters and rating systems. These differences are due to the diversity of affecting parameters and the degree of influence on the rock slope stability. Another important point in rock slope stability is appraisal hazard and risk analysis. In the risk analysis, the degree of danger of rock slope instability is determined. The Lashotor pass is located in the Shiraz-Isfahan highway in Iran. Field surveys indicate that there are high potentialities of instability in the road cut slopes of the Lashotor pass. In the current paper, the stability of the rock slopes in the Lashotor pass is studied comprehensively with different classification methods. For risk analyses, we estimated dangerous area by use of the RocFall software. Furthermore, the dangers of falling rocks for the vehicles passing the Lashotor pass are estimated according to rockfall hazard rating system.

Download Full-text

ROCK SLOPE SURFACE STABILITY ANALYSIS: A CASE STUDY ON HON LON ISLAND, KIEN HAI DISTRICT, KIEN GIANG PROVINCE, VIETNAM

Journal of Southwest Jiaotong University ◽

10.35741/issn.0258-2724.56.5.29 ◽

2021 ◽

Vol 56 (5) ◽

pp. 340-350

Author(s):

Ngoc Binh Vu ◽

Truong Thanh Phi ◽

Thanh Cong Nguyen ◽

Hong Thinh Phi ◽

Quy Nhan Pham ◽

...

Keyword(s):

Slope Failure ◽

Rock Slope ◽

Slope Surface ◽

Plane Failure ◽

Surface Stability ◽

Average Percentage ◽

The Road ◽

Wedge Failure ◽

Analytical Results

The research aimed to study 24 rock slope surfaces along the road around Hon Lon Island, Kien Hai district, Kien Giang province, Vietnam. The analytical results have determined slope failure, wedge failure, and toppling, which occurred on almost slope surface and the average percentage of plane failure is the largest. The average percent of plane failure is 19.23%, the wedge failure is 15.35%, and the toppling fault is 6.73%. Besides, the analytical results have also identified the slope surfaces which can be the key blocks: ND-13, 18, 23, 25, 34, 37, 45, 51, 62, 63. The other analytical results show that the existence of key blocks at the rock slope surfaces in the N-S direction, dip to E at the survey locations: ND-13, 23, 63 and dip to W at the survey locations: ND-37, 45; in the NE-SW direction, dip to SE at the survey locations: ND-15, 62 and dip to NW at the survey locations: ND-18, 34; in the NW-SE direction, dip to SW at the survey location ND-51. These results have important significance to support for protecting slope surface safety.

Download Full-text

An algorithm for the 3D ROck Slope Kinematic Analysis (ROKA) based on RPAS digital photogrammetry data.

10.5194/egusphere-egu21-12323 ◽

2021 ◽

Author(s):

Niccolò Menegoni ◽

Daniele Giordan ◽

Cesare Perotti

Keyword(s):

Kinematic Analysis ◽

Rock Slope ◽

Traditional Approach ◽

Rock Slopes ◽

Digital Photogrammetry ◽

Modes Of Failure ◽

Wedge Sliding ◽

Flexural Toppling ◽

The Stability ◽

Digital Outcrop

<p>Among the several adopted methods for the kinematic analysis of the possible modes of failure that could affect a rock slope, the Markland test is the most used. Whereas, it has the advantage of being simple and fast, it has some limits, as the impossibility to manually consider the several different slope orientations and their interaction with the discontinuity dimensions and positions.</p><p>Recently, the improvements in the Remote Piloted Aerial System (RPAS) digital photogrammetry techniques for the development and mapping of Digital Outcrop Models (DOMs) have given the possibility of developing new automatized digital approaches. In this study, ROKA (ROck slope Kinematic Analysis) algorithm is presented. It is an open-source algorithm, written in MATLAB language, which aims to perform the kinematic analysis of the stability of a rock slope using the discontinuity measurements collected onto 3D DOMs. Its main advantage is the possibility to identify the possible critical combination between the 3D georeferenced discontinuities and the local surface of the slope. In particular, the critical combinations that can activate the planar sliding, flexural toppling, wedge sliding and direct toppling modes of failures can be detected and highlighted directly on the DOM. Hence, the ROKA algorithm can make the traditional approach for the kinematic analysis of a rock slope more effective, allowing not only to simplify the analysis, but also to increase its detail. This can be very important, in particular, for the analysis of large and complex rock slopes.</p>

Download Full-text

Dynamic Response of Rock Slopes under Obliquely Incident Seismic Waves

Advances in Civil Engineering ◽

10.1155/2020/8859584 ◽

2020 ◽

Vol 2020 ◽

pp. 1-19

Author(s):

Biao Liu ◽

Boyan Zhang

Keyword(s):

Dynamic Response ◽

Peak Ground Acceleration ◽

Rock Slope ◽

Incident Angle ◽

Slope Angle ◽

Amplification Coefficient ◽

Slope Surface ◽

Ground Acceleration ◽

Obliquely Incident ◽

Acceleration Amplification

In this study, the seismic input model of slope is proposed to investigate the dynamic response of the rock slope under obliquely incident seismic wave on the basis of the time-domain wave analysis method. The model includes viscoelastic boundary considering the infinite foundation radiation damping and the seismic obliquely incident method. The semi-infinite space numerical example is simulated to verify the validity and accuracy of the model. Based on the established model, the effects of the variation of the seismic wave incident angles and slope angles on the dynamic response of a rock slope are analyzed. The results demonstrate that the changes of the incident angle and the slope angle have no discernible effect on the dynamic response of the rock slope when the P wave is obliquely incident. As the SV wave is obliquely incident, the peak ground acceleration amplification coefficient along the slope surface gradually increases with the increase of the incident angle; when the slope angle gradually increases, the peak ground acceleration amplification coefficient along the slope surface will also gradually increase at the upper part of the slope. The research results can provide some basis for the pseudostatic method to determine the seismic action coefficient.

Download Full-text

Study on Failure Mechanism and Prevention Measures of Typical Rock Slope in Tibetan Plateau

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.587-589.1012 ◽

2014 ◽

Vol 587-589 ◽

pp. 1012-1020

Author(s):

Jie Zhao

Keyword(s):

Tibetan Plateau ◽

Positive Reinforcement ◽

Rock Slope ◽

Sliding Mode ◽

Geological Structure ◽

Climatic Conditions ◽

Natural State ◽

Rock Slopes ◽

Prevention Measures ◽

Reinforcement Measures

The special geographical, climatic conditions and geological structure in Tibetan Plateau making high steep rock slopes along the valleys wide-spread in this area, and they are especially common in the construction of highways. In this study, geological genesis and potential sliding mode are discussed firstly, then numerical model results as well as actual data are used to analyze the cause and influence depth of unloading fissures. Finally, common problems exist in rock slope are summed up. Based on these, natural state, disturbed state and steady state after reinforcement are analyzed respectively. It is believed that rock slopes in this area should be considered to minimize unloading, changing their shapes, and should try to reinforce actively or take positive reinforcement measures, so that the disturbance caused by rock soil environment will be effectively controlled, and the ecological restoration work will be done.

Download Full-text