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

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.

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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.

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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.

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Seismic Response of Rock Slopes with the Anchor Cable in Centrifuge Modeling Tests

Advances in Civil Engineering ◽

10.1155/2020/8170258 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Yong Nie ◽

Yufei Zhao ◽

Xiaogang Wang ◽

Linhao Li ◽

Hongtao Zhang

Keyword(s):

Seismic Response ◽

Rock Slope ◽

Centrifuge Modeling ◽

Amplification Coefficient ◽

Rock Slopes ◽

Acceleration Response ◽

Structural Plane ◽

Horizontal Acceleration ◽

Anchor Cable ◽

Acceleration Amplification

In order to study the seismic response of the rock slopes with the anchor cable, centrifuge modeling tests were performed on concrete slope models. Different seismic loadings were performed to investigate the horizontal acceleration response, the rock slope displacement, and the stress of anchor cables. The results show that the horizontal acceleration response is obviously amplified by a rock slope. Under the same conditions, the higher the seismic intensity is, the larger the acceleration amplification coefficient will be. Anchor cable can effectively reduce the acceleration amplification effect of the slope. For the slope with a structural plane, the anchor cable at the structural plane is stressed greatly during the seismic action, and the strength of anchor cables near the expected structural plane is important.

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Numerical Investigation on Dynamic Response and Failure Modes of Rock Slopes with Weak Interlayers Using Continuum-Discontinuum Element Method

Frontiers in Earth Science ◽

10.3389/feart.2021.791458 ◽

2021 ◽

Vol 9 ◽

Author(s):

Chengwen Wang ◽

Xiaoli Liu ◽

Danqing Song ◽

Enzhi Wang ◽

Jianmin Zhang

Keyword(s):

Dynamic Response ◽

Failure Modes ◽

Failure Process ◽

Amplification Coefficient ◽

Rock Slopes ◽

Earthquake Excitation ◽

Good Correspondence ◽

Response Characteristics ◽

Damage Degree ◽

Element Method

In order to better understand the dynamic response and failure modes of rock slopes containing weak interlayers subjected to earthquake excitation, a series of numerical simulations were carried out using the continuum-discontinuum element method (CDEM), considering the influence of seismic amplitude and weak interlayers inclination. The seismic response characteristics of slopes were systematically analyzed according to the waveform characteristics, amplification effect, equivalent crack ratio, etc. The numerical results show that the acceleration waveform characteristics and peak ground displacement (PGD) amplification coefficient have good correspondence with the dynamic failure process of landslides. Comprehensive analysis of waveform characteristics and PGD amplification coefficient can determine the damage time, damage location, and damage degree of landslides. The landslide process can be divided into three stages according to the equivalent crack ratio: rapid generation of a large number of microcracks, expansion and aggregation of microcracks, and penetration of micro-cracks and the formation of slip surfaces. The equivalent crack ratio provides a new idea for evaluating slope stability. In addition, under the combination of different amplitudes and weak interlayers, these earthquake-induced landslides exhibit different failure modes: the failure of the gentle-dip slope is mainly local rockfall; The mid-dip and steep-dip slopes with small amplitudes experience “tensile cracking-slip-collapsing” failure; The steep-dip slopes under strong earthquake failed in the form of “tensile cracking-slip-slope extrusion-collapsing”. The research results are of great significance for a deeper understanding of the formation mechanism of rock landslides with weak interlayers and the prevention of such landslide disasters.

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Failure Mechanism of Rock Slopes under Different Seismic Excitation

Advances in Materials Science and Engineering ◽

10.1155/2021/8866119 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Hua Tang ◽

Zhenjun Wu ◽

Ailan Che ◽

Conghua Yuan ◽

Qin Deng

Keyword(s):

Rock Slope ◽

Local Area ◽

Seismic Excitation ◽

Horizontal Motion ◽

Rock Slopes ◽

Slope Surface ◽

Seismic Acceleration ◽

Maximum Value ◽

Structural Surface ◽

Seismic Wavefield

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.

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Shear Effects on the Anchorage Interfaces and Seismic Responses of a Rock Slope Containing a Weak Layer under Seismic Action

Mathematical Problems in Engineering ◽

10.1155/2020/1424167 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Zhe Long ◽

Zhi-xin Yan ◽

Chun-bo Liu

Keyword(s):

Shear Stress ◽

Rock Slope ◽

Theoretical Research ◽

Amplification Coefficient ◽

Seismic Action ◽

Seismic Responses ◽

Weak Layer ◽

Peak Shear Stress ◽

Shear Effects ◽

Rock And Soil

The shear effects on the anchorage interfaces under seismic action is a key problem requiring urgent investigation in the field of rock and soil anchorages. In this paper, the model of rock slope with a weak layer was constructed by pouring, and the large-scale shaking table model test was completed. The shear strain on the anchorage interfaces and the acceleration of the slope were collected using built measurement systems. The shear effects on the two anchorage interfaces (a bolt-grout interface and a grout-rock interface) and seismic responses of the slope under seismic action were investigated. The distribution laws of the shear stress on the two anchorage interfaces along the axial direction of the bolt under seismic action were gained. The variations of the peak acceleration amplification coefficient on the slope surface, the magnitude, and the growth rate of peak shear stress on the anchorage interfaces under seismic action with different excitation directions and intensities were obtained. Furthermore, the positive relationship between the shear effect on the anchorage interfaces and the seismic response of slope was revealed. This study provides support for theoretical research, numerical simulation analysis, and aseismic design of rock and soil anchorages under dynamic conditions.

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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.

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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.

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