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

Symmetry ◽  
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.

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

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.

scholarly journals Dynamic Response of Rock Slopes under Obliquely Incident Seismic Waves

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.

scholarly journals Seismic Response of a Bridge Pile Foundation during a Shaking Table Test

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Yunxiu Dong ◽  
Zhongju Feng ◽  
Jingbin He ◽  
Huiyun Chen ◽  
Guan Jiang ◽  
...  
Keyword(s):  
Seismic Wave ◽  
Pile Foundation ◽  
Large Scale ◽  
Amplification Factor ◽  
Shaking Table Test ◽  
Seismic Intensity ◽  
Shaking Table ◽  
Acceleration Amplification ◽  
Bedrock Surface ◽  
Bridge Pile Foundation

Puqian Bridge is located in a quake-prone area in an 8-degree seismic fortification intensity zone, and the design of the peak ground motion is the highest grade worldwide. Nevertheless, the seismic design of the pile foundation has not been evaluated with regard to earthquake damage and the seismic issues of the pile foundation are particularly noticeable. We conducted a large-scale shaking table test (STT) to determine the dynamic characteristic of the bridge pile foundation. An artificial mass model was used to determine the mechanism of the bridge pile-soil interaction, and the peak ground acceleration range of 0.15 g–0.60 g (g is gravity acceleration) was selected as the input seismic intensity. The results indicated that the peak acceleration decreased from the top to the bottom of the bridge pile and the acceleration amplification factor decreased with the increase in seismic intensity. When the seismic intensity is greater than 0.50 g, the acceleration amplification factor at the top of the pile stabilizes at 1.32. The bedrock surface had a relatively small influence on the amplification of the seismic wave, whereas the overburden had a marked influence on the amplification of the seismic wave and filtering effect. Damage to the pile foundation was observed at 0.50 g seismic intensity. When the seismic intensity was greater than 0.50 g, the fundamental frequency of the pile foundation decreased slowly and tended to stabilize at 0.87 Hz. The bending moment was larger at the junction of the pile and cap, the soft-hard soil interface, and the bedrock surface, where cracks easily occurred. These positions should be focused on during the design of pile foundations in meizoseismal areas.

Dynamic Behaviour of Minimum Platforms Under Random Seas

2003 ◽  
Author(s):  
Micaela Pilotto ◽  
Beverley F. Ronalds
Keyword(s):  
Dynamic Response ◽  
Dynamic Behaviour ◽  
Amplification Factor ◽  
Finite Element Models ◽  
Dynamic Amplification Factor ◽  
Maximum Value ◽  
Random Seas ◽  
Exponential Stretching ◽  
Structural Configurations ◽  
Dynamic Amplification

This paper describes the dynamic response of minimum facilities with different structural configurations which are subjected to random seas. The finite element models are kept simple with the aim of focusing on the physics of the phenomena involved. The response is studied in terms of the dynamic amplification factor (DAF), representing the ratio between the dynamic and the static response. Two different formulations of the DAF under random seas are compared. The first is defined in terms of standard deviation (DAF1), the second in terms of the most probable maximum value (DAF2). Ringing is observed to be a relevant feature of the dynamic response and to affect primarily the braced monopod configurations. Ringing is detected using DAF2. The paper also addresses the importance of the kinematic representation above the still water level. Different methods of stretching the velocity field in the wave zone (delta, Wheeler and exponential stretching) are shown to have a significant impact on the dynamic response of the platforms.

scholarly journals Failure Mechanism of Rock Slopes under Different Seismic Excitation

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.

Laws of Influence upon Dynamic Response of High Rock Slope by Seismic Wave Frequency

2012 ◽  
Vol 170-173 ◽  
pp. 615-625
Author(s):  
Shi Guo Xiao ◽  
Guang Cen Zhu ◽  
Jing Kai Li
Keyword(s):  
Dynamic Response ◽  
Shear Strain ◽  
Seismic Wave ◽  
Rock Slope ◽  
Simulation Analysis ◽  
Time History ◽  
Wave Frequency ◽  
Principal Stresses ◽  
Response Characteristics ◽  
High Rock Slope

On the basis of seismic wave recorded by Wolong Measuring Station in Wenchuan Earthquake occurred on May 12, 2008, and taking a high rock slope (about 1397m in height) at the bank of Zipingpu Reservoir as the specific example, analyses have been made, with Plaxis dynamical simulation analysis program, on characteristics of influence upon acceleration time history, shear strain distribution, principal stresses distribution and stability of high rock slope by original seismic wave, and seismic wave with frequency expanded by 1.5, 2 and 3 times, respectively. Results of the analyses demonstrate that dynamic response characteristics of the slope top are notably influenced by multiplication factor of seismic wave frequency. As far as the real slope in this article is concerned, it generally presents a gradual decrease of PGA of the top of high rock slope, reduction of slope body shear strain and a corresponding drop of dynamic response of slope body as a whole, with the increase of seismic wave frequency.

scholarly journals Research on Seismic Dynamic Response Characteristics of Weak Surrounding Rock Slope With Double-Arch Tunnel

2021 ◽  
Author(s):  
Xueliang Jiang ◽  
Yonghui Qian ◽  
Jiqi Zhang ◽  
Yong Liu ◽  
RiWe Deng ◽  
...  
Keyword(s):  
Seismic Wave ◽  
Amplification Factor ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Dynamic Displacement ◽  
Displacement Response ◽  
Response Characteristics ◽  
Acceleration Amplification ◽  
Dynamic Response Characteristics ◽  
Peak Value

Abstract Through the shaking table test, Wenchuan wave (WC) was used as the excitation wave of the shaking table test. The vibration was excited in three directions: horizontal (x), vertical (z), and horizontal and vertical (xz) and the dynamic response characteristics of rock slopes was studied. The results show:(1) The acceleration amplification factor of each measuring point of the slope shows a nonlinear increasing trend with the increase of the slope height.The slope changes the frequency spectrum of the loaded seismic wave.The slope has a filtering effect on the high frequency band of the seismic wave.(2) Under the unidirectional cyclic loading of Wenchuan wave, the slope acceleration amplification factor increases with the increase of the peak value of the seismic wave. Under the bi-directional excitation of Wenchuan wave, the slope acceleration amplification coefficient generally decreases with the increase of the peak value of the seismic wave.The slope acceleration amplification factor presents the characteristics of first increasing and then decreasing with the increase of the relative height of the slope.(3) The dynamic displacement response characteristics of the tunnel slope with double-arch tunnel are mainly affected by the seismic wave in the same direction and the peak value of the dynamic displacement response increases with the increase of the seismic wave peak value.(4) The peak dynamic displacement response of the double-arch tunnel slope shows a non-linear change trend with the increase of slope height. The dynamic displacement peak growth rate is slower below the rock interface and the dynamic displacement peak increases rapidly above the interface and Maximum displacement occurred at the top of the slope.

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