Numerical Investigation on Dynamic Response and Failure Modes of Rock Slopes with Weak Interlayers Using Continuum-Discontinuum 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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Research on the Shock Response Characteristics of a Threaded Connection Using the Thin-Layer Element Method

Applied Sciences ◽

10.3390/app11125611 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5611

Author(s):

A’min Yan ◽

Xiaofeng Wang ◽

He Yang ◽

Fenglei Huang ◽

Aiguo Pi

Keyword(s):

Dynamic Response ◽

Thin Layer ◽

Contact Stiffness ◽

Maximum Error ◽

Elastic Model ◽

Material Parameters ◽

Response Characteristics ◽

Threaded Connection ◽

Constraint Method ◽

Element Method

Nonlinear factors such as the contact stiffness and friction damping at the threaded interface of a projectile–fuse system significantly affect the dynamic response characteristics. To obtain the dynamic response of the fuse body accurately during penetration, it is necessary to characterize these nonlinear factors reasonably. Because the existing structural dynamics software cannot effectively deal with nonlinear factors, the thin-layer element method was used to represent the nonlinear factors in this study. By combining the thread elastic model with thin-layer element principles, an effective method for determining the material parameters of the thin-layer element was established theoretically, which provided a different method of determining material parameters, not just relying on experiments. The accuracy of the material parameters was verified based on modal experiments with threaded tubes having different specifications. The errors were within 5%, indicating the reliability of the theoretical determination method for the material parameters. In addition, projectile penetration into a semi-infinite concrete target was tested to verify the accuracy of the thin-layer element modeling. Compared with the ‘TIED’ constraint method, the resonant frequency obtained with the thin-layer element method was in better agreement with that of the experimental data. The maximum error decreased from 15.7 to 7.8%, indicating that the thin-layer element method could accurately represent the nonlinear factors. Thus, this study serves as a reference for accurately evaluating the dynamic response of the fuse body of a penetrator.

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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.

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Dynamic Failure Mode and Dynamic Response of High Slope Using Shaking Table Test

Shock and Vibration ◽

10.1155/2019/4802740 ◽

2019 ◽

Vol 2019 ◽

pp. 1-19 ◽

Cited By ~ 10

Author(s):

Zhijun Zhou ◽

Chenning Ren ◽

Guanjun Xu ◽

Haochen Zhan ◽

Tong Liu

Keyword(s):

Dynamic Response ◽

Failure Modes ◽

Shaking Table Test ◽

Shaking Table ◽

Amplification Coefficient ◽

Seismic Load ◽

Dynamic Failure ◽

High Slope ◽

Amplification Effect ◽

Slope Line

A shaking table test was performed to study the dynamic response and failure modes of high slope. Test results show that PGA amplification coefficients increased with increasing elevation and the PGA amplification coefficient of the concave slope was slightly larger than that of the convex slope. The slope type affected the dynamic response of the slope. The elevation amplification effect of the concave slope under seismic load was more significant than that of the convex slope; thus, the concave slope was more unstable than the convex slope. Additionally, the PGA amplification coefficient measured on the slope surface was always larger than that inside the slope, and the data show an increasing trend with the broken line. The dynamic amplification effect of the high slope was closely related to the natural frequency of the slope. Within a certain range, the higher the frequency, the more significant the amplification effect. The dynamic failure process of concave and convex slopes was studied through tests. Findings indicate that the dynamic failure modes of the concave slope are characterized by shoulder collapse, formation of the sliding surface, and integral sliding above the slope line. Dynamic failure modes of the convex slope are mainly slips in the soil layer and collapse of the slope near the slope line.

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Study on the Vertical Acceleration Effect on Slope Stability

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.744-746.632 ◽

2015 ◽

Vol 744-746 ◽

pp. 632-640

Author(s):

Hong Gang Wu ◽

Tao Yang ◽

Zhi Wen Xue ◽

Hui Min Ma ◽

Hong Li Zhang ◽

...

Keyword(s):

Numerical Analysis ◽

Dynamic Response ◽

Near Field ◽

Seismic Stability ◽

Amplification Coefficient ◽

Vertical Acceleration ◽

Analysis Method ◽

Response Characteristics ◽

Dynamic Response Characteristics ◽

Peak Value

It is found from the earthquake statistics in recent decades that the vertical seismic oscillation of near field was strong. And even the recorded peak value of vertical seismic oscillation was far more than the peak value of horizontal seismic oscillation in some sites. In order to study the characteristics of vertical and horizontal seismic oscillation acceleration acted on the slope. Calculate the slope earthquake dynamic response characteristics under the horizontal and vertical seismic acceleration by the FLAC3D numerical analysis method. Compared the acceleration, velocity and the displacement amplification coefficient under two kinds of excitation. Analyzed the influence on seismic stability by the acceleration of different direction.

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