scholarly journals Dynamic Response Characteristics of Aeolian Sediment along Sichuan-Tibet Railway

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Kan Han ◽  
Chunxiao Xue

In order to reduce the damage of liquefaction of aeolian sand along the Sichuan-Tibet railway, the dynamic response characteristics of saturated aeolian sand in the study area were discussed by using shaking table test. The results show that the macroscopic characteristics of saturated aeolian sand in the study area are subsidence, water flow and fracture. The displacement time history shows that the surface displacement increases with increasing the input ground motion acceleration. When the acceleration is small (0.1g), the vibration in the soil layer has an obvious tendency to enlarge continuously from bottom to top. With the increase of the acceleration (0.2g), the amplification trend basically disappeared. When the acceleration increases to 0.3g, the ground motion increases first and then decreases.

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lin Li ◽  
Xiaodan Guo ◽  
Zuyin Zou ◽  
Zhanyuan Zhu ◽  
Zihong Guo ◽  
...  

The structural damage of the lining structure at the entrance of a tunnel is the most common instability problem. The instability problem may cause dynamic effects such as earthquakes and blasting. Based on the seismic damage data collected from previous major earthquakes at the entrance of shallow-buried tunnel, the shaking table test and numerical simulation are used to analyze dynamic response characteristics and damage evolution characteristics of the tunnel in the shallow-buried hole at 30°. The study revealed the stress characteristics of tunnel lining and the mechanism of structural damage under earthquake excitation. The research results show that the biased tunnel (30°) is susceptible to damage on the unsymmetrical loading side, the biased ground surface leads to acceleration, and high speed also significantly increases the effect. The biased side leg of the tunnel lining cross section is a location with a large internal force distribution. The biased tunnel has a relatively unfavorable internal force value distribution and a larger peak, and the peak at the larger bias side has the largest peak value. The skewback and spandrel portion of the biased tunnel lining load are more likely to be damaged.


2014 ◽  
Vol 919-921 ◽  
pp. 960-964 ◽  
Author(s):  
Xiao Fu ◽  
Jun Wei Bi ◽  
Zhi Jia Wang ◽  
Chang Wei Yang

Based on the design of the large-scale shaking table test of an underground pipeline under three dimension seismic excitation, the dynamic response of the soil-structure is analyzed by using ANSYS. In the numerical simulation, Drucker-Prager constitutive model is adopted to simulate the soil, the interface between soil and pipeline are simulated with zero thickness contact elements, size effects of test box are diminished by defining viscoelastic boundary around soil, the acceleration time history curve of the original earthquake wave is compressed and processed according to using the model scale similarity and energy duration which is presented by Trifunac-Brady [1] , and then the characteristic of seismic response of the pipeline can be found. The results show that the top of pipeline is the seismic response intense regional, deformation displacements of the central areas at the bottom and top of pipeline are always larger than others, the entrance and exit are the weak positions of anti-seismic structure; moreover, the dynamic response and interactions of soil-pipeline in the model experiment can be more accurately simulated by the methods presented in the paper. Thus, it can be served as reference for the design and construction of subsurface structures.


2019 ◽  
Vol 9 (13) ◽  
pp. 2644 ◽  
Author(s):  
Junfeng Cheng ◽  
Xiaoyong Luo ◽  
Yizhou Zhuang ◽  
Liang Xu ◽  
Xiaoye Luo

The pile foundations below approach slab in a semi-integral abutment jointless bridge (SAJB) that requires high flexibility to accommodate the horizontal cyclic deformation of approach slab generated by the girder’s thermal expansion and contraction as well as earthquake action. In this paper, reactive powder concrete (RPC) and reinforce concrete (RC) micro piles were designed and fabricated. The shaking table tests on dynamic response of micro piles-soil interaction were conducted to investigate the dynamic response characteristics such as the strain time history of pile-soil system, the bending moment, and the deformation of piles. The maximum strain response of piles was observed at the buried depth of 4.2 D (D is the diameter of pile). Meanwhile, the maximum bending moments of RPC and RC piles appear at the depth of 0.64 D and 0.42 D, respectively, under the dynamic load excitation, and the peak horizontal deformation of piles were observed at pile head. It is found that the bending moment and the strain response of the RPC pile are larger than that of the RC micro pile, and increased by 40% and 98%, respectively. The RPC micro pile has better crack resistance, higher ductility, and flexural rigidity than that of the RC pile, and it can be widely used as pile foundations in SAJBs for the earthquake area.


2020 ◽  
Vol 13 (18) ◽  
Author(s):  
Jiaxu Jin ◽  
Qianshen Ding ◽  
Hongzhi Cui ◽  
Pingyi Zhang ◽  
Xiaochun Xiao ◽  
...  

2021 ◽  
Author(s):  
Xueliang Jiang ◽  
Yonghui Qian ◽  
Jiqi Zhang ◽  
Yong Liu ◽  
RiWe Deng ◽  
...  

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.


2021 ◽  
Author(s):  
Cong Zhang ◽  
Zhong Ju Feng ◽  
Yuan Yuan Kong ◽  
Yun Hui Guan ◽  
Yun Xiu Dong ◽  
...  

Abstract Taking Puqian bridge as the prototype, a 1:30-scale pile-soil-fault interaction model was established. Through the shaking table test, the difference of dynamic response of pile foundation on both sides of fault under 0.15~0.60g ground motion intensity was studied. The pile acceleration, pile top relative displacement, and pile bending moment on both sides of the fault are compared respectively. Research results showed that under the action of a strong earthquake, the pile foundation on the hanging wall was greatly affected by ground motion, and “the hanging wall effect” was significant. As the ground motion intensity increased, the “hanging wall effect” of the pile foundation was more obvious. Combined with the fundamental frequency response and the test phenomenon, when ground motions intensity was strong, cracks appeared near the joint of pile top and platform, soil interface, and bedrock surface. When building a bridge pile foundation near the fault, the seismic design of the pile foundation on the hanging wall of the fault is mainly considered.


2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Guang-wei Liu ◽  
Dan-qing Song ◽  
Zhuo Chen ◽  
Ju-wen Yang

Rock slopes with weak intercalated layers could experience disturbance from various deep mining activities; however, their dynamic stability has not been thoroughly investigated. In this paper, the dynamic response characteristics and failure mechanism of the coal slopes with weak intercalated layers under blasting loads were studied by means of numerical analysis, shaking table tests, and field tests. The effects of dynamic loads with different frequencies on the dynamic response of the slope were analyzed, and the natural frequency of the slope was also determined. The results show that the dynamic amplification effect of the slope is smaller than that of the homogeneous slope, and weak layers weaken the wave propagation in the rock mass. Both experimental and field investigation results show that the slope’s natural frequency was approximately 35 Hz. The slope deformation decreased with the distance of the blasting source. Cracks appear along the weak interlayer firstly under the action of horizontal vibration; then, longitudinal cracks occur at the slope crest. With the increase of dynamic loads, cracks continue expanding, deepening, and penetrating in the main controlled weak interlayer; then, the sliding body presents tensile shear failure along the sliding surface. This study could provide insights into the understanding of the coal slope instability and failure mechanism; this could benefit the blasting operation of the coal slope in fields.


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