scholarly journals Analysis of Time-Dependent Soil Behavior Above High-Filled Cut-and-Cover Tunnels Using Discrete Element Method

2022 ◽  
Author(s):  
Sheng Li ◽  
Guoqiang Han ◽  
I-Hsuan Ho ◽  
Li Ma ◽  
Balasingam Muhunthan ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Time Dependent ◽  
Soil Behavior ◽  
Element Method

Analysis of Time-Dependent Soil Behavior above High-Filled Cut-and-Cover Tunnels Using Discrete Element Method

2021 ◽  
Author(s):  
Sheng Li ◽  
Guoqiang Han ◽  
I-HSUAN HO ◽  
Li Ma ◽  
Balasingam Muhunthan ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Load Transfer ◽  
Earth Pressure ◽  
Vertical Displacement ◽  
Discrete Element ◽  
Time Dependent ◽  
Structural Safety ◽  
Dependent Behavior ◽  
Element Method

Abstract In the Northwest Loess Plateau of China that is full of mountains and deep valleys, high-filled cut-and-cover tunnels (HFCCTs) not only satisfy transportation demands, but they create usable land as well. Several studies have been conducted to investigate the feasibility of HFCCTs, but the time-dependent behavior of the significant backfill needed for HFCCTs has not been adequately examined. Settlement can be severely underestimated due to the time-dependent behavior of ultra-high backfill, and the earth pressure becomes redistributed accordingly. Therefore, the ability to predict the long-term behavior of backfill on HFCCTs is necessary to ensure the long-term safety of the structure. Using a discrete element method (DEM), the changes in vertical earth pressure (VEP), vertical displacement, and load transfer mechanisms above an HFCCT were investigated in this study under scenarios with and without considering backfill creep. The results show that the differential displacement of the soil and the surface settlement obviously increase due to creep and the subsequent cycles of primary and secondary consolidation. Moreover, the stress surrounding the HFCCT is redistributed, causing both the stress concentration and slope effect to weaken over time, but the VEP increases significantly. The micromechanical parameters also change correspondingly. Our results clearly show that the creep of high backfill soil must be considered carefully in HFCCT projects to ensure structural safety.

Discrete element method to model cracking for two layer systems

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 101-108
Author(s):  
Daniel Varney ◽  
Douglas Bousfield
Keyword(s):  
Discrete Element Method ◽  
Flexural Modulus ◽  
Single Layer ◽  
Discrete Element ◽  
Flexural Stress ◽  
Layer System ◽  
Three Point Bending ◽  
Moving Force ◽  
Coating Layers ◽  
Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

Discrete element method–computational fluid dynamics analyses of flexible fibre fluidization

2021 ◽  
Vol 910 ◽  
Author(s):  
Yiyang Jiang ◽  
Yu Guo ◽  
Zhaosheng Yu ◽  
Xia Hua ◽  
Jianzhong Lin ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Dynamics Analyses ◽  
Element Method

Abstract

scholarly journals Numerical simulation on coal loading process of shearer drum based on discrete element method

2021 ◽  
pp. 014459872110135
Author(s):  
Zhen Tian ◽  
Shuangxi Jing ◽  
Lijuan Zhao ◽  
Wei Liu ◽  
Shan Gao
Keyword(s):  
Numerical Simulation ◽  
Discrete Element Method ◽  
Loading Rate ◽  
Low Cost ◽  
Element Model ◽  
Discrete Element ◽  
Helix Angle ◽  
Loading Process ◽  
Coal Particles ◽  
Element Method

The drum is the working mechanism of the coal shearer, and the coal loading performance of the drum is very important for the efficient and safe production of coal mine. In order to study the coal loading performance of the shearer drum, a discrete element model of coupling the drum and coal wall was established by combining the results of the coal property determination and the discrete element method. The movement of coal particles and the mass distribution in different areas were obtained, and the coal particle velocity and coal loading rate were analyzed under the conditions of different helix angles, rotation speeds, traction speeds and cutting depths. The results show that with the increase of helix angle, the coal loading first increases and then decreases; with the increase of cutting depth and traction speed, the coal loading rate decreases; the increase of rotation speed can improve the coal loading performance of drum to a certain extent. The research results show that the discrete element numerical simulation can accurately reflect the coal loading process of the shearer drum, which provides a more convenient, fast and low-cost method for the structural design of shearer drum and the improvement of coal loading performance.

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