scholarly journals Techniques for Progressive Failure Simulation of Hard Brittle Surrounding Rockmass: Taking the URL Test Tunnel as an Example

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Daning Zhong ◽  
Jianlin Chen ◽  
Hui Zhou ◽  
Xiangrong Chen ◽  
Yali Jiang ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Progressive Failure ◽  
Failure Process ◽  
High Stress ◽  
Constitutive Models ◽  
Discrete Element ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Underground Engineering ◽  
And Control

Accurate simulation of the failure process of hard brittle surrounding rockmass is very important for the analysis and control of the structural stability in deep underground engineering. In order to simulate the progressive failure process of the hard brittle surrounding rockmass, a continuous discontinuous deformation analysis method that couples the finite element and discrete element is adopted. Taking the URL test tunnel in Canada as an engineering case, the constitutive model of the contact considering the effects of cohesion weakening and friction strengthening is applied, and the 2D approximation to 3D excavation by applying elastic modulus reduction technology is adopted to simulate the range and depth of crack growth of the surrounding rockmass. Then, the comparison between simulated results and on-site monitoring results is performed, which shows good consistency. At the same time, the key factors in the numerical simulation of progressive failure in hard brittle rockmass are identified, including the number of elements, excavation effects, and constitutive models. The results show that the constitutive model determines the basic form of crack propagation, but in order to accurately simulate the progressive propagation of cracks, the number of elements must be sufficient enough and the effects of 3D excavation must be considered. The analysis accurately simulates the progressive failure characteristics of hard brittle surrounding rockmass under high stress, achieving the purpose of reasonably grasping the degree of damage to the surrounding rockmass, and provides technical reference and support on how to accurately simulate the failure of hard brittle surrounding rockmass using the finite discrete element method.

Enhanced Discrete Element Method (EDEM) and its Application to Stability Analysis of the Slope with Non-Through Joints

2014 ◽  
Vol 644-650 ◽  
pp. 1539-1542 ◽  
Author(s):  
Yong Zheng Ma ◽  
Ke Jian Cai ◽  
Zhan Tao Li ◽  
Jun Li
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Discontinuous Deformation Analysis ◽  
Iteration Step ◽  
Deformation Analysis ◽  
Analysis Method ◽  
Meshfree Approximation ◽  
Discontinuous Deformation ◽  
Cracked Solids ◽  
Element Method

A new enhanced Discrete Element Method (EDEM) for modeling the system composed of cracked solids is developed by coupling the traditional Discontinuous Deformation Analysis method (DDA, a kind of implicit version of DEM) with Moving Least-Squares (MLS) meshfree approximation functions. Tracing crack growth inside fracturing blocks and other related capabilities are available in the postprocessing procedure at each iteration step. Some numerical examples are provided to verify this method, and it is prospective to solve stability problems of the slope with non-through joints and other fracture mechanics problems in a new way.

Seismic deformation analysis of Tuttle Creek Dam

2012 ◽  
Vol 49 (3) ◽  
pp. 323-343 ◽  
Author(s):  
Timothy D. Stark ◽  
Michael H. Beaty ◽  
Peter M. Byrne ◽  
Gonzalo Castro ◽  
Francke C. Walberg ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Constitutive Models ◽  
Deformation Analysis ◽  
East Central ◽  
Fine Grained ◽  
Upstream Slope ◽  
Downstream Slope ◽  
Soil Constitutive Models ◽  
Seismic Deformation

To facilitate the design of seismic remediation for Tuttle Creek Dam in east central Kansas, a seismic finite difference analysis of the dam was performed using the software FLAC and the UBCSAND and UBCTOT soil constitutive models. The FLAC software has a key advantage because it can use calibrated site-specific constitutive models. Earlier deformation analyses using a hyperbolic constitutive model for the foundation fine-grained materials did not properly represent the modulus and strength reduction and predicted extremely large permanent deformations. Cyclic triaxial laboratory tests using high-quality samples and in situ vane shear tests were used to calibrate the FLAC constitutive model herein. The resulting FLAC analysis of the unremediated dam predicted an upstream slope toe deformation of about 0.6 m, a crest settlement of about 0.6 m, and a downstream slope toe deformation of about 1.5 m using the design ground motion. Based on the estimated permanent deformations and other factors, it was decided that the anticipated upstream slope and crest deformations were tolerable and only the downstream slope had to be remediated to protect the downstream seepage control system.

scholarly journals DDA Simulation Study on Mechanical Failure of Heterogenous Rock

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Youjun Ning ◽  
Xinyang Lv ◽  
Zheng Yang
Keyword(s):  
Simulation Study ◽  
Failure Process ◽  
Mechanical Failure ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Rock Fracturing ◽  
Response Curves ◽  
Heterogeneity Index ◽  
Heterogeneous Rock ◽  
Dda Method

Heterogeneity is an important characteristic that affects the mechanical behavior of rock. In the present work, a statistical rock mesoheterogeneity model based on the Weibull distribution function is introduced into the discontinuous deformation analysis (DDA) method to simulate the mechanical failure of heterogeneous rock, in which the general heterogeneity degree is controlled by a heterogeneity index and the mechanical property of each subblock element is randomly assigned. Brazilian disc and uniaxial compressive rectangular specimens are simulated as examples. Results show that it is more reasonable to consider the heterogeneity of elasticity properties (the elastic modulus and Poisson’s ratio) and strength properties (the tensile strength, cohesion, and friction angle) simultaneously in the heterogeneity model. It is also shown that with a larger heterogeneity index, which means a lower degree of heterogeneity, the reproducibility of the macroscopic response curves of a specimen gets better, while the exact cracking always differs but with less scattered cracks, and the global fracturing failure pattern and mode are weakly influenced by the heterogeneity. Moreover, with the increase in the heterogeneity index, the macroscopic equivalent modulus and strength get larger and approach those of a homogeneous specimen. This work indicates the importance of heterogeneity for rock mechanical behaviors including the macroscopic equivalent response and the fracturing failure. By the subblock DDA method to simulate fracturing realistically, the fracturing failure process of heterogeneous rock can be successfully reproduced, which builds good foundation for the simulation study of heterogeneous rock fracturing in practical problems, e.g., coal and rock fracturing in fluidization mining in the future.

Y-Mat: an improved hybrid finite-discrete element code for addressing geotechnical and geological engineering problems

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gang Liu ◽  
Fengshan Ma ◽  
Maosheng Zhang ◽  
Jie Guo ◽  
Jun Jia
Keyword(s):  
Contact Force ◽  
Mechanical Response ◽  
Progressive Failure ◽  
Failure Process ◽  
Discrete Element ◽  
Content Type ◽  
Geological Engineering ◽  
Natural Rock ◽  
Engineering Problems ◽  
Process Failure

PurposeContinua and discontinua coexist in natural rock materials. This paper aims to present an improved approach for addressing the mechanical response of rock masses based on the combined finite-discrete element method (FDEM) proposed by Munjiza.Design/methodology/approachSeveral algorithms have been programmed in the new approach. The algorithms include (1) a simpler and more efficient algorithm to calculate the contact force; (2) An algorithm for tangential contact force closer to the actual physical process; (3) a plastic yielding criterion (e.g. Mohr-Coulomb) to modify the elastic stress for fitting the mechanical behavior of elastoplastic materials; and (4) a complete code for the mechanical calculation to be implemented in Matrix Laboratory (MATLAB).FindingsThree case studies, including two standard laboratory experiments (uniaxial compression and Brazilian split test) and one engineering-scale anti-dip slop model, are presented to illustrate the feasibility of the Y-Mat code and its ability to deal with multi-scale rock mechanics problems. The results, including the progressive failure process, failure mode and trajectory of each case, are acceptable compared to other corresponding studies. It is shown that, the code is capable of modeling geotechnical and geological engineering problems.Originality/valueThis article gives an improved FDEM-based numerical calculation code. And, feasibility of the code is verified through three cases. It can effectively solve the geotechnical and geological engineering problems.

On Using Discrete Particle Approaches for Simulating the Perforation Process of Concrete Slab by Hard Projectile

2007 ◽  
Vol 353-358 ◽  
pp. 2973-2976 ◽  
Author(s):  
Yu Yong Jiao ◽  
Xiu Li Zhang ◽  
Shui Lin Wang ◽  
Huo Zhen Wu
Keyword(s):  
Discrete Element Method ◽  
Numerical Investigation ◽  
Concrete Slab ◽  
Discrete Element ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Discrete Particle ◽  
Discontinuous Deformation ◽  
Element Method

This study is to present a numerical investigation on fragmentation and perforation of concrete slab by hard projectile using discrete particle approaches. Discrete Element Method (DEM) and Discontinuous Deformation Analysis (DDA), the two representative discrete particle approaches, are employed to simulate a normal perforation of concrete slab by a hard ogival-nose shaped projectile, and the phenomena of spalling, plugging and scabbing are reproduced.

scholarly journals Influence of “X” Fracture, Confining Pressure, and Temperature on Rock Masses’ Failure Process

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yunjuan Chen ◽  
Yi Jing ◽  
Yanchun Yin ◽  
Fuqiang Yin ◽  
Chenglong Zhao
Keyword(s):  
Crack Propagation ◽  
Similarity Theory ◽  
Failure Process ◽  
Confining Pressure ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Confining Pressures ◽  
Discontinuous Deformation ◽  
Loading And Unloading ◽  
Cracking Process

Based on the similarity theory, sandstone was taken as the prototype, and rock-like specimens were made with the strength ratio of 1 : 1. Single “X” fracture and double “X” fractures were prefabricated in rock-like specimen, and crack propagation was studied through the compressive test. An improved discontinuous deformation analysis method (DDARF) was adopted to simulate on the cracking process. Further, other factors should not be ignored such as confining pressure and temperature, which were considered: rock’s crack propagations under loading and unloading with different confining pressures were studied; influences of temperature from 20°C to 300°C on crack propagation were analyzed.

scholarly journals Numerical comparison of some contact detection algorithms

2017 ◽  
Vol 34 (3) ◽  
pp. 832-851 ◽  
Author(s):  
Guillermo Gonzalo Schiava D'Albano ◽  
Tomas Lukas ◽  
Fang Su ◽  
Theodosios Korakianitis ◽  
Ante Munjiza
Keyword(s):  
Discrete Element Method ◽  
Detailed Comparison ◽  
Discrete Element ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Contact Detection ◽  
Numerical Comparison ◽  
Content Type ◽  
Discrete Element Simulations ◽  
Element Method

Purpose Contact interaction and contact detection (CD) remain key components of any discontinua simulations. The methods of discontinua include combined finite-discrete element method (FDEM), discrete element method, molecular dynamics, etc. In recent years, a number of CD algorithms have been developed, such as Munjiza–Rougier (MR), Munjiza–Rougier–Schiava (MR-S), Munjiza-No Binary Search (NBS), Balanced Binary Tree Schiava (BBTS), 3D Discontinuous Deformation Analysis and many others. This work aims to conduct a numerical comparison of certain algorithms often used in FDEM for bodies of the same size. These include MR, MR-S, NBS and BBTS algorithms. Design/methodology/approach Computational simulations were used in this work. Findings In discrete element simulations where particles are introduced randomly or in which the relative position between particles is constantly changing, the MR and MR-S algorithms present an advantage in terms of CD times. Originality/value This paper presents a detailed comparison between CD algorithms. The comparisons are performed for problem cases with different lattices and distributions of particles in discrete element simulations. The comparison includes algorithms that have not been evaluated between them. Also, two new algorithms are presented in the paper, MR-S and BBTS.

scholarly journals Microseismic Monitoring, Positioning Principle, and Sensor Layout Strategy of Rock Mass Engineering

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Tianhui Ma ◽  
Daoyuan Lin ◽  
Chun’an Tang ◽  
Kedar Prasad Yadav ◽  
Zhiqiang Feng ◽  
...  
Keyword(s):  
Rock Mass ◽  
Progressive Failure ◽  
Failure Process ◽  
Microseismic Monitoring ◽  
Underground Engineering ◽  
Monitoring Technology ◽  
Sensor Arrangement ◽  
Initial Stage ◽  
Practical Engineering ◽  
Scientific Nature

Microseismic monitoring technology can start from the most initial stage of rock deformation and track and monitor the progressive failure process of rock mass from the fracture of rock blocks to the instability of rock mass. Thus, the scientific nature of monitoring work is greatly promoted, and the accuracy and advance of the prediction of engineering and geological disasters are improved. In this paper, the fracture and instability of rock can be analyzed by analyzing the microseismic signals produced by rock failure; The location of microseismic source can be determined by multipoint synchronous data acquisition to determine the time when each sensor (at least 5) receives microseismic signals; Combined with practical engineering experience for underground engineering in growth, heading tunnel, put forward only sensor arrangement to take mobile, follow the semienclosed layout network. We hope to give some reference to the researchers who are concerned with microseismic monitoring technology.

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