Theoretical dynamic displacement analysis for rock bolt with surrounding rock-soil body

2021 ◽  
Vol 141 ◽  
pp. 104698
Author(s):  
Haichun Ma ◽  
Luwang Chen ◽  
Xiaohui Tan ◽  
Jiazhong Qian ◽  
Zhitang Lu
Keyword(s):  
Surrounding Rock ◽  
Rock Bolt ◽  
Dynamic Displacement ◽  
Displacement Analysis

scholarly journals Dynamic displacement analysis of reinforced concrete deep beams made of high strength concrete. Part II: Dynamic displacement analysis of reinforced concrete deep beams made of high strength C200 grade concrete

2018 ◽  
Vol 67 (2) ◽  
pp. 25-48
Author(s):  
Waldemar Cichorski
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Load ◽  
High Strength Concrete ◽  
Construction Materials ◽  
High Strength ◽  
Deep Beam ◽  
Deep Beams ◽  
Dynamic Displacement ◽  
Displacement Analysis ◽  
Strength Concrete

The dynamic load displacements were analysed of rectangular concrete deep beams made of very high strength concrete, grade C200, including an evaluation of the physical non-linearity of the construction materials: concrete and reinforcing steel. The analysis was conducted using the method presented in [1]. The numerical calculation results are presented with particular reference to the displacement state of rectangular concrete deep beams. A comparative analysis was conducted on the effect of the high-strength concrete and the steel of increased strength on a class C200 concrete deep beam versus the results produced in [10] for a class C100 concrete deep beam. Keywords: mechanics of structures, reinforced concrete structures, deep beams, dynamic load, physical non-linearity

scholarly journals Theoretical Calculation and Analysis on the Composite Rock-Bolt Bearing Structure in Burst-Prone Ground

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Liang Cheng ◽  
Yidong Zhang ◽  
Ming Ji ◽  
Mantang Cui ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Theoretical Calculation ◽  
Rock Burst ◽  
Mechanical Model ◽  
Surrounding Rock ◽  
Rock Bolt ◽  
Mining Engineering ◽  
Calculation Formula ◽  
Mining Depth ◽  
Rock Parameters ◽  
Bearing Structure

Given the increase in mining depth and intensity, tunnel failure as a result of rock burst has become an important issue in the field of mining engineering in China. Based on the Composite Rock-Bolt Bearing Structure, which is formed due to the interaction of the bolts driven into the surrounding rock, this paper analyzes a rock burst prevention mechanism, establishes a mechanical model in burst-prone ground, deduces the strength calculation formula of the Composite Rock-Bolt Bearing Structure in burst-prone ground, and confirms the rock burst prevention criterion of the Composite Rock-Bolt Bearing Structure. According to the rock burst prevention criterion, the amount of the influence on rock burst prevention ability from the surrounding rock parameters and bolt support parameters is discussed.

scholarly journals Quality Assessment of Installed Rock Bolts

2021 ◽  
Author(s):  
Andrzej Staniek
Keyword(s):  
Element Model ◽  
Surrounding Rock ◽  
Rock Bolt ◽  
Impact Excitation ◽  
Modal Parameters ◽  
Front Part ◽  
Rock Bolts ◽  
Visible Part ◽  
Additional Equipment ◽  
Non Destructive

The chapter presents a method for non-destructive identification of discontinuity of a resin layer (grout) surrounding rock bolts. The method uses modal analysis procedures and is based on an impact excitation where a response transducer is positioned at a visible part of a rock bolt. Since the installed rock bolt acts as an oscillator, its modal parameters are changed by different lengths and positions of grouting discontinuity. Thanks to proper extraction of these parameters, with a resonant frequency seen as the most valuable, the intended identification is possible. The measurements and analyses were performed in laboratory conditions and subsequently at experimental and working coal mines where the measurement system was verified. The developed finite element model of the system under test, rock bolt - resin - rock mass, may be used as reference data base for investigated rock bolts. The advantages of the method include plausibility of grouting discontinuity assessment at any time after its installation, a non-destructive character of the method and the fact that it is not necessary to install any additional equipment into a roof section. It enables a localization of a grout discontinuity, whether it is the back part or the front part of a rock bolt.

scholarly journals Numerical Simulation of the Dynamic Responses and Cumulative Damage of Underground Caverns under Multiple Explosions

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Guangyong Wang ◽  
Ansheng Cao ◽  
Zhilin Dun ◽  
Lianwei Ren ◽  
Xiaowang Sun
Keyword(s):  
Wave Attenuation ◽  
Surrounding Rock ◽  
Cumulative Damage ◽  
Rock Bolt ◽  
Dynamic Responses ◽  
Physical Model Test ◽  
Underground Engineering ◽  
Finite Element Software ◽  
Underground Caverns ◽  
Highly Nonlinear

Attacking underground caverns with earth-penetrating bombs usually involves multiple explosions in succession. To assess the dynamic responses and cumulative damage of underground caverns under multiple explosions, based on a reduced-scale physical model test, the modified Riedel–Hiermaier–Thoma (RHT) model in the finite-element software LS-DYNA is used to build an underground cavern model that encounters four explosions above the vault. The characteristics of the stress wave attenuation and the evolution laws for the cumulative damage of the surrounding rock in the process of the four explosions are presented. Also, the displacement of the vault, the strain of the cavern wall, and the damage of a rock bolt-supported cavern and an unanchored cavern are compared. The results indicate that the peak pressure is attenuated increasingly in the latter three explosions. The circumferential strain of the cavern wall changes from tensile to compressive from the vault to the corner. The damage of the surrounding rock on the left and right sides of the explosion source is attenuated with increasing distance from the explosion source, and the attenuation curve has a reverse “S” shape. Moreover, the attenuation rate of the curve decreases with each explosion. Multiple explosions do not affect the size of the crushed zone, but they do increase the range of the fracture zone. With each explosion, the cumulative damage of the surrounding rock increases irreversibly, but the damage increment decreases. The cumulative damage of the surrounding rock exhibits a highly nonlinear relationship with successive explosions, and the effect of the rock bolt reinforcement becomes more obvious with successive explosions. Accordingly, the present research results offer a reference for antiexplosion design and support the optimization of underground engineering.

scholarly journals Application of 3D-FSM Boundary Element Method in Stress and Displacement Analysis of Roadway

2015 ◽  
Vol 9 (1) ◽  
pp. 484-488
Author(s):  
Wang Chong ◽  
Liu Cheng-lun ◽  
Cui Xiaohua
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Numerical Integration ◽  
Elastic Body ◽  
Three Dimensional ◽  
Surrounding Rock ◽  
Rational Method ◽  
Displacement Analysis ◽  
Element Method

Conventional fictitious stress methods (FSM) employ numerical integration to calculate displacements or stresses on each element unit. The paper represents a kind of three-dimensional fictitious stress method adopting analytical integrals over triangular leaf elements instead of numerical integration and describes how to analyze stress and displacement of surrounding rock around roadway by the 3D-FSM. The results computed by this method were compared with the results obtained by Flac3d, which proved that it is a correct and rational method to solve three-dimensional mechanics problems especially about hole and crack in an elastic body.

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