Dynamic Numerical Simulation for the Problem of Tunnel Rock Mass Large Deformation of a Hydropower Project in the Upper Reaches of Lancang River

2011 ◽  
Vol 250-253 ◽  
pp. 1315-1319
Author(s):  
Yu Sheng Li ◽  
Guang Peng Cao ◽  
Jie Bao
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Large Deformation ◽  
Surrounding Rock ◽  
Underground Engineering ◽  
Rock Mass Structure ◽  
Roof Fall ◽  
Relaxation Stress ◽  
Stress Environment ◽  
Dynamic Numerical Simulation

It is a very effective technology methods that using dynamic numerical simulation of discrete element method to study the large deformation problems of underground engineering rock mass which in the complex rock mass mechanics environmental conditions.Research achievements show that the development of deformation failure of the tunnel surrounding rock and the final convergence stability are mainly controlled by rock mass structure and its stress environment in the special toppling deformation rock mass. Deformation of the rock mass that in the lateral unloading and relaxation and also has a complex rock mass structure developed sustainably and progressivity over time,will eventually seriously damaged in roof fall. The surrounding rock deformation of the tunnel ,which have a good rock mass integrity and do not have the obvious unloading and relaxation stress environment, gradually tended to be stable after the initial deceleration-type development.

Study on the Rockmass Instability of Open-Pit Mine by Block Theory and Numerical Simulation Methods

2013 ◽  
Vol 353-356 ◽  
pp. 1077-1081
Author(s):  
Hai Gang Li ◽  
Zhi Jun Yang ◽  
Tong Lin Han
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Finite Difference ◽  
Surrounding Rock ◽  
Open Pit ◽  
Rock Mechanic ◽  
Mining District ◽  
Lagrangian Analysis ◽  
Rock Mass Structure ◽  
Block Theory

On the background of rock masses and field engineering geology of a mine, the feature of rock mechanics and rock mass structure of surrounding rock at mining district are analyzed. Based on the finite difference theory and block theory, FLAC3D program (Fast Lagrangian Analysis for Continuum), rock mechanic and rock mass structure results are used to construct the finite difference mechanical model, which reflected the surrounding rock stability when mining. By the numerical simulation, the mechanical effect is studied by the process of mining and its results can be used to produce some theory and actual basis.

Application of ABAQUS in Surrounding Rock Stability Analysis of Shallow Large Cross-Section Tunnel

2015 ◽  
Vol 777 ◽  
pp. 8-12 ◽  
Author(s):  
Lin Zhen Cai ◽  
Cheng Liang Zhang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Strong Support ◽  
Surrounding Rock ◽  
Tunnel Engineering ◽  
Tunnel Excavation ◽  
Rock Stability ◽  
Rock Bolting ◽  
Excavation Support ◽  
The Stability

HuJiaDi tunnel construction of Dai Gong highway is troublesome, the surrounding-rock mass give priority to full to strong weathering basalt, surrounding rock integrity is poor, weak self-stability of surrounding rock, and tunnel is prone to collapse. In order to reduce disturbance, taking advantage of the ability of rock mass, excavation adopt the method of "more steps, short footage and strong support". The excavation method using three steps excavation, The excavation footage is about 1.2 ~ 1.5 m; The surrounding rock bolting system still produce a large deformation after completion of the first support construction, it shows that the adopted support intensity cannot guarantee the stability of the tunnel engineering. Using ABAQUS to simulate tunnel excavation support, optimizing the support parameters of the tunnel, conducting comparative analysis with Monitoring and Measuring and numerical simulation results, it shows that the displacement - time curves have a certain consistency in numerical simulation of ABAQUS and Monitoring and Measuring.

scholarly journals Numerical Simulation on Large Deformation of Weak Rock Mass Tunnel Under High Geostress

2018 ◽  
Vol 175 ◽  
pp. 03025
Author(s):  
Feng Zhou ◽  
Hongjian Jiang ◽  
Xiaorui Wang
Keyword(s):  
Rock Mass ◽  
Large Deformation ◽  
Lateral Pressure ◽  
Simulation Analysis ◽  
Pressure Coefficient ◽  
Surrounding Rock ◽  
Analog Simulation ◽  
Lateral Pressure Coefficient ◽  
High Geostress ◽  
The Stability

The problem about the stability of tunnel surrounding rock is always an important research object of geotechnical engineering, and the right or wrong of the result from stability analysis on surrounding rock is related to success or failure of an underground project. In order to study the deformation rules of weak surrounding rock along with lateral pressure coefficient and burying depth varying under high geostress and discuss the dynamic variation trend of surrounding rock, the paper based on the application of finite difference software of FLAC3D, which can describe large deformation character of rock mass, analog simulation analysis of surrounding rock typical section of the class II was proceeded. Some conclusions were drawn as follows: (1) when burying depth is invariable, the displacements of tunnel surrounding rock have a trend of increasing first and then decreasing along with increasing of lateral pressure coefficient. The floor heave is the most sensitive to change of lateral pressure coefficient. The horizontal convergence takes second place. The vault subsidence is feeblish to change of lateral pressure coefficient. (2) The displacements of tunnel surrounding rock have some extend increase along with increasing of burying depth. The research conclusions are very effective in analyzing the stability of surrounding rock of Yunling tunnel. These are going to be a reference to tunnel supporting design and construction.

Experimental Study and Numerical Simulation of Rock Mass Seepage Characteristics of Tunnel Engineering

2011 ◽  
Vol 243-249 ◽  
pp. 3538-3545
Author(s):  
Yong Dong Jiang ◽  
Ling Xiong ◽  
Xing Yang Yang ◽  
Quan Zhen ◽  
Zong Ling Yan
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Pore Pressure ◽  
Confining Pressure ◽  
Test System ◽  
Surrounding Rock ◽  
Simultaneous Action ◽  
Seepage Field ◽  
Variation Characteristics ◽  
Seepage Characteristics

In this research, the MTS815 rock mechanics test system , produced by American MTS co., has been conducted with transient method to study the seepage characteristics of rock under different confining pressure. Experiments have obtained the following results: with the confining pressure increased, penetration ability of water in rock decreased, but the start-up pressure gradient increased; permeability of rock decreased with the increase of effective confining pressure, which had negative exponent functional relationship between them. Based on previous researches, the study has established filtration equation which couples with stress field, temperature field and seepage field. Combined with the practical tunnel project, numerical simulated the variation characteristics of deformation of tunnel surrounding rock, pore pressure and seepage field under three fields non-coupling and coupling, numerical simulation obtained: the difference among deformation of surrounding rock, pore pressure and seepage field distribution under the coupling and non-coupling is remarkable, so it must consider the simultaneous action of fluid - solid - heat when we need to research the working of seepage law of groundwater in tunnel rock mass, and the research results enjoy important theoretical significance and practical application value.

Research on the Surrounding Rock Damage of Deep Hard Rock Tunnels Caused by Bottom Excavation

2012 ◽  
Vol 170-173 ◽  
pp. 1700-1703
Author(s):  
Zhen Wang ◽  
Chu Nan Tang ◽  
Tian Hui Ma ◽  
Lian Chong Li ◽  
Yue Feng Yang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Hard Rock ◽  
Surrounding Rock ◽  
Rock Damage ◽  
Simulation Approach ◽  
High Geostress ◽  
Intact Rock Mass ◽  
Rock Tunnels ◽  
Rock Tunnel

The damage features of surrounding rock in the process of bottom excavation in deep hard rock tunnel were investigated, combining with the actual tunnel data of JinpingⅡHydropower Station and using numerical simulation approach. The evolution mechanism of microfractures initiation, growth and expansion in deep intact rock mass was performed. It’s shown that the fractures caused by bottom excavation develop to deeper surrounding rock due to stress adjustment, and the zone that have been supported also has some damage. The research results provide important references to understand the damage features of surrounding rock in deep hard rock under high geostress.

Numerical Analysis of Damage for Y-Shape Tunnel

2011 ◽  
Vol 368-373 ◽  
pp. 2517-2520
Author(s):  
Da Ming Lin ◽  
Yan Jun Shang ◽  
Guo He Li ◽  
Yuan Chun Sun
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Numerical Analysis ◽  
Plastic Zone ◽  
Comprehensive Analysis ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Deformation And Failure ◽  
Single Beam ◽  
Flac 3D

There are many effective researches about tunnel at home and abroad, because the complexity of design and construction for Y-shape tunnel, in public there is no research about it yet, with the background of nanliang-tunnel which merge two single-beam into a two-lane tunnel as Y-shape. This paper obtains the rock mass mechanics parameters on the basis of nonlinear Hoek-Brown criterion first, and has a numerical simulation according the tunnel construction with FLAC-3D. we arrange many monitor sections in this model and discuss the law of deformation and failure in different section, at last have a comprehensive analysis of displacement, stress, plastic zone of different sites which caused by tunnel construction and discover that: with the distance of two single tunnels decreased, the interaction caused by the merging increase together with the compressive stress, tensile stress. The displacements of surrounding rock increase corresponding, the amplitude of variation is up to 44.8%, After the two-lane tunnel is 15m long, the stress and displacements redistribution of surrounding rock become stable.

Numerical Simulation of Advanced Small Pipe in Tunnels during Excavation by Steps

2013 ◽  
Vol 353-356 ◽  
pp. 3699-3702
Author(s):  
Chang Yu Jin ◽  
Zi Feng Xia ◽  
Chun Fu Xiang ◽  
Long Bin Dong ◽  
Pan Pan Zhao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Wall Rock ◽  
Support Effect ◽  
Surrounding Rock ◽  
Tunnel Engineering ◽  
Engineering Construction ◽  
Support Mechanism ◽  
Deterioration Model ◽  
Advanced Support

Advanced small pipe support is one of the advanced support patterns in tunnel engineering construction for weak and fractured surrounding rock. The support effect cannot be predicted because of depending on engineering experiences. Efforts are made to study and analyze the support mechanism of advanced small pipe in the excavation of soft - fracture wall rock. By the numerical simulation of FLAC3D of Dawangou tunnel based on rock mass deterioration model (RDM), the plastic zone, displacement and stress filed of the surrounding rock are simulated with and without the advanced small pipe support. The support effect of advanced small ducts in tunnels during excavation by steps is presented.

scholarly journals Numerical Simulation of Stress Arching Effect in Horizontally Layered Jointed Rock Mass

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1138
Author(s):  
Xiao Huang ◽  
Huaining Ruan ◽  
Chong Shi ◽  
Yang Kong
Keyword(s):  
Rock Mass ◽  
Pressure Coefficient ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Surrounding Rock ◽  
Beam Structure ◽  
Underground Engineering ◽  
Joint Spacing ◽  
Arching Effect ◽  
The Stability

Stress arching effect during the excavation of broken surrounding rock in underground engineering has an important influence on the stability of surrounding rock after underground excavation. To determine the stress arching effect in horizontally layered jointed rock mass, the stress arching characteristics of surrounding rock mass after excavation is analyzed in this study by using a series of numerical tests. The formation mechanism of stress arch is revealed through a comparison of the stress characteristics of a voussoir beam structure and theoretical analysis of multi-block mechanical relationship of jointed rock mass. The method for determining the boundaries of a stress arching zone is proposed, and the influence of various factors on a stress arch is further discussed. Results show that after the excavation of horizontally layered jointed rock mass, the stress arch bunch (SAB) is formed in the lower strata above the cavern, and the global stress arch (GSA) is formed in the higher strata, both of which are symmetrical arch stress patterns. The SAB is the mechanical manifestation of the voussoir beam structure formed by several low-level sandstone layers, and the GSA is caused by the uneven displacement between blocks. Compared with the GSA, the SAB is more sensitive to various influencing factors. The extent of stress arching zone decreases with the increase of an internal friction angle of the joint, lateral pressure coefficient, and overburden depth. In addition, the joint spacing of rock strata is conducive to the development of a stress arch. Results can provide technical support for deformation control and the stability analysis of broken surrounding rock in underground engineering.

scholarly journals Numerical Simulation of Rock Mass Structure Effect on Tunnel Smooth Blasting Quality: A Case Study

2021 ◽  
Vol 11 (22) ◽  
pp. 10761
Author(s):  
Jianxiu Wang ◽  
Ansheng Cao ◽  
Jiaxing Liu ◽  
Huanran Wang ◽  
Xiaotian Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Layered Structure ◽  
High Speed ◽  
Numerical Test ◽  
Great Influence ◽  
Structure Effect ◽  
Rock Mass Structure ◽  
Massive Structure ◽  
Smooth Blasting

Taking the Zigaojian tunnel, Hangzhou–Huangshan high-speed railway, China, as background, the rock mass structure effect on smooth blasting quality was studied. Four rock mass structures were determined on the basis of the information collected on the tunnel site. Smooth blasting finite element models were established using LS-DYNA. The accuracy of the numerical calculation model was verified by comparing the overbreak and underbreak between the numerical simulation and monitoring. Orthogonal numerical test was used to study the rock mass structure effect through single factor and main effect analysis methods. With the decrease in rock mass integrity, the smooth blasting overbreak of tunnels with massive integrity structure, massive structure, layered structure, and cataclastic structure increased. For massive integrity structure and cataclastic structure, the peripheral hole spacing should be emphatically considered. Meanwhile, in massive structure and layered structure, the included angle and spacing of structural planes had a great influence on the smooth blasting quality. The research results could provide a reference to improve the quality of similar tunnel smooth blasting.

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