The Viscoelastic-Plastic Displacement Back Analysis of Rock Mass with Non-Stationary Parameters

2012 ◽  
Vol 455-456 ◽  
pp. 1538-1544 ◽  
Author(s):  
Quan Sheng Liu ◽  
Jin Lan Li
Keyword(s):  
Rock Mass ◽  
Back Analysis ◽  
Optimization Method ◽  
Finite Element Program ◽  
Displacement Back Analysis ◽  
Element Program ◽  
Zone Development ◽  
Stationary Creep ◽  
Plastic Displacement ◽  
Creep Constitutive Model

The FEM positive analysis is made using H-K non-stationary creep constitutive model in this paper, the finite element program for non-stationary viscoelastic-plastic displacement back analysis is compiled combining the non-stationary viscoelastic-plastic program with the complex shape optimization method, and the displacement back analysis of soft tunnel engineering is conducted. The result indicates that the viscous aging characteristics of rock mass can be reflected objectively if rock mass is regarded as non-stationary viscoelastic-plastic model, and the plastic zone development of surrounding rock can be predicted considering the plastic flow of rock mass and regarding the back analysis results as the calculation parameters.

scholarly journals The impact of drilling and slitting construction on damage field: evolution characteristics in low-permeability coal seam

2021 ◽  
Vol 37 ◽  
pp. 205-215
Author(s):  
Heng Chen ◽  
Hongmei Cheng ◽  
Aibin Xu ◽  
Yi Xue ◽  
Weihong Peng
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Damage Mechanics ◽  
Effective Strain ◽  
Secondary Development ◽  
Distribution Area ◽  
Finite Element Program ◽  
Element Program ◽  
Mining Face ◽  
The Impact

ABSTRACT The fracture field of coal and rock mass is the main channel for gas migration and accumulation. Exploring the evolution law of fracture field of coal and rock mass under the condition of drilling and slitting construction has important theoretical significance for guiding efficient gas drainage. The generation and evolution process of coal and rock fissures is also the development and accumulation process of its damage. Therefore, based on damage mechanics and finite element theory, the mathematical model is established. The damage variable of coal mass is defined by effective strain, the elastoplastic damage constitutive equation is established and the secondary development of finite element program is completed by FORTRAN language. Using this program, the numerical simulation of drilling and slitting construction of the 15-14120 mining face of Pingdingshan No. 8 Mine is carried out, and the effects of different single borehole diameters, different kerf widths and different kerf heights on the distribution area of surrounding coal fracture field and the degree of damage are studied quantitatively. These provide a theoretical basis for the reasonable determination of the slitting and drilling arrangement parameters at the engineering site.

Research on Back Analysis of Parameters for Excavation of the Underground Cavern Group of a Large-Scale Hydro-Power Station by Using Orthogonal Optimization

2012 ◽  
Vol 170-173 ◽  
pp. 3356-3360
Author(s):  
Wen Dong Yang ◽  
Xi Chao Gao ◽  
Yan Mei Zhang ◽  
Jia Yang ◽  
Gang Wang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Back Analysis ◽  
Element Model ◽  
Optimization Method ◽  
Orthogonal Experimental Design ◽  
Grey System ◽  
Power Station ◽  
Hydro Power ◽  
Underground Cavern

Engineering rock mass is a highly complex grey system, it is impossible to get all the parameters of rock mass by theoretical methods or field measurement approach. Underground engineering feedback analysis method is a reliable way to improve the design, optimization and construction. Based on the field data of underground cavern of a large-scale hydro-power station, the three-dimensional finite element model is established, and orthogonal experimental design and multi-objective optimization method are used for the rapid back analysis. This method could be used for obtaining the rock parameters by inversion calculating in the underground cavern construction of a large-scale hydro-power station. Meanwhile, the inversion parameters could also be applied in the excavation simulation for the next phase and the rock deformation and stability is predicted afterwards. The design and construction sectors are supposed to get its feedback in time, which effectively guarantees the stability of the surrounding rocks.

Modelling of Dynamic Recrystallization in Hot Working

2007 ◽  
Vol 340-341 ◽  
pp. 779-786
Author(s):  
Bing Ye Xu ◽  
Jie Qu ◽  
Quan Lin Jin ◽  
Han Xiong Huang
Keyword(s):  
Finite Element ◽  
Dynamic Recrystallization ◽  
Microstructure Evolution ◽  
Optimization Method ◽  
Experimental Result ◽  
Element Formulation ◽  
Rigid Plastic ◽  
Finite Element Program ◽  
Element Program ◽  
Updated Lagrangian

Dynamic recrystallization, on which grain size of the final forging depends mainly, is one of the most important microstructure evolution processes in moderate-to-low stacking fault energy metals. In this paper, the process of dynamic recrystallization is simulated by numerical method. The paper first gives a visco-plastic model considering dynamic recrystallization in detail; secondly gives the applied finite element formulation and compiles an finite element program in Visual Fortran 6.5 based on the updated Lagrangian formulation rigid-plastic finite element; thirdly the material parameters are identified through inverse analysis, based on the compiled finite element program and the developed global optimization method; at last, the compiled finite element program is applied to simulate the microstructure evolution caused by dynamic recrystallization, the calculated result agrees with the experimental result relatively well.

Intelligent Displacement Back Analysis Method of Three-Dimension Applied in Unsymmetrical Pressure Tunnel with Shallow Depth

2011 ◽  
Vol 90-93 ◽  
pp. 2286-2291
Author(s):  
Liang Yong Wan ◽  
Xue Feng Zhang ◽  
Kai Yun Liu
Keyword(s):  
Back Analysis ◽  
Optimization Method ◽  
Small Sample ◽  
Shallow Depth ◽  
Support Vector ◽  
Three Dimension ◽  
Direct Optimization ◽  
Generalization Performance ◽  
Pressure Tunnel ◽  
Displacement Back Analysis

Artificial neural network has been widely used in displacement back analysis, but it has the problems of large sample, over-fitting, local optimization and poor generalization performance, so it has the poor adaptability in the Geotechnical Engineering. Support Vector Machines algorithm has the advantages of small sample, global optimization and generalization performance. A direct optimization method based on genetic algorithm and the improved support vector regression algorithm (GA-SVR) is applied in order to identify multinomial parameters intelligently and forecast displacements fast and exactly, combined with an unsymmetrical pressure tunnel with shallow depth section of the left line of import in BEIKOU Tunnel on Zhangjiakou-Shijiazhuang highway. The application result shows the new type of intelligent displacement back analysis could obtain accurately the parameters of rock mechanics and initial stress in limited monitoring data and provide parameters for ahead-forecast of rock deformation.

scholarly journals Determination of the mechanical parameters of rock mass based on a GSI system and displacement back analysis

2017 ◽  
Vol 14 (4) ◽  
pp. 939-948 ◽  
Author(s):  
Kwang-Song Kang ◽  
Nai-Lian Hu ◽  
Chung-Sik Sin ◽  
Song-Ho Rim ◽  
Eun-Cheol Han ◽  
...  
Keyword(s):  
Rock Mass ◽  
Back Analysis ◽  
Mechanical Parameters ◽  
Displacement Back Analysis
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