Back Analysis and Numerical Simulation of Surrounding Rock Parameters of Tunnel Close Construction Based on PSO-BP Algorithm

Under construction disturbance, the surrounding rock of a soft rock tunnel shows obvious aging characteristics. The creep characteristics of a rock mass under stress-seepage coupling greatly influence the long-term stability of a project. How to simply, quickly, and accurately determine the creep parameters of a rock mass under coupling conditions is significant to engineering structure design and construction. The optimal weights and thresholds of the BP neural network are sought through the immune algorithm to avoid the problem of slow convergence speed of the BP neural network and easy to fall into local optimum. Therefore, an intelligent back analysis method based on the IA-BP algorithm is established, which leads to the development of the corresponding intelligent back analysis program. The creep effect of the rock mass was simulated herein using the Drucker–Prager yield criterion and the time hardening creep law as the forward optimization method constitutive model. In addition, a sensitivity analysis of the parameters was performed to determine the optimal number of inversion parameters. By comparing and analyzing the residual between the inversion results of the IA-BP algorithm, PSO-BP algorithm, and the test values, the high precision of the IA-BP algorithm is proved. Taking the Lan Zhou-Hai Kou national expressway tunnel as an engineering example, a multiparameter creep inversion of the tunnel surrounding rock under the stress-seepage coupling condition was conducted using the inverse analysis method of the IA-BP algorithm. The results showed that the proposed IA-BP algorithm can effectively prevent the BP neural network from falling into a local minimum. Also, the algorithm is fast and accurate. The intelligent back analysis method based on the IA-BP algorithm is applied to the multifield coupling parameter back analysis, provides the basis and help for the structural design and construction of soft rock tunnel in water-rich stratum.

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Reasonable Entry Layout of Lower Seam in Multi-Seam Mining Based on Numerical Simulation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.295-298.2980 ◽

2013 ◽

Vol 295-298 ◽

pp. 2980-2984

Author(s):

Xiang Qian Wang ◽

Da Fa Yin ◽

Zhao Ning Gao ◽

Qi Feng Zhao

Keyword(s):

Numerical Simulation ◽

Stress Distribution ◽

Coal Seam ◽

Coal Mine ◽

Abutment Pressure ◽

Surrounding Rock ◽

Geological Conditions ◽

Seam Mining

Based on the geological conditions of 6# coal seam and 8# coal seam in Xieqiao Coal Mine, to determine reasonable entry layout of lower seam in multi-seam mining, alternate internal entry layout, alternate exterior entry layout and overlapping entry layout were put forward and simulated by FLAC3D. Then stress distribution and displacement characteristics of surrounding rock were analyzed in the three ways of entry layout, leading to the conclusion that alternate internal entry layout is a better choice for multi-seam mining, for which makes the entry located in stress reduce zone and reduces the influence of abutment pressure of upper coal seam mining to a certain extent,. And the mining practice of Xieqiao Coal Mine tested the results, which will offer a beneficial reference for entry layout with similar geological conditions in multi-seam mining.

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Numerical Simulation of Blasting-Induced Damage in Grouting Curtain of Sandstone Aquifer for Vertical Shaft

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.723.271 ◽

2015 ◽

Vol 723 ◽

pp. 271-278

Author(s):

Yu Liang Zhou ◽

Dong Feng Yuan ◽

Jun Zheng ◽

Hua Wang

Keyword(s):

Numerical Simulation ◽

Prevention And Control ◽

Damage Zone ◽

Surrounding Rock ◽

Damage Effect ◽

Vertical Shaft ◽

Control Methods ◽

Sandstone Aquifer ◽

And Control ◽

Dynamic Damage

To provide a theoretical basis for water prevention and control methods and reasonable supporting techniques for vertical shaft, and to ensure the shaft construction to pass the sandstone aquifer safely and rapidly, numerical simulation using dynamic damage constitutive model, which was a user-defined constitutive modules in FLAC3D, a lagrangian analysis code in three dimensions, has been applied to investigate the dynamic damage effect in the surrounding rock of the grouting curtain near the driving working face for vertical shaft excavated by blasting. The results indicate that the distribution of the damage zone in the surrounding rock of the shaft, which decreases the effective thickness of the grouting curtain, was like a ellip-se, and that the depth of the damage zone in the surrounding rock of the shaft grouting curtain is fewer than that of the driving face floor. It can be concluded that the centre part of the driving face floor, especially the cutting hole zones, and the shaft wall in the greater horizontal stress side are the " key parts " for shaft water prevention and control methods.

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Numerical Simulation on the Effect of Compound Roof Separation Position on Bolting Performance

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.953-954.1638 ◽

2014 ◽

Vol 953-954 ◽

pp. 1638-1642

Author(s):

Ai Qing Liu ◽

Jian Zhang ◽

Peng Cheng ◽

Yu Hai Zhang

Keyword(s):

Numerical Simulation ◽

Simulation Analysis ◽

Surrounding Rock ◽

Cohesive Force ◽

Roof Strata ◽

Poor Stability ◽

Key Parameter

Prestress is a key parameter in bolting, while the cohesive force of layers in the compound roof strata is low and prone to separation, causing the prestress proliferation very poor. With the method of numerical simulation analysis,the location of separation in compound roof to affect the performance of bolting support was researched. It is concluded the roof separation in the edge of anchorage zone, the prestress field superpose, but is away from the deep surrounding rock and shows poor stability,however the role of cable can make up for the defect of rockbolts support. It has been found the highly prestressed strength bolting system adapts to the compound roof.

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Study on the Prediction Method of Tunnel Surrounding Rock Pressure Based on the Theory of Progressive Destruction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.1432 ◽

2012 ◽

Vol 446-449 ◽

pp. 1432-1436

Author(s):

Suo Wang

Keyword(s):

Rock Pressure ◽

Characteristic Curve ◽

Prediction Method ◽

Surrounding Rock ◽

Progressive Damage ◽

Tunnel Excavation ◽

Practical Engineering ◽

Surrounding Rock Pressure ◽

The Relationship ◽

Rock Parameters

In order to predict tunnel surrounding rock pressure, this paper puts forward a series of dynamic numerical simulative model on the tunnel excavation. According to the change of rock damage in the construction program, it adjusts dynamically the mechanical material parameters of surrounding rock. So the model achieves the purpose which is controlling and simulating the process of tunnel progressive damage. In accordance with the numerical simulative results, it analyzes the relationship between the rock parameters with the plastic strain, radial displacement. Then this paper proposes a prediction method of tunnel surrounding rock pressure based on the theory of the progressive damage and method of characteristic curve. Finally, it compares the pressure on the numerical simulative models with on the site date, and it proves that the prediction method has practical engineering value.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.777.8 ◽

2015 ◽

Vol 777 ◽

pp. 8-12 ◽

Cited By ~ 1

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.

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Characteristic Law of Borehole Deformation Induced by the Temperature Change in the Surrounding Rock of Deep Coalbed Methane Well

Journal of Energy Resources Technology ◽

10.1115/1.4051826 ◽

2021 ◽

pp. 1-18

Author(s):

Xin Li ◽

Jie Zhang ◽

Cuinan Li ◽

Weilin Chen ◽

Jingbin He ◽

...

Keyword(s):

Numerical Simulation ◽

Coalbed Methane ◽

Linear Equations ◽

Surrounding Rock ◽

Experimental Temperature ◽

Borehole Stability ◽

Fracture Angle ◽

High Deformation ◽

Rock Temperature ◽

Primary Fracture

Abstract The borehole stability of the coalbed methane (CBM) well has always been vital in deep CBM exploration and development. The borehole instability of the deep CBM well is due to many complicated reasons. The change in the surrounding rock temperature is an important and easily overlooked factor among many reasons. In this research, we used methods that include experiment and numerical simulation to study the characteristic law of the borehole deformation induced by the changes in the surrounding rock temperature of deep CBM well. The experimental results of the stress–strain curves of five sets of experiments show that when the experimental temperature rises from 40 °C to 100 °C, the average stress when coal samples are broken gradually decreases from 81.09 MPa to 72.71 MPa. The proportion of plastic deformation in the entire deformation stage gradually increases from 7.8% to 25.7%. Moreover, the characteristics that some key mechanical parameters of coal samples change with the experimental temperature are fitted, and results show that as the experimental temperature rises from 40 °C to 100 °C, the compressive strength, elastic modulus, and main crack length of coal samples show a gradually decreasing trend. By contrast, the Pois-son's ratio and primary fracture angle show a gradually increasing trend. Moreover, the relativity of the linear equations obtained by fitting is all close to 1, which can accurately reflect the corresponding change trend. Numerical simulation results show that a high temperature of the surrounding rock of the deep CBM well results in a high range of stress concentration on the coal seam borehole and high deformation.

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Study on Deformation and Damage of Rock Mass Subject to High In Situ Stress by Using a Elastoplastic Damage Model and Considering the Impact of Weak Planes

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.838-841.705 ◽

2013 ◽

Vol 838-841 ◽

pp. 705-709

Author(s):

Yun Hao Yang ◽

Ren Kun Wang

Keyword(s):

Rock Mass ◽

Large Scale ◽

Damage Model ◽

Back Analysis ◽

In Situ Stress ◽

Surrounding Rock ◽

High In Situ Stress ◽

Underground Caverns ◽

The Impact

Large scale underground caverns are under construction in high in-situ stress field at Houziyan hydropower station. To investigate deformation and damage of surrounding rock mass, a elastoplastic orthotropic damage model capable of describing induced orthotropic damage and post-peak behavior of hard rock is used, together with a effective approach accounting for the presence of weak planes. Then a displacement based back analysis was conducted by using the measured deformation data from extensometers. The computed displacements are in good agreement with the measured ones at most of measurement points, which confirm the validities of constitutive model and numerical simulation model. The result of simulation shows that damage of surrounding rock mass is mainly dominated by the high in-situ stress rather than the weak planes and heavy damage occur at the cavern shoulders and side walls.

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Back Analysis for Mass Parameters of Tunnel Surrounding Rock

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.170-173.20 ◽

2012 ◽

Vol 170-173 ◽

pp. 20-24 ◽

Cited By ~ 1

Author(s):

Kai Cui ◽

Xue Kai Pan

Keyword(s):

Deformation Mechanism ◽

Strain Softening ◽

Back Analysis ◽

Surrounding Rock ◽

Tunnel Engineering ◽

Railway Tunnel ◽

Displacement Back Analysis ◽

Information Construction ◽

Engineering Information ◽

The Common

Tunnel engineering information construction has been widely used, and the back analysis is its core. As the common useful method, displacement back analysis is of special advantages. This paper introduces the calculative method based on the application in a railway tunnel. The result shows that strain softening model can be used to simulate the large deformation mechanism of surrounding rock.

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