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Back analysis of geomechanical parameters in underground engineering using artificial bee colony.

Zhu C, Zhao H, Zhao M - ScientificWorldJournal (2014)

Bottom Line: To the problem without analytical solution, optimal back analysis is time-consuming, and least square support vector machine (LSSVM) was used to build the relationship between unknown geomechanical parameters and displacement and improve the efficiency of back analysis.The proposed method was applied to a tunnel with analytical solution and a tunnel without analytical solution.The results show the proposed method is feasible.

View Article: PubMed Central - PubMed

Affiliation: School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454003, China.

ABSTRACT
Accurate geomechanical parameters are critical in tunneling excavation, design, and supporting. In this paper, a displacements back analysis based on artificial bee colony (ABC) algorithm is proposed to identify geomechanical parameters from monitored displacements. ABC was used as global optimal algorithm to search the unknown geomechanical parameters for the problem with analytical solution. To the problem without analytical solution, optimal back analysis is time-consuming, and least square support vector machine (LSSVM) was used to build the relationship between unknown geomechanical parameters and displacement and improve the efficiency of back analysis. The proposed method was applied to a tunnel with analytical solution and a tunnel without analytical solution. The results show the proposed method is feasible.

Show MeSH
The comparison of stress between actual and recognized parameters.
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Related In: Results  -  Collection


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fig5: The comparison of stress between actual and recognized parameters.

Mentions: The displacement of monitored point of tunnel can be computed by the above formula. In this study, six monitored points were used in circular tunnel to monitor the displacements at the horizontal direction for ABC search. The distance between central of tunnel and 6 monitored points is 1.0 m, 1.1 m, 1.3 m, 1.5 m, 1.7 m, and 2.1 m, respectively (see Figure 3). The radius of tunnel is 1 m. The parameter of rock is listed in Table 1. ABC-based back analysis is used to identify geomechanical parameters (e.g., Young's modulus, E, cohesion, c, and friction angle, φ) from displacements of six monitored points. The recognized parameters and their error are listed in Table 2. The maximum relative error is 1.6%. It shows the recognized parameters agree well with the real parameters. The comparison between recognized and real parameters about the displacement and stress of surrounding rock of tunnel is shown in Figures 4 and 5. The results show stresses and displacements of surrounding rock identified by ABC are in well agreement with real stresses and displacements of surrounding rock and ABC is an excellent optimization method. The relationship between fitness and cycle is shown in Figure 6. The relationship between identified parameters and cycle is shown in Figure 7. They show that the performance and convergence of ABC are good and quick for identification of geomechanical parameters using ABC.


Back analysis of geomechanical parameters in underground engineering using artificial bee colony.

Zhu C, Zhao H, Zhao M - ScientificWorldJournal (2014)

The comparison of stress between actual and recognized parameters.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4127281&req=5

fig5: The comparison of stress between actual and recognized parameters.
Mentions: The displacement of monitored point of tunnel can be computed by the above formula. In this study, six monitored points were used in circular tunnel to monitor the displacements at the horizontal direction for ABC search. The distance between central of tunnel and 6 monitored points is 1.0 m, 1.1 m, 1.3 m, 1.5 m, 1.7 m, and 2.1 m, respectively (see Figure 3). The radius of tunnel is 1 m. The parameter of rock is listed in Table 1. ABC-based back analysis is used to identify geomechanical parameters (e.g., Young's modulus, E, cohesion, c, and friction angle, φ) from displacements of six monitored points. The recognized parameters and their error are listed in Table 2. The maximum relative error is 1.6%. It shows the recognized parameters agree well with the real parameters. The comparison between recognized and real parameters about the displacement and stress of surrounding rock of tunnel is shown in Figures 4 and 5. The results show stresses and displacements of surrounding rock identified by ABC are in well agreement with real stresses and displacements of surrounding rock and ABC is an excellent optimization method. The relationship between fitness and cycle is shown in Figure 6. The relationship between identified parameters and cycle is shown in Figure 7. They show that the performance and convergence of ABC are good and quick for identification of geomechanical parameters using ABC.

Bottom Line: To the problem without analytical solution, optimal back analysis is time-consuming, and least square support vector machine (LSSVM) was used to build the relationship between unknown geomechanical parameters and displacement and improve the efficiency of back analysis.The proposed method was applied to a tunnel with analytical solution and a tunnel without analytical solution.The results show the proposed method is feasible.

View Article: PubMed Central - PubMed

Affiliation: School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454003, China.

ABSTRACT
Accurate geomechanical parameters are critical in tunneling excavation, design, and supporting. In this paper, a displacements back analysis based on artificial bee colony (ABC) algorithm is proposed to identify geomechanical parameters from monitored displacements. ABC was used as global optimal algorithm to search the unknown geomechanical parameters for the problem with analytical solution. To the problem without analytical solution, optimal back analysis is time-consuming, and least square support vector machine (LSSVM) was used to build the relationship between unknown geomechanical parameters and displacement and improve the efficiency of back analysis. The proposed method was applied to a tunnel with analytical solution and a tunnel without analytical solution. The results show the proposed method is feasible.

Show MeSH