首页 » 文章 » 文章详细信息
Advances in Civil Engineering Volume 2018 ,2018-04-03
The Numerical Simulation of Hard Rocks for Tunnelling Purposes at Great Depths: A Comparison between the Hybrid FDEM Method and Continuous Techniques
Research Article
Nicholas Vlachopoulos 1 Ioannis Vazaios 1
Show affiliations
DOI:10.1155/2018/3868716
Received 2017-12-01, accepted for publication 2018-02-27, Published 2018-02-27
PDF
摘要

Tunnelling processes lead to stress changes surrounding an underground opening resulting in the disturbance and potential damage of the surrounding ground. Especially, when it comes to hard rocks at great depths, the rockmass is more likely to respond in a brittle manner during the excavation. Continuum numerical modelling and discontinuum techniques have been employed in order to capture the complex nature of fracture initiation and propagation at low-confinement conditions surrounding an underground opening. In the present study, the hybrid finite-discrete element method (FDEM) is used and compared to techniques using the finite element method (FEM), in order to investigate the efficiency of these methods in simulating brittle fracturing. The numerical models are calibrated based on data and observations from the Underground Research Laboratory (URL) Test Tunnel, located in Manitoba, Canada. Following the comparison of these models, additional analyses are performed by integrating discrete fracture network (DFN) geometries in order to examine the effect of the explicit simulation of joints in brittle rockmasses. The results show that in both cases, the FDEM method is more capable of capturing the highly damaged zone (HDZ) and the excavation damaged zone (EDZ) compared to results of continuum numerical techniques in such excavations.

授权许可

Copyright © 2018 Nicholas Vlachopoulos and Ioannis Vazaios. 2018
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

图表

Schematic of the Hoek–Brown criterion strength envelope and the composite strength envelope of the DISL model [16] (modified after [17]).

Tunnel model configuration created in Irazu (left) and in RS2 (right). The geometrical characteristics of the excavation and the applied geostatic stresses correspond to the ones recorded and monitored at the URL Test Tunnel.

Unconfined compressive strength (UCS) test for the calibration of the FDEM elastic microparameters based on the deformability properties of the LdB granite. (a) The initial UCS configuration and (b) the UCS specimen at its postpeak condition. Black fractures indicate failure in tension (Mode I), and yellow fractures indicate failure in shear (Mode II).

Unconfined compressive strength (UCS) test for the calibration of the FDEM elastic microparameters based on the deformability properties of the LdB granite. (a) The initial UCS configuration and (b) the UCS specimen at its postpeak condition. Black fractures indicate failure in tension (Mode I), and yellow fractures indicate failure in shear (Mode II).

Axial stress-axial strain and axial stress-lateral strain curves obtained from UCS testing of the calibrated FDEM model. Recording of stress-strain results ceased once the peak strength was achieved, as the UCS numerical model is used only for the calibration of the elastic parameters of the model.

(a) Photograph of URL Test Tunnel (after [16] modified from [24]) showing the damage profile observed in situ. (b) Damage profile from the FDEM model (highlighted black) after the completion of the numerical analysis.

(a) Photograph of URL Test Tunnel (after [16] modified from [24]) showing the damage profile observed in situ. (b) Damage profile from the FDEM model (highlighted black) after the completion of the numerical analysis.

Calibration process employed for determining the required input parameters in the FDEM model. The microscopic Young’s modulus E and Poisson’s ratio ν refer to the elastic constants of the triangular elements (E and ν at element scale). The macroscopic values refer to the Young’s modulus and Poisson’s ratio obtained from the UCS testing in Figures 2 and 3 (Erm and νrm at 7.5 m height specimen scale). For more information, the reader is referred to [46].

Major principal stress σ1 contours of the intact FEM model using the Hoek–Brown criterion (GSI = 80). (a) Elastic response of the model at 60% of the induced stresses (tunnel advancing) and (b) final model state after the completion of the excavation. Yielded elements in shear (×) and in tension (○) are plotted.

Major principal stress σ1 contours of the intact FEM model using the Hoek–Brown criterion (GSI = 80). (a) Elastic response of the model at 60% of the induced stresses (tunnel advancing) and (b) final model state after the completion of the excavation. Yielded elements in shear (×) and in tension (○) are plotted.

Major principal stress σ1 contours of the intact FEM model using the DISL approach [16]. (a) Elastic response of the model at 60% of the induced stresses (tunnel advancing), and (b) final model state after the completion of the excavation. Yielded elements in shear (×) and in tension (○) are plotted. Yielded elements in tension at the crown and floor of the excavation are the result of extensile fracturing. Numerical results are consistent with the results by [16].

Major principal stress σ1 contours of the intact FEM model using the DISL approach [16]. (a) Elastic response of the model at 60% of the induced stresses (tunnel advancing), and (b) final model state after the completion of the excavation. Yielded elements in shear (×) and in tension (○) are plotted. Yielded elements in tension at the crown and floor of the excavation are the result of extensile fracturing. Numerical results are consistent with the results by [16].

Major principal stress σ1 contours of the intact FDEM model. (a) Elastic response of the model at 60% of the induced stresses (tunnel advancing), and (b) final model state after the completion of the excavation. Cohesive elements failing in tension (Mode I fractures) are coloured red, and cohesive elements failing in shear (Mode II fractures) are coloured yellow.

Major principal stress σ1 contours of the intact FDEM model. (a) Elastic response of the model at 60% of the induced stresses (tunnel advancing), and (b) final model state after the completion of the excavation. Cohesive elements failing in tension (Mode I fractures) are coloured red, and cohesive elements failing in shear (Mode II fractures) are coloured yellow.

Damage profiles obtained from each intact numerical model (DFN geometries are not integrated in the models): purple continuous line—FEM Hoek–Brown model, red dashed line—FEM-DISL model, blue dotted line—collapsed material of the FDEM model (HDZ), blue dash-dotted line—damaged (fractured) material of the FDEM model (EDZ). In Figure 8, it can be observed that the collapsed material is detaching from the rockmass. On the contrary, the damaged material fractures but maintains its integrity and does not collapse. The results are compared to the actual damaged profile as observed at the URL Test Tunnel [48], and acoustic emission (AE) and microseismic (MS) events are also plotted for comparison [49].

Major principal stresses σ1 monitored along the line (AB) (Figure 12) for the intact FEM Hoek–Brown model (purple line), the intact FEM-DISL model (red line), and the intact FDEM model (blue line). In situ stress measurements (stress cell SM-5) are plotted for comparison [50]. The purple hatched area indicates the extent of the damaged zone (yielded elements) for the FEM Hoek–Brown model along line (AB). The red hatched area indicates the extent of the damaged zone (yielded elements) for the FEM-DISL model along line (AB). The blue hatched area indicates the extent of the damaged zone (failure of cohesive elements) for the FDEM model along line (AB). The blue dashed line indicates the ending point of the collapsed material and the starting point of the damaged zone in the FDEM model. The red dashed line indicates the ending point of the HDZ and the starting point of the EDZ in the FEM-DISL model. The red continuous line indicates the ending point of the EDZ in the FEM-DISL model.

Monitoring line along the Y axis placed at the crown of the tunnel within the intact FDEM (left) and FEM (right) models for monitoring the principal stresses. The symbols (A) and (B) indicate the starting and ending point of the monitoring line, respectively. The obtained stress results are shown in Figures 11 and 13 for the major and minor principal stresses, respectively. (Left) Cohesive elements failing in tension (Mode I fractures) are coloured red, and cohesive elements failing in shear (Mode II fractures) are coloured yellow. (Right) Yielded elements in shear (×) and in tension (○) are plotted.

Minor principal stresses σ3 monitored along the line (AB) (Figure 12) for the intact FEM Hoek–Brown model (purple line), the intact FEM-DISL model (red line), and the intact FDEM model (blue line). In situ stress measurements (stress cell SM-5) are plotted for comparison [50]. The purple hatched area indicates the extent of the damaged zone (yielded elements) for the FEM Hoek–Brown model along line (AB). The red hatched area indicates the extent of the damaged zone (yielded elements) for the FEM-DISL model along line (AB). The blue hatched area indicates the extent of the damaged zone (failure of cohesive elements) for the FDEM model along line (AB). The blue dashed line indicates the ending point of the collapsed material and the starting point of the damaged zone in the FDEM. The red dashed line indicates the ending point of the HDZ and the starting point of the EDZ in the FEM-DISL model. The red continuous line indicates the ending point of the EDZ in the FEM-DISL model.

Major principal stress σ1 contours of the fractured FEM model using the Hoek–Brown criterion (GSI = 80). Yielded elements in shear (×) and in tension (○) are plotted. The dashed black line indicates the damage profile based on the recorded yielded elements. White lines indicate the contributing joints to the obtained damage profile.

Major principal stress σ1 contours of the fractured FEM model using the DISL approach [16]. Yielded elements in shear (×) and in tension (○) are plotted. The dashed black line indicates the damage profile based on the recorded yielded elements. White lines indicate the contributing joints to the obtained damage profile.

Major principal stress σ1 contours of the fractured FDEM model. Cohesive elements failing in tension (Mode I fractures) are coloured red, and cohesive elements failing in shear (Mode II fractures) are coloured yellow. The dashed black line indicates the damage profile based on the monitored fractures. The continuous black line indicates the collapsed material. White lines indicate the contributing joints to the obtained damage profile.

Comparison between damage profiles for (a) the FEM Hoek–Brown intact (purple continuous line) and fractured (black dashed line) models, (b) the FEM-DISL intact (red dashed line) and fractured (black dashed line) models, and (c) the FDEM intact (blue dotted line-collapsed material and blue dash-dotted line-damaged material) and fractured (black continuous line-collapsed material and black dashed line-damaged material) models.

Comparison between damage profiles for (a) the FEM Hoek–Brown intact (purple continuous line) and fractured (black dashed line) models, (b) the FEM-DISL intact (red dashed line) and fractured (black dashed line) models, and (c) the FDEM intact (blue dotted line-collapsed material and blue dash-dotted line-damaged material) and fractured (black continuous line-collapsed material and black dashed line-damaged material) models.

Comparison between damage profiles for (a) the FEM Hoek–Brown intact (purple continuous line) and fractured (black dashed line) models, (b) the FEM-DISL intact (red dashed line) and fractured (black dashed line) models, and (c) the FDEM intact (blue dotted line-collapsed material and blue dash-dotted line-damaged material) and fractured (black continuous line-collapsed material and black dashed line-damaged material) models.

通讯作者

Nicholas Vlachopoulos.Department of Civil Engineering, Royal Military College of Canada, Kingston, ON, Canada, rmc.ca.vlach@rmc.ca

推荐引用方式

Nicholas Vlachopoulos,Ioannis Vazaios. The Numerical Simulation of Hard Rocks for Tunnelling Purposes at Great Depths: A Comparison between the Hybrid FDEM Method and Continuous Techniques. Advances in Civil Engineering ,Vol.2018(2018)

您觉得这篇文章对您有帮助吗?
分享和收藏
0

是否收藏?

参考文献
[1] Rocscience Inc.. (2015). RS2–Phase 2 Version 9.010 64 bit. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[2] A. Munjiza, D. R. J. Owen, N. Bicanic. (1995). A combined finite-discrete element method in transient dynamics of fracturing solids. Engineering Computations.12:145-174. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[3] W. S. Dershowitz, H. H. Herda. Interpretation of fracture spacing and intensity. . DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[4] M. Jonsson, A. Backstrom, Q. Feng, J. Berglund. et al.(2009). Äspö Hard Rock Laboratory: Studies of Factors That Affect and Controls the Excavation Damage/Disturbed Zone. SKB Report R-09–17. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[5] Geomechanica Inc.. (2017). Irazu 2D Geomechanical Simulation Software, Version 3.0. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[6] A. Munjiza, K. R. F. Andrews, J. K. White. (1999). Combined single and smeared crack model in combined finite-discrete element analysis. International Journal for Numerical Methods in Engineering.44:41-57. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[7] K. Farahmand, I. Vazaios, M. S. Diederichs, N. Vlachopoulos. et al.(2017). Investigating the scale-dependency of the geometrical and mechanical properties of a moderately jointed rock using a synthetic rock mass (SRM) approach. Computers and Geotechnics.95:162-179. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[8] P. Bossart, P. M. Meier, A. Moeri, T. Trick. et al.(2002). Geological and hydraulic characterisation of the excavation disturbed zone in the opalinus clay of the mont terri rock laboratory. Engineering Geology.66(1-2):19-38. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[9] C. D. Martin, R. S. Read, J. B. Martino. (1997). Observations of brittle failure around a circular test tunnel. International Journal of Rock Mechanics and Mining Sciences.34(7):1065-1073. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[10] D. O. Potyondy, P. A. Cundall. (2004). A bonded-particle model for rock. International Journal of Rock Mechanics and Mining Sciences.41(8):1329-1364. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[11] C. D. Martin. (1994). The Strength of Massive Lac du Bonnet Granite Around Underground Openings. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[12] M. S. Diederichs. (2007). The 2003 Canadian geotechnical colloquium: mechanistic interpretation and practical application of damage and spalling prediction criteria for deep tunnelling. Canadian Geotechnical Journal.44(9):1082-1116. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[13] E. Hoek, E. T. Brown. (1997). Practical estimates of rock mass strength. International Journal of Rock Mechanics and Mining Sciences.34(8):1165-1186. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[14] A. Munjiza. (2004). The Combined Finite-Discrete Element Method. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[15] G. I. Barenblatt. (1962). The mathematical theory of equilibrium cracks in brittle fracture. Advances in Applied Mechanics.7:55-129. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[16] V. Falmagne. (2001). Quantification of Rock Mass Degradation Using Micro-Seismic Monitoring and Applications for Mine Design. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[17] M. Cai, P. K. Kaiser, C. D. Martin. (2001). Quantification of rock mass damage in underground excavations from microseismic event monitoring. International Journal of Rock Mechanics and Mining Sciences.38(8):1135-1145. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[18] C. D. Martin, P. K. Kaiser. (1996). Mine-by Experiment Committee Report, Phase 1: Excavation Response Summary and Implications, AECL Report, AECL-11382. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[19] P. K. Kaiser, M. S. Diederichs, C. D. Martin, J. Sharpe. et al.Invited keynote lecture: underground works in hard rock tunnelling and mining. :841-926. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[20] L. R. Myer, J. M. Kemeny, Z. Zheng, R. Suarez. et al.(1992). Extensile cracking in porous rock under differential compressive stress. Applied Mechanics Reviews.45(8):263-280. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[21] V. Hajiabdolmajid, P. K. Kaiser, C. D. Martin. (2002). Modelling brittle failure of rock. International Journal of Rock Mechanics and Mining Sciences.39(6):731-741. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[22] M. Diederichs. (2000). Instability of Hard Rockmasses: The Role of Tensile Damage and Relaxation. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[23] N. Cho, C. D. Martin, D. C. Sego. (2007). A clumped particle model for rock. International Journal of Rock Mechanics and Mining Sciences.44(7):997-1010. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[24] A. A. Griffith. (1921). The phenomena of rupture and flow in solids. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.221:163-198. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[25] D. S. Dugdale. (1960). Yielding of steel sheets containing slits. Journal of the Mechanics and Physics of Solids.8(2):100-104. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[26] D. Mas Ivars, D. O. Potyondy, M. Pierce, P. A. Cundall. et al.The smooth-joint contact model. . DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[27] D. O. Potyondy. A flat-jointed bonded –particle material for hard rock. . DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[28] O. K. Mahabadi. (2012). Investigating the Influence of Micro-Scale Heterogeneity and Microstructure on the Failure and Mechanical Behaviour of Geomaterials. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[29] M. Christianson, M. Board, D. Rigby. UDEC simulation of triaxial testing of lithophysal tuff. . DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[30] I. Vazaios, N. Vlachopoulos. The evolution of the excavation damage zone of tunnels in brittle rockmasses using a FEM/DEM approach. . DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[31] T. Kazerani, J. Zhao. (2010). Micromechanical parameters in bonded particle method for modelling of brittle material failure. International Journal for Numerical and Analytical Methods in Geomechanics.34(18):1877-1895. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[32] N. Vlachopoulos, M. S. Diederichs. (2014). Appropriate uses and practical limitations of 2D numerical analysis of tunnels and tunnel support response. Geotechnical and Geological Engineering.32(2):469-488. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[33] T. R. Stacey. (1981). A simple extension strain criterion for fracture of brittle rock. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts.18(6):469-474. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[34] E. Hoek, C. Carranza-Torres, B. Corkum. Hoek-Brown failure criterion-2002 edition. :267-271. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[35] A. Lisjak. (2013). Investigating the Influence of Mechanical Anisotropy on the Fracturing Behaviour of Brittle Clay Shales with Application to Deep Geological Repositories. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[36] B. S. A. Tatone, G. Grasselli. (2015). A calibration procedure for two-dimensional laboratory-scale hybrid finite-discrete element simulations. International Journal of Rock Mechanics and Mining Sciences.75:56-72. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[37] C. D. Martin. (1997). The 17th Canadian geotechnical colloquium: the effect of cohesion loss and stress path on brittle rock strength. Canadian Geotechnical Journal.34:698-725. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[38] E. Hoek, P. Marinos. GSI: a geological friendly tool for rock mass strength estimation. :1422-1446. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[39] T. I. Addenbrooke, D. M. Potts. (2001). Twin tunnel interaction: surface and subsurface effects. International Journal of Geomechanics.1(2):249-271. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[40] K. Farahmand, M. S. Diederichs. A calibrated synthetic rock mass (SRM) model for simulating crack growth in granitic rock considering grain scale heterogeneity of polycrystalline rock. . DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[41] S. Kwon, C. S. Lee, S. J. Cho, S. W. Jeon. et al.(2009). An investigation of the excavation damaged zone at the KAERI underground research tunnel. Tunnelling Underground Space Technology.24(1):1-13. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[42] M. A. Perras, M. S. Diederichs. (2016). Predicting excavation damage zone depths in brittle rocks. Journal of Rock Mechanics and Geotechnical Engineering.8(1):60-74. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[43] J. B. Martino, D. A. Dixon, E. T. Kozak. (2007). The tunnel sealing experiment: an international study of fullscale seals. Physics and Chemistry of the Earth, Parts A/B/C.32(1–7):93-107. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[44] N. A. Chandler. Twenty years of underground research at Canada’s URL. . DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[45] F. Q. Gao, D. Stead. (2014). The application of a modified Voronoi logic to brittle fracture modelling at the laboratory and field scale. International Journal of Rock Mechanics and Mining Sciences.68:1-14. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[46] J. F. Labuz, S. P. Shah, C. H. Dowding. (1985). Experimental analysis of crack propagation in granite. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts.22(2):85-98. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[47] E. Hoek. (1968). Brittle failure of rock. Rock Mechanics in Engineering Practice:99-124. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[48] Q. Lei, J. P. Latham, J. Xiang, C. F. Tsang. et al.(2017). Role of natural fractures in damage evolution around tunnel excavation fractured rocks. Engineering Geology.231:100-113. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[49] A. Munjiza, K. R. F. Andrews. (2000). Penalty function method for combined finite-discrete element systems comprising large number of separate bodies. International Journal for Numerical Methods in Engineering.49:1377-1396. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
[50] M. S. Diederichs. (2003). Manuel Rocha medal recipient rock fracture and collapse under low confinement conditions. Rock Mechanics and Rock Engineering.36(5):339-381. DOI: 10.1061/(asce)1532-3641(2001)1:2(249).
文献评价指标
浏览 84次
下载全文 9次
评分次数 0次
用户评分 0.0分
分享 0次