An, J. H. and Lee, S. D. (2009). “Reinforcing effect of pre-tensioned rock bolts in the jointed rocks condition.” Tunnel and Underground Space, Korean Society for Rock Mechanics, Vol. 19, No. 5, pp. 388-396 (in Korean).An, J. H. and Lee, S. D. (2009). “Reinforcing effect of pre-tensioned rock bolts in the jointed rocks condition.” Tunnel and Underground Space, Korean Society for Rock Mechanics, Vol. 19, No. 5, pp. 388-396 (in Korean).

Cho, T. C. and Lee, C. I. (1993). “Reinforcement effect of viscoplastic rockbolt-numerical study.” The journal of engineering geology, The Korean Society of Engineering Geology, Vol. 3, No. 3, pp. 215-230 (in Korean).Cho, T. C. and Lee, C. I. (1993). “Reinforcement effect of viscoplastic rockbolt-numerical study.” The journal of engineering geology, The Korean Society of Engineering Geology, Vol. 3, No. 3, pp. 215-230 (in Korean).

10.1016/j.ijrmms.2006.12.001Goel, R. K, Swarup, A. and Sheroey, P. R. (2007). “Bolt length requiremental in underground openings.” International Journal of Rock Mechanics and Mining Sciences, Vol. 44, No. 5, pp. 802-811.Goel, R. K, Swarup, A. and Sheroey, P. R. (2007). “Bolt length requiremental in underground openings.” International Journal of Rock Mechanics and Mining Sciences, Vol. 44, No. 5, pp. 802-811.

Jung, H. S. and Moon, H. K. (1999). “A study on the rein-forcement effects of fully-grouted rock bolts.” Tunnel and Underground Space, Korean Society for Rock Mechanics, Vol. 9, pp. 194-203 (in Korean).Jung, H. S. and Moon, H. K. (1999). “A study on the rein-forcement effects of fully-grouted rock bolts.” Tunnel and Underground Space, Korean Society for Rock Mechanics, Vol. 9, pp. 194-203 (in Korean).

Kim, D. G. and Jung, H. S. (2007). “The enlargement of a tunnel in operation for improve function.” Geotechnical Engineering, Korean Geotechnical Society, Vol. 23, No. 3, pp. 14-20 (in Korean).Kim, D. G. and Jung, H. S. (2007). “The enlargement of a tunnel in operation for improve function.” Geotechnical Engineering, Korean Geotechnical Society, Vol. 23, No. 3, pp. 14-20 (in Korean).

Kim, W. K., Baek, K. H., Sea, K. W., Kim, D. G. and Woo, S. B. (2010). “Numerical study of reinforcing effect for rock bolt by installation angle.” Annual Conference and General Assembly of Korean Society for Rock Mechanics, Korean Society for Rock Mechanics, Vol. 2010, No. 3, pp. 199-204 (in Korean).Kim, W. K., Baek, K. H., Sea, K. W., Kim, D. G. and Woo, S. B. (2010). “Numerical study of reinforcing effect for rock bolt by installation angle.” Annual Conference and General Assembly of Korean Society for Rock Mechanics, Korean Society for Rock Mechanics, Vol. 2010, No. 3, pp. 199-204 (in Korean).

10.12652/Ksce.2012.32.5C.231Lee, J. D., Kim, B. I., Piao, M. S. and Yoo, W. K. (2012). “Model test study on the reinforcing effect of inclined system bolting.” Journal of the Korean Society of Civil Engineers, Korean Society of Civil Engineers, Vol. 32, No. 5C, pp. 231-238 (in Korean).Lee, J. D., Kim, B. I., Piao, M. S. and Yoo, W. K. (2012). “Model test study on the reinforcing effect of inclined system bolting.” Journal of the Korean Society of Civil Engineers, Korean Society of Civil Engineers, Vol. 32, No. 5C, pp. 231-238 (in Korean).

Lee, Y. K., Lee, C. I. and Cho, T. C. (1995). “A study on the visco-plastic behavior of the jointed rock mass reinforced by rockbolts during excavation.” Tunnel and Underground Space, Korean Society for Rock Mechanics, Vol. 5, pp. 123-133 (in Korean).Lee, Y. K., Lee, C. I. and Cho, T. C. (1995). “A study on the visco-plastic behavior of the jointed rock mass reinforced by rockbolts during excavation.” Tunnel and Underground Space, Korean Society for Rock Mechanics, Vol. 5, pp. 123-133 (in Korean).

Moon, W. J., Im, H. D., Jung, K. B., Kim, J. S. and Lee, S. D. (2005). “Supporting effects of system bolting at the tunnel in sandy ground.” The 2005 KSCE Annual Conference & Civil Expo, Korean Society of Civil Engineers, Vol. 2005, No. 10, pp. 5555-5558 (in Korean).Moon, W. J., Im, H. D., Jung, K. B., Kim, J. S. and Lee, S. D. (2005). “Supporting effects of system bolting at the tunnel in sandy ground.” The 2005 KSCE Annual Conference & Civil Expo, Korean Society of Civil Engineers, Vol. 2005, No. 10, pp. 5555-5558 (in Korean).

Noh, S. H., Lee, C. I. and Lee, Y. K. (2004). “Numerical analysis of the visco-plastic behavior of rock mass considering continuum joints and rock bolt elements.” Tunnel and Underground Space, Korean Society for Rock Mechanics, Vol. 14, No. 3, pp. 215-228 (in Korean).Noh, S. H., Lee, C. I. and Lee, Y. K. (2004). “Numerical analysis of the visco-plastic behavior of rock mass considering continuum joints and rock bolt elements.” Tunnel and Underground Space, Korean Society for Rock Mechanics, Vol. 14, No. 3, pp. 215-228 (in Korean).

10.1016/j.enggeo.2009.05.003Osgoui, R. R. and Erdal, Ü. (2009). “An empirical method for design of grouted bolts in rock tunnels based on the geological strength index(GSI).” Engineering Geology, Vol. 107, No. 3-4, pp. 154-166. Osgoui, R. R. and Erdal, Ü. (2009). “An empirical method for design of grouted bolts in rock tunnels based on the geological strength index(GSI).” Engineering Geology, Vol. 107, No. 3-4, pp. 154-166.

Sea, K. W., Baek, K. H. and Kim, W. K. (2008). “Construction reports of the enlargement of a tunnel in operation-foreign countries(Ⅱ).” Tunnelling Technology, Korean Tunnelling and Underground Space Association, Vol. 10, No. 2, pp. 71-79 (in Korean).Sea, K. W., Baek, K. H. and Kim, W. K. (2008). “Construction reports of the enlargement of a tunnel in operation-foreign countries(Ⅱ).” Tunnelling Technology, Korean Tunnelling and Underground Space Association, Vol. 10, No. 2, pp. 71-79 (in Korean).