[2] حشمتی، ع.، صالح زاده، ح.، فرهادی، م.، اثر حفرات کارستی بر روی تغییرشکل های پوشش تونل حفر شده در سنگ آهک انحلالی، ششمین کنگره ملی مهندسی عمران، سمنان، 1390.
[2] قارونی نیک، م.، توکلی، م.، مظفری شمس، ا.، طراحی پوشش تونل در زمینهای کارستی – مطالعه موردی: تونل دالا، پنجمین کنفرانس تونل ایران، تهران، 1380.
[3]Casagrande, G., “ Hazard connected to railway tunnel construction in karstic area: applied geomorphological and hydrogeological surveys”, Natural Hazards and Earth System Sciences, 4(5); 243–250, 2005.
[4]]Beck, B. F. and Pearson, F. M., “Karst geohazards – Engineer-ing and environmental problems in karst terrain”, Proceedings of the Fifth Multidisciplinary Conference on Sinkholes and the En-vironmental Impacts of Karst, A. A. Balkema, p. 581, 1995.
[5]Scesi, L., and Papini, M., “Studi geologici nei progetti di gallerie”, Geo-gaph S.n.c. Ed., Segrate., 244, 1998.
[6]Knez, M., Slabe, T., and Sebela, S., “Karstification of the aquifer discovered during the construction of the expressway between Klanec and Crni kal”, Classical Karst, Acta Carsologica, 33(1); 205–217, 2004.
[8] S. Miao, P.Z. Pan, Z. Wu, S. Li, S. Zhao, Fracture analysis of sandstone with a single filled flaw under uniaxial compression, Eng. Fract. Mech. 204 (2018) 319 –343 .
[9] Q. Wu, L. Weng, Y. Zhao, B. Guo, T. Luo, On the tensile mechanical characteristics of fi ne-grained granite after heating/cooling treatments with diff erent cooling rates, Eng. Geol. 253 (2019) 94 –110 .
[10] Z. Zhou, L. Tan, W. Cao, Z. Zhou, X. Cai, Fracture evolution and failure behaviour of marble specimens containing rectangular cavities under uniaxial loading, Eng. Fract. Mech. 184 (2017) 183 –201 .
[11] Q. Dong, C. Xiong, C. Ma, H. Wei, Experimental study on cracking behaviour of intermittent double S-shaped fi ssures under uniaxial compression, KSCE J. Civ. Eng. 23 (6) (2019) 2483 –2494 .
[12] H. Haeri, A. Khaloo, M.F. Marji, Fracture analyses of different pre-holed concrete specimens under compression, Acta Mech. Sin. 31 (6) (2015) 855 – 870.
[13] S.Q. Yang, Y.H. Huang, W.L. Tian, J.B. Zhu, An experimental investigation on strength, deformation and crack evolution behavior of sandstone containing two oval flaws under uniaxial compression, Eng. Geol. 217 (2017) 35 –48 .
[14] X. Fan, R. Chen, H. Lin, H. Lai, C. Zhang, Q. Zhao, Cracking and failure in rock specimen containing, Adv. Civ. Eng. 2018 (2018) .
[15] N. Hudyma, B.B. Avar, M. Karakouzian, Compressive strength and failure modes of lithophysae-rich Topopah Spring Tuff specimens and analog models containing cavities, Eng. Geol. 73 (1–2) (2004) 179 –190
[16]Itasca Consulting Group. PFC2Duser’s manual, ver. 3.0. Minneapo-lis: Minnesota; 2003.