Finite element and distinct element analysis of the stability of a large underground hydropower machine hall in the Himalayas

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• 作者：Rajinder Bhasin ; Thomas Pabst
• 关键词：rock support system ; Q ; system ; high stress ; UDEC ; phase
• 刊名：KSCE Journal of Civil Engineering
• 出版年：2015
• 出版时间：March 2015
• 年：2015
• 卷：19
• 期：3
• 页码：725-732
• 全文大小：1,122 KB
• 参考文献：1. Bhasin, R. and H?eg, K. (1997). “Numerical modelling of block size effects and influence of joint properties in multiply jointed rock.- / Tunnelling and Underground Space Technology, Vol. 22, No. 3, pp. 407-15, DOI: 10.1016/S0886-7798(97)00030-8 }. CrossRef
  2. Bhasin, R. and H?eg, K. (1998). “Parametric study for a large cavern in jointed rock using a distinct element model (UDEC-BB).- / Int. J. Rock Mech. Min. Sci., Vol. 35, No. 1, pp. 17-9, DOI: 10.1016/S0148-9062(97)00312-4 . CrossRef
  3. Bhasin, R. and Kaynia, A. M. (2004). “Static and dynamic simulation of a 700-m high rock slope in western Norway.- / Engineering Geology, Vol. 71, pp. 213-26, DOI: 10.1016/S0013-7952(03)00135-2 . CrossRef
  4. Bhasin, R., Pabst, T., and Olsson, R. (2013). “Numerical study of the stability of a large hydropower machine hall in the Himalayas under dynamic loading.- / Proceedings of the 7th Nordic Grouting Symposium and 2nd Nordic Rock Mechanics Symposium, 13-14 November, Gothenburg, Sweden.
  5. Chowdhry, A. K. (2007). “Crown failure in the machine hall cavern of Tala Hydroelectric Project, Bhutan Himalaya.- / Proceedings of the International Workshop on Experiences Gained in Design and Construction of Tala Hydroelectric Project Bhutan, June 14-15, New Dehli, pp. 93-05.
  6. Gupta, M., Chitra, R., and Dhawan, A. K. (2007). “Stability analysis of power house cavern of Tala H.E. project.- / Proceedings of Int. Workshop on Experiences Gained in Design and Construction of Tala Hydroelectric Project Bhutan, June 14-15, New Delhi, pp. 321-27.
  7. Hashash, Y. M. A., Hook, J. J., Schmidt, B., and Yao, J. I. C. (2001). “Seismic design and analysis of underground structures.- / Tunnelling and Underground Space Technology, Vol. 16, No. 4, pp. 247-93, DOI: 10.1016/S0886-7798(01)00051-7 . CrossRef
  8. Khazanchi, R. N., Tshering, S., and Tamang, B. (2004). “Hydropower development in Bhutan -A perspective.- / Proceedings of Hydro Vision 2004, Montreal, Canada.
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  11. Naik, S. R., Nair, R., Sudhakar, K., and Nawani, P. C. (2011a). / Final report on back analysis using numerical modeling of powerhouse complex of tala hydroelectric project, Bhutan, Report No. NM1003C.
  12. Naik, S. R., Sudhakar, K., and Nair, R. (2011b). / Final report on instrumentation, monitoring and data analysis at power complex, tala hydro power plant, Bhutan, Report No. NM1001C/02.
  13. Palmstr?m, A. (1995). “RMi- a system for characterizing rock mass strength for use in rock engineering.- / Journal of Rock Mechanics and Tunnelling Technology, Vol. 1, No. 2, pp. 69-08.
  14. Sengupta, S., Subrahmanyam, D. S., Joseph, D., and Sinha, R. K. (2007). “The role of National Institute of Rock Mechanics in in situ geotechnical investigations (1979 to 2002) at Tala hydroelectric project Bhutan.- / Proceedings of Int. Workshop on Experiences Gained in Design and Construction of Tala Hydroelectric Project Bhutan, June 14-15, New Dehli, pp. 150-72.
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• 作者单位：Rajinder Bhasin (1)
  Thomas Pabst (1)
  
  1. Norwegian Geotechnical Institute, P.O. Box. 3930, Ullev?l Stadion, Oslo, N-0806, Norway
  
• 刊物类别：Engineering
• 刊物主题：Civil Engineering
  Industrial Pollution Prevention
  Automotive and Aerospace Engineering and Traffic
  Geotechnical Engineering
  
• 出版者：Korean Society of Civil Engineers
• ISSN：1976-3808

文摘

Numerical simulations have been performed to assess the stability of a large underground powerhouse in the Himalayas, using both finite element and distinct element approaches. Large convergences (around 250-00 mm) along the 45 m high wall of the Machine Hall have been measured by total station measurements during construction and up to 60 mm in the post construction and operational phase. Displacements are continuing at a reduced rate of about 3 to 6 mm per year. A large number of rock bolts have failed in the powerhouse and the shotcrete liner presents cracks and failure marks, thus questioning the long-term integrity and stability of the existing rock support system. The purpose of the numerical analysis was to back-calculate the prevailing rock mass conditions surrounding the machine hall, thereby gaining a better understanding of the mechanisms responsible for the instability in the cavern. The results from the analysis indicate that there was possibly an underestimation of the rock support requirements needed for the cavern, coupled with a not so good installation (incomplete grouting of the bolts). Both the length and the capacity of the rock bolts were underestimated presumably due to the existence of a high stress regime in the area, which may not have been taken into consideration in the design of rock support. The effect of a possible earthquake, frequent in this area, has also been studied and proves to induce a significant increase of the displacements and the support failure.