Ground Characteristic Curve and Convergence Confinement Method - A case study

Ground Characteristic Curve (GCC) describes the relationship between the initial stress of rock mass and the displacement of rock mass on the boundary of tunnels. Another way that indicates the relationship of support pressure and the level of Convergence Confinement of tunnels by percent. The using GCC to design supports in the underground construction has many advantages to ensure full utilization of the loading bearing capacity of rock mass, and release a part of initial stress in the rock mass around tunnels. However, this method is limited in the field of underground mines in Viet Nam. This article analyzed and applied GCC and Convergence Confinement Method (CCM) to design the supports of underground constructions and applied them to the geological conditions of the Nam Mau coal mine - Vinacomin. The research results show that at the geological conditions of the drift at level +125 in Nam Mau coal mine, TH section steel ribs with flange width 124 mm, section depth 108 mm, weight 21 kg/m, maximum support pressure 1.98 MPa, and spacing 700 mm were applied. Results of research in this method can be applied to design rock supports for deep roadways and other drifts in the underground mines in Quang Ninh province of Viet Nam. By a factor of safety, mobilized support pressure, wall displacement of roadways, and convergence of roadways the designation and selection of rock support around roadways will become clearer. Near future this method should be widely applied in the combined protection design in deep roadways in underground mines in Viet Nam. Although the method has great advantages, it is still necessary to have complete and detailed monitoring data of the geological and hydrogeological conditions in the area under consideration.

How to Cite

Dang, T.Trung, Tran, M.Tuan and Nguyen, H.Huy 2022. Ground Characteristic Curve and Convergence Confinement Method - A case study (in Vietnamese). Journal of Mining and Earth Sciences. 63, 3a (Jul, 2022), 68-77. DOI:https://doi.org/10.46326/JMES.2022.63(3a).08.

References

Baklashov, I. V., Kartozia, B. A., (2002). Mechanics of underground construction and structures, Moscow, 543p. Carranza-Torres, C., Fairhurst, C., (2000). Application of convergence confinement method of tunnel design to rock masses that satisfy the Hoek-Brown failure criterion. Tun. and Undergr. Sp. Tech. 15 (2), 187-213.Carranza-Torres, C., (2004). Elasto-plastic solution of tunnel problems using the generalized form of the Hoek-Brown failure criterion. International Journal of Rock Mechanics and Mining Sciences, Proceedings of the ISRM SINOROCK 2004 Symposium, edited by J.A. Hudson and Xia-Ting Feng, Vol.41, Iss 3.Dao, N. C., Bui, M. C., (2004). Geological map of Quang Ninh coal area. Mining geological company. (In Vietnamese).Do, N. T., (2011). About the determinate support in tunnel by convergence confinement method arccoding to the criterion of Hoek-Brown, Road and bridge journal. (In Vietnamese).Hoek, E., and Brown, E. T., (1980). Underground Excavations in Rock. Instn. Min. Metall., London. 527p.Lee, Y. K., and Pietruszczak, S., (2014). A new numerical procedure for elasto-plastic analysis of a circular opening excavated in a strain-softening rock mass, Tunnelling and Underground Space Technology, Vol. 23, No. 5, 588-599.Manuel, F., Taherzadeh, R., Sulem, J., Nguyen, X. S., Subrin, D., (2019). Applicability of the Convergence-Confinement Method to Full-Face Excavation of Circular Tunnels with Stiff Support System. Rock Mechanics and Rock Engineering, Springer Verlag, 2019, 52 (7), pp.2361-2376.Naouz, Y., Ouadif L., Bahi, L., (2019). Convergence-Confinement Method Applied to Shallow Tunnels. In: Badr M., Lotfy A. (eds) Sustainable Tunneling and Underground Use. GeoMEast 2018. Sustainable Civil Infrastructures. Springer, Cham. https://doi.org/10.1007/ 978-3-030-01884-9_5.Nguyen, N. T., (2006). Explanation of Nam Mau exploitation by inclined shaft project - Uong Bi coal company - Technical design explanation - TDT exploiting the Nam Mau coal mine. Mining and industrial investment and consulting JSC, 150p. (In Vietnamese).Nguyen, Q. P., (2007). Rock mechanics, Construction publisher, 356p (In Vietnamese).Panet, M., (1995). Calcul des Tunnels par la Me´thode de Convergence-Confinement. Presses de l’Ecole Nationale des Ponts et Chausse´es. Paris, 178p. Tran, T. M., Do, Q. T., Nguyen, Q. H., Nguyen, V. D., Pham, Q. N., (2018). The calculation methods for underground structures, Ha Noi university of science and technology publisher, 590p. (In Vietnamese).Vlachopoulos, N., Diederichs, M. S., (2009). Improved longitudinal displacement profiles for convergence-confinement analysis of deep tunnels, Rock Mechanics and Rock Engineering (Accepted - In Press), 16 pgs. Vo, T. H., Phung, M. D., (2006). Rock mechanics for underground construction and mining, Scientific and technical publisher, 463p. (In Vietnamese).Vrakas, A., (2016). A finite strain solution for the elastoplastic ground response curve in tunnelling: rocks with non-linear failure envelopes, International Journal for Numerical and Analytical Methods in Geomechanics, Vol. 41(7), 1077-1090. Vrakas, A., Anagnostou, G., (2014). A finite strain closed-form solution for the elastoplastic ground response curve in tunnelling, International Journal for Numerical and Analytical Methods in Geomechanics, Vol. 38, No. 11, 1131-1148.

	Citations	850
	h-index	10
	i10-index	11

Abstracting & Indexing