Issue 45

Q.-C. Li et alii, Frattura ed Integrità Strutturale, 45 (2018) 86-99; DOI: 10.3221/IGF-ESIS.45.07 99 [32] Loh, M., Falser, S. Babu, P. Linga, P. Palmer, A. and Tan, T. S. (2012). Dissociation of Fresh- And Seawater Hydrates along the Phase Boundaries between 2.3 and 17 MPa, Energy & Fuels, 26(10), pp.6240-6246. DOI: 10.1021/ef3008954. [33] Li, Q., Cheng, Y. Li, Q. Zhang, C. Ansari, U. and Song, B. (2018). Establishment and evaluation of strength criterion for clayey silt hydrate bearing sediment, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 40(6), pp.742-750. DOI: 10.1080/15567036.2018.1457742. [34] Ng, M.Y.A., Klar, A. and Soga, K. (2008). Coupled soil deformation-flow-thermal analysis of methane production in layered methane hydrate soils, In Proceedings of the Offshore Technology Conference, Houston, TX, USA, 5–8. NOMENCLATURE Symbol Interpretation Symbol Interpretation σ tot The total stress, MPa Az and Inc The azimuth and the inclination, ° σ eff The effective stress, MPa P m Drilling mud pressure, MPa P p The pore pressure, MPa v The Poisson's ratio σ P The in-situ stress tenser, MPa θ The polar angle in borehole cylindrical coordinate system R S and R B The transformation matrices T eq Equilibrium temperature of methane hydrate α , β and γ Three rotation angles, ° P eq Equilibrium pressure of methane hydrate