Influences of anisotropy and inhomogeneity on supporting pressure of tunnel face with kinematical approach

Abstract

Based on the active failure mechanism generated by a spatial discretization technique, the stability of tunnel face was studied. With the help of the spatial discretization technique, not only the anisotropy and inhomogeneity of the cohesion but also the inhomogeneity of the internal friction angle was taken into account in the analysis of the supporting forces. From the perspective of upper bound theorem, the upper bound solutions of supporting pressure were derived. The influence of the anisotropy and heterogeneity on the supporting forces as well as the failure mechanisms was discussed. The results show that the spatial discretization characteristics of cohesion and internal frictional angle impose a significant effect on the supporting pressure, which indicates that above factors should be considered in the actual engineering.

Keywords

tunnel face / supporting forces / anisotropy / inhomogeneity / upper bound theorem

References

[1] SaadaZ, MaghousS, GarnierD. Pseudo-static analysis of tunnel face stability using the generalized Hoek-Brown strength criterion [J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2013, 37(18): 3194-3212

[2] LiY, EmeriaulF, KastnerR, ZhangZ X. Stability analysis of large slurry shield-driven tunnel in soft clay [J]. Tunnelling and Underground Space Technology, 2009, 24: 472-481

[3] SenentS, MollonG, JimenezR. Tunnel face stability in heavily fractured rock masses that follow the Hoek-Brown failure criterion [J]. International Journal of Rock Mechanics and Mining Sciences, 2013, 60(1): 440-451

[4] MaoN A-B T, SoubraA H. Probabilistic analysis and design of strip foundations resting on rocks obeying Hoek-Brown failure criterion [J]. International Journal of Rock Mechanics and Mining Sciences, 2012, 49: 45-58

[5] AzamiA, PietruszczakS, GuoP. Bearing capacity of shallow foundations in transversely isotropic granular media [J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2010, 34: 771-793

[6] SaadaZ, MaghousS, GarnierD. Pseudo-static analysis of tunnel face stability using the generalized Hoek-Brown strength criterion [J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2013, 37(8): 3194-3212

[7] MichalowskiR, NadukuruS. Three-dimensional limit analysis of slopes with pore pressure [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2012, 139(9): 1604-1610

[8] QinC B, SunZ B, LiangQ. Limit analysis of roof collapse in tunnels under seepage forces condition with three-dimensional failure mechanism [J]. Journal of Central South University, 2013, 20(8): 2314-2322

[9] SunZ-b, ZhangD-b. Back analysis for soil slope based on measuring inclination data [J]. Journal of Central South University, 2012, 19(11): 3291-3297

[10] SunZ-b, LiQ. Back analysis of general slope under earthquake forces using upper bound theorem [J]. Journal of Central South University, 2013, 20(11): 3274-3281

[11] SubrinD, WongH. Tunnel face stability in frictional material: A new 3D failure mechanism [J]. Computes Mechanique, 2012, 330(7): 513-519

[12] MollonG, DiasD, SoubraA H. Probabilistic analysis and design of circular tunnels against face stability [J]. International Journal of Geomechanics, 2009, 9(6): 237-249

[13] MollonG, DiasD, SoubraA H. Rotational failure mechanisms for the face stability analysis of tunnels driven by a pressurized shield [J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2011, 35(12): 1363-1388

[14] MOLLON G, PHOON K K, DIAS D, SOUBRA A H. Validation of a new 2D failure mechanism for the stability analysis of a pressurized tunnel face in a spatially varying sand [J]. Journal of Engineering Mechanics, 2011(1): 8–20.

[15] CasagrandeA, CarilloN. Shear failure of anisotropic materials [J]. Journal of Boston Society of Civil Engineers, 1944, 31(4): 74-81

[16] LoK Y. Stability of slopes in anisotropic soils [J]. Journal of the Soil Mechanics and Foundations Division, 1965, 91(4): 85-106

[17] DavisE H, BookerJ R. The effect of increasing strength with depth on the bearing capacity of clays [J]. Geotechnique, 1973, 23(4): 551-563

[18] LeeK M, RoweR K. Effects of undrained strength anisotropy on surface subsidence induced by the construction of shallow tunnels [J]. Canadian Geotechnical Journal, 1986, 26(3): 279-291