Research


The following is a concise overview of the research that the group is involved with. It is organized by topics, but of course there is a necessary overlap among topics. Credit must be given to the students, visitors, and faculty collaborators who have worked with us and have pushed the field forward.

Fracture Mechanics
Discontinuous Media
Autoadaptive Systems
Analytical and Numerical Models
Soil-Structure Interaction
Tunnels
Problem Soils
Extreme Events
Current Projects

Tunnels

Work is conducted to create a better understanding between tunnel excavation, ground behavior, water conditions and tunnel support, and to develop practical tools to be used by practitioners.

For deep circular tunnels, assuming that both ground and support remain within their elastic regime, the load on the primary support does not change with drainage conditions; it is the same whether there is flow towards the tunnel (drained tunnel) or the pore pressure behind the support is hydrostatic (no-drainage tunnel). Stresses and deformations in the ground, however, are quite different, with larger stresses and deformations occurring for the drainage case. In tunnels where there is an impermeable layer between the primary and secondary supports, as the secondary support is placed there is a load transfer from the primary to the secondary support. The primary support unloads and moves outwards, while the secondary support takes load and moves inwards.
The Wellenberg site as a potential location for nuclear waste storage.
Analytical solutions have been developed to estimate ground deformations due to tunnel excavation. Comparisons between predictions and observations from 28 tunnels show good agreement, generally within 15% difference. The analyses show that: (1) Most of the ground movements are caused by the gap parameter; (2) Most of the ground deformations take place within a distance of three to four radii around the tunnel; (3) The horizontal movements around the tunnel are relatively small.
A new, exciting topic of investigation recently started by the group is that of Extraterrestrial Habitat Engineering. Research is actively being conducted on the stability of lunar and martian lava tubes, including hazards such as seismicity, either in the form of moonquakes or marsquakes or induced seismicity due to meteorite impacts.
  • Einstein, H.H., and Bobet, A. (1997). Mechanized Tunneling in Squeezing Ground - From Basic Thoughts to Continuous Tunneling. Proceedings of the World Tunnel Congress '97. Vienna, Austria, pp. 619-632.

  • Bobet, A., Aristorenas, G. and Einstein, H.H. (1998). Feasibility Analysis for a Radioactive Waste Repository Tunnel. Tunnelling and Underground Space Technology, Vol. 13, No. 4, pp. 409-426.

  • Vinard, P., Bobet, A. and Einstein, H.H. (2001). Generation and Evolution of Hydraulic Underpressures at Wellenberg, Switzerland. Journal of Geophysical Research, Vol. 106, No. B12, pp. 30,593-30,605.

  • Bobet, A. (2001). Analytical Solutions for Shallow Tunnels in Saturated Ground. ASCE Journal of Engineering Mechanics, Vol. 127, No. 12, pp. 1258-1266.

  • Chou, W. and Bobet, A. (2002). Predictions of Ground Deformations in Shallow Tunnels in Clay. Tunnelling and Underground Space Technology, Vol. 17, pp. 3-19.

  • Bobet, A. (2002). Mechanically Anchored Rockbolts in Tunnels in Saturated Ground. Proceedings of the North American Rock Mechanics Symposium: NARMS-TAC 2002, pp. 797-804.

  • Bobet, A. (2003). Effect of Pore Water Pressure on Tunnel Support During Static and Seismic Loading. Tunnelling and Underground Space Technology, Vol. 18, pp. 377-393.

  • Chou, W. and Bobet, A. (2003). Discussion: Predictions of ground deformations in shallow tunnels in clay. Tunnelling and Underground Space Technology, Vol. 18, pp. 95-97.

  • Bobet, A. (2006). A Simple Method for the Design of Tunnel Support with Anchored Rockbolts. Rock Mechanics and Rock Engineering, Vol. 39, No. 4, pp. 315-338.

  • Nam, S. and Bobet, A. (2006). Liner Stresses in Deep Tunnels below the Water Table. Tunnelling and Underground Space Technology, Vol. 21, No. 6, pp. 626-635.

  • Nam, S. and Bobet, A. (2007). Radial deformations induced by groundwater flow on deep circular tunnels. Rock Mechanics and Rock Engineering, Vol. 40, No. 1, pp. 23-39.

  • Bobet, A. and Nam, S. (2007). Stresses around Pressure Tunnels with Semi-Permeable Liners. Rock Mechanics and Rock Engineering, Vol. 40, No. 3, pp. 287-315.

  • Bobet, A. (2007). Ground and Liner Stresses due to Drainage Conditions in Deep Tunnels. Felsbau, Vol. 25, No. 4, pp. 42-47.

  • Chou, Y.L. and Bobet, A. (2008). Stresses around Unsupported Tunnels. Proceedings of the ASCE Geocongress 08.

  • Bobet, A. and Einstein, H.H. (2008). Deep Tunnels in Clay Shales: Evaluation of Key Properties for Short and Long Term Support. Proceedings of the ASCE Geocongress 08.

  • Bobet, A. (2009). Elastic Solution for Deep Tunnels. Application to Excavation Damage Zone and Rockbolt Support. Rock Mechanics and Rock Engineering, Special Issue on "Deep Tunnel: Issues in Rock Engineering", Vol. 42, No. 2, pp. 147-174.

  • Bobet, A. (2009). Drained and undrained response of deep tunnels subjected to far-field shear loading. Tunnelling and Underground Space Technology, Vol. 25, pp. 21-31.

  • Bobet, A. (2010). Characteristic curves for deep circular tunnels in poroplastic rock. Rock Mechanics and Rock Engineering, Vol. 43, pp. 185-200.

  • Bobet, A. (2010). Response by the Author to: Comments on "Characteristic Curves for Deep Circular Tunnels in Poroplastic Rock" by G. Anagnostou and R. Schürch. Rock Mechanics and Rock Engineering, Vol. 43, pp. 235-239.

  • Bobet, A. and Einstein, H.H. (2010). Tunnel Support with Point-Anchored and Grouted Rockbolts. Tunnelling and Underground Space Technology. Vol. 26, pp. 100-123.

  • Bobet, A. (2010). Lined circular tunnels in transversely anisotropic rock at depth. Rock Mechanics and Rock Engineering, Vol. 44, pp. 149-167.

  • Wang, J., Huang, H., Xie, X. and Bobet, A. (2014). Void-induced Liner Deformation and Stress Redistribution. Tunnelling and Underground Space Technology, Vol. 40, pp. 263-276.

  • Blair, D.M., Chappaz, L., Sood, R., Milbury, C., Bobet, A., Melosh, H.J., Howell, K.C. and Freed, A.M. (2015). Determining the Structural Stability of Lunar Lava Tubes. 46th Lunar and Planetary Science Conference, March 16-20, The Woodlands, Texas.

  • Blair, D.M., Chappaz, L., Sood, R., Milbury, C., Bobet, A., Melosh, H.J., Howell, K.C. and Freed, A.M. (2015). Modeling the Structural Stability of Lunar Lava Tubes. 2nd International Planetary Caves Conference, October 20-23, Flagstaff, Arizona.

  • Yu, H., Chen, J,. Bobet, A., and Yuan, Y. (2016).Damage observation and assessment of the Longxi tunnel during the Wenchuan earthquakeg. Tunnelling and Underground Space Technology, Vol. 54, pp. 102-116.

  • Bobet, A. and Yu, H. (2016). Full Stress and Displacement Fields for Steel-Lined Deep Pressure Tunnels in Transversely Anisotropic Rock. Tunnelling and Underground Space Technology, Vol. 56, pp. 125-135.

  • Bobet, A. (2016). Lined Circular Tunnels in Transversely Anisotropic Rock at Depth: Complementary Solutions. Rock Mechanics and Rock Engineering, DOI: 10.1007/s00603-016-0942-z.

  • Bobet, A. (2016). Deep Tunnel In Transversely Anisotropic Rock with Groundwater Flow. Rock Mechanics and Rock Engineering, accepted.

  • Tao, F. and Bobet, A. (2016). Effect of Temperature on Deep Lined Circular Tunnels in Transversely Anisotropic Elastic Rock. Underground Space, Vol. 1, pp. 79-93.

  • Blair, D., Chappaz, L., Sood, R., Milbury, C., Bobet, A., Melosh, J., Howell, K., and Freed, A. (2017). The Structural Stability of Lunar Lava Tubes. Icarus, Vol. 282, pp. 47-55.

  • Blain, Ch. A., Ramirez, J. A., Bobet, A., Browning, J., Edge, B., Holmes, W., Johnson, D., Robertson, I., Smith, T., Zuo, D. (2017). NHERI: Advancing the Research Infrastructure of the Multi-Hazard Community. Abstract No. NH33C-05 presented at Fall Meeting AGU (American Geophysical Union), New Orleans, LA,11-15 December.

  • Vitali, O., Bobet, A., Celestino, T. (2018). 3D Finite Element Modeling Optimization for Deep Tunnels with Material Nonlinearity. Underground Space, Vol. 3, No. 2, pp. 125-139.

  • Vitali, O., Celestino, T. and Bobet, A. (2018). Analytical solution for tunnels not aligned with geostatic principal stress directions. Tunnelling and Underground Space Technology, Vol. 82, pp. 394-405.

  • Maghareh, A., Gomez, D., Dyke, S. J., Bobet, A., Ramirez, J., Melosh, H. J., Modiriasari, A., and Theinat, A. (2018). Resilience for Permanent Extraterrestrial Habitats. 49th LPSC, Lunar and Planetary Science Conference, The Woodlands, Texas.

  • Dyke, S. J., Bobet, A., Ramirez, J., Melosh, H. J., Gomez, D., Maghareh, A., Modiriasari, A. and Theinat, A. (2018). Resilient Extraterrestrial Habitat Engineering. 49th LPSC, Lunar and Planetary Science Conference, The Woodlands, Texas.

  • Theinat, A., Modiriasari, A., Bobet, A., Melosh, J., Dyke, S., Ramirez, J., Maghareh, A. and Gomez, D. (2018). Geometry and Structural Stability of Lunar Lava Tubes. 2018 AIAA SPACE and Astronautics Forum and Exposition, Orlando, FL. https://arc.aiaa.org/doi/abs/10.2514/6.2018-5185.

  • Modiriasari, A., Theinat, A., Bobet, A., Melosh, H.J., Dyke, S.J., Ramirez, J., Maghareh, A., Gomez, D. (2018). Size and structural stability assessment of lunar lava tubes. 49th Lunar and Planetary Science Conference, The Woodlands, Texas, March-2018.

  • Vitali, O., Celestino, T. and Bobet, A. (2019). Shallow Tunnel not aligned to the geostatic principal stress directions, ASCE Geocongress 2019, Philadelphia, March 24-27, 2019, accepted.

  • Modiriasari, A., Theinat, A.K., Melosh, H.J., Bobet, A., Dyke, S.J., Ramirez, J., Maghareh, A., and Gomez, D. (2019). Stability of Lunar Lava Tubes as Permanent ExtraTerrestrial Habitats. International Space Development Conference, Back To The Moon To Stay (ISDC2019), Arlington, VA, June 6-9, accepted.

  • Vitali, O., Celestino, T. and Bobet, A. (2019). Buoyancy effect on shallow tunnels. International Journal of Rock Mechanics and Mining Sciences, Vol. 114, pp. 1-6.

  • Yu, H., Cai, Ch., Bobet, A. and Yuan, Y. (2019). Analytical Solution for Longitudinal Bending Stiffness of Shield Tunnels. Tunnelling and Underground Space Technology, Vol. 83, pp. 27-34.

  • Vitali, O., Celestino, T. and Bobet, A. (2019). Shallow tunnels misaligned with geostatic principal stress directions: analytical solution and 3D face effects. Tunnelling and Underground Space Technology, Vol. 89, pp. 268-283, https://doi.org/10.1016/j.tust.2019.04.006.

  • Theinat, A. K., Modiriasari, A., Bobet, A., Melosh, H. J., Dyke, S. J., Ramirez, J., Maghareh, A. and Gomez, D. (2019). Lunar Lava Tubes: Morphology to Structural Stability, Icarus, Vol. 338, Article 113442, https://doi.org/10.1016/j.icarus.2019.113442.

  • Modiriasari, A., Theinat, A.K., Melosh, H.J., Bobet, A. (2019). Stability Analysis of Lunar Lava Tubes for Permanent ExtraTerrestrial Habitation”. 53rd US Rock Mechanics / Geomechanics Symposium held in New York, NY, USA, 23-26 June, Paper 19-387, accepted.

  • Theinat, A.K., Modiriasari, A., Bobet, A., Melosh, H.J., Dyke, S.J., Ramirez, J. Choi, J., Maghareh, A. and Gomez, D. (2019). Geology Explorations of Lava Tubes in the National Beds Lava Monuments. Proceedings of the 50th Lunar and Planetary Science Conference, The Woodlands, Texas, March 2019.

  • Modiriasari, A., Boener, A., Theinat, A.K., Bobet, A., Melosh, H.J., Dyke, S.J., Ramirez, J., Maghareh, A. and Gomez, D. (2019). Effect of Induced Seismicity of Indirect Meteorite Impacts on the Stability of Lunar Lava Tubes. Proceedings of the 50th Lunar and Planetary Science Conference, The Woodlands, Texas, March 2019.

  • Maghareh, A., Lenjani, A., Dyke, S., Marais, K., Bobet, A., Ramirez, J., Whitaker, D., Modiriasari, A. and Theinat, A. (2019). Design Framework for Resilient Extraterrestrial Habitats. Engineering Mechanics Institute Conference 2019, Caltech., CA, June 18-21, 2019. Accepted.

  • Vitali, O., Celestino, T. and Bobet, A. (2019). Progressive failure due to tunnel misalignment with geostatic principal stresses. ISRM 14th International Congress of Rock Mechanics, Iguassu Falls, Brazil, September 13-18, 2019. Accepted.

  • Maghareh, A., Lenjani, A., Dyke, S., Marais, K., Whitaker, D., Bobet, A., Ramirez, J., Melosh, H., Modiriasari, A. and Theinat, A. (2019). Resilience-oriented Design of Extraterrestrial Habitat Systems. AIAA Propulsion and Energy Forum and Exposition, 19-22 August, Indianapolis, IN.

  • Vitali, O., Celestino, T. and Bobet, A. (2020). Analytical solution for a deep circular tunnel in anisotropic ground and anisotropic geostatic stresses. Rock Mechanics and Rock Engineering, Vol. 53, pp. 3859-3884. https://doi.org/10.1007/s00603-020-02157-5.

  • Vitali, O., Celestino, T. and Bobet, A. (2020). Tunnel misalignment with geostatic principal stress directions in anisotropic rock masses. Soils and Rocks, Vol. 43, No.1, pp. 123-138. DOI: 10.28927/SR.431123.

  • Vitali, O., Celestino, T. and Bobet, A. (2020). Deformation patterns and 3D face effects on tunnels misaligned with the geostatic principal stresses in isotropic rock masses. 54th US Rock Mechanics / Geomechanics Symposium. Paper ARMA 2020-1248. Accepted.

  • Vitali, O., Celestino, T. and Bobet, A. (2021). New modeling approach for tunnels under complex ground and loading conditions. Soils and Rocks, Vol 44, No. 1, pp. 1-8, doi: https://doi.org/10.28927/SR.2021.052120.

  • Vitali, O., Celestino, T. and Bobet, A. (2021). 3D face effects of tunnels misaligned with the principal directions of material and stress anisotropy. Tunnelling and Underground Space Technology, https://authors.elsevier.com/c/1eMjA39eM4EPf5.

  • Vitali, O., Celestino, T. and Bobet, A. (2021). Construction strategies for a NATM tunnel in Sao Paulo, Brazil, in residual soil. Underground Space, https://doi.org/10.1016/j.undsp.2021.04.002.

  • Vitali, O., Celestino, T. and Bobet, A. (2021). Behavior of tunnels excavated with dip and against the dip. Underground Space, https://doi.org/10.1016/j.undsp.2021.04.001.

  • Vitali, F.P.M., Vitali, O.P.M., Bobet, A. and Celestino, T.B. (2024). Technical Note: Modeling Optimization for Highly Nonlinear Shallow Tunnel Analyses. Soils and Rocks, Vol. 47, No. 1, 7 pp. https://doi.org/10.28927/SR.2024.000923.

  • Vitali, F.P.M., Vitali, O.P.M., Celestino, T.B. and Bobet, A. (2024). Numerical Analysis of Relative Density Effects on Shallow TBM Tunnel Excavation: Ground Behavior and Principal Strai ns at Surface in Greenfield Conditions. Tunnelling and Underground Space Technology, Vol. 154, https://doi.org/10.1016/j.tust.2024.106104.