Using gripper forces of an open gripper TBM to evaluate rock mass stiffness

T. Marcher, G. Sackl, C. Reinhold

Research output: Contribution to conferencePaperpeer-review


An open gripper TBM continuously records gripper forces. This enables to determine the rock mass stiffness of the surrounding ground by using the gripper as the pressure unit of a plate load test. The gripper tests have been executed in the exploratory tunnel of the Brenner Base Tunnel project in Austria. Two different in situ test procedures have been developed upon constant agreement with the owner, the construction company and the site supervision team of the project. Evaluation of the rock mass stiffness (deformation moduli) indicated good agreement with the characteristic stiffness values for the rock mass from the lab tests. Numerical studies have been executed to validate the depth of influence for the gripper tests. The in situ test data and the results of the gripper test evaluations are discussed and an interpretation on the meaningfulness of the different results are given. Finally, suggested modifications on the gripper-TBM and an outlook on further research requirements on the evaluation of the monitored gripper data are given.

Original languageEnglish
Publication statusPublished - 1 Jan 2020
Event54th U.S. Rock Mechanics/Geomechanics Symposium - Virtual, Online, United States
Duration: 28 Jun 20201 Jul 2020


Conference54th U.S. Rock Mechanics/Geomechanics Symposium
Country/TerritoryUnited States
CityVirtual, Online

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Geotechnical Engineering and Engineering Geology

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