Seismic tunnel response in jointed rock mass

摘要

A series of pseudo-static discrete element analyses are performed to evaluate the effect of rockrnjoint on the seismic response of tunnels. The parameters considered joint spacing, stiffness and strength, andrndip. The results show that the joint stiffness and strength have the most critical influence on the tunnel response.rnIncrease in the spacing of the joints results in localized concentration of shear deformation, and hence the momentrnand shear stress of the tunnel lining increase accordingly. The tunnel response is shown to be lowest for jointsrndipping at 45◦, while the responses are largest for vertical and horizontal joints. In summary, it is shown thatrnsmooth, widely spaced joints with shear stiffness lower than 0.25 GPa/m can significantly increase the tunnelrnresponse under seismic loading. The tunnel linings are shown to be most susceptible to damage due to inducedrnshear stress, and therefore should be checked in the seismic design.