Earthquake engineering of large underground structures

TLDR: A review of the past performance of 127 underground openings during earthquakes indicates that underground structures in general are less severely affected than surface structures at the same geographic location, however, some severe damage, including collapse, has been reported as mentioned in this paper.

Abstract: This study identifies and evaluates the current state of the art of earthquake engineering of transportation tunnels and other large underground structures. A review of the past performance of 127 underground openings during earthquakes indicates that underground structures in general are less severely affected than surface structures at the same geographic location. However, some severe damage, including collapse, has been reported. Stability of tunnels during seismic motion is affected by peak ground motion parameters, earthquake duration, type of support, ground conditions, and in situ stresses. The literature on the nature of underground seismic motion is reviewed in detail. Although recorded underground motions tend to substantiate the idea that motion does reduce with depth, amplification at depth has been observed. The current procedures used in the seismic design of underground structures vary greatly depending upon the type of structure and the ground conditions. Procedures for subaqueous tunnels are fairly well formulated; however, procedures for structures in soil and rock are not as well formulated. Numerical procedures to predict dynamic stresses are not completely compatible with current static design procedures, which are more strongly affected by empirical methods than by stress-prediction models. Recommended research activities include the systematic reconnaissance of underground structures following major earthquakes, the placement of instrumentation for recording seismic motion in tunnels, analytical studies of underground motion, and the further development of seismic design procedures for structures in soil and rock. (Author)