Reply to the two discussions on my paper "An alternative mechanism of pile failure in liquefiable deposits during earthquakes"
This paper proposes an alternative mechanism of pile failure in liquefiable deposits during earthquakes. This failure mechanism, based on pile buckling, is formulated by back-analysing 14 case histories of pile foundation performance during earthquakes and verified using dynamic centrifuge tests. A new parameter, the slenderness ratio of a pile, is introduced to classify pile performance in liquefiable soils. This parameter fits very well both the reported case histories and the centrifuge test results.
Buckling of Fully and Partially Embedded Piles
Variation of axial force along the embedded length of the piles and boundary conditions have considerable influence on the buckling loads of piles. Partially embedded and some fully embedded piles are vulnerable to buckling. Furthermore, buckling loads are useful in the study of the behavior of axially and laterally loaded piles. Therefore, using beam vibration functions and the Rayleight-Ritz energy method, buckling loads have been obtained for fully and partially embedded piles. Numerical results have been obtained for axial force variation and different boundary conditions assuming constant and linear soil modulus variation with depth for clays and sands, respectively.
Meteor Crater: Energy of formation - Implications of centrifuge scaling
Recent work on explosive cratering has demonstrated the utility of performing subscale experiments on a geotechnic centrifuge to develop scaling rules for very large energy events. The present investigation is concerned with an extension of this technique to impact cratering. Experiments have been performed using a projectile gun mounted directly on the centrifuge rotor to launch projectiles into a suitable soil container undergoing centripetal accelerations in excess of 500 G. The pump tube of a two-stage light-gas gun was used to attain impact velocities of approximately 2 km/sec. The results of the experiments indicate that the energy of formation of any large impact crater depends upon the impact velocity. This dependence, shown for the case of Meteor Crater, is consistent with analogous results for the specific energy dependence of explosives and is expected to persist to impact velocities in excess of 25 km/sec.