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Seismic Shear Deformation of Compliant Fine-Grained Soil

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Large Strain Deformation

G.K. Gilbert on Large Strain Deformation of Mud At Inverness, Tomales Bay During the San Francisco Earthquake, 1906

Click on photos for enlargement (36K), (32K), (40K), (36K)
1908 photo of Tomales Bay. Ground displacement in Tomales Bay.
1908 photos of Martinelli's Pier. Map and sketches of Inverness piers.
Text from G.K. Gilbert (Lawson, et al., 1908): (a) 'Ridged mud plain', ...'it would seem that in the production of this ridging the tidal mud must have behaved as a quasi liquid, being thrown into waves by the agitation to which it was subjected'., (b) 'There was also a horizontal shifting of mud over a considerable area.', 'At various places along the shore...the tidal mud seemed crowded against the firmer ground at the shore, being pushed up into a ridge', (c) At Martinelli's Pier, '...more than half the pier, the part nearer the shore, remained straight... . The outer part suffered most violence near the junction of the shifting mud with the firmer ground, being there so completely wrecked that the platform fell down.' 'Maximum shifting...was not less than 30 feet'. (d) 'In the case of Bailey's pier,...nearly the whole structure was transported by the shifting mud'.

Diagram of traditional vs multidimensional model Traditional (Newmark-type) analysis of soil displacement assumes a rigid mass shearing at its base in response to 1-D dipslope earthquake motion (a). Kramer (1997) modified the Newmark 1-D approach by making the mass compliant. Our model incorporates a compliant mass and the multidirectional components of earthquake motion, block inertial motion and block resonant motions.


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