The Earthquake Engineering Online Archive

Response of non-uniform soil deposits to travelling seismic waves

Dezfulian, Houshang; Seed, H. Bolton

UCB/EERC-69/13, Earthquake Engineering Research Center, University of California, Berkeley, 1969-09-01, 31 pages (450/D45/1969)

The study was undertaken to investigate to what extent a travelling wave response analysis of a soil deposit with inclined rock boundaries would differ from a corresponding rigid-base solution. Only the horizontal component of the base motion is considered. In order to determine how response evaluations for travelling wave conditions differ from those for rigid-base conditions, eight soil deposits were analyzed. In each case, three different wave velocities of 2000, 5000, and 10,000 ft/sec were used. A velocity V subscript X = 4000 ft/sec probably represents a realistic lower bound veloicty for use in the analyses. Analyses using the 2000 ft/sec velocity were included mainly for the purpose of studying the extreme variations in the response patterns. It should also be recognized that due to the nonsymmetry of a cross section waves approaching the deposit from different directions are likely to have different influences on the response. Therefore for each velocity, analyses were made with the seismic wave travelling horizontally across the base both away from the rock slope towards the semi-infinite half-layer beyond the toe of the rock slope, and towards the slope. Each of the eight cases thus included seven different response evaluations; namely, one for the rigid-base solution and six for the three velocities travelling in the two directions, comprising a total of 56 response computations. Medium sand, hard clay, and Bay mud soil conditions were considered. Three different base motions were used in the analyses. The response value of greatest interest for the purposes of the present study was considered to be the distribution of maximum horizontal acceleration developed at the surface of a deposit.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-69-13.pdf (2 MB)