EXH1242050078

TO: Pete Douglass, P.E.and Embankment Technical Review Board Members So,to, FROM: Douglas Lindquist, E.I.T.,and Michael Bailey, P.E.,Hart Crowser, Inc. RE: ProposedLiquefaction Procedure under Walls and Slopes o_,,._o 4978-30 CC: Jim Thomson, P.E.,HNTB Denver This memorandum describes the proposed procedure that will be used to evaluate liquefaction potential for areas beneath walls and slopes of the Third Runway embankment. The liquefaction procedure takes into account (a) the anticipated level of ground shaking, (b) the existing soil conditions as reflected in measured standard penetration test resistances, F_,r,':._,,k_ (C)the irregular topography associated with the embankment (i.e., walls and slopes), (d) the high confining pressuresthat will exist beneath the embankment, and (e) the potentially high static shear stressesthat may exist beneath walls and/or slopes. J,_rsey City The following procedure accounts for each of these factors in a practical and reasonably conservative manner. It uses conventional, one-dimensional, equivalent linear site response analysesto evaluate liquefaction potential in areas unaffected by the presence of walls or slopesand two-dimensional FLAC analyses to account for geometric/topographic effects in areasthat are affected by walls and slopes. The procedure allows evaluation of liquefaction J_'"*.'_ potential for a variety of improved zone geometries so that an optimum improved zone geometry can be identified. A simplified representation of a typical profile through the edge of the embankment is LongOe_h shown on Figure 1; note that the transition from embankment grade to adjacent natural grade may occur through a slope or a retaining wall. A generalized soil profile consists of dense natural soils overlain…

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Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]