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I I I I I I I I I I I I I I I I I I Simons, Li and Associates, Inc. Job Number 6143J002 Project Portland Flume Reconstruction No. 6 at the top of the flume. The rock consisted of light to moderately weathered, moderate to heav- ily cemented limestone. Maximum particle size generally decreased from the top of the flume to the river. Traces to some clayey fines were encountered in the pits nearest the river while the fine grained material in the remainder of the pits was generally non-plastic, The material in all pits was relatively well consol- idated, The sides of the test pits remained temporarily stable at slopes ranging from 1/2:1 (H:V) to near vertical. However, the test pits remained open for only a short period of time before being backfilled, Test pit depths for this flume ranged from 2 to 12 feet below existing grade, No groundwater was encountered in any of the test pits at the time of this exploration. However, some evidense of seepage was noted in several of the pits. Due to the granular nature and large particle size of the soils encountered in all of the test pits, laboratory testing was limited to classification tests, The results of the testing pro- gram are included in this report. Headwall Foundations: It has been assumed that concrete box cul- verts will be used at the roadway crossings, It is further assumed that cast-in-place, concrete head and wingwalls will be constructed at the majority of the crossings. Shallow spread footings bearing upon undisturbed subsoils are recommended for support of the structures. An allowable bearing capacity of 3000 psf may be used for footings founded a minimum of 4 feet below lowest adjacent finished grade for frost protection, Settlements for footings subjected to maximum assumed loading con- ditions and founded as recommended are estimated to be less than 3/4 of an inch. Additional total or differential settlements of 1/4 to 1/2 inch could occur if bearing soils become saturated, It -3- @