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<br />I <br />I <br />1 <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />weathered to a bright orange; Due to the consistency of the regional <br />foliation, it was possible to orient the core and measure the attitude of the <br />principal joints. The most pronounced jointing in the core was parallel to <br />fol i ati on. The coeffi ci ent of permeabi 1 ity of the bedrock ranged from 1 x <br />1 -3 -9 <br />o to 2 x 10 cm/sec. Samples were obtained from the bore holes for <br />laboratory testing. <br /> <br />Three test pits were excavated in the dam. Test pit TLP-6 was excavated in <br />the downstream face, just above and parallel to the masonry rock wall at the <br />toe. The pit revealed one foot of topsoil underl ain by four feet of poorly <br />compacted, poorly-graded gravelly sand with silt. Test pit TLP-5 was <br />excavated in the downstream face, approximately six feet below the dam crest. <br />This pit revealed uniform material as found in TLP-6, except the top two feet <br />contained a higher percentage of gravel. A bulk sample was obtained from this <br />pit for roll er compacted concrete (RCC 1 aggregate testi ng and cyl i nder test <br />mi xes. An i n-pl ace density test was conducted in the pi t with a nucl ear <br />density gauge. Test pit TLP-4 was excavated in the upstream face and showed a <br />six-i nch 1 ayer of ri prap underl ai n by fi ve feet of loose, si lty sand with <br />gravel overlying weathered bedrock which was easily excavated with the backhoe. <br /> <br />Seismic refraction data did not correlate well with the borehole data; This <br />was probably due to the narrowness of the site in relation to the distance <br />between geophones. It indicated the embankment materials had a velocity of <br />from 1,200 to 2,100 fps, weathered rock and boulders from 2,700 to 3,700 fps, <br />and sound rock from 9,000 to 14,000 fps. The seismic velocities in <br />feet-per-second (fpsl are indicative of the relative density of the subsurface <br />material. <br /> <br />2.1. 3. 2 Spillway <br /> <br />Test pit TLP-l was excavated to a depth of fi ve feet in sand and gravel <br />glacial till. Below a depth of three feet the incidence of large, sound <br />boulders increased to where, at a depth of eight feet, the backhoe was unable <br />to penetrate any further. Seismic refraction results showed the surficial <br />layer to have a velocity of 1700 fps to a depth of seven feet, overlying the <br /> <br />-48- <br />