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<br />~ <br />t <br />v <br />~ <br />f <br /> <br />8-08. Railroad bridge foundation. Subsurface investigation for the <br />railroad bridge at Station 390+50 consisted of auger h~les AH-72. and AH-73. <br />Location of the auger holes and the visual logs .are shown on plate 1. <br />Auger hole A11-72 was drilled to shale at a depth of 10 feet using a <br />flight auger. From 10 feet to 27.5 feet, samples were taken with a <br />denison barrel and from 27.5 feet to 30.6 feet, 6" core samples were <br />taken. Auger hole AH 73 was drilled to shale at a depth of 13 feet using <br />a flight auger and from 13 to 30.5 feet samples were takne with a denison <br />barrel. The unconfined compression strength of the shale samples ranged <br />from 2.2 TSF at a depth of 10 feet in auger hole AH-72 to 26.5 TSF at <br />a depth of 21. feet in the same auger hole. A detailed description of <br />the results of the shale testing is presented in exhibit 2, Appendix A. <br />Overburden materials found at these locations consisted of a 2-foot <br />layer of sandy clay (CL) underlain by granular soils classigying as <br />clayey sand (SC) gravelly sand (SP-SC) or sandy gravel (GP) with a lense <br />of sandy clay (CL). the existing bridge is supported on spread footings <br />excavated into the shale. The shale is suitable foundation material for <br />the railroad bridge. Excavation of 5 feet into the shale would provide <br />an allowable bearing capacity of 4000 pounds per square foot for found- <br />ing of the bridge piers. <br /> <br />8-09. Pump house foundation. Deleted. <br /> <br />8-10. Required excavation. Required excavation for the interior <br />drainage ditch, toe trench, inspection trench, ponding area, and pump <br />house will be in fine-grained overburden and in the coarser grained river <br />alluvium. There will be no rock excavation. the alluvial materials <br />classify as sand (SP, SW-S~l, SP-SM, SW), silty sand (SM), and clayey sand <br />(SC). Overburden materials classify as sandy clay (CL) to silt (ML) <br />with some fat clay (CH). The estimated volume of required excavation, <br />excluding excavation for the toe trench, is about 403,000 cubic yards of <br />which 238,000 cubic yards will be available for levee fill; 128,500 cubic <br />yards will be waste fill resulting from stripping; 10,800 cubic yards <br />will be used as required waste fill in an old river channel meander right <br />of station 72+00 to 82+00; and 25,700 cubic yards will be used for un- <br />compacted fill berm loading from Station 386+00 to 463+00. TIle uncom- <br />pacted fill is required because of anticipated uplift pressures at the <br />landward toe, and will be placed between the landward toe of the levee <br />and the edge of the drain ditch as shown on the typical levee section <br />on plate 18. <br /> <br />8-11 Borrow materials. Construction of the levee sections will <br />require 1,366,000 cubic yards of compacted fill. Required excavation <br />of 238,000 cubic yards "ill provide 207,000 cubic yards of compacted <br />materials. The remaining 1,159,000 cubic yards of compacted fill will <br />require excavation of 1,333,000 cubic yards of borrow materials. Borrow <br />areas designated on plates 2 and 3 will provide adequate quantities of <br />borrow. No borrow excavation will be permitted within 400 feet of the <br /> <br />L <br /> <br />20 <br /> <br />Revised 6-26-69 <br /> <br /> <br />