AG 1997 09 15 - Laserfiche WebLink

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Proposed Radio Tower Page 3 Cabarrus County Sheriff's Dept. fine to generally coarse sand was encountered from 14 ft to the boring termination depth of 30.5 fi. The 24-hour static groundwater level was 24 ft. Boring B-2 was drilled at the stake for the east leg of the proposed tower. Stiff orange, tan, and brown clayey fine to medium silt to fine sandy clayey silt was encountered in the upper 5 ft. Dense silty fine to medium sand was encountered from 6 ft to a depth of 25.5 ft. Very dense tan, orange and black speckled brown slightly silty fine to medium sand was encountered from 29 ft to the boring temfination depth of 30.5 ft. The 24-hour static groundwater level was 24 ft. Boring B-3 Boring B-3 was drilled at the stake for the north leg of the proposed tower. Firm fine sandy clayey silt and fine to medium sandy silt was encountered in the upper 5 ft. Silty fine to medium sand and sandy silt was encountered to the premature temfination depth of 11.5 ft. An offset boring, B-3A, was drilled to continue the boring data to the desired depth of 30 ft: t~oring B-3A Boring B-3A was drilled about five feet from the stake for the north leg of the proposed tower (B-3), toward the stake marking the tower center. Dense silty fine to medium sand was encountered from 14 ft to roughly 19 ft. Very dense partially weathered rock was encountered from 19 ft to the boring temfination depth of 30.5 ft. The 24-hour static groundwater level was 24 ft. Groundwater levels may fluctuate several feet depending on recent rainfall events, seasonal climatic variations, and fluctuations in water level in any adjacent drainage features. The highest seasonal groundwater levels usually occur in late winter and spring, while the lowest levels usually occur in late summer and fall. At the time of this exploration, the groundwater levels were probably relatively low due to the long dry period the area has experienced this summer. Note that groundwater was encountered at a depth of about 24 ft at the time the borings were made. The previous descriptions of the soils encountered in the borings provide a somewhat more general summary of the subsurface conditions represented by the borings than do the boring logs themselves. The attached test boring records contain more detailed information and represent my engineering interpretation of the field logs based upon my examination of the field samples. Note that the lines indicating interfaces between various strata are approximate and are a simplification ora reality where actual interfaces may be gradual transitions between strata. It should also be noted that the sides of all the borings caved below the water table. The significance of this fact is discussed in the following section. File: 97-026R.sam