Laserfiche WebLink
Fat /Lean clay - Below the fill material in Boring No. 4 and at the surface in the remaining borings, a dark <br />brown to light brown fat /lean clay with traces of fine gravel was encountered. Based on field and <br />laboratory data this soil, in its current moist state, offers low to moderately low bearing capacities while <br />possessing low swell potentials subjected to a 500 p.s.f wet surcharge. However, it should be noted that <br />these clay soils can exhibit high to very high shrink /swell characteristics if they are allowed to dry out and <br />then become re- wetted. Differential movement on the order of several inches is possible. <br />Sands and Gravels - Below the clay soils at depths ranging from 4 to 7 feet, an alluvial deposit consisting <br />of layers of silty sands and sandy gravels was found. Tests indicated the silty sandy layers offers moderate <br />bearing capacities while the sandy gravels exhibit moderate to high bearing capacities. <br />Groundwater - At the time of this investigation and 24 hours later, free groundwater was encountered in <br />all borings at depths ranging from 2.7' to 4.8'. These water levels should be anticipated to fluctuate <br />throughout the year, therefore, current water measurements may not be indicative o f the high groundwater <br />table. It would take a long -term groundwater monitoring program, including the installation ofpiezometers, <br />to determine the high groundwater table. <br />FOUNDATION RECOMMENDATIONS <br />The selection of the foundation type for a given situation and structure is governed by 2 basic <br />considerations. First, the foundation elements must be designed to be safe against shear failure in the <br />underlying soils or sands and gravels; and second, differential settlement or other vertical movement of the <br />foundation must be reduced to a reasonable level. <br />3 <br />