Laserfiche WebLink
M99~38GE <br />• The site construe=ion surface should be graded to drain surface <br />water away from the site excavations. Surface water should not be <br />allowed to accumulate in excavations during construction. Accumul- <br />ated water could necatively influence the site soil conditions. <br />Construction surface drainage should include swales, if necessary <br />to divert surface water away from the construction excavations. <br />Organic soil materials were encountered in the test borings. The <br />organic soil materials are not suitable for support of the struc- <br />ture or structural components or use as a compacted embankment fill <br />material. The orga^ic soil materials should be removed prior to <br />foundation construction. <br />It has been our experience that sites in developed areas may con- <br />tain existing subterranean structures or poor quality man placed <br />fill. If subterranean structures or poor quality man placed fill <br />are suspected or encountered, they should be removed and replaced <br />with compacted structural fill as discussed under COMPACTED STRUC- <br />TURAL FILL below. <br />4.0 EMBANKMENT SLOPE STABILITY <br />The stability of any slope is dependent on many factors. Typi- <br />cally the stability of a slope is analyzed by calculating the <br />• anticipated gravitational forces that tend to drive the mass of <br />soil downhill and the anticipated internal strength of the soil <br />along the expected plane of failure that will resist the downhill <br />movements. If the driving forces are equal to or greater than the <br />resisting forces then failure is imminent. A theoretical calculat- <br />ed factor of safety of 1.5 is considered by the geotechnical <br />engineering industry as a minimum factor of safety for a slope to <br />be considered as stable. A calculated factor of safety of 1.0 or <br />less indicates that slope movement is imminent or in process. <br />Failure can occur as slow deformation, creep, or as a somewhat <br />spontaneous failure. <br />Factors that have an adverse influence on slope stability can <br />generally be classified as those that increase the stress (driving <br />force) on the system or decrease the strength (resisting forces) of <br />the soil. <br />Our stability analyses of the proposed pond slope soil material <br />was based on the Bishops method of slices. This method is based on <br />the assumption that the slope soil mass will fail in a rotation <br />mode on a circular arc plane. In this method of analysis the mass <br />of soil is divided into vertical slices. The forces acting on each <br />4 <br />• <br />~Lamberr ana ~,~,~oriates <br />CONSULTING GE OTEGNNIUL ENGIN EEgS eNG <br />Mi'E AI1L TESTING <br />