4711 GLENHAVEN DR 2016-01-01 MF Import

_ - Since the dens'ty of the on-site soil is variable, random soft pockets may exist and the depth and extent of excavation can best be deteimined in the field by the geotechnical engineer or " engineering geologist at the time of construcdon. The on-site soils contain a high percentage of fine-grained material �hich makes them moisture-scnsitive and subject to disturbance when wet. Therefore, the use of these soils as swctural fill should be lunited to favorable dry weat6er conditions. The contractor must use caze during site prepantion and the foundaaon excavation operations so that the underlying soils are not softened. If disturbance occurs, the softened soils should be removed and the azea brought to grade with compacted granular fill (structural fill). Consideration should be given to protecting the driveway and consuvction s[aging areas with an appropriate thickness of crushed rock. This surfacing may require additional material as the weather and construction traffic dictates. 9.1 Strucmral Fill - Structural fill is defined as any inorganic soil, acceptable to the geotecluiical engineer, compacted to the specified densiry ucider buildings, roadways, slabs, pavements or any other load-bearing areas. Structural fi!1 should extend beyond the outside edge of all foundation elements a lateral distance equal to the depth of supporting structural fill. Structural fill should extend horizontally beyond the edge of the pavement or footing areas a nw�imum distance of 3 feet before the start of any required fill slopes. Stivctural fill located under foundations, driveway and parking area should be placed in horizontal lifts not exceeding 12 inches in loose thicl�ess and compacted ro a minimum of 95 percent of its laboratory maxinrum dry density, cietermined in accordance with ASTM Test Designation D-1�57 (modified Proctor). The fiil materials should be placed at or within 2 - percent of the optimum moisture content. If fill is placed during wet weather or if proper compaction cannot be obtained, a select import material consistine of a clean, free-draining gravel and/or sand should be used. Free-draining fill consists of non-organic soil with the amo�nt of fine-grained material lunited to 5 percent by weieht when measured on the minus No. 4 sieve fraction. The contractor should note that any proposed fill soils must be evaluated by Associated Earth Sciences, Ir.c. (AESI) prior to d�eir use in fills. This wou]d require that we have a saznple of d�e material 48 hours in advance ro perform a Proctor test and deternrine its field compaction standard. Soils in which the amount of +"ine-grained material (smaller than No. 200 sieve) is greatcr dian approximately 5 percent (measured on the minus No. 4 sieve size) should be considered moisture-sensitive. Where fill soil will be placed on e�isting grades exceeding a slope inclination of �3H:1V, the slope should be benched and provided with a toe key. The benching is intended to ensure adequate interlocking between the ne�i� fill and esisting soils. 9