20 SW EVERETT MALL WAY Geotech Report 2018-01-02 MF Import

— Campbell-Fleury Investments/Mallwest Center W-3103-1 9 April 1986 Page 10 It should be noted that rockeries are not designed to act as retaining structures. ^ Their primary function is to face stable slopes and protect them from erosion and sloughing. Therefore, the materials in rockery-faced cut slopes snould consist of "-" relatively dense strata. It should also be realized that rockeries, even when they are properly constructed, are a maintenance item sinilar to roofing, exterior paint or asphalt pavement. Therefore, the rockery should periodically be inspected and serviced as required. Also, rockeries should be located so they can readily be _ reached by a contractor when service and repairs are necessary. 4.7 Drainage Considerations Seepage was encountered in five of the seven test pits. However, due to variations in rain accumulation throughout the year, fluctuations in ground and surface water conditions may occur. The site soils are silty and susceptible to disturbance when wet. Prior to construction, surface water should be routed away from the work and building areas. The silty subsoils will impede surface water infiltration and/or produce a"perched" ground water condition. Any flat, depression or topographically -- . low areas can lead to ponded water. Therefore, we recomnend that the building and any retaining wall be provided with a perimeter drain system at the footing elevation to collect and carry away any available water. The footing drain should consist of at least a 4-inch diameter, perforated pipe fully surrounded by at least 4 inches of pea gravel. The drain pipe should lead away from the building by gravity to a storm sewer or other suitable discharge. Site grades should be planned to slope away from the buildings. Roof and surface runoff should not discharge into the footing drain system. Instead, a separate tight-line drain network should be — installed or splash blocks should be used. -- 5.0 CLOSURE . The conclusions and recommendations presented in this report are based on the � explorations accomplished for this study. Tfi� number, locations and the depths of the explorations were completed within the site and scope constraints, so as to yield the information to formulate our recommendations. Successful performance of any of the foundation options depend on proper site preparation and construction