1600 MADISON ST 2016-01-01 MF Import

Mr. Chris Lark February 20, 2001 6.3 WET WEATHER EARTNWORK AND EROSION CONSIDERATIONS 'fhe site soils contain a considerable amoun; of fines, and aze therefore moisture sensitive. As a result, it may be more economical to perform earthwork in the drier summer months to prcvent the site soils from becoming soft due to excessive moisture. Any softened soils should be removed and replaced with properly compacted granulaz structural fill. General recommendations relative to earthwork performed in wet weather or in wet conditions aze presented below: EaRhwork should be performed in small areas to minimize exposure to wet weather. Excavation or the � emoval of unsuitable soil should be followed promptly by the placement and compaction of clean structural fill. The size and rype of construction equipment used may have to be limited to prevent soil disturbance. Under some circumstances, it may be necessary to excavate soils with a backhoe to minimize subgrade disturbance caused by equipment traffic. • During wet weather, the allowable fines content of the structural fill should be reduced to no more than 5 percent by weight based on the portion passing'/.-inch sieve. The fines should be non-plastic. . The ground surface within the consttuction azea should be graded to promote run-off of surtace water and to prevent the ponding of water. i• A smooth drum vibratory roller, or equivalent should seal the ground surface within the construction azcea, and under no circumstances should soil be left uncompacted I� and exposed to moisture. • Bales of straw and/c,r geotextile sili fences should be strategically located to control erosion and the movement of soil. 6.4 DRAINAGE CONSIDERATIONS Adequate drainage provisions aze imperative and �ve recommend both shor[ and long tetm drainage measures be inco�porated into the project design and construction. Surface runoff can be controlled during construction by cazeful grading pnctices. Typically, this includes the construction of shallow, upgrade perimeter ditches or low earthen berms and the use of temporary sumps to collect runoff and prevent water from damaging exposed subgrades. All collected water should be directed under control to a positive and permanent dischazge system, such as a storm sewec If encountered, we anticipate that groundwater can be controlled in excavations by using ditches, sumps, and pumps. Permanent control of surface water should be incoiporated in the final grading design. Water should not be allowed to pond immediately adjacent to buildir.gs or paved azeas. Perimeter 00-046-100 Geotech Report 7 PanGEO, Ine.