Laserfiche WebLink
SHANNON ~WII.SON, INC. <br /> <br />Prior to placement of fill, we recommend that topsoil and organic material within the footprint of <br />the fill area be removed. The topsoil should be stockpiled such that it can be re-used when the <br />excess spoil fill is completed. We do not anticipate that benching of the ground surface will be <br />required. Keyway cuts or rock toe buttresses are not required. <br />In accordance with CDMG Regulations, we recommend that the fill be placed in approximately <br />horizontal lifts. To maintain comparatively high permeability within the fill, the use of thick lifts <br />is desirable. It is our opinion that lifts on the order of 50 to 100 feet can be used because of the <br />insensitivity of the spoil site to post-construction settlement. Previous experience with the <br />Section 16 and West Pit Fills (References 6 and 7) has shown that fills intended for open <br />rangeland following construction perform satisfactorily with thick lifts. <br />Performance of the excess spoil fill is dependent on following the recommendations presented in <br />this report and good construction practice. Therefore, observation of the fill placement should be <br />performed quarterly as required by CDMG Regulations to observe and document stripping, drain <br />constmction, fill placement, and surface drainage conditions. <br />• Because the performance of the fill is influenced by groundwater, we recommend installation of <br />an observation well. The monitoring well should be located near the centerline of the valley, be <br />at least 100 feet in elevation above the toe, and extend down through the spoil and natural soils <br />to at least 20 feet into bedrock. A bench for access to install and monitor the well should be <br />provided. Water levels should be monitored to confirm free water is not developing within the <br />spoil fill. <br />8.0 LIMITATIONS <br />This report was prepared for the exclusive use of RTEA for planning and construction of the <br />excess spoil fills, and not as a warranty of subsurface conditions, such as those interpreted from <br />the exploration logs and presented in the discussions of subsurface conditions included in this <br />report. <br />The analyses, conclusions, and recommendations contained in this report are based on site <br />conditions as they presently exist. We further assume that the current explorations are <br />representative of the subsurface conditions at the site; that is, the subsurface conditions <br />everywhere are not significantly different from those disclosed by the explorations. If, during <br />construction, subsurface conditions different from those encountered in the explorations or <br /> <br />23-1-01105-200-Rl.doc <br />23-1-01105-200 <br />11 <br />