Laserfiche WebLink
Mr. Steve Pesce <br /> April 18,2008 <br /> We recommend that the compacted soil liner have a minimum thickness of two feet. The soil liner material <br /> should be moisture conditioned to within 2 percent of its optimum moisture content,placed in uniform loose lifts <br /> of 12 inches or less, and mechanically compacted to a minimum of 95 percent of the soil's maximum dry density, <br /> as determined by ASTM Test Designation D1557 (Modified Proctor) using a sheep's foot roller. We <br /> recommend that the geoteclniical engineer provide construction observation and testing services on a full <br /> time basis during construction of the soil liner. A compacted soil pond liner detail is attached. <br /> If a flexible membrane liner(FML) is used, we recommend that it have a minimum thickness of 40 mils. Plastic, <br /> HDPE, or a composite liner can be considered. The liner should be installed on a properly prepared subgrade in <br /> accordance with the liner manufacturer's specifications. If the pond slopes are required to be vegetated,it will be <br /> necessary to specify a liner that will exhibit sufficient friction to insure topsoil will not slide off the liner when <br /> the pond is in service. Alternatively,a geo-cell confinement system could be installed over the liner and infilled <br /> with topsoil. As penetrations through the liner would not be allowed, the geo-cell system would need to be <br /> anchored at the top of the pond in a keyway and supported by tendons that extend through the geo-cell webbing. <br /> Geo-Web cellular confinement or similar systems could be considered for this purpose. <br /> Soil conditions in the planned pond location should be verified by supplemental exploration prior to construction. <br /> These explorations will also allow evaluation of possible drainage needs to reduce impacts of cut slope seepage <br /> to the pond liner. <br /> We trust the information presented is sufficient for your current needs. If you have any questions or require <br /> additional information,please call. <br /> Sincerely yours, <br /> TERRA ASSOCIATES,INC. `k.' ee, r, 1.1> <br /> p. <br /> r f C <br /> i � of WRSjy� is. <br /> -0/ A la <br /> min Sadler,L.E.G.,L.H.G. <br /> Project Manage ! r <br /> 320391 <br /> • <br /> Kevin P.Roberts,P.E. .ft1Nltt.. <br /> A. <br /> Senior Engineer <br /> EXPIRES 08l08/69 <br /> Encl: Figure 1 —Compacted Soil Pond Liner Detail <br /> Project No.T-5922-1 <br /> �/Page No. ��� <br />