CORRESPONDENCE_1994-1998 - Laserfiche WebLink

Home Browse Search

(2/94) Sec. 10-1, Construction Details Std. Spec. Sec. 19 Special Page 1 of 4 CLAY BARRIER LAYER. -- Attention is directed to Section 19, "Earthwork, " of the Standard Specifications and these special provisions. The clay barrier layer shall consist of 80 percent on-site selected soils mixed with 20 percent imported Ione clay. Selected on-site soils for the clay barrier layer shall be designated by the Engineer from material excavated from Excava-ion Areas A and B. Material shall be excavated to the lines and grades shown on the project plans. If additional material is needed, Area B shall be utilized and shall be excava_ed as directed by the Engineer. on-site selected soils used in the barrier layer must have a minimum of 60 percent passing through the No. 4 sieve and be classi'ied as the following: C , CL, SC, ML, and/or SM (USCS) . ?:o clean sandy (SP) soils shall a used in the construction of the clay barrier layer. Clean sandy (SP) soils, as determined by the Engineer during excavation, shall be stockpiled at the location shown on the project plans. The final compacted mixed soils shall have a maximum water hydraulic permeability of 1 x 10-6 cm/sec as verified by the Engineer. The County has tested and prequalified, with the Regional Water Quality Control Board, the fcllowing clay mixture and method of construction. Ione clay used in the barrier layer must be obtained from one of the fcllowing approved sources unless otherwise approved by the ngineer. Ipproved sources of Ione clay: 1) North American Refractories Attn. : John Cole (209) 274-2471 2) Superior Clay Products Attn. : Steve Walenta (209) 274-0550 The Icne clay shall have a maximum water hydraulic permeability of 1 :F: 10'$ cm./sec prior to mixing. Moisture content of Ione clay shall not exceed 5 percent over optimum prior to mixing opera ions at the landfill.