there is a coral reef on the north side of Cactus Crater. In this area the keywall will be tied one foot into the existing coral reef. In areas where no coral reef existed or where the reef has been fractured the keywall will be constructed to a depth 8'-0O below the top of the adjacent coral reef. driving sheet piling, This wall can be constructed by excavating the space between the piling, dumping concrete below the water line and terminating with conventional concrete placement above the water line, [Pe wall can also be * constructed by excavating, placing forms, pouring concrete as described above and then backfilling. indicated on the drawing| A precast concrete option has been The depth of this 8'-O embedment will * preclude scouring and undermining of the keywall from tidal waves and severe storm wave action. c. Concrete Cap. See Appendix C, The contaminated material will be encapsuled with a 18" thick concrete cap, The cap will be poured in fioxcimum, 20' x 20' panels (22 cy) to reduce shrinkage cracks, a strength of 3000 psi at 28 days will be used. Concrete with Keys will be formed at slab joints to prevent differential movement between slabs, (Rev. 16Dec76) awe wha Bee . rught 4. s DOOR TM Te es *