ARCHIVED REPORTS XR0012718 - Laserfiche WebLink

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Project No- 90161.e y June 1990 of the walls to within 12 inches of the surface. A 4 inch ' er€orations facing diameter drain Pipe should be installed with p dz holes provided dawn in the bottom of the filter blanket or we at least 4 if applicable. Drain pipe should be underlain by Filter material should conform er-type material. inches of filt 4-� to Class one, 'Type Permeable material as designated in Section ! ecificationsr 68, "Subsurface Drains", of the Caltrans Standard Sp 4 concrete coarse aggregate mix current edition. A typical 1"x # . g approximates this sp ecravel is also ification. A clean pea rovided to discharge acceptable. Adequate gradients should be p lls to an adequately controlled water that collects behind the wa discharge system. j the should be 3, If redwood retaining walls are utilized., y E.:.3 a supported by posts 1 foot in diameter . set in concrete <<t least : hosts to within 6 inches of and extending from the base of the _ ground surface at the base of the wall. For a 3 or 4 foot the gr the effective height of wall with level. surfaces above and below, a posts should be at 4 foot centers and they should extend depth below the ground surface equal to the effective height.. `To to drain, moisture collected with its the grain of the wood .,low moravel drain ; it is suggested that the posts be set on 4 inches of q material. The woad planking on the wa'.l should extend 3 inches filter blanket behind soil at the base of the wall. A so below the planking and reduce the wall will allow free drainage between thethe wall. o€._the...fine soils to pipe through the propensity... - --... 15