-sC^wt' 



Figure 51. Concrete L-wall under construction, Dana Point, California. Note filter cloth 

 taped to concrete at weepholes and expansion joints preparatory to backfilling. 



of opposing grooves on the edges of the piles above the mudline (Fig. 52). After all the 

 sheets have been driven, joint grooves are jetted clean and grout is pumped into them by 

 starting from the bottom. To contain the grout if serious leaks occur, elongated plastic bags 

 can be inserted into the joint along with the grouting pipe. The grouting pipe is lifted out as 

 the grout is pumped in, and the bag remains in the groove preventing escape of the grout 

 through cracks along the opposing edges. Although the plastic material prevents bonding of 

 the grout to the concrete, the joint is closed enough for sand tightness. Sometimes it is 

 possible to place a strip of filter cloth behind each joint, thus obviating the need of joint 

 grouting for sand tightness. 



Concrete sheet piles must be reinforced and, in a saltwater environment, the reinforcing 

 steel must be kept 3 inches behind the concrete saltwater interface. Sheet piles with a single 

 plane of reinforcing can be used for walls with less than about an 8-foot exposure; two 

 planes are required to provide the necessary section modulus for walls of greater height. 

 Since the backfilled face of the wall will not be visible, the sheet piles can be cast directly on 

 the grourid provided the bed is first carefuUy rolled and graded to a perfect plane. To 

 achieve a smoother face, a thin polyethelene sheet may be spread over the bed before setting 

 the reinforcing cage and edge forms. 



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