Batter Protection Road Construction

Embankment Protection by Pitching

Embankment protection by pitching  (hand  placed  rip  rap)  consists  of  large  stones  placed  by  hand  on  the  batter. Smaller rock fragments are placed in the voids between the larger rocks.
The pitching  may also  be cement grouted, in which case a sand cement grout (usually  3:1)  is broomed or rodded into the voids between the stone. The finished product is rigid but has very little  strength.  Pitching  requires  adequate,  firm  support  from  the  embankment  and  must  be protected from undermining at the toe and ends. Some joints should be left ungrouted to prevent uplift from water pressure.

The quality of stone used should be similar to that used for rip rap except that the stone needs  to  be  selected  to  obtain  more  uniformly  sized  and  cubically  shaped  pieces  to  facilitate hand placing.

During  construction  the  shape  of  the  batter  is  controlled  from  string  lines  stretched between timber profile boards set to the batter profile.

Pitching  has  been  used  extensively  in  the  past  as  a  form  of  embankment  protection, however its construction is labor intense. It is more rigid than dumped rip rap and consequently does  not  have  an  equal  capacity  to  adjust  to  any  movement  of  the  supporting  material,  or  to arrest an undermining scour.