FOUNDATIONS. 



263 



slipping be rendered impossible, or by benching the rock, as 

 represented by the dotted line abc, in Fig. 82. Either plan 

 would be equally effective, so the mode of procedure should be 

 determined, in each particular case, by expediency and relative 

 cost. 



CROSS SECTION OF 

 BREAKWATER 



FIG. 82. 



4. Steeply inclined rock strata, crossing a breakwater and 

 terminating by an abrupt face across the scar-end of the work. 



In a case of this kind, any attempt to bench the rock by 

 blasting or otherwise would be almost sure to loosen it back to 

 its natural beds, bb } in Fig. 83, and so make matters worse 



FIG. 83. 



rather than better. It would, however, be out of the question 

 to attempt to found upon such a sloping face, unless there were 

 a substantial buttress in front of it to prevent forward slipping. 

 Probably, therefore, the best mode of procedure in such cases is 

 to set as much work as possible ahead of the slope, and then 

 work backwards, closing up to the rock by means of mass 

 concrete, as shown in Fig. 84. 



