Table 10 ~ lists values of sjigle a, the slope ratio, and 

 (Is 09 cos a - sin ay for slopes ranging frora 

 1 on 1»1 to 1 on 10) 



Plates 7-llj Appendix D - are curves sho>ri.ng the variation 

 of "¥/'K * " f ror.i eqiiation (k6) for seax^-ater, i/ri.th 

 wave height H (or Ii')« Values of the f-unctions 

 liave been coiiputed for slopes of 1 on 1 l/lt to 

 1 on 10 with stone density being used as a 

 paraj-netera 



Plate 12, Ap pendix D - shows the variation of K' iiri-th d/L 

 for slopes ranging, 1 on 1 to 1 on 3. 



226 (, Applications . - Since the equations for above surface and sub-surface 

 stone xireights are not entirely conpatible, the determination of sub-surface 

 weights as outlined above should be restricted to depths below a wave height 

 from the surface^ slopes for above surface stones being carried to that level* 

 The crest height of a breaki'iater should be at least one and one-half wave 

 heights above design water level, if relatively corrplete wave obstruction 

 is desired,; 



227» Effect of Wave Angle of Approach ^ - If the waves approach a struc- 

 tvire at an angle p '(Fig'i^e 82), there is a chance that shock pressures x^rill 

 not be produced, iDut for design purposes, the possibility of their e^cLstence 

 must be accepted ^ HoT.jever, the pressures developed will be spread over a 

 longer reach of wall than would be the case for normal incidence p Therefore^ 

 the horizontal dynamic pressure due to either waves breald.ng on or seaxrard 

 of a structure may be considered to be reduced to 



P„ =^ P sin^ B (It8) 



pm . m • 



In the case of a rubble mound structure, the value of H may be considered 

 to be reduced to 



H = v^sin ,8 (H) (h9) 



228 -J In this case, it is assumed the energy between two orthogonals 

 a unit distance apart is spread along the structure over a distance 

 l/sin p or the energj^ per unit lengt h of s tructure is e«sin p* Since xrave 

 height is proportional to v^ H = y/s±n p (H).- No fxirther reduction in wave 

 height is made to coEpensate for angle of approach because of the irregu- 

 larity of the structure sxirface^ 



BARTK FORCES 



229» Activ e Forces .-. - The horizontal coirponent of the active earth 

 force is evaluated from the general xredge theory formula: 



117 



