(4) Sliding . 



Coefficient of friction (see Table 7-16) for concrete on sand 



Mg = 0.40 



Vertical Forces for L^ = 18.5 m 



W = 275.26 Lg = 5092.31 kN/m 



B, = -16.979 L = -314.11 kN/m 

 1 c 



B = -135.68 Lg = -2510.08 kN/m 

 X Fy = 5092.31 - 314.11 - 2510.08 = 2268.12 kN/m 



(5) Horizontal Force to Initiate Sliding . 



% = Ug Fy = 0.40 (2268.12) = 907.25 kN/m 



Since the actual net horizontal force is only 601.39 kN/m , the caisson will 

 not slide. 



c. Caisson Stability after Backfilling . 

 (1) Assumptions : 



(a) No wave action (protected by breakwater). 



(b) Voids filled with dry sand. 



(c) Minimum water level at -0.91 MLW. 



(d) Surcharge of 0.6 meter on fill (dry sand). 



OVERTURNING SEAWARD 



MINIMUM SWL == -0.91m 



0.6-m SURCHARGE 



^- ELEVATION = 7.9m 

 ■DRAINED SAND '/'.'.■. .^ MLW 



ELEVATION = -12.0m 



8-81 



