238 



The wave channel was filled with water during sand placement to minimize 

 air entrapment and to selectively remove light organics from the material. A 

 target beach profile was painted on the walls of the wave channel. Soundings 

 were taken to establish the depth of the deposited material relative to the 

 target profile. Water was drained from the channel and refilled, then waves 

 were run to condition the beach. This process was repeated four times to 

 clean the sand prior to instrument installation. 



Approximately 700 cu yd (540 cu m) of sand were placed on the original 

 beach. An additional 200 cu yd (150 cu m) were placed during the final 

 phase of the project to simulate an offshore berm. Perforated drain pipe was 

 placed through the base of the berm to facilitate filling and emptying of the 

 wave channel. A photograph of the offshore berm is shown in Figure 12-3. 



Dune erosion studies were conducted early in the project. Dunes were 

 prepared to simulate many seasons of sand accumulation. To meet this 

 requirement, the sand was placed in 1-ft (0.3-m) layers, dampened, and 

 compacted with a gas-powered panel vibrator. The resulting dune face 

 appears in Figure 12-4. 



Sand-core densitometer 



Instrument description. The American Society for Testing Materials has 

 established Standard Tests D2049-64T for determining in-place relative 

 density. The tests consist of determination of minimum and maximum density 

 corresponding to the loosest and most dense states of the soil and determi- 

 nation of in-place density using Standard Test D1556 (sand cone test). The 

 loosest state of the soil is achieved by slowly pouring the sand into a standard 

 mold. The most dense state is achieved by placing the sand in the mold in 

 five layers, applying a confining pressure corresponding to a load of at least 

 12 kg, and striking the mold 30 times with a rubber mallet. These two tests 

 are repeated three times and extreme values are used. 



In the sand cone test, a hemispherical hole 17 cm in diameter is excavated 

 using a standard template. All sand removed from the hole is placed in plastic 

 bags and sealed tighdy. This hole is then filled with a standard sand; for 

 these tests Ottawa sand was used. The weight of the Ottawa sand required to 

 fill the hole is used to estimate the volume of the hole. Wet samples taken 

 from the site are weighed and then oven-dried for 24 hr to determine the dry 

 weight. A photograph of the sand core apparatus appears in Figure 12-5. 



Location. The apparatus for determining in-place density is located onsite 

 at the O.H. Hinsdale Wave Laboratory, Oregon State University (OSU), and 

 equipment for determining minimum and maximum density is located at the 

 Soil Mechanics Laboratory, OSU. Specific sample locations are noted in 

 Table 12-1. 



Chapter 12 Pore Pressure and Sediment Density Measurements 



