Personal contacts should be made to acquire existing information on 

 sites and determine ongoing or planned activities. These contacts may dictate 

 whether a site will be available for use. As an example, in the conduct of the 

 initial phases of the preliminary site survey for ocean construction experiments, 19 

 it was learned through personal contacts that the sites immediately south of the 

 Channel Islands (off Port Hueneme) could not be used for bottom stations 

 because the operations of the Pacific Missile Range would be inhibited by the 

 presence of the bottom station and surface support activity. Thus, personal 

 contacts should be made prior to conducting a reconnaissance survey. 



In the event that the existing information is insufficient for placement 

 of the particular structure and information from personal contacts is favorable, 

 a reconnaissance survey is then conducted to locate specific candidate sites. 

 The data collected from this survey are then evaluated and a particular site is 

 selected for detail investigations in the next phase commensurate with the 

 requirements for the particular bottom installation. 



Detail Survey 



I n this survey, the site selected in the preliminary survey phase is 

 subjected to detailed investigations. Those parameters for which there are 

 sufficient existing data need not be reassessed; the quantities that lack suffi- 

 cient information, however, must be evaluated in this survey. In general, 

 only those parameters significant to the particular bottom station need be 

 measured. Once the requirements of the structure are known, the field sur- 

 vey can be initiated, using the appropriate combination of survey gear presented 

 in the next section. 



Presently, there are two methods that could be used to assess the 

 foundation engineering parameters. The first method is to secure core samples 

 from the site using appropriate techniques and subjecting these samples to 

 applicable tests. To obtain samples of minimum disturbance for these tests, 

 the optimum corer dimensions described by Hvorslev 20 should be used. These 

 are as follows: 



D 2 - D 2 



Kerf or Area Ratio, C a = — x 100 > 10% 



Inside Clearance Ratio, Ci = x 100 = 0.75 to 1.5% 



(for long samples) 



= to 0.5% 



(for short samples) 



22 



