LABORATORY TESTS OF SOIL-PILE INTERACTION BEHAVIOR 

 Purpose and Approach 



The preceding background has shown the lack of knowledge of calcar- 

 eous soils, their engineering behavior, and designing piles for use in 

 calcareous soils. 



The problem confronting the Navy is that the design of piles in 

 calcareous soils cannot be done with confidence and this poses a threat 

 to the successful completion of expedient operations. Planning for these 

 operations becomes extremely difficult when, for example, it is not known 

 how much piling to send with an elevated causeway that must be constructed 

 in order to support an amphibious operation. 



A program for improving pile design capability in calcareous soils 

 was presented by Bailard and McCarel (1981). They recommended a four- 

 point program that included: laboratory and field studies to determine 

 the geotechnical behavior of piles driven in calcareous sediments; devel- 

 opment of improved pile technology for calcareous soils; and, development 

 of geotechnical design procedures for piles used in calcareous soils. 

 The corner stone of the program was a comprehensive research program 

 aimed at gaining a better understanding of the geotechnical behavior of 

 piles during inserting and loading in calcareous soils, and how this 

 behavior differs from that in terrigenous soils. The goal of this pro- 

 gram was to discover what specific failure mechanisms cause the widely 

 divergent behavior. Particular attention was given to the relative im- 

 portance of cementation, grain crushability , carbonate content, and 

 crushed grain fraction in governing the behavior. Because of the dif- 

 ficulty and expense of conducting full-scale field experiments, the bulk 

 of this work has been conducted in the laboratory. Later, verification 

 of these results will be obtained by partial and full-scale field tests 

 using instrumented piles. 



The purpose of this report is to document the results of the labora- 

 tory investigations designed to determine the factors influencing pile 

 behavior in calcareous soils and to examine alternative pile concepts 

 for calcareous soils. A general investigation designed to bound the 

 problem and provide guidance for the other investigations was performed 

 by the Naval Civil Engineering Laboratory (NCEL) . A study of f rictional 

 behavior, particularly in regard to crushed friction was performed by 

 Dr. Iraj Noorany (Noorany, 1982b). The study of grain crushing and the 

 study of alternative pile concepts were performed by Earth Technology 

 Corporation (ERTEC, 1983a and b) . 



General Investigation 



The background information clearly points out that an understanding 

 of the calcareous soil-pile interaction and the ability to provide ade- 

 quate pile design and installation guidelines or procedures is not avail- 

 able to the engineering community. NCEL conducted a series of laboratory 

 experiments to gain a better understanding of the general behavior of 

 the calcareous soil-pile interaction, and to bound the geotechnical 

 parameters controlling this interaction. The investigators determined 

 that a visual representation of the calcareous sand media during pile 



