INTRODUCTION 



Naval Construction Battalion (NCB) engineers and constructors are 

 responsible for building and modifying advanced bases so that the Navy 

 can carry out its mission. This building activity is usually outside 

 the continental United States and in some cases must be accomplished 

 quickly and without a thorough siting program. While many types of con- 

 struction are undertaken, particular interest is shown for waterfront 

 construction of permanent and advanced bases that require pilings. 

 Because of the remoteness of many construction sites and the need to 

 build quickly, most of these bases are planned and designed using pre- 

 engineered drawings contained in the Advanced Base Functional Components 

 system (NAVFAC (1982)). However, the foundation design must be site 

 specific and therein lies a potential weakness. 



The thin layer of soil that covers the earth is highly variable 

 making pre-engineered foundations difficult to achieve. Foundations 

 that rest on or are embedded in soils require soil surveys, testing, and 

 analyses so that specific designs can be made to accommodate the variety 

 of conditions encountered. The Navy has prepared two manuals to assist 

 the NCBs in designing foundation systems (NAVFAC (1971) and Rocker 

 (Ca 1984)). Application of the design procedures provided by these 

 manuals is successful when the soils encountered behave similar to ter- 

 restrial soils. However, in the equatorial regions of the earth, a 

 region of interest to the Navy, the soil is calcareous and engineering 

 experience has shown that calcareous soils behave quite differently than 

 terrestrial soils. In particular, pile foundations in calcareous soils 

 have not always performed well even when designed with higher factors of 

 safety than normally applied to designs in noncalcareous soils. The 

 Naval Facilities Engineering Command has funded a project to investigate 

 the performance of piles in calcareous soils, because of the expected 

 additional construction of pile supported structures in equatorial 

 regions. The intent of this program is to improve the technology related 

 to pile behavior in calcareous soil and enhance the Navy's ability to 

 quickly and efficiently construct pile-supported facilities. 



BACKGROUND 



Calcareous soils are composed of calcium carbonate. They are pre- 

 dominantly sedimentary and differ from terrigenous soils in several ways 

 (McClelland Engineers, Inc., 1980; Noorany, 1982a; and Datta et al. , 

 1981). Calcareous soils are products of biological activity, having 

 more intra-granular voids, are easier to crush, and are more susceptible 

 to post-depositional physical and chemical alterations. Calcareous de- 

 posits can have significant spatial variations and discontinuities such 

 as cavities, solution channels, and highly cemented zones. 



