ABSTRACT

A series of field tests was made to develop criteria for the design of laterally loaded piles in sand under both static and cyclic loads. Two 24-in. diameter piles were instrumented with strain gages for measuring bending moment at points along the piles. The gages were calibrated by applying known moments and reading the output of the gages. hydraulic equipment was developed for applying both static and cyclic loads. A calibrated load cell, employing strain gages, was used for measuring lateral load, and linear-displacement transducers were used for measuring the deflection of the pile at two points above the ground surface. The output from the moment gages, from the load cell, and from the linear -displacement transducers was recorded with a high- speed digital system.

A site was selected at Mustang Island, Texas, and two soil borings were taken. The instrumented piles, the reaction piles, and the loading apparatus were installed, and a comprehensive series of field tests was prefixed. This paper describes the field testing of the two piles

FOREWORD

A companion paper, "Analysis of Laterally Loaded Piles in Sand" by Lymon C. Reese, William R. Cox and Francis D. Koop presents the analysis of the test data and the development of design criteria. The tests were sponsored by Shell Development Company, Esso Production Research Company, Amoco Production Company, Mobil Oil Corporation, and Chevron Oil Company. The program was operated by Shell Development Company.

INTRODUCTION

Some of the first major offshore discoveries of petroleum reserves were located in areas where the soils consisted primarily of soft clays. Design of laterally loaded piles in these areas was a critical problem for which there was a scarcity of knowledge. For this reason, theoretical investigations were made and a number of field tests were run on piles in soft to medium clays. Based on these investigations, criteria were developed for the design of laterally loaded piles in clays whose consistency is soft to medium. The tests and criteria have been discussed by Matlock1.

As activities in offshore exploration pushed into areas where thick beds of sand are encountered, it became increasingly important that knowledge of the behavior of piles under lateral loads be expanded to include behavior in sands. This paper describes field tests for determining the force-deformation characteristics in sand. A companion paper2 presents the development of criteria for predicting the force-deformation behavior of sand along a laterally loaded pile.

SOIL BORINGS

As indicated in Fig. 1, a test site was selected at the Shell Oil Company tank battery on Mustang Island, near Port Aransas, Texas. Two soil borings were made at the test site. Soil samples were taken from one hole by continuously alternating a 2 -in. split- spoon sampler with a 3-in. piston sampler. Between the samples, the hole was increased in depth 6 to 9 in. by drilling and washing. Samples from the second hole were taken at 5 =ft intervals with a 2-in. split-spoon to 15 ft.

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