Lateral load analysis of piles in very soft clay
Description
In this dissertation the results of two lateral load tests, performed at Chalmette, Louisiana for the Louisiana Power and Light Company, is presented. The two instrumented test piles were both forty feet long. However, the geometry of the two piles was different, resulting in piles having differing stiffness and resistability to lateral loads. One pile was fabricated without wings. The other, the rocket shaped pile, had wings attached to the upper twenty feet The soil at the test site generally consisted of fifteen feet of very soft organic clay and peat, overlying very soft to soft highly plastic clay. The water table was above the ground surface. The lateral load was applied to the foundation pile at fifty nine feet above ground line, simulating hurricane generated loads on tower structures. The loading procedure followed in the testing program included (1) short-term static loading, (2) cyclic loading, (3) unloading and reloading, and (4) load to failure The reaction of the test piles was predicted, utilizing an available finite difference computer program and procedures for constructing soil resistance and pile deflection (p-y) curves. In situ-p-y curves were developed from the field data and compared to those calculated from laboratory compression tests. Correlations between the in situ p-y curves and experimental curves were made and a new method for constructing p-y curves for very soft cohesive soil is presented. Other subjects addressed include (1) the relative insensitivity of highly plastic, very soft soils to cyclic loading, (2) the effect of unloading the test piles and subsequent reloading, (3) the effectiveness of the wings on the upper twenty foot length, and (4) design optimization