Experimental Study on Load-Settlement Behavior of Circular Plate Supported on Small Diameter Timber Piles Under Vertical Loading

Abstract

Locally available wooden piles have been traditionally used in this region for improvement of bearing capacity through decades. Use of reinforced concrete pile is quite effective in improving bearing capacity, but there are sometimes disagreements between efficiency, cost effectiveness, sustainability, etc. Experimental study has been done on model footing (circular plate) supported on small diameter timber piles. Both single and groups of piles of variable length with variable spacing have been tested. Timber piles of 3 (three) different length to diameter ratio with different spacing have been used. The study is conducted on test tank constructed with steel plates and filled with zone-II sand. Load test was carried out on a model circular footing of 0.225 m diameter resting on sand with and without timber piles. The piles were installed in sand bed of 3 (three) different relative densities and subjected to vertical loading. Group efficiencies of pile groups were determined for three length to diameter ratio of 20, 25, and 30 with spacing of 2D, 3D, 4D, and 5D. The diameter of piles were taken as 15 mm. Length to diameter ratio, relative density, and spacing between the piles are found to be major factors that influence the performance of the model footing. A regression analysis was done to relate bearing capacity to relative density, spacing of piles, angle of internal friction, unit weight, and length of the pile.