Proceedings of DFI-India 2018: 8th Conference on Deep Foundation Technologies for Infrastructure Development in India, (DFI)
Performance of Large-Diameter Bored Pile with Short Socketed Length in Igneous Rock in Thailand
Zaw Zaw Aye, Thayanan Boonyarak, Ph.D., Sereyroath Chea and Nutthapon Thasnanipan
Large-diameter bored piles have been utilized extensively in soft soil for more than four decades in Thailand, whereas there are only limited numbers of rock-socketed bored pile constructed. To date, load transfer and settlement behavior of piling in rock in Thailand is still not fully understood, especially when the socketedlength is less than one time the pile diameter. The objectives of this paper are to analyze load distribution and to investigate load-settlement relationship of bored pile in rock. Collected data in this study was from pile load test results of more than 90 large-diameter bored piles, socketed in igneous rock such as granite and andesite. Bored piles were constructed using rotary drilling method, having socketed length varying from 0.3 to more than 3 times the pile diameter. Factors that influenced pile settlement behavior, consisting of socketed length and construction method were analyzed. The effects of socketed length on loadsettlement relationship and ultimate load bearing capacity were investigated. Load-settlement behavior, unit shaft resistance and unit end bearing is presented and discussed. Also, guidelines of estimation of pile settlement in rock is proposed. According to measured and calculated data, settlement of pile was mainly due to elastic shortening. This is because shaft friction in granite was the major component for pile resistance. For piles with socketed length per diameter ratio (S/D) of greater equal one, the mobilized shaft friction and end bearing are significantly larger than those with S/D of less than one. This is because socketed length is sufficient in rock to provide fully mobilized end bearing, resulting in relatively large stiffness at pile base.
|article #3152; publication #1050 (India2018)|