Analysis On The Settlement Characteristic And Isolation Effect Of High Cap Pile Foundation In The Large LNG Tank

With the rapid development of China’s economy, the rapid expansion of demand for resources, energy efficient and environmentally friendly LNG in China has been widely used. To protect our LNG supply and reserves, most of them using a large LNG storage tanks. Large LNG storage tanks with a large diameter, high volume, mass and other characteristics of the foundation demanding. In large LNG storage tank construction in infrastructure is particularly important. In this paper, based on a LNG terminal project in Tianjin instance, the use of geotechnical engineering simulation software FLAC3 D establish a numerical model to simulate the pile works, analyze the nature of the pile. From large LNG storage tanks pile settlement calculation method, pile arrangement, three aspects of isolation design optimization analysis and rationalization proposals put forward feasible, provide experience and reference for future similar projects. In a large number of domestic and foreign literature review on the basis of the work done as follows:(1) Summary of pile foundation settlement calculation methods commonly used at domestic and abroad, for analysis and evaluation. Pier base such as generation method and correction method of generation of pier base, load transfer method, the pile foundation settlement calculation and FLAC3 D numerical model was established, and simulation of pile foundation settlement, the final settlement of simulation results。(2) The use of variable rigidity design, by changing the pile length, pile spacing and other methods to adjust the pile differential settlement. The use of geotechnical engineering simulation software FLAC3 D build two large groups of large LNG storage tanks high pile caps leveling scheme. Analysis of results: two groups under different scenarios showed a large pile settlement outside small "dish" distribution, consistent with past experience. Increasing the pile length can effectively reduce the pile settlement, but did not reduce the pile gradient differential settlement. Non fabric pile spacing, the local reinforcement of piling combined pile arrangement not only effectively reduces the group piles foundation settlement, differential settlement in the control also has a significant effect, as the best variable rigidity program.(3) Analysis of the actual wave seismograms under Tianjin,Tangshan wave, EI-Centro wave and Taft wave, caps before adding isolation design displacement and velocity changes. Join isolation pad caps displacement peak and peak velocity significantly decreased. The result speaks isolation layer played a very good isolation effect, greatly reducing the seismic response of pile caps.