The Pile Group Effect Research Of Great Pile Group Under Vertical Load

In order to understand pile group effect of great pile group under geological condition such as Lizigou bridge and provide some help to the pile foundation design for the next under similar geological condition to Lizigou bridge, this paper mainly is based on experimental study in Lizigou bridge, and conductes the numerical simulation calculation by the FLAC^3D finite difference software. It is analyzed aspect on side resistance and subsidence influences under the vertical load such as bearing platform, the pile length to diameter ratio, the pile distance, length to width ratio of the pile length and bearing platform width, and so on.The paper primary work is as follows:1. This article was brief summarized research results about work character of the pile group domestic and foreign.2. It is done the preliminary study to theory background of the FLAC^3D software, and introduction to the FLAC^3D software computation principle and some construction models.3. Uses the FLAC^3D software to create the single pile modelling and to simulate, and compare with the test result which does with the scene, screens the analogue result which most tallies with the actual situation, finally determines reasonable computation parameter in FLAC^3D software environment.4. Such as bearing platform, the pile length to diameter ratio, the pile distance, length to width ratio of the pile length and bearing platform width, separately establishes the corresponding three dimensional pile group models using the FLAC^3D software, and analysis to the analogue result. Some influential factors,such as bearing platform, the pile length to diameter ratio, the pile distance, length to width ratio of the pile length and bearing platform width have been analyzed on side resistance and settlement.The paper primary achievements are as follows: 1. FLAC^3D software is available in pile group foundation simulation analysis, its simulation effect is ideal.2. The reasonable pile distance should be situated between 2.5D and 6.0D, either does not favor the display pile side resistance outside the scope spacing, either can create the project cost increase.3. Under geological condition such as Lizigou bridge ,the pile number is primary factor which causes the pile group settlement, the pile distanceis and the length to diameter ratio influence is smaller. Enhances the foundation supporting capacity in the design process first is considered to increase pile length.