Laboratory Investigation of the Pile Group Behavior in Sandy Soils under Lateral Loads

Subject Areas : Analysis of Structure and Earthquake

Amir vakili ¹ , Mohammad Ali Zomorrodian ² , Mohammad Hosein Ahmadi ³

1 - دانشگاه آزاد اسلامی واحد بیضا
2 - دانشیار دانشگاه شیراز
3 - استادیار دانشگاه آزاد اسلامی واحد بیضاء

Received: 2019-04-09 Accepted : 2019-07-16 Published : 2019-09-02

Keywords: Pile group, Lateral load, P-Y method, Group reduction factor,

Abstract :

Structures are often subjected to lateral loads due to earthquakes, winds, and waves of water. It is very necessary to predict and measure the "load-deflection" behavior of the pile group, as well as its strain behavior, in order to create a safe and economical design. The behavior of piles embedded in soil, placed under the lateral load, is typically modeled and analyzed using the Winkler nonlinear springs method. In this method, the soil-pile interaction is modeled by nonlinear curves of P-Y in a way that P-Y curve modifies and adjust the single pile using a p-multiplier ( ) for each row of piles in the group. The  factor depends upon the configuration of pile group and the pile spacing. The value of this factor for the leading rows are considered higher and for the trailing rows lower. The present study was conducted to investigate the effects of various parameters, such as the pile spacing in the group and different layouts on the  factor. The  factor obtained from this study has good compatibility with the results of the full-scale test on pile group. The results show that the value of the  factor for pile groups with different layouts of 2.5-diameter pile spacing was in the range of 0.42 to 0.54, which is very close to the value of  obtained by previous study.Structures are often subjected to lateral loads due to earthquakes, winds, and waves of water. It is very necessary to predict and measure the "load-deflection" behavior of the pile group, as well as its strain behavior, in order to create a safe and economical design. The behavior of piles embedded in soil, placed under the lateral load, is typically modeled and analyzed using the Winkler nonlinear springs method. In this method, the soil-pile interaction is modeled by nonlinear curves of P-Y in a way that P-Y curve modifies and adjust the single pile using a p-multiplier ( ) for each row of piles in the group. The  factor depends upon the configuration of pile group and the pile spacing. The value of this factor for the leading rows are considered higher and for the trailing rows lower. The present study was conducted to investigate the effects of various parameters, such as the pile spacing in the group and different layouts on the  factor. The  factor obtained from this study has good compatibility with the results of the full-scale test on pile group. The results show that the value of the  factor for pile groups with different layouts of 2.5-diameter pile spacing was in the range of 0.42 to 0.54, which is very close to the value of  obtained by previous study.