Numerical Analysis of Piled Raft Foundation on Port Said Soil
Oral Presentation , Page 1-10 (10)
Volume Title: ICASGE2025
Paper ID : 1166-ICASGE (R1)
Authors
1studying master degree at Al-Azhar university and work as a lecture assistant at MTI university
2Egypt,tanta
Abstract
The main purpose of any foundation system is to distribute and transmit the load from the structure to the soil. This study investigates the performance of piled raft foundations in multi-layered soils, specifically under the unique geotechnical conditions of Port Said, Egypt, using advanced finite element modeling with PLAXIS 3D. The research focuses on settlement reduction, shear stress, and bending moment behavior under vertical loading. The methodology includes investigating the most effective pile diameter and length, determining that a 1-meter diameter and 48-meter length pile provides the best performance. The case study varies the pile group-to-raft width ratio (Bg/Br) at 0.7, 0.8, and 0.9 values, with pile spacing adjusted accordingly. Additionally, the raft thickness varies at 2.0, 1.5, 1.2, 1.0, and 0.8 meters, while the number of piles is distributed gradually in configurations of 10x10, 9x9, 8x8, 7x7, 6x6, and 5x5.
The study results show that a pile group-to-raft width ratio (Bg/Br) of 0.9 with 81 piles and a 2.0-meter raft thickness offers the best performance in terms of settlement reduction, providing a 22% improvement compared to configurations with fewer piles. For more cost-sensitive projects, a Bg/Br ratio of 0.8 with 49 piles was found to be a practical and economical alternative, achieving a similar level of settlement reduction while significantly reducing the number of piles. Thinner rafts, such as those with a thickness of 0.8 meters, led to up to 18% greater bending moments and 4% higher shear stresses compared to the 2.0-meter raft.
The study results show that a pile group-to-raft width ratio (Bg/Br) of 0.9 with 81 piles and a 2.0-meter raft thickness offers the best performance in terms of settlement reduction, providing a 22% improvement compared to configurations with fewer piles. For more cost-sensitive projects, a Bg/Br ratio of 0.8 with 49 piles was found to be a practical and economical alternative, achieving a similar level of settlement reduction while significantly reducing the number of piles. Thinner rafts, such as those with a thickness of 0.8 meters, led to up to 18% greater bending moments and 4% higher shear stresses compared to the 2.0-meter raft.
Keywords
Piled raft; Port Said East Egypt; Stiff Clay; Multi-Layer; settlement; straining actions; Bending moment; Shear Stresses
Subjects