Effect of earthquakes on piles embedded in a liquefiable soil / Noha Elsaeed Mostafa Elfiky ; Supervised Adel Yahia Akl , Kamal Ghamery Metwally

Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Civil Engineering

A 3D model was carried out using ANSYS program in order to investigate the behavior of piles embedded in a liquefiable area during earthquakes. The model contained a CPT215 element that is able to represent the soil under such conditions; as it has an additional degree of freedom for water pressure. An interface element is employed also to simulate the interface between the pile and the enclosing soil. The factors that are considered for well simulating the liquefaction process are: the accumulation of pore water pressure, the reduction of soil stiffness, shear modulus, and the increase of coefficient of permeability. The results showed good model accuracy compared to the previous tests and numerical models, two components of movement are employed to the model; the horizontal and vertical component of EL-CENTRO earthquake. When the model is subjected to horizontal movement only, the lateral pile displacement decreased with the increase of top non-liquefiable layer thickness and vice versa. Whereas when both horizontal and vertical component of motion are applied to the model; the lateral pile displacement increased significantly in the case of the top non-liquefiable depth is 3m only, and the vertical pile displacement increased with the reduction of top layer thickness. The presence of top liquefiable layer is very influential on the lateral pile displacement as it increased by 120% from 0.52m to 2.2m

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