Engineering and Technology Journal

Experimental and Numerical Analysis of Piled Raft Foundation Embedded within Partially Saturated Soil

M.R. Mahmood; S.F.A. Al-Wakel; A.A. Hani

Volume 35, 2A , February 2017, , Page 97-105

https://doi.org/10.30684/etj.35.2A.1

Abstract

This paper presents an experimental and numerical study to investigate the load carrying capacity of piled raft foundation embedded within partially saturated sandy soil. The effect ... Read More ... This paper presents an experimental and numerical study to investigate the load carrying capacity of piled raft foundation embedded within partially saturated sandy soil. The effect of matric suction on the bearing capacity of the foundation system was investigated. The experimental work consists of two models of foundation, circular raft foundation and circular piled raft foundation. The circular raft foundation has dimensions of 10cm in diameter, and 2.5cm thickness, while the piled raft foundation has the same dimensions of the circular raft model but with a single pile of 2.0cm in diameter and 40.0cm in length fixed at the center of the raft. Both models are loaded and tested under both fully saturated condition and unsaturated conditions, which are achieved by, predetermined lowering of water table. The lowering of water table below the soil surface was achieved in to two different depths to get different values of matric suction and the relationship between matric suction and depth of ground water table was measured in suction profile set by using three Tensiometers (IRROMETER). The soil water characteristic curve (SWCC) estimated by applying fitting methods through the software (SoilVision). A validation process then was carried out for the case of circular piled raft foundation with lowering the water table 45cm bellow soil surface in the aid of a sufficient finite element computer program ABAQUS 6.12. An eight-node axisymmetric quadrilateral element CAX8RP and CAX8R were used to simulate the soil continuum and piled raft respectively. The interaction method used to simulate the intersect surfaces of the system (pile-raft-soil) is a surface-to-surface discretization method under the concept of master and slave theory. The behavior of piled raft material is simulated by using a linear elastic model while the behavior of soil is simulated by an elasto-plastic model by the use of the Mohr-Coulomb failure criterion. The results of the experimental work demonstrate that the matric suction has a significant role on the bearing capacity of all tested models. It shows that the ultimate bearing capacity of circular raft foundation under a partially saturated condition is increases by about (7.0-8.0) times than the ultimate bearing capacity of fully saturated condition when lowering the water table 45 cm below the soil surface. While the ultimate bearing of circular piled raft foundation under partially saturated condition increases by about (8.0-9.0) times than the ultimate bearing capacity of fully saturated condition when lowering the water table 45 cm below the soil surface. The results of the ultimate bearing capacity of piled raft foundation that obtained from the experimental model and from the numerical modelling for the same soil condition and same matric suction indicate that a successful validation is achieved for the simulation process.

Experimental Study on Compressibility, Volume Changes, Strength and Permeability Characteristics of Unsaturated Bentonite-Sand Mixtures

Mohammed Y. Fattah; Nahla M. Salim; Entesar J. Irshayyid

Volume 34, 7A , July 2016, , Page 1308-1323

https://doi.org/10.30684/etj.34.7A.5

Abstract

Expansive soils are generally found in arid and semiarid regions. These soils undergo volumetric changes upon wetting and drying, thereby causing ground heave and settlement problems. ... Read More ...

Plug Length Developed in Pipe Pile Embedded Within Partially Saturated Cohesionless Soils (Part 1)

Mahmood Rashid Mahmood; Karim H. Ibrahim Al -Helo; Ali M. AL-Gharbawee

Volume 34, 7A , July 2016, , Page 1335-1346

https://doi.org/10.30684/etj.34.7A.7

Abstract

This paper presents an experimental study to investigate the change of plug length for pipe pile under different state of saturation and investigate the effect of number of pipe piles ... Read More ...

Behavior of Single Pile in Unsaturated Clayey Soils

Mohammed Y. Fattah; Nahla M. Salim; Israa Mohammed Mohsin

Volume 32, Issue 3 , March 2014, , Page 763-787

https://doi.org/10.30684/etj.32.3A.15

Abstract

The mechanical behavior of partially saturated soils can be different from that of fully saturated soils. It has been found that for such soils, changes in suction do not have the same ... Read More ...

مساهمة في دراسة العلاقة بين التداعي والانتفاخ مع اجهادات مص التربة

Volume 25, Issue 5 , July 2007, , Page 207-224

https://doi.org/10.30684/etj.25.5.5

Abstract

This research aims to study the role of soil suction and clay minerals on volumetric changes of a collapsible soil selected from Hawy Al-Kanissa area in Mosul city. The effect of low ... Read More ...

Keywords = Soil Suction

Experimental and Numerical Analysis of Piled Raft Foundation Embedded within Partially Saturated Soil

Abstract

Experimental Study on Compressibility, Volume Changes, Strength and Permeability Characteristics of Unsaturated Bentonite-Sand Mixtures

Abstract

Plug Length Developed in Pipe Pile Embedded Within Partially Saturated Cohesionless Soils (Part 1)

Abstract

Behavior of Single Pile in Unsaturated Clayey Soils

Abstract

مساهمة في دراسة العلاقة بين التداعي والانتفاخ مع اجهادات مص التربة

Abstract