Effect of cavity in sandy soil on load distribution of Pile Group

Dissertant

Abid, Halah Hani

Thesis advisor

Fattah, Muhammad Yusuf
al-Hulw, Karim Hadi Ibrahim

University

University of Technology

Faculty

-

Department

Department of Building and Construction Engineering

University Country

Iraq

Degree

Master

Degree Date

2013

English Abstract

The present study investigates the influence of presence of cavities on adjacent buildings especially in the case of piled structures.

The presence of cavity affects on the bearing capacity and settlement of piled foundation.

This thesis presents an experimental and numerical study to investigate the behavior of model piles embedded in sandy soil of dry unit weight 16.8 kN/m3.

Model piles were tested in a sand box with load applied by a hydraulic compression jack and measured by means of a load cell.

The settlement of the piles was measured by means of two dial gages; three strain gages were attached on piles to measure the strains and to calculate the load carried by each pile in the group by the strain indicator.

Three groups of piles (single pile, group of piles (1x2), and group of piles (2x2)) were tested in the laboratory as a free standing pile group.

A prototype of a cavity was used and placed adjacent to the piles at different distances ^om the pile centerline and different depths from the surface.

The effect of variation of cavity locations (X), cavity depths (Y), and cavity diameter (d) on the load and settlement of the pile and groups of piles have been studied for all tests.

It was concluded that the presence of the cavity in the soil reduces the ultimate failure load of the pile.

For single pile, the reduction rate is about (10% to 60%) at (d/D=1), while the rate at (d/D=2) is about (40% to 90%).

For pile group (1x2), the reduction rate is about (40% to 80%) at (d/D=1), while the rate at (d/D=2) is about (65% to 85%).

For pile group (2x2), the reduction rate is about (0% to 60%) at (d/D=1), while at (d/D=2) it is about (60% to 75%).

The settlement corresponding to a specked pile load embedded in soil with cavity at (d/D=2) is more than at (d/D=1), also the settlement of pile embedded in soil without cavity is less than the settlement of pile embedded in soil with cavity.

The numerical analysis of the pile-cavity problem based on finite difference method showed that the lateral soil movements increase with depth to the cavity centerline and then decreases, reaching a maximum at the depth of the cavity.

The settlement of pile embedded in soil without cavity is much less than that with cavity; the reduction ratio is about 60%- 70%.

The settlement of the pile decreases with increase of (X/D); the reduction value is about 80%-95%.

A high reduction in the settlement appears at (X/D=5.5), inducing low settlement as well as high stresses on the pile.

Main Subjects

Engineering & Technology Sciences (Multidisciplinary)

Topics

• Soil mechanics

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-417719