Enhancement of Seepage Behavior in Earth Dams Subjected to Saturated Conditions Using Lime and Fly Ash Additives

Ali Madhloom; Abdulaziz A.  Al-Kifae; Saleh I.  Khassaf

Article Details

Enhancement of Seepage Behavior in Earth Dams Subjected to Saturated Conditions Using Lime and Fly Ash Additives

Authors:

Ali Madhloom | Abdulaziz A. Al-Kifae | Saleh I. Khassaf

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.59 Issue 1B, pp.76-88

Document Type:

Article

Publication Date:

2/2026

Document Language:

English

Document ID (Org No.):

2001836979

pISSN:

2663-8754

Keywords:

Abstract:

 When earth dams are re-operated after prior reservoir discharge, the soil often remains saturated or nearly saturated due to earlier wetting, creating continuous flow paths that intensify seepage and threaten dam stability. This study examines improvements in seepage control in earth dams under saturated conditions by incorporating lime and fly ash additives into sandy soil cores. Five physical dam models were constructed and tested: one untreated model, serving as the control and representing natural sandy soil, and four treated models (M-1, M-2, M-3, and M-4) whose cores were stabilised with progressively higher lime–fly ash proportions. Permeability tests confirmed reductions in hydraulic conductivity, from 8.17 × 10⁻⁵ m/s in the control model to 3.125 × 10⁻⁷ m/s in the most highly treated model (M-4). Pressure head monitoring revealed that treated models delayed the attainment of steady-state seepage compared with the control, with delays ranging from 20 minutes in the control model to 100 minutes in the M-4 model. Steady-state seepage rates decreased with increasing additive content, achieving reductions of 74.1%, 87.4%, 96.4%, and 98.28% relative to the control model for models M-1 to M-4, respectively. The treated models also exhibited downward shifts of the phreatic line, with M-4 demonstrating the lowest seepage surface. Numerical analysis showed strong agreement with the experimental results, with the exit hydraulic gradient decreasing from 0.5 in the control to nearly zero in the treated models. These findings demonstrate that lime-fly ash treatment enhances the hydraulic performance of sandy soils, offering a viable alternative to conventional clay cores.

Article Details

Enhancement of Seepage Behavior in Earth Dams Subjected to Saturated Conditions Using Lime and Fly Ash Additives

Authors:

Ali Madhloom | Abdulaziz A. Al-Kifae | Saleh I. Khassaf

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.59 Issue 1B, pp.76-88

Document Type:

Article

Publication Date:

2/2026

Document Language:

English

Document ID (Org No.):

2001836979

pISSN:

2663-8754

Earth dams

Seepage

Exit gradient

Saturated Conditions

Lime and Fly Ash additives

Issues

Article Details

Enhancement of Seepage Behavior in Earth Dams Subjected to Saturated Conditions Using Lime and Fly Ash Additives

Authors: Ali Madhloom | Abdulaziz A. Al-Kifae | Saleh I. Khassaf

Publisher: Iraqi Geologists Union (Union of Iraqi Geologists)

Journal: The Iraqi Geological Journal Vol.59 Issue 1B, pp.76-88

Document Type: Article

Publication Date: 2/2026

Document Language: English

Document ID (Org No.): 2001836979

pISSN: 2663-8754

Earth dams

Seepage

Exit gradient

Saturated Conditions

Lime and Fly Ash additives

Issues

Authors:

Ali Madhloom | Abdulaziz A. Al-Kifae | Saleh I. Khassaf

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.59 Issue 1B, pp.76-88

Document Type:

Article

Publication Date:

2/2026

Document Language:

English

Document ID (Org No.):

2001836979

pISSN:

2663-8754