Mahdi Al-Naddaf

• Ph.D.
• Professor (Associate) at University of Karbala

Buried structures (e.g., culverts and pipes under roadways) installed several decades ago are reaching the end of their service life. Excavation and replacement of these structures will cause disturbances to the transportation network and require significant funding. Trenchless techniques (e.g., sliplining) have been increasingly employed to rehabi...

Load transfer platform (LTP) plays an important role in load transfer between piles and subsoil in pile-supported embankments over soft soils. This study conducted spring-based trapdoor tests to investigate the load transfer mechanisms of LTPs with unreinforced and geosynthetic-reinforced river sand and lightweight aggregate (LWA) subjected to diff...

Protecting existing utility lines in densely populated metropolitan areas is a significant concern, particularly when new roadways or bridges are constructed over these vital infrastructures. Various accidents or natural disasters may damage them. As a result of the pipe’s wall full force and non-uniform load, shallowly buried pipes exposed to surf...

Wicking geotextile can reduce water contents in pavement layers under unsaturated conditions due to capillary action through grooves of wicking fibers. Reduction of soil water content under the pavement can minimize pavement distresses. So far, there have been limited use and verification of the wicking geotextile in reducing water content of soil...

Pile-supported (PS) embankments have been used increasingly to support highways and railways on soft subsoils. In addition to the self-weight of the embankment, this embankment system is often subjected to surface localized loading, such as traffic loading. In this embankment system, soil arching is a key load transfer mechanism. Stability of soil...

Buried pipes are among the most important urban facilities due to their use in multiple key applications such as drainage, sewerage, oil lines, electrical conduits, and culverts. The performance of such infrastructure under different loading conditions relies highly on their design, yet adequate design cannot be achieved unless their actual behavio...

Geosynthetic-reinforced retaining (GRR) walls have been used as bridge abutments to support bridge beams on spread footings instead of traditional deep foundations (such as piles and shafts). However, so far limited studies have been carried out to investigate the performance of the GRR wall subjected to footing loads considering possible failure s...

Buried concrete box culverts have commonly been used at shallow depths under roadways for drainage. Higher stiffness of these buried culverts relative to their surrounding soil affects traffic load distribution. For instance, in embankment culverts, the deformation of the soil column above the culvert is less than that of the surrounding soil due t...

To investigate the behavior of piles and the performance of the mechanically stabilized earth (MSE) walls under static and cyclic lateral loading, six reduced-scale model tests of single and group piles within the MSE walls were conducted inside a test box. In the single pile tests, a hollow aluminum tube as a pile was placed at a distance of 2D or...

To investigate the behavior of laterally loaded piles within mechanically stabilized earth (MSE) walls, reduced-scale physical model tests of single piles within the MSE walls were conducted inside a test box. Sensors were installed in each model test to monitor the responses of the wall facing and the pile during the laterally loaded pile test. Th...

Corrugated steel pipes installed under roadways several decades ago are reaching the end of their service lives. Excavation and replacement of these buried structures cause disruption to the transportation network and require significant funding. Trenchless rehabilitation methods have been increasingly used to reduce the overall cost of a project a...

Geosynthetic-reinforced retaining (GRR) walls have been utilized as bridge abutments to support shallow foundations of bridges instead of traditional deep foundations, such as piles. In this technology, GRR walls support both bridge beams on spread footings constructed directly on the reinforced soil mass and approaching roadway embankments. Howeve...

Soil arching exists in many geotechnical applications, including tunnels, buried pipes, and geosynthetic-reinforced pile-supported (GRPS) embankments. Soil arching has been mostly investigated using trapdoor tests under soil self-weight and/or uniform surcharge. In real applications, localized surface loading, such as traffic loading, may be applie...

Cement modification of soils has been widely practiced for the last few decades. Recently, cement has become a more economical binder to modify in situ subgrade soil because other binders, such as fly ash, have become less available and therefore their prices have gone up significantly. In addition, a much higher percentage of fly ash needs be used...

Some culverts and pipes installed under roadways several decades ago are reaching the end of their service life. The excavation and replacement of these buried structures will cause disruption to their service and require significant funding. Trenchless methods (e.g., sliplining) have been increasingly used to rehabilitate deteriorated buried struc...

Culverts and pipes installed under roadways several decades ago are reaching the end of their service life. Excavation and replacement of these buried structures will cause disruption to their service and require significant funding. Trenchless methods (e.g., sliplining) have been increasingly used to rehabilitate deteriorated buried structures (e....

The simplified GRC proposed by the writers can be adequately used to describe the progressive development of two-dimensional soil arching with displacement. The simplified GRC requires fewer parameters than the original GRC. The simplified GRC includes three basic (control) points of the original GRC; therefore, the simplified GRC can describe the...

Buried structures, such as pipes and culverts, installed under low embankments, are subjected to surface loading and additional stresses are transferred from their surrounding soil due to negative soil arching. Higher stresses on a buried structure may cause excessive deformations and even failure of the structure. The Induced Trench Installation (...

Buried structures, such as pipes and culverts, are extensively used for transportation applications. The existence of these structures within the soil mass causes a redistribution of stresses. The stiffness of the buried structure relative to the surrounding soil affects the magnitude and distribution of vertical stresses. Higher stresses on a buri...

Soil arching exists in many geotechnical applications, including Geosynthetic-Reinforced Pile-Supported (GRPS) embankments. Soil arching is associated with pressure distribution on and between piles at different levels of differential settlement resulting from the stiffness difference between soil and piles. When GRPS embankments are used for high...

Soil arching is a phenomenon describing stress re-distribution due to relative movement between adjoining portions. It commonly exists when soil interacts with structure elements, for example, tunnels, retaining walls, buried structures, and piles in pile-supported embankments. A yielding or ultimate state of soil (i.e., the shear stress in soil is...

Soil arching is a phenomenon describing stress re-distribution due to relative movement between adjoining portions. It commonly exists when soil interacts with infrastructure, for example, tunnels, retaining walls, buried structures, and pilesupported earth structures. A yielding state of soil (i.e., the shear stress in soil is equal to its shear s...