Ali Maroof - Academia.edu (original) (raw)

Papers by Ali Maroof

Acta polytechnica Hungarica, 2024

Ground deformation, due to tunneling, is one of the most significant challenges in tunnel design ... more Ground deformation, due to tunneling, is one of the most significant challenges in tunnel design in soft ground along with, the predicting the related effects of tunneling on nearby structures. One of the methods of predicting ground settlement in tunneling projects, is to use analytical and numerical methods. By measuring the amount of settlement with accurate instruments and back-analysis of behavioral measurement data, in addition to estimating the state of settlement of the ground and surrounding structures, it is possible to determine the geotechnical parameters of the soil and structure in the design of upcoming sections and future designs. In this study, an attempt has been made to verify the measured settlements caused by digging the tunnel of an urban train line, by using back analysis. For this purpose, comparisons with predictions obtained from empirical and analytical methods and the Geotechnical Engineering Finite Element Analysis software (PLAXIS) was used. The results show that often, the empirical methods obtain values more than the measured values, for ground settlement.

Effects of grain morphology on suffusion susceptibility of cohesionless soils

Granular Matter, 2021

Transporting finer fractions inside the soil skeleton or the erosion of base soils within the fil... more Transporting finer fractions inside the soil skeleton or the erosion of base soils within the filter are the two main challenges for earthen hydraulic structures, their foundations, and filter design. Soil particle morphology could influence pore size distribution and transport of fine grains; however, there is not sufficient knowledge on the effect of grain shape on internal erosion. Some experiments designed and conducted in the present study to evaluate the suffusion potential of aggregates with various shapes and different gradations. Particles with six types of grain morphologies and five gradations were collected, and 26 tests were performed. Furthermore, using 3D image processing and visual comparison, particle shape assessed in terms of three features, including sphericity, roundness, and roughness. Results indicated that particle shape influences flow rate, washed-out fine grains in permeameter wall, vertical strain, and mass loss. An increase in the sphericity and roundness causes an increase in the loss of fine grains, pipe in cell sidewall, and vertical strain. Concerning the particle regularity as an indicator of grain morphology, it was demonstrated that the grains with lower regularity are more resistant to suffusion, and thus the resistance to suffusion would decrease with particle regularity. Spherical glass bead and rounded/ medium sphericity specimens were more prone to suffusion at an equivalent or even lower hydraulic gradient than the soil samples with angular/low sphericity grains. Graphic abstract

Effects of particle morphology on the minimum and maximum void ratios of granular materials

Granular Matter, 2022

The minimum and maximum void ratios ( e min and e max , respectively) of soils are intrinsic soil... more The minimum and maximum void ratios ( e min and e max , respectively) of soils are intrinsic soil properties related to their particle size distribution (PSD) and particle shape. Different attempts have been made to predict these reference void ratios for cohesionless soils through the involved particle morphology. However, these predictive models do not handle flaky and elongated particles. Besides, these kinds of models just consider the particle shape throughout a two-dimensional analysis. In this current study, experimental work has been carried out on particles with five different geological and morphological properties and nine different gradations. The particle shape effect involves glass beads, rounded, angular, flaky, and elongated particles to expand both the range of particle sphericity and roundness. A wide range of particle sizes, including uniformly distributed, widely distributed, and upward concave graded soils were chosen. Particle sphericity and roundness were measured by micro CT images and image processing. Furthermore, a comprehensive database was gathered based on past experimental results from the literature. This database was used to derive the predictive equations for determining e min , e max , and the void ratio range ( e max - e min ), considering sphericity, roundness, and uniformity coefficient. The developed new formulas show good agreement with the current and past experimental results.

Advanced Powder Technology, 2020

The specific surface area of soil grains (SSA) influences the physical and chemical properties of... more The specific surface area of soil grains (SSA) influences the physical and chemical properties of soil. 29 Despite the widespread application of the SSA, it is often determined by analytical equations or estimated 30 using empirical relationships and visual comparisons. On the other hand, little attention has been paid, 31 especially to three-dimensional and precise measurements. In this study, the precise SSA and shape coef-32 ficient was measured in a group of aggregate with different sizes and shapes using a novel method. 33 Geometrical properties such as volume and surface area were measured for each particle using X-ray 34 micro-computed tomography (µCT) images and image processing. The particle shape coefficient was 35 obtained from the specific surface area and effective diameter. Further, the particle shapes were mea-36 sured in three distinct characteristics, sphericity, roundness, and roughness. Particle's roundness was 37 measured by Wadell's formula in the plan outline, which did not show an agreement with the shape coef-38 ficient. Nevertheless, as the particle sphericity decreases and roughness increases, the shape coefficient is 39 increased. Hence, the shape coefficient of grains was classified based on the sphericity and the surface 40 roughness. The measured SSA and shape coefficient, for 12 gradations with the three different particle 41 size distribution and four different particle shapes, indicated good agreement with predictive analytical 42 relations for rounded and crushed grains and more dissimilarity for flaky and elongated grains. This novel 43 method can provide the quantitative/qualitative classification for non-spherical particles and also 44 improve our understanding on the properties of granular media. 45

Transportation Geotechnics, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Lecture Notes in Civil Engineering

The soil fabric can be expressed as a network model. Granular media voids connectivity and constr... more The soil fabric can be expressed as a network model. Granular media voids connectivity and constriction size distribution may lead to movement of air, fluids, and solids in the soil, and therefore affect the chemical, physical and mechanical properties of soils. Understanding the soil voids areas and their interconnection might be helpful in understanding different phenomena such as transport in porous media, water retention, fluid flow in the soil, soil contamination, internal erosion, suffusion, and filtration. In addition, specifying the soil voids interconnectivity can help researchers and practical engineers to provide the best rehabilitation and remediation approaches. The pore network was investigated in the current study, assuming the soil particles to be similar to discrete spheres and particles with different shapes. Also, based on the modelling techniques, the profiles of pore connectivity and constriction size distribution were assessed.