Matin Jalali Moghadam

Bio: Matin Jalali Moghadam is an academic researcher from Islamic Azad University Central Tehran Branch. The author has contributed to research in topics: Train & Retaining wall. The author has an hindex of 2, co-authored 5 publications receiving 27 citations. Previous affiliations of Matin Jalali Moghadam include Islamic Azad University.

Experimental evaluation of mechanically stabilized earth walls with recycled crumb rubbers

Abstract: Traditional techniques for treatment of waste rubber, such as burning, generate some highly non-degradable synthetic materials that cause unrepairable environmental damages by releasing heavy metals, such as arsenic, chromium, lead, manganese and nickel. For this, scrap tires are used as lightweight alternative materials in many engineering applications, such as retaining wall backfilling. In the present study, 90 laboratory models were prepared to evaluate the stability of mechanically stabilized earth (MSE) walls with plate anchors. Then, the bearing capacity and horizontal displacements of the retaining walls were monitored by exerting a static loading to investigate the effects of adding different contents (5 wt%, 10 wt%, 15 wt% and 20 wt%) of recycled crumb rubber (RCR) to the fill of a mechanically stabilized retaining wall with plate anchors. To visualize the critical slip surface of the wall, the particle image velocimetry (PIV) technique was employed. Results showed that the circular anchor plates almost continually provided a higher bearing capacity and wall stability than the square plates. Moreover, the backfill with 15 wt% RCR provided the maximum bearing capacity of the wall. Increasing the weight percentage of RCR to 20 wt% resulted in a significant reduction in horizontal displacement of the wall, which occurred due to the decrease in lateral earth pressure against the whole walls. An increase in RCR content resulted in the decrease in the formation of failure wedge and the expansion of the wall slip surface, and the failure wedge did not form in the sand mixtures with 15 wt% and 20 wt% RCRs.

Experimental study on the performance of plate anchor retaining walls

Abstract: Plate anchors are one the most important retaining objects that are widely used in onshore and offshore structures. This study was conducted to evaluate the performance of plate anchor retaining wa...

Numerical Analysis of Railways on Soft Soil Under Various Train Speeds

Abstract: Instability and settlement of railways constructed on soft soils are among the main concerns of railway engineers. These settlements reduce the quality of the railway and its facilities and lead to financial and life losses. Therefore, several studies have shown the importance of safety in railways constructed over soft ground due to large vibrations caused by high-speed trains, especially under critical speeds. The present study was conducted to investigate the performance of railways on soft soil and the effect of its improvement using geogrid reinforcement layer in the embankment-bed contact. For this purpose, a numerical model was developed in the finite element PLAXIS software ver. 8.6 to investigate the effect of 4 train speeds (20, 80, 140, and 200 km/h) and 5 heights of the embankment (1 to 5 m) on mobilized loads on geogrid, lateral displacement of the embankment, the safety factor of the whole track, and failure surface beneath the track. The results of this study revealed that in loose beds, a large dynamic amplification occurs in ground dynamic response as the train speed reaches a critical speed which was determined in the range of 20 to 80 km/h and found that the maximum mobilized load in geogrid occurs in this speed range.

Introducing expandable mechanical plate anchors for onshore and offshore anchoring

Abstract: Soil anchors are among the most widely used reinforcements to stabilize unstable soil mass or stabilize and anchor structures built in onshore and offshore regions. Anchors are generally installed ...

Theory of cross-correlation analysis of PIV images : Image analysis as measuring technique in flows

Abstract: To improve the performance of particle image velocimetry in measuring instantaneous velocity fields, direct cross-correlation of image fields can be used in place of auto-correlation methods of interrogation of double- or multiple-exposure recordings. With improved speed of photographic recording and increased resolution of video array detectors, cross-correlation methods of interrogation of successive single-exposure frames can be used to measure the separation of pairs of particle images between successive frames. By knowing the extent of image shifting used in a multiple-exposure and by a priori knowledge of the mean flow-field, the cross-correlation of different sized interrogation spots with known separation can be optimized in terms of spatial resolution, detection rate, accuracy and reliability.

Study of Active Earth Pressure behind a Vertical Retaining Wall Subjected to Rotation about the Base

Abstract: Retaining structures are often restrained in the case of cantilever in situ embedded walls, anchor, strutted, and bridge abutments and thus are subjected to rotation. The earth pressure dis...

Numerical Analysis of the Interference of Two Active Machine Foundations

Abstract: This study examines the influence of the interference on the dynamic response of two active machine foundations using the finite element analysis. The finite element model has been built carefully to ensure that the finite element model extend, and the mesh size do not influence the obtained results. Furthermore, the methodology of the finite element analysis has been verified using well-known and robust analytical solutions of wave propagation and machine vibration. Loose sand, medium sand, and dense sand and a vibration frequency range of 0.5–20.0 Hz have been considered in the analyses. The results showed that the interference of two active machine foundations remarkably increases the dynamic settlement with a percentage increase range from 1 to 77%. This percentage increase declines as the frequency of vibration or the distance between the foundations increases and rises as the soil stiffness increases. It was also found that the critical distance after which the interference effect terminates depends on the frequency of vibration and the stiffness of the soil, where the critical distance increases as the frequency of vibration declines or as the stiffness of the soil increases. Finally, a methodology has been proposed based on the results of the analyses to implicate the effect of interference in the calculation of the dynamic settlement.

Failure and Deformation Mechanisms of Vertical Plate Anchors Subjected to Lateral Loading in Sand

Abstract: This paper presents an experimental study on the pullout behavior of a vertical plate anchor buried in sand under lateral loading, using the digital image correlation (DIC) technique. Base...

Determination of active failure surface geometry for cohesionless backfills

Abstract: The extent by which economy and safety concerns can be addressed in earth retaining structure design depends on the accuracy of the assumed failure surface. Accordingly, this study attempts to investigate and quantify mechanical backfill properties that control failure surface geometry of cohesionless backfills at the active state for translational mode of wall movements. For this purpose, a small scale 1 g physical model study was conducted. The experimental setup simulated the conditions of a backfill behind a laterally translating vertical retaining wall in plane strain conditions. To monitor the influence of dilative behavior on failure surface geometry, model tests were conducted on backfills with different densities corresponding to different dilation angles. Failure surface geometries were identified using particle image velocimetry (PIV) method. Friction and dilation angles of the backfill are calculated as functions of failure stress state and relative density of the backfill using a well-known empirical equation, making it possible to quantify the influence of dilation angle on failure surface geometry. As a result, an empirical equation is proposed to predict active failure surface geometry for cohesionless backfills based on peak dilatancy angle. It is shown that the failure surface geometries calculated using the proposed equation are in good agreement with the identified failure surfaces.