Buried pipes are subjected to static and dynamic loads depending on their areas of use. To mitigate the risk of damage caused by these effects, various materials and reinforcement methods are utilized. In this study, five buried uPVC pipes designed in accordance with ASTM D2321 standards were reinforced with three different ground improvement materials: Geocell, Geonet, and Geocomposite, and experimentally subjected to dynamic impact loading. Acceleration, velocity, and displacement values were obtained from the experiments. Subsequently, finite element analysis (FEA) was performed using the ABAQUS software to determine stress values and volumetric displacements in the pipes, and the model was validated with a 5-7% error margin. In the final stage of the study, a parametric analysis was conducted by modifying the soil cover height above the pipe and the Geocell thickness in the validated finite element model. The parametric study revealed that the displacement value in the pipe decreased by 78% with an increase in soil cover height, while a 16% reduction was observed with an increase in Geocell thickness. The results demonstrate that the soil improvement techniques examined in this study provide an effective solution for enhancing the impact resistance of buried pipeline systems.

The objective of the present study is to evaluate the performance of a levee when subjected to flooding and subsequent seepage through centrifuge model tests. For this, six centrifuge model tests were conducted on a 240 mm high levee model at 30g in a 4.5 m radius large beam geotechnical centrifuge available at the Indian Institute of Technology Bombay, India. A custom-developed flooding simulator is employed to induce identical flood rates on the upstream side of the levee models. Further, using (a) geocomposite (GC) and (b) sand-sandwiched geocomposite (SSGC) as internal chimney drain, the suitability of GC material for dissipation of pore-water pressure (PWP) is also studied. The results of the centrifuge tests are presented and discussed in terms of the development of upstream flood function, subsequent PWP development within the levee body, and the surface settlements observed at the levee's crest. Further, the influence of an internal chimney drain, the material used for its construction, and its type and composition on the seepage response of the levee is discussed in detail. The performance GC chimney drain placed within the levee subjected to flooding-induced seepage is compared with a conventional sand chimney drain. It is observed that a GC-based chimney drain with sand cushioning on both sides in the horizontal portion of the chimney drain performs well. Further, digital image analysis of SEM micrographs of exhumed GC after centrifuge tests and the analyzed PWP data during sustained flooding-induced seepage is found to corroborate well.

The expansive/reactive subgrade issue has been prevalent in pavement construction throughout Australia, with an estimated 30% of the country's land surface covered by expansive soil. The shrink-swell problem caused by subgrade movement poses a significant challenge, damaging constructed pavements. Various approaches have been implemented to address this issue, mitigate the detrimental effects, and combat the damage caused by expansive soil. A minimum non-reactive or stabilised cover depth is recommended for low to moderately reactive subgrades. However, in the case of highly reactive subgrades, Austroads and state road agencies advise conducting a comprehensive geotechnical assessment to explore alternative solutions. This article evaluates the potential of geogrid and geotextile in resisting movement caused by reactive soil and assesses their effectiveness in minimising pavement damage. Three road sections were constructed using different configurations. One road utilised only geogrid, another combined geogrid and geotextile, while the control had no geogrid or geotextile. The geogrid and geotextile were placed over the expansive subgrade. The design traffic, subgrade CBR (California Bearing Ratio), and reactivity index of the subgrade were consistent across all three road sections to evaluate the performance of pavement configurations. Similar road sections were constructed on three different reactive soils in Adelaide. Over a period of time, road performance surveys were conducted following the guidelines provided by Austroads. The findings revealed that both the geogrid and the geogrid with geotextile outperformed the control in all three locations. This indicates that the inclusion of geogrid and geotextile significantly improved the performance and durability of the road sections constructed on reactive soils.

A self -sensing cementitious geocomposite was developed based on laboratory data, and it demonstrated good physical and mechanical properties, durability, and piezoresistivity performance. It consisted of stabilized cemented sand containing multiwalled carbon nanotubes (MWCNTs) with graphene nanoplatelets (GNPs) as conductive fillers. This geocomposite could be used to detect damage based on the relationship between electrical impedance and mechanical performance, making it suitable for use as structural layers in railway lines. In this study, the effects of MWCNTs and GNPs, as well as of degree of saturation, were evaluated on the compaction, secant modulus, resilient modulus, electrical resistance, and piezoresistivity of the geocomposite. Scanning electron microscopy (SEM) and microscopic imaging were used to analyse microstructural alterations induced by varying concentrations of MWCNTs and GNPs. This innovative geocomposite, intended for installation in Portuguese railway lines as part of the EU project IN2TRACK3, is aimed at capturing performance data, identifying structural damage levels, and estimating load intensity, axle numbers, and train speed. The feasibility of its use is discussed based on literature studies and research conducted under the IN2TRACK2 and IN2TRACK3 projects, and its potential advantages over traditional methods for monitoring rail track health are highlighted.