Analysis of the traffic load–induced stresses of embankment

This article represents traffic loads on the road structure distribution and evaluation of the vertical and horizontal stresses formation in the soil embankment. This evaluation allows to predict the depth and intensity of the propagation of additional stresses resulting from traffic loads. The calculations were performed in accordance with four normative documents applied in Lithuania, which define the loads on the road structure. The obtained results showed that the area to which the load is distributed has the greatest influence on the intensity of stresses and the distance of propagation. The maximum horizontal stress in the embankment was found to be no more than 70 kPa and the maximum stress propagation depth did not exceed 0.9 m. The results can be applied to a triaxial test apparatus to restore horizontal stresses in the embankment. It is recommended to select a lateral pressure from 20 kPa to 70 kPa for tests provided with triaxial test device. The mechanical properties of the soil determined with triaxial test device and recommended lateral pressure would be representative of the test results obtained in the field of embankment. Article in Lithuanian. Grunto sankasos, veikiamos automobilių kelių apkrovomis, įtempių analizė Santrauka Straipsnyje yra apžvelgiamos kelio konstrukcijai tenkančios automobilių apkrovos ir apskaičiuoti vertikalūs ir horizontalūs įtempiai, atsirandantys grunto sankasose. Šie skaičiavimai leidžia prognozuoti nuo automobilių apkrovų atsirandančių papildomų įtempių sklidimo gylį bei intensyvumą. Skaičiavimai atlikti pagal keturis Lietuvoje galiojančius norminius dokumentus, kurie apibrėžia kelio konstrukcijai tenkančias apkrovas. Gauti rezultatai parodė, kad didžiausią įtaką įtempių intensyvumui ir sklidimo atstumui turi plotas, į kurį išskirstyta apkrova. Nustatyta, kad didžiausias horizontalus įtempis, tenkantis grunto sankasai, yra ne didesnis nei 70 kPa, o didžiausias įtempių sklidimo atstumas neviršija 0,9 m. Rezultatus galima pritaikyti atliekant statinius grunto bandymus su triašio slėgio aparatu, kada norima atkurti horizontalius sankasoje vyraujančius įtempius. Rekomenduojama šoninį slėgį parinkti nuo 20 kPa iki 70 kPa. Su šiuo šoniniu slėgiu nustatytos grunto mechaninės savybės būtų reprezentatyvios, taikant gautus bandymų rezultatus sankasų projektavimo srityje. Reikšminiai žodžiai: įtempių analizė, apkrovų parinkimas, grunto sankasa, automobilių keliai, vertikalūs įtempiai, horizontalūs įtempiai

The Effects of Mineral Wool Fly Ash on Cohesive Soil Strength Behaviour

This research work represents updated results of cohesive soil strength improvement with mineral wool fly ash. In the investigations, these materials were used: Portland cement CEM I 42.5 R, fly ash obtained from a mineral wool production process, sand and clay. Mixtures were prepared as follows: dry mixing of Portland cement and fly ash; dry mixing of sand and clay; adding water into Portland cement and fly ash; adding sand and clay mixture into already prepared Portland cement and fly ash suspension. The content of fly ash replacing Portland cement varied from 0% to 40%, and the content of sand mixture varied from 20% to 60%. After 24 hours, investigated samples were taken out from cylinder forms and kept in a desiccator with a humidity of 90% and at 20 °C temperature. Uniaxial compressive strength of the samples was determined after 548 days and compared to previous research results obtained after 7, 28 and 183 days. The most predictable compressive strength is for samples, which composition is 100% cement and 0% fly ash. In these samples, the highest compressive strength was obtained, comparing them to the other investigated samples. Compressive strength change is minimal for samples with a 10–30% amount of fly ash. The most significant decrease in compressive strength was obtained for samples with a 40% fly ash after 183 days. Nonetheless, the compressive strength of these samples increased after 548 days and is almost the same as for samples with 100% Portland cement

Stabilization of clay powder with mineral wool fly ash

The aim of this article – to determine short term and long term strengthening of clay soil, by strengthening it with fly ash obtained during the production of mineral wool. This article introduces research which is used to determine the optimal ratio of fly ash in cement suspension for strengthening of clay soil. Samples which were investigated in this research work prepared by mixing Portland cement, mineral wool fly ash, clay powder, sand and water. All investigated samples compressive strength after 6 months exceeded 1.7 MPa. It is enough of such strength in geotechnics to conduct strengthening of soil and it is possible to argue that soil is strengthened. First published online 13 February 202

Proceedings of The HKIE Geotechnical Division 42nd Annual Seminar: A New Era of Metropolis and Infrastructure Developments in Hong Kong, Challenges and Opportunities to Geotechnical Engineering

This seminar proceedings contain articles on the various research ideas of the academic community and practitioners presented at The HKIE Geotechnical Division 42nd Annual Seminar (GDAS2022). GDAS2022 was organized by the Geotechnical Division, The Hong Kong Institution of Engineers on 13th May 2022. Seminar Title: The HKIE Geotechnical Division 42nd Annual SeminarSeminar Acronym: GDAS2022Seminar Date: 13 May 2022Seminar Location:  Hong KongSeminar Organizers: Geotechnical Division, The Hong Kong Institution of Engineers Link to the GDAS2021 Proceedings: Proceedings of The HKIE Geotechnical Division 41st Annual Semina