The current study focuses on the long term strength reduction in lime stabilised Cochin marine clays with sulphate content. By introducing 6% lime and 4% sulphates to untreated Cochin marine clay, the research aims to investigate the effect of sulphates in these clays. Unconfined compression tests were conducted on lime treated clay both with and without additives, immediately after preparation and over 1 week, 1 month, 3 months, 6 months, 1 year and 2 years of curing. Test results indicated that both sodium sulphate and lithium sulphate has a negative impact on the strength gain of lime stabilised clay. To address this issue, Barium hydroxide, in both its pure laboratory form and the commercial product known as baryta, was incorporated into the lime stabilised soil. The study showed a consistent increase in shear strength with the addition of both barium hydroxide and baryta. When twice the predetermined quantity of baryta was added to lime stabilised clay, it outperformed pure barium hydroxide in terms of strength enhancement. Results of SEM and XRD analysis align with the strength characteristics. The cost-effective use of baryta offers a practical solution to counteract strength loss in lime stabilised, sulphate bearing Cochin marine clays.

The investigation of river levees holds significant implications for mitigating flood damage. Sand boiling, backward erosion piping, and phenomena manifesting along the riverside of levees directly imperil the integrity of these structures. It is imperative to address these phenomena comprehensively to safeguard both lives and property amidst flood events. The principal aim of this research is to delineate the variances in geotechnical conditions between sand boils observed at slope toes on the landside and those occurring at a distance from this region along the levee. Therefore, this study conducted extensive boring investigations at sites where sand boils occurred. The soil samples sampled from the boring investigations were analysed for grain size. The results of a series of geotechnical investigations showed that in the cases where sand boils occurred near the toe of the slope, a series of sandy soils with grain size characteristics similar to those of the sand boils were deposited in the foundation of the levee. On the other hand, in the case where the sand boil occurred far from the toe of the slope, sandy soil with grain size characteristics similar to that of the sand boil was deposited only on the landside.

Soil-rubber mixtures have been proposed as cost-effective seismic and dynamic risk mitigation techniques. The granulated rubber used for these mixtures is obtained from end-of-life tires, allowing for stockpiles of waste rubber tires to be recycled. To date, most of the research has focused on the mechanical properties of sand-rubber mixtures, while limited studies have been performed on gravel-rubber mixtures (GRMs). In particular, GRMs with well-graded gravel (wgGRMs), which are of significant practical interest due to their availability, have only been poorly characterised. As part of a wider investigation aimed at facilitating the use of wgGRMs as geotechnical dynamic isolation systems, this paper presents bender element and small-strain cyclic triaxial test results performed on mixtures with 25%, 40%, and 55% volumetric rubber content. It is found that, thanks to their excellent energy absorption properties, wgGRMs can be efficiently adopted as geotechnical dynamic isolation to mitigate seismic risk of and anthropically induced vibrations on existing and new structures/infrastructures. Their easy implementation, low-cost, and widespread availability further facilitate their use.

Earthquake-induced liquefaction is a prominent and impactful natural hazard responsible for substantial economic losses worldwide. Hence, engineers and researchers are currently interested in developing methods and techniques to mitigate this destructive phenomenon. Reducing the degree of saturation is a reliable method to improve the liquefaction resistance of sandy soils since it directly influences the pore pressure build-up during seismic action. This paper reviews the mechanisms and assessment of earthquake-induced liquefaction in sandy soils with various degrees of saturation, a crucial parameter for reducing the phenomenon triggering. In addition, it presents novel approaches that delve into interpreting cyclic behaviour with diverse degrees of saturation using stress-based and energy-based approaches. The experimental results compiled and discussed show that, effectively, reducing the degree of saturation holds promise as a viable strategy for enhancing soil liquefaction resistance and mitigating associated risks. Moreover, the interpretation of cyclic behaviour addressed in this paper offers valuable insights into the reliability of interpreting methods to quantify the liquefaction resistance under several degrees of saturation (that may be achieved by desaturation or induced partial saturation techniques), contributing to strategies for resilience against earthquake-induced damages.