The biocemented coral sand pile composite foundation represents an innovative foundation improvement technology, utilizing Microbially Induced Carbonate Precipitation (MICP) to consolidate a specific volume of coral sand within the foundation into piles with defined strength, thereby enabling them to collaboratively bear external loads with the surrounding unconsolidated coral sand. In this study, a series of shaking table model tests were conducted to explore the dynamic response of the biocemented coral sand pile composite foundation under varying seismic wave types and peak accelerations. The surface macroscopic phenomena, excess pore water pressure ratio, acceleration response, and vertical settlement were measured and analysed in detail. Test results show that seismic wave types play a decisive role in the macroscopic surface phenomena and the response of the excess pore water pressure ratio. The cumulative settlement of the upper structure under the action of Taft waves was about 1.5 times that of El Centro waves and Kobe waves. The most pronounced liquefaction phenomena were recorded under the Taft wave, followed by the El Centro wave, and subsequently the Kobe wave. An observed positive correlation was established between the liquefaction phenomenon and the Aristotelian intensity of the seismic waves. However, variations in seismic wave types exerted minimal influence on the acceleration amplification factor of the coral sand foundation. Analysis of the acceleration amplification factor revealed a triphasic pattern-initially increasing, subsequently decreasing, and finally increasing again-as burial depth increased, in relation to the peak value of the input acceleration. This study confirms that the biocemented coral sand pile composite foundation can effectively enhance the liquefaction resistance of coral sand foundations.

Planning embankments demands comprehensive studies to select suitable materials, enhance soil stability, ensure optimal performance, and comply with building code requirements and sustainability standards. This study offers an evaluation of various alternatives and their effectiveness for constructing embankments on weak soil using the 2D finite element software Plaxis 8. It highlights the convergence of different techniques, offering flexibility in selecting the optimal strategy for projects. The behaviour of multilayer clayey soil under an embankment of lightweight filling materials such as mixed sawdust or geo-foam and that carrying an embankment of traditional fill material improved by deep replacement techniques like concrete piles (CP), deep-mixing columns (DMC), stone columns (SC), and sand piles (SP) were compared considering factors like stress distribution, pore water pressure, and settlement of the soil. The results demonstrate that lightweight materials reduced settlement by 11-98% and stress by 5-89%, while deep replacement techniques reduced settlement by 8.5-75% and stress by 44-88%. Notably, the study underscores the effectiveness of DMC in promoting soil reuse compared to CP.