In order to maintain the current standard of living without deteriorating the global environment, it is necessary to develop and spread the effective power generation methods using clean energy. Rational ground reinforcement is necessary to minimize the ground damage caused by frequent natural disasters such as earthquakes. It is important to actively reuse the construction waste material for reducing the economic cost of civil works. In this study, one of the useful tools for constructing and maintaining a recycling-oriented society is considered. First, a concept of the total system to perform both ground reinforcement and electric power generation using the recycled asphalt pavement material and newly prepared T-shaped unit is proposed. The T-shaped unit that is referred as a PG unit in this study mounts the electric circuit with Peltier device. A series of the field monitoring for electric power generation and the laboratory test for the mechanical properties of protected ground are conducted for discussing the feasibility of the proposed total system. The results of the field monitoring show that the newly prepared PG unit can generate the electric power by using the temperature on the ground surface. In the laboratory test, it is also confirmed that the bearing capacity of the ground can be improved by using recycled asphalt pavement material and PG unit waste. The both results of field monitoring and laboratory test imply that the proposed total system can be realized.

Natural gas hydrate is an important resource in the future. To get this resource safely and sustainably, the shear rate-dependent behaviors of Toyoura sand with and without hydrate have been studied with a plane strain shear test. By analysis of picture information and PTV technology, it was found that: increasing the shear rate did not significantly change the angle of the hydrate-bearing sediment samples, but it delayed the appearance of the shear band. The large local maximum shear strain of the Toyoura sand with hydrate was more concentrated in the shear band and local volume expansion was more significant with the increase of the shear rate.

In geotechnical engineering, thermal energy storage in embankments can be considered as a new economically efficient, and environmentally friendly structure for space heating. In these structures, horizontal heat exchanger tubes can be installed inside the different layers of compacted soil to store the heat in the medium during the summer, to be extracted in the winter. Seasonally temperature variations caused by heat exchangers can affect Thermo-Hydro-Mechanical (THM) properties of the compacted soil in the embankment. Both the short and long term behavior of this compacted soil should be investigated. The aim of this study was to investigate the effect of temperature variations in the range of 5° to 50 °C, on THM behavior of a compacted sandy lean clay in saturated state. To achieve this, temperature-controlled œdometric and direct shear tests were performed. The results showed that, the effect of the temperature on mechanical properties are more pronounced under a vertical stress higher than the preconsolidation pressure. Heating changed the void ratio during consolidation phase but has a negligible effect on the shear characteristics. The results also showed that the cooling slightly changed the shear parameters.

In this study, a two-dimensional finite difference model was used to simulate the heat transfer occurred during a 17-day heat extraction test performed in an MSW landfill cell in Santee, California. The heat extraction was performed using serpentine horizontal heat exchangers installed 6 m above the base liner of the cell, and it started after the waste reached a stable temperature value of 52 °C. The model was developed based on the differential heat conduction equation and an inverse analysis was performed to estimate the thermal diffusivity of the waste. The values of in-situ thermal diffusivity obtained ranged from 7.85 × 10-7 m2/s to 1.05 × 10-6 m2/s and are consistent with the higher range of values presented in the literature for MSW.