UROP Proceedings 2020-21

School of Engineering Department of Civil and Environmental Engineering 90 Engineering Properties of Soil Amended by Hydrochar, a New Resource Derived from Food Wastes Supervisor: LEUNG Anthony / CIVL Student: LEUNG Chun Yu / CIVL Course: UROP1000, Summer Geotechnical engineering is primarily concerned with determining the strength and deformation characteristics of soil. In geotechnics, clay, silt, sand, rock, and snow are essential materials. Soil and rock mechanics, geophysics, hydrogeology, and related sciences such as geology are all part of geotechnical engineering. Civil engineering includes geotechnical engineering and engineering geology. While soil mechanics is one of the aspects we have got in touch with frequently, especially in Hong Kong. With mountainous terrain, it is common to see different natural and man-made slope in the city. These slopes need to be maintained in order to keep its stability and ecological value. Recently, engineers are trying to develop a mixture of soil and hydrochar to improve soil property. In this project, the soil behaviours mixed with coffee grounds and biochar burnt from coffee ground were investigated through a series of direct-shear tests. Engineering Properties of Soil Amended by Hydrochar, a New Resource Derived from Food Wastes Supervisor: LEUNG Anthony / CIVL Student: MAK Cheuk Yiu / IPO Course: UROP1000, Summer Hydrochar is a product of the hydrothermal carbonization of biomass, which is obtained in the form of slurry, a mixture of liquid and solid. It could be produced with either dry or wet biomass, with water added during the hydrothermal carbonization process. This project considers the effects on geomechanical properties when hydrochar derived from coffee ground is mixed into completely decomposed granite soil (CDG), as soil amendment is known to be an important application of hydrochar. Apart from the hydrochar, similar experiments were carried out with its feedstock. This project compares their effects on soil shear strength, which appeared to be rather diverse in terms of soil cohesion and friction angle. Engineering Properties of Soil Amended by Hydrochar, a New Resource Derived from Food Wastes Supervisor: LEUNG Anthony / CIVL Student: WONG Tsz Fung / SENG Course: UROP1000, Summer Geotechnical engineering is one of the civil engineering disciplines that involves detailed investigation in the behaviour of soil and rock, design of geotechnics work like slope stability, foundation piling, material testing, risk assessments of mass movement hazards. Coping into our urban living, the coexistence of both the concrete and natural jungles all around proves the significance of geotechnical engineering, and its value to the development of infrastructure construction and the community safety. To better enhance our living standards and safety, engineers are developing a mixture of soil and ameliorated materials - biochar, to improve soil property. In this project, the shear strength of soil was measured by comparing the behaviour of coffee grounds and its derived hydrochar in saturated conditions through a series of direct-shear tests.

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