Environmental Assessment Methods for Dissolution of Soil

Water plays a crucial role in the environment and in the process of liquefaction, which can occur during moderate to major earthquakes and cause significant structural damage. Liquefaction is defined as the transformation of granular material from a solid state to a liquid state, a process driven by increased pore water pressure and reduced effective stress within the soil. When an earthquake strikes, the shaking causes the pore water pressure between the sand grains to rise, which in turn reduces the contact forces between the grains. As a result, the sand loses its effective shear strength and starts to behave more like a fluid, leading to instability and potential collapse of structures built on such ground. Liquefaction can occur in moderate to major earthquakes, resulting in severe damage to structures. The transformation of granular material from a solid state to a liquid state due to increased pore pressure and reduced effective stress is defined as liquefaction. When this happens, the sand grains lose their effective shear strength and will behave more like a fluid. This phenomenon of dissolution of soil damages trees’ stability and disturbs the formation of the earth’s surface. Liquefaction resistance of soil depends on the initial state of soil to the state corresponding to failure. The liquefaction resistance can be evaluated based on tests on laboratory and in situ tests. For this research, liquefaction resistance using in-field tests based on SPT N values is attempted. Cyclic resistance ratio (CRR) is found based on the corrected N value. About 16 bore logs have been selected for the factor of safety calculation. The factor of safety for soil was arrived at by taking into account of corresponding corrected SPT N values. The liquefaction hazard map is prepared for the moment magnitude of 7.5-7.6 M w. It is also found that the areas close to water bodies and streams have the factor of safety less than unity. The bore log of locations having a factor of safety less than one indicates that up to a depth of about 6 m, very loose silty sand with clay and sand is present, which are defined as medium to fine sand having low field N values.