Seismic Refraction and Uphole Logging Based Geophysical Engineering Survey of Rawat Area & Development of Moisture Recording Instrument and Derivation of a Velocity-Moisture Empirical Relation

Abstract

Seismic refraction method is widely used to delineate the Low-Velocity Weathered Layers for computation of Statics corrections that are applied to the main reflection data. In addition it is considered as a valuable tool for near-surface geophysics & engineering, such as delineation of bed rock or basement and determining the engineering properties of ground. The refraction method utilizes the first arrival times of refracted waves propagating along the shallow subsurface layers. Variations in the near surface layers need to be mapped before the construction of any heavy industrial zone or highway. Uphole Logging and Near surface Seismic Refraction based Engineering survey of Rawat area is carried out for construction of heavy Engineering site, to map the near surface layers and estimate their velocities. In addition the near surface data is also used to compute Static corrections that can be applied to seismic reflection data for deep imaging of the Earth. The processing and interpretation of the data is performed on a highly interactive software, K-tron SeiRA along with Visual Oil Scripts and Golden Software Surfer. Weathered layer and Sub-weathered layer velocities are used to calculate Elastic properties for civil Engineering purposes to estimate the strength of Soil/Rock of Study Area. Contour maps of various important parameters; elastic moduli, standard penetration test, soil amplification factor, allowable bearing pressure, soil fundamental period, average horizontal spectral amplification are used for seismic zoning or classification of the study area. As part of thesis work, an Arduino Based Moisture of Enginerring Recording Instrument has been developed which is capable of recording moisture of top soil and it can be used as a useful instrument for Engineering studies