Determination of dynamic elastic moduli by integration of geophysical, geotechnical and rock physics diagnostic techniques for construction at Ba Na, Da Nang City, Vietnam

Dynamic elastic moduli are essential for civil engineering for many purposes since it has represented the load capacity of the soil before deformation to failure. To estimate the dynamic moduli such as Bulk moduli, Shear moduli, Young moduli, P-wave acoustic impedance, and Poisson's ratio for construction design at Ba Na, Dang Nang City, Vietnam both compressional (P) and shear (S) wave velocity are acquired and interpreted by integrating seismic refraction data and geotechnical data that has been validated by a useful technique called rock physics diagnostic (RPD). The subsurface profile is well divided into distinguished three weathering layers which characterized by compressional (P) wave velocity and shear (S) wave velocity ranging from 300 to 2900 m/s, 500–1500 m/s, respectively, and the unweathered granitic rock beneath the three weathering layers having P-wave velocity, S-wave velocity up to 3000 m/s and 1500–2500 m/s, respectively. The results found that the northwestern part of the survey area has much higher unweathered solid rock layers than those of the southeastern part, implying the higher moduli could be recognized in the northwest that is potentially suggested as an eligible area for foundation design.