CORRELATION BETWEEN N-SPT, VP, VS AND ELASTIC MODULUS BASED ON GEOTECHNICAL AND GEOPHYSICAL SURVEY FOR YOGYAKARTA - BAWEN TUNNEL

• Main Author: Dwi Nurcahyo, Wahyu
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/77161
• Institution: Institut Teknologi Bandung

Tunnels are a cheap means of transportation because they have a gentler slope, relatively cheaper development cost, and shorter mileage than surface transportation. Shear wave velocity (Vs), compressional wave velocity (Vp) and elastic modulus is an important parameter for tunnel design before tunnel construction is carried out. Unfortunately, determining in situ shear wave velocity for large areas is expensive and takes along time. To overcome these problems, a correlation between the standard penetration test (N-SPT), Vp, Vs and elastic modulus. N-SPT data were obtained from a total of 41 boreholes ranging from 40 to 85 m in depth. Seismic downhole and seismic refraction were carried out to obtain Vp and Vs data. Pressuremeter test was carried out to obtain elastic modulus in-situ. The correlation between N-SPI ana Vp, Vs and elastic modulus in this study has coefficient of determination (R2) value of 0.901, 0.878 and 0.693 respectively. Comparison between measured and predicted data, normal consistency ratio and scaled error percent graph were used to evaluate the performance of this study correlation. Normal consistency ratio maximum of 12, 25 and 2 for Vp, Vs and elastic modulus correlation respectively and more than 9096 Vp and Vs data has less than 1099 error, but there is only 3529 elastic modulus data has less than 1020 error. Correlation between N-SPT and Vp and Vs can be used as a predictor to estimate Vp and Vs value for initial design.