Site Soil Classification Interpretation Based on Standard Penetration Test and Shear Wave Velocity Data

Windu Partono (Civil Engineering Department, Engineering Faculty, Diponegoro University, Semarang, 50275)
Muhammad Asrurifak (Faculty of Civil Engineering and Planning, Institut Sains dan Teknologi Nasional, Jl. Moh. Kaffi II, Srenseng Sawah, Jagakarsa, Jakarta Selatan, Indonesia)
Edy Tonnizam (Centre of Tropical Geoengineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Baru, Johor, Malaysia)
Frida Kistiani (Civil Engineering Department, Engineering Faculty, Diponegoro University, Jl. Prof. Soedarto SH., Tembalang, Semarang 50275, Indonesia)
Undayani Cita Sari (Civil Engineering Department, Engineering Faculty, Diponegoro University, Jl. Prof. Soedarto SH., Tembalang, Semarang 50275, Indonesia)
Kukuh Cahya Adi Putra (Civil Engineering Department, Engineering Faculty, Diponegoro University, Jalan Prof. Soedarto SH., Tembalang, Semarang 50275, Indonesia)

Journal of Engineering and Technological Sciences
Vol. 53 No. 2 (2021)

Site soil classification provides vital information for predicting the soil amplification or the site factor. The site factor is important for calculating the surface spectral acceleration in the seismic design of buildings. Based on the Indonesian seismic code, site soil classification can be conducted by calculating the average standard penetration (N-SPT) resistance, the average shear wave velocity (VS) and the average undrained soil strength (Su) of the upper 30 m of a subsoil layer. Different results may be obtained at the same location when the site soil classification is predicted using N-SPT than when using VS data. The restriction of N-SPT values until a maximum of 60 compared to a VS maximum of 750 m/sec can produce different soil classes and will directly impact the calculation of the surface spectral acceleration. This paper describes the different results of site soil classification prediction calculated using the average N-SPT and the average VS, conducted at Semarang City, Indonesia. Site soil classification maps developed based on both datasets are also presented, to evaluate the different site soil classification distributions. Only soil classes SD and SE were observed using N-SPT maximum 60, whereas soil classes SC, SD and SE were observed using N-SPT maximum 120.