ESTIMATION OF NON-FLAT SUB-SURFACE STRUCTURE BY USING SOME GEOPHYSICAL EXPLORATIONS AND ITS APPLICATION TO SEISMIC DESIGN

Abstract

  In seismic design for railway structures, it is essential to evaluate the effects of the subsurface structure appropriately. In order to estimate the ground structure, the boring investigation is mainly used. The boring investigation, however, may be difficult in case of certain circumstances, such as the soft ground condition, the deep engineering bedrock, the space condition for investigation and so on. In such cases, it is necessary to estimate the ground structure using other estimation methods. In this report, the authors presented another estimation method using microtremor and gravity survey. Moreover, we clarified the importance of structure estimation by calculating the ground motions based on the estimated subsurface structure.