Abstract:

Aiming at the special landform, near surface conditions and subsurface objects in loess districts of western China, the authors studied detecting applications of the seismic techniques. To examine the efficiency of different seismic methods, a comprehensive geological model was designed. This model included some typical defects such as sag, fault, ground fissure, hidden low velocity body, weak intercalated layer and landslide. Multi-component seismic reflections and surface wave records were numerically computed with the finite difference method. Reflection imaging and high order surface wave imaging were acquired respectively. The results of numerical modeling proved that all the typical defects models such as sag, fault, ground fissure, hidden low velocity body, weak intercalated layer and landslide were imaged clearly. The numerical modeling results indicated the feasibility of shallow geological defects detection under roadbed by seismic methods.

Key words: roadbed, geological defects, reflection seismic, surface wave seismic