Application Of Seismic Refraction Survey To Investigation For Tunnel Construction

The seismic refraction method has been widely used in Japan for engineering purposes<br>such as investigations for tunnel and dam construction. The following features of the<br>seismic refraction survey are considered as reasons why it has been widely used.<br>(1) It is feasible to determine subsurface structure (in seismic velocity) with enough<br>resolution and accuracy even though at a site with complex topography and<br>subsurface structure.<br>(2) It is feasible to detect faults and fracture zones where careful design will be required.<br>(3) A lot of data relating with mechanical properties of rock, including seismic velocity,<br>have been gathered and are utilized as database. By using the database, mechanical<br>properties of rock can be evaluated with seismic velocity, so that results of the<br>seismic refraction survey bring useful information for designing and execution<br>management of construction.<br>This paper reviews practical technique of the seismic refraction method that is commonly<br>carried out in Japan, including survey planning, data acquisition technique and analysis<br>technique, necessary for getting reliable results. Also, a case study of the seismic refraction<br>survey with survey line 6.5 km long, carried out to investigate tunnel construction site is presented.