Earthquake may damage structures and facilities, and harm human beings and cause seismic failure phenomenon by ground motion. As they become more concerned about earthquake damage due to the increase of earthquake magnitude and number of earthquake, issue of earthquake proof socially comes to the front. Currently research on the subject is actively carried out by various institutions and academic societies and so on. And as importance of earthquake proof is recognized in construction work, it is being applied to design.
Because soil nailing method much used as stabilizing measures for excavated slope in Korea proved to be effective in terms of economical efficiency, constructability, applicability, and flexibility, and so on, frequency and scope of use increases. However, as design and construction is carried out under the conditions that efficiency for the behavior of integrated nails is not verified, each nail head is independently treated.
At the early stage of applying soil nailing to domestic and foreign excavated slope, most researches on slope stability analysis method, resistance, and failure mechanism for static load was mainly performed, and as importance of earthquake resistant design is socially augmented recently, the researches on resistance and failure mechanism of slope reinforced with soil nail for dynamic load is fully being carried out, However, the researches on slope behavior with respect to the effect of constrained soil nail head is meager, and it is expected that stability problem occurs in case that dynamic load is applied to the slope, and therefore it is necessary to study the characteristics of dynamic behavior of slope according to constrained head of soil nail.
In this study, the tests were carried out about the behavior according to method of constrained nail head of slope reinforced with soil nail under dynamic loading, by using shaking table. Shaking table tests were carried out by applying Hachinohe seismic wave having the long-period characteristics and Ofunato seismic wave having short-period characteristics, as changing constrained and unconstrained condition of nail head, interval between nails, and so on. Failure mode, ground acceleration characteristics, vertical displacement and horizontal displacement of slope were compared and analyzed on the basis of results obtained from the test.
Results of carrying out shaking table test showed that both short-period wave and long-period wave had large effects on slope, and constraint of nail head was found to have large shear resistance for dynamic load. And it was confirmed that stability of slope under seismic loading was largely improved by constrained head of soil nail.