Abstract:

The seismic response acceleration within reinforced slopes directly affects their anti-seismic characteristics and serves as a key parameter in seismic design. Current research on horizontal response acceleration in reinforced slopes primarily focuses on unidirectional seismic action, with limited consideration of bidirectional seismic effects, particularly for multi-tiered reinforced slopes. To address this, two sets of shaking table model tests were conducted on multi-tiered slopes subjected to varying seismic excitations. The results demonstrate that, under bidirectional seismic excitation, the amplification characteristics of horizontal and vertical accelerations differ significantly: the horizontal amplification is more pronounced compared to its vertical counterpart, and the synchronization between accelerations in two directions diminishes with increasing loading amplitude. The phase difference between horizontal response acceleration and input acceleration exhibits a decreasing trend from the slope surface toward the interior, as well as from the crest to the base, with the maximum phase difference under bidirectional seismic excitations being approximately double that observed under unidirectional conditions. The horizontal acceleration amplification factor exhibits higher values under bidirectional seismic excitation compared to unidirectional excitation, particularly within the third-tier reinforced slope when the input acceleration surpasses 0.4g. The pseudo-static method can effectively predict design values of horizontal response acceleration under different seismic directions, but it underestimates the acting height of the horizontal response acceleration.

Key words: seismic design, multi-tiered reinforced slopes, acceleration, shaking table model test, phase difference, amplification factor