Dynamic performance of root-reinforced slopes by centrifuge modeling tests

Abstract

Slope instability is a major problem in geotechnical engineering and can cause catastrophic failure and the loss of human lives. Generally, slope instability can be induced by either internal or external factors. An earthquake is one such external factor, as was demonstrated during the Chi-Chi earthquake in 1999 and the Kumamoto earthquake in 2016. There has been considerable development of slope protection for reducing slope instability susceptibility, and currently, more attention is being given to ecological protection. It is hoped that green engineering can replace environmentally unfriendly and unfeasible slope stabilization methods. Therefore, a series of centrifuge modeling tests was conducted to evaluate the performance of a root-reinforced slope under gravity and dynamic conditions. The test results show that the fibrous root system is more suitable for sandy soil slope reinforcement than the taproot system under gravity and a small base input motion (PBA ≒ 0.15 g, intensity VI on the MMI scale). The fibrous root system, on average, had a 32% higher critical height, 61% smaller sliding area ratio, 36% lower depletion volume of soil mass, 49% lower accumulation volume of soil mass, and 5.5% higher yield acceleration under both conditions in comparison to the taproot system. However, both reinforcement systems are susceptible to failure under large input motion (PBA ≒ 0.30 g, intensity VII on the MMI scale) cases but provide better stability for the toe area than the unreinforced soil counterpart, as shown by depletion and accumulation in soil volume and by higher yield acceleration.

Appendix

Table 6 Variability of the root system structure

Fig. 17

Accelerometer responses: a accelerometer responses under small base input motion (PBA ≒ 0.15 g) and b accelerometer responses under large base input motion (PBA ≒ 0.30 g)