| dc.description.abstract | Landslides are a catastrophic event that often occurs in the world. Landslides can be induced by several factors, including geological factors, hydrological factors, and human intervention. Root reinforcement is an effective and useful solution to increase slope stability. The root-reinforcement system on the slope has several benefits: reducing evaporation, increasing soil suction by root uptake and transpiration, mechanical reinforcement by roots, erosion control, and restrain caused by the interaction between the roots system and the surrounding soil.
A series of centrifuge tests have been performed using National Central University geotechnical centrifuge research facilities to evaluate the impact of static and dynamic conditions on the stability of the root-reinforced slope and evaluate the different types of roots and their distribution to the slope failure mechanism. Wheatgrass, red bean, and sunflower are selected in this research based on the type of soil, environment, and the type of root system. A 45 degrees slope with 200 mm in height is modeled in this study. The slope is made out of 50% dry relative density, which corresponds to 14.95 kN/m3 of unit weight and mixed with 10% water content. These plants were only grown on the slope face with seven days of growing time.
From this research, it can be concluded that (1) the root-reinforcement system in the soil will reduce the soil’s permeability and insignificantly enhance the shear strength of the soil. In this study, cohesion is increased by about 3 kPa, and friction angle is increased by about 4 degrees, (2) the root-reinforcement system effectively improves slope stability which is shown by the higher critical slope height compared to the bare soil model. The fibrous root type is the most effective root system to improve sandy slope stability, (3) the fibrous root type also effectively stabilizes the sandy slope when subjected to dynamic conditions (PBA ≒ 0.15g) because the vegetation’s roots spread to a deeper layer and interconnect with other roots. In this condition, the fibrous root type can reduce the sliding area by about 30%, (4) the root reinforcement on the slope can prevent large horizontal movement after the dynamic condition (PBA ≒ 0.30g). This was proven by the smaller normalized horizontal movement of depletion and accumulation of root reinforcement slope compared to the bare soil slope counterpart after being subjected to the same input motion, and (5) during dynamic condition with PBA ≒ 0.30g, the bare soil slope has a more profound and more extensive area of the main scarp than slope with root reinforcement systems. | en_US |