Load Sharing Mechanism of Bamboo Pile Mattress for Reinforced Embankment

Abstract

In Indonesia, bamboo pile mattress is commonly utilized for reinforced embankments over deep soft soil, especially for shallow ground water table or even over the ground surface as the water functions as timeless preservation for the bamboo. However hardly any articles have been published for design references. This work intends to evaluate bamboo pile mattress for embankment reinforcement numerically by means of Plaxis 2D. A parametric analysis was conducted to assess the effect of both piles spacing s and length L on embankment settlement, stability, and pile load ratio αp. A ratio s/L is introduced to evaluate the combination of s and L effects. Furthermore, normalized settlement S/S∞ and normalized factor of safety SF/SF∞ are proposed to facilitate the assessment, in which S∞ and SF∞ are ones at s/L = ∞ (bamboo mattress with no pile condition). The results show that S/S∞ increases with increasing s/L. Inversely, SF/SF∞ and αp decrease with decreasing s/L. When s and L are increased independently, S/S∞ and SF/SF∞ curves initially follow different paths. When s/L > 0.1 the curves merge into a line. Meanwhile, αp curves blend into a line and separate with a different slope when s/L > 0.1. s/L = 0.1 becomes an onset point to show that L provides more significant effects than s for S/S∞ and SF/SF∞ at s/L < 0.1. However, L produces less influence on αp than s at s/L > 0.1. Furthermore, the findings may provide insight and direction for reinforced embankment design using bamboo pile mattress.