Biopolymer-Reinforced Levee for Breach Development Retardation and Enhanced Erosion Control

Abstract

This study proposes an earthen levee reinforcement method with a new biopolymer-based material to prevent levee scour and breach. It is an eco-friendly method that can efficiently protect the levee slope as it enhances soil strength, even at a very low concentration of biopolymer, and has high resistance to surface runoff in addition to promoting vegetation growth. The function and effectiveness of this method were demonstrated through an overflow-based semi-scale experiment in a previous study. In this study, we examined the effect of biopolymer-mixed soil layer on levee stability against an overflow-induced breach. In these experiments, biopolymer-mixed soils were sprayed on the crest and land-side levee surface. Two full-scale tests were conducted (2.5–2.7 m high and 14 m wide on bottom). Case 1 (control case) consisted of bare sand without any treatment, while Case 2 consisted of a 1.0% biopolymer-mixed soil sprayed on the crest and landside slope of the levee and turf put on it. By applying an image analysis technique, we analyzed the breach phenomenon and breach retardation effect of the levee treated with a biopolymer and covered with vegetation. In this experiment, the slope loss rate of Case 2 was retarded 1.5 to 2.3 times over time as compared to Case 1. During the experiment, we observed that soil erosion followed through the narrow water channel formed by the stripped turfs. This means that the grasses did not root firmly enough to protect the surface. In this regard, although the experimental results may seem unsatisfactory, the biopolymer was found to help improve erosion retardation. In 2020, we will conduct more experiments with different compositions and concentrations of the biopolymer regardless of levee vegetation. With this research, we expect to confirm that the new technology of using biopolymer-treated soils is promising for solving the levee overflow breach problem.

Experimental study on mechanical and hydraulic properties of xanthan gum improved low liquid limit silty soil

“…School of Architecture and Civil Engineering, Liaocheng University, Liaocheng 252059, China. * email: zhangxutao@ lcu.edu.cn the permeability of the improved soil was reduced, and the ability to resist hydraulic and wind erosion was enhanced [16][17][18][19] . In addition, the biopolymers are rich in carbon and nitrogen elements, which can provide nutrients for soil and promote plant growth.…”

Characteristics of Biopolymer Guar Gum Solution Injection for Eco-Friendly Ground Reinforcement

“…바이오폴리머는 식품 산업, 포장, 제조, 의학 등 다양한 분야에서 응용되고 있다. 지반 개량에 활용된 바이오폴리머는 잔탄검(Xanthan gum), 아가검(Agar gum), 구아검(Guar gum), 베타글루칸(β-glucan), 카제인(Casein) 등 다양하며 이들은 전단강도 증가, 투수계수 저감, 표면 침식 저항성 증가, 사막화 방지, 지반 복원, 석유 회수 증진 (Enhanced Oil Recovery) 등의 효과가 있다 (Bouazza et al, 2009;Jung et al, 2014;Ayeldeen et al, 2016;Jung et al, 2016;Jang et al, 2017;Lee et al, 2017;Chang and Cho, 2018;Fatehi et al, 2018;Ham et al, 2018;Ko and Kang, 2020). 바이오폴리 머의 지반공학적 적용에는 현장 분사 공법을 활용한 제방의 보수가 대표적이며 범용성 증진을 위한 추가 연구가 필요한 실정이다 (Seo et al, 2019).…”

Fragility Curves for Slope Stability of Geogrid Reinforced River Levees

“…Instabilities on the landside may also be initiated by surface erosion during overflow. The resistance against such action can be increased by placing a reinforcing layer of standard geosynthetics or other specific products [68] such as biopolymers [69,70] over the slope, but in this case, there is no such additional protection. The same applies for the riverside slope where surface erosion might be caused by the flow of the river and during the rapid decrease of water level in the river (RDD).…”