Investigation of Erosion of Cement-Bentonite via Piping

Abstract

Cement-bentonite is one of the main materials used in the seepage barriers to protect earth dams and levees from water erosion. However, the current understanding of the erodibility of the cementitious materials and the interactions between cracked seepage barriers and the water flow is inadequate. Based on the laboratory pinhole erosion test, we first investigated the impacts of cementbentonite treatments by using the ground granulated blast-furnace slag (GGBS) as replacement on the erosion characteristics, compared with the original mixtures; the inclusion of GGBS highlighted a potential advantage against water erosion. In addition, we proposed to calculate the erosion percentage and establish the mathematical relationships between the erosion percentage and different regimes, that is, different curing period, erosion time, and sizes of initial holes. Results showed that enough curing period was critical to avoid the increases of hydraulic conductivity in the macrofabric of the barrier; meanwhile, the materials were eroded quickly at the beginning and slowed down with the erosion time, where the enlargement of the initial creaks would be stabilised at some point in time. Moreover, the sizes of initial holes may affect the erosion situation varying from the sample curing periods.

Influencing Factors and Prediction Model for the Antierosion Performance of Cement‐Improved Loess Compacted Using Different Compaction Methods

“…It can be seen that the effects of the eroding time on the CEML of CIL with different cement contents (2%, 3%, 4%, and 6%) are consistent, which indicates that there is a good linear correlation between the eroding time and the CEML of CIL. Moreover, these findings are in agreement with research that showed that there is an overall increase in the erosion of cement-bentonite when there is an increase in the erosion time [2].…”

“…To find methods of improving the erosion resistance of the subgrade, studies have researched how the strength of the subgrade filler could be improved and how eroding tests could be optimized according to the actual situation of the subgrade and have proposed antierosion measures. In particular, extensive attention has been paid to efforts that seek to improve the strength of subgrade materials, and some chemical binders, such as cement [1][2][3][4], lime [5], nano-MgO [6], coal ash [7], fiber [8], marine-dredged soil [9], sustainable regenerated binding materials [10], and manganese slag [11], have been applied to the subgrade to investigate their effect on the water stability and the erosion resistance of the soil subgrade. Researchers at home and abroad have found that using the aforementioned materials (especially cement) not only greatly increases the strength of the subgrade, but also additionally improves the water damage resistance.…”

Experimental Studies on the Stability Assessment of a Levee Using Reinforced Soil Based on a Biopolymer

“…Existing studies on levees, which have been performed in South Korea and other countries, include small-scale experiments for understanding the formation and process of an overtopping breach or erosion according to the levee material (e.g., [1][2][3][4]); a levee model experiment under most real-scale conditions, which could minimize the scale effect for analyzing the breach behavior according to the seepage and overflow (e.g., [5][6][7][8][9]); an analysis of the retardation effects on a levee breach from the use of reinforcement methods (e.g., [10,11]); an investigation of improving the stability of the levee against erosion and infiltration using mixed materials with cement (e.g., [12][13][14][15]); and methods of improving soil behavior using biopolymers (e.g., [16,17]). All advanced countries should establish and implement effective countermeasures to prevent levee erosion from flooding.…”