Slope failure of biotreated sand embankments under rainfall conditions: experimental investigation and numerical simulat
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ORIGINAL PAPER
Slope failure of biotreated sand embankments under rainfall conditions: experimental investigation and numerical simulation Zhaoyu Wang 1 & Qi Li 2 & Nan Zhang 3 & Yong Jin 4 & Haibo Qin 1 & Jinhua Ding 1 Received: 1 April 2019 / Accepted: 20 May 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Rainfall has become a main trigger of slope failure for embankments in most coastal areas in China. The microbially induced carbonate precipitation (MICP) technique has great potential to improve soil strength and slope stability. In this study, three small-scale biotreated sand embankments and one untreated embankment were first prepared using the injection method. Rainfall scouring tests were then conducted to investigate the slope failure of the embankments. Experimental results revealed that scouring/erosion resistance of biotreated sand embankments was significantly improved comparing to that of the untreated one. The failure time of the embankment increased as the treatment cycles increased. The failure mode of the untreated embankment was the general shear failure, whereas the failure was most likely to occur at shallow depth in biotreated embankments. Using the finite element method (FEM), flow analysis was conducted to simulate the rainfall infiltration in sand embankments and study the effect of biotreatment on the infiltration process. The simulation results were found to be consistent with the experimental results. This study preliminarily investigates the effectiveness of using the MICP technique to prevent slope failure of sand embankments. Considering the complicated environmental factors, more effort towards optimization is still needed for field implementation in the future. Keywords Slope failure . MICP . Sand embankments . Rainfall conditions . Numerical simulation
Introduction Jiangsu province has the largest area of coastal wetlands, which are about 25% of the total area of the tidal flat, and the length of the coast is approximately 6% of the coastline in mainland China. As shown in Fig. 1, the embankments in the coastal areas of Jiangsu province are extremely vulnerable to heavy rainfall events, as well as typhoons and perennial waves. Consequential scouring/erosion and slope failure of embankments remain a geotechnical challenge in most coastal
and estuarine areas. Moreover, soil erosion induced by high intensity or long duration rainfall has become one of the main triggers to the slope failure of embankments. Thus, the necessity of improving soil scouring/erosion resistance to prevent slope failure under rainfall conditions is obvious. Some methods have been proposed in the literature to improve the scouring/erosion resistance of embankments. For example, geotextiles have been used to increase the scouring resistance of coastal embankments and slopes (Faure et al. 2010; Lee and Douglas 2012). In addition, the feasibility of
* Nan Zhang [email protected]
Jinhua Ding [email protected]
Zhaoyu Wang [email protected]
1
College of Civil Engineering, Yanchen
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