Function of Palm Fiber in Stabilization of Alluvial Clayey Soil in Yangtze River Estuary

Abstract

Palm fiber is one of the favorable materials used in stabilization of soft soil in geotechnical engineering projects in recent years due to its nature of sustainability, no harm to the environment, biodegradability, availability and cost-effectiveness in the context of widespread appeal from the world for returning to nature and protecting the earth our homestead. This paper is aimed at exploring the mechanical performance of Shanghai clayey soil reinforced with palm fiber. The unconfined compressive tests are carried out on samples treated with palm fibers of different lengths and contents, and the unconfined compressive strength (UCS), ductility rate (DR), secant modulus (SM), energy absorption capacity (EAC) and failure pattern (FP) of the reinforced and unreinforced samples have been analyzed with regard to their relationship with palm fiber contents and lengths. Then multiple regression, grey correlation and general correlation relationship analysis are applied to the resultant test data so as to obtain the mathematical and statistical equation of related soil indexes. It has been concluded from the analysis that the unconfined compressive strength, ductility and energy absorption capacity of reinforced soil will increase with the increase in content and length of palm fiber, which are maximized when palm fiber content and length are 0.4% and 15 mm, respectively. On the contrary, the secant modulus of reinforced soil decreases considerably with content and length of palm fiber as a whole. Additionally, the failure pattern also changes from brittle to ductile gradually with the content and length of palm fiber. The data provided by the analysis of reinforced soil can be referred to and used for the related geotechnical engineering in the future. And the mathematical model obtained from the statistical regression is significantly meaningful because it can be used to predict the soil performance without the need for doing the additional tests, with saving in cost and time. What’s more, the application of palm fiber to soft soil is completely in accordance to the concept of sustainable development and environment protection.