Consolidation Characteristics of Fiber Reinforced Cohesive Soil

 

Rabindra Kumar Kar*

Asst. Professor, Department of Civil Engineering, Indira Gandhi Institute of Technology, Sarang - 759146, Odisha, India
*Corresponding Author, e-mail: rabikkar@gmail.com

Pradip Kumar Pradhan

Professor, Department of Civil Engineering, Veer Surendra Sai University of Technology, Burla-768018, Odisha, India
e-mail: pkpradhan1@yahoo.co.in

Ashutosh Naik

Professor, Department of Earth Science, Sambalpur University, Jyotivihar, Burla-768019, Odisha, India
e-mail: asutos@rediffmail.com

 

 ABSTRACT

Clay soils and their related abnormal behavior such as excessive shrinkage, swelling, consolidation settlement and cracking on drying has been the subject of many investigations. In recent years, an increasing need is being felt for various types of constructions in marginal, low or reclaimed lands and coastal areas which are not suitable normally for construction purposes. Clays, well known for its high compressibility and poor shear strength, pose numerous problems to builders. Previous studies mainly evaluated the effects of additives such as lime, cement and sand on these characteristics of clays. Initial results indicated that the soil characteristics were improved. However, reportedly in many cases, these additives resulted in a decrease in plasticity and increase in hydraulic conductivity. As a result, there has been a growing interest in soil/fiber reinforcement. The present investigation has focused on the impact of short random fiber inclusion on consolidation settlement in compacted clays. To examine the possible improvements in the consolidation characteristics, local clayey soil was reinforced with random distribution of polypropylene (synthetic) and coir (natural) fibers as percentage (0-1% at an increment of 0.2%) of dry weight of soil with 10, 15 and 20 mm lengths. Results indicated that the compression index and coefficient of volume change decrease with inclusion of polypropylene/coir fibers in the soil up to certain fiber content and increase thereafter. The coefficient of consolidation increases with increase in fiber content and fiber length in the range of fibers considered in the investigation. Thus, the time required to achieve primary consolidation decreases for fiber-reinforced soil for a given degree of consolidation and a given drainage path.

Keywords: Aspect ratio, polypropylene fibers, coir fibers, consolidation test, void ratio, compression index

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