Volume No. 7 Issue No.: 4A Page No.: 1628-1638 April-June 2013

 

A CONCEPTUAL MODEL FOR THE ROLE OF COAXIAL AND NON-COAXIAL COMPONENTS OF SHEAR STRENGTH OF SOILS ON SEDIMENT DYNAMICS

 

Rajaraman J.* and Thiruvenkatasamy K.

Department of Harbour Engineering and Off Shore Technology , AMET University, 135 East, Kanathur, Chennai (INDIA)

 

Received on : November 15, 2012

 

ABSTRACT

 

Many factors affect the erosional properties of cohesive sediments, including its grain size, textural property, arial exposure and other factors. To understand the distribution of non cohesive and cohesive sediments in coastal areas of lowlands, which leads to zonation of sand, mud and mixed deposits is of great importance. It determines which areas collect nutrients and pollutants, as these tend to adhere to or be part of cohesive sediments and which areas form the right habitat for flora and fauna. The most important factor in sediment dynamics is the shear in the form of coaxial and non-coaxial component of shear strength of the soil and the shear force from the environment. All other factors are only secondary compared to natural ones. Pure shear or coaxial shear component is applicable only for pure clay. The non-coaxial shear or simple shear is applicable only for sand. However in nature the combinations in various percentages of clay and sand are only possible. The simple ocean sediment is a combination of clay, sand and mud. In general, sediment transport is of two types : non cohesive and cohesive. In the noncohesive type sand and mud are assumed to behave independently during erosion and deposition. In cohesive type the erosional behavior of sand and mud is not independent deviating from the conventional rule- of- thumb the calmer the water, the finer the bed sediments, in this paper, an attempt is made as a conceptual model, the role of coaxial and non-coaxial component of shear strength of soils on sediment dynamics in the marine environment.

 

Keywords : Coaxial, Non-coaxial shear, Lowland, Pure shear, Simple shear, Erosion, Deposition

 

 

BACK