Experimental Investigations on Desiccation Induced Stress Strain Characteristics of Clay

Abstract

The desiccation of clayey soils results in (i) volumetric shrinkage of the matrix newlineand (ii) shrinkage stress generation, eventually leading to crack formation. The soil newlineshrinkage can result in various engineering problems such as, differential settlement in newlineinfrastructures, pavement distress, slope instability, failure of earthen dams, cracks in newlineclay liners, etc. Thus, a better understanding of the soil shrinkage behaviour necessitates newlinethe measurement of stress and strain associated with drying. Conventionally, the newlineshrinkage behaviour of soil is established either in terms of soil shrinkage curve and/or newlinetensile stress induced upon shrinkage. However, in real-time, volume reduction and newlinestress development transpire in tandem. In this context, the focus of this thesis is on the newlinedetermination of shrinkage stress, volumetric shrinkage strain and the combined newlineshrinkage associated stress-strain analysis. In the present study a novel isotropic newlinepressure monitoring device (I-PMD) has been developed to map the evolution of newlineshrinkage stress (termed as the Soil Shrinkage Stress Curve, SSSC) in clayey soil newlinedesiccated from slurry and consolidated state. Further, the study could also establish an newlineapproach to measure the linear and radial volumetric shrinkage of slurry and newlineconsolidated soils by employing image processing technique and laser distance newlinemeasuring device through desiccation test (all-round drying). From the volumetric newlineshrinkage measurements, it has been inferred that the shrinkage in the linear direction newlineis higher for slurry soils, specifically when the moisture content is above the liquid newlinelimit. In addition, the radial volumetric shrinkage has been observed to have a marginal newlinereduction when the soils were desiccated from consolidated state when compared with newlineslurry soils. Further, the volumetric stress-strain response from the desiccation test and newlineexternal loading (isotropic compression test) has been compared and identified to be newlineanalogues. In this context, the well-established Selig s equation, widely employed