M. Julina

Bio: M. Julina is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Hydraulic conductivity & Expansive clay. The author has an hindex of 4, co-authored 5 publications receiving 57 citations. Previous affiliations of M. Julina include National Institute of Technology, Puducherry.

Quantification of desiccation cracks using X-ray tomography for tracing shrinkage path of compacted expansive soil

Abstract: Compacted expansive soils undergo large volumetric changes during wet–dry cycles owing to the seasonal moisture fluctuations, and during drying the shrinkage is accompanied with the desiccation cracks. This paper presents the shrinkage behaviour of compacted expansive soil specimen, under a vertical stress of 12.5 kPa, in terms of void ratio–water content plot during second drying cycle. Accurate characterization of shrinkage behaviour along with the soil–water characteristic curve in terms of degree of saturation versus water content helps in the development of constitutive relation such as void ratio–suction relationship, which is vital for the prediction of unsaturated soil properties. However, the expansive soils develop large desiccation cracks during drying, which hinder the accurate volume measurement of desiccated soil specimen using vernier caliper as the vernier caliper measurements do not capture the volume of cracks developed within the soil specimen. The mercury displacement method and fluid displacement methods measure the volume of the soil specimens accurately, but the methods are either destructive or hazardous, and consequently, the continuous measurements are not possible. In order to overcome these limitations, the XCT imaging experiments were carried out along with the image analysis technique using ImageJ software and vernier caliper height measurements for tracing the volume change during the second drying path. The exact volume change during and at the end of drying process was estimated by deducting the cracks volume from the volume of specimen arrived from the vernier caliper measurements. Also the volume change at the end of drying process was measured using both XCT imaging experiments and mercury displacement method, and the results were compared. The cracks volume was used for defining the void ratios pertaining to specific components like cracks void ratio, annular gap void ratio, discontinuities void ratio (annular gap + cracks), soil pores void ratio and total void ratio (including and excluding the annular gap). The experimental results in terms of void ratio pertaining to various components, during drying process, were presented in terms of void ratio–water content plots and compared with the void ratio–water content plot of specimen reconstituted from slurry. The void ratio–matric suction constitutive relationship was developed from the void ratio–water content plot and soil–water characteristic curve.

Determination of volumetric shrinkage of an expansive soil using digital camera images

Abstract: The volume change during drying of compacted expansive soils occurs in the form of reduction in overall volume and development of cracks. Accurate determination of volume of shrunken soil specimens...

Effect of pore fluid and wet-dry cycles on structure and hydraulic conductivity of clay

Abstract: Compacted clays in landfill applications are subjected to both physico-chemical changes and wet–dry cycles. Physico-chemical interactions occur at the microstructural level between the clay particl...

Effect of hydraulic gradient on swell and hydraulic response of desiccated expansive soil–an experimental study

Abstract: Desiccation cracks in compacted clay liners act as preferential flow paths and affect the hydraulic response during initial stage of wetting. This paper investigates the effect of initial hydraulic...

Engineering Characteristics and Performance of Polypropylene Fibre and Silica Fume Treated Expansive Soil Subgrade

Abstract: This study presents the experimental results of the effective utilization of polypropylene (PP) fibre and silica fume (SF) to stabilize the expansive soil subgrade as a possible alternative from the environment, economic, and technical perspective. During the drying cycle, clayey soil undergoes unpredictable shrinkage deformation. The nonrecurring shrinkage behaviour of expansive soil caused the adverse effect on lightweight civil engineering structures. Therefore, expansive soil is not considered suitable subgrade material for paved structure construction. Paved structures constructed on clayey soil subgrade experience severe damages occur in its life cycle. The numerous mechanical, biological, and chemical techniques have been successfully demonstrated to reduce the swelling–shrinkage nature and improve the strength behaviour of expansive soil subgrade. This study aims to utilize industrial waste SF as chemical and PP fibre as a mechanical stabilizer. The mecho-chemical stabilization of expansive soil has been carried out by reinforcing the expansive soil with PP fibre and chemically stabilizing with SF. To evaluate the performance of waste material as a stabilizer, compaction, Atterberg’s limits, free swelling index (FSI), electrical conductivity (EC), pH, swelling pressure, and California bearing ratio (CBR) tests have been conducted on treated and untreated specimens. Over the past few years, images from digital cameras have been successfully used to study crack morphology and various parameters of soils. The image processing technique has been used to evaluate the shrinkage limit by developing the MATLAB program code. The microstructural analysis has been carried out using scanning electron microscopy (SEM) analysis. The varying percentage of silica fume (2%, 4%, and 8%) and polypropylene fibre (0.25%, 0.5%, and 1%) by weight of dry soil were used to stabilize the expansive soil. The results show that the value of CBR increases and the shrinkage area decreases with an addition of SF and PP fibre. The experimental results also show a reduction in Atterberg’s limit with the addition of SF and PP fibre; as a result, the shrinkage behaviour of clayey soil reduces exponentially. The digital image processing technique showed a higher potential to understand the soil morphology for the large area.

Determination of volumetric shrinkage of an expansive soil using digital camera images

Abstract: The volume change during drying of compacted expansive soils occurs in the form of reduction in overall volume and development of cracks. Accurate determination of volume of shrunken soil specimens...