Abstract:
The entire dissertation work has been divided into four parts as Geotechnical
Investigation in the piping and non-piping region, Electrical resistivity survey in a soil
piping susceptible area, Evaluation of Dispersion potential of the samples collected
from various piping and non-piping regions and Stabilization of Dispersive soils using
lime.
An assessment of the geotechnical parameters in the Soil piping affected region in the
Kasaragod district of Kerala, India is presented in the first part. Undisturbed samples
were collected, analyzed and a comparative study of various geotechnical properties
was done in the piping and non-piping region of Kasaragod district and the non-piping
region of Kozhikode district. Sieve analysis, Atterberg’s limits, specific gravity,
permeability and direct shear tests were carried out on the samples.. The comparative
study shows that the visual classification, Atterberg’s limits, and particle size analysis
do not provide sufficient basis to differentiate between dispersive clays and ordinary
erosion resistant clays. High rainfall and sloping nature of study area are found to have
great impact in piping erosion to occur, so that water is the main culprit. The piping
erosion has affected the foundation of a house under construction in the study area. The
mitigation works suggested in the area are dewatering techniques along with renovation
of the damaged foundation by underpinning using polyurethane resins.
Electrical resistivity results gave the maximum depth information and idea of presence
of saturated zone. The saturated zone indicates the area having more probability to
occur piping. Below which the low resistivity saturated zone, there was rise in
resistivity value indicating at a particular zone is an indication of probably hard
crystalline basement rock.
The study of evaluation of dispersive nature of soil using double hydrometer test shows
that the Idukki soils are highly dispersive in nature comparing to samples of other sites
having a range of 13.11 – 27.21 %. Samples collected from the pipe wall were found to
be more dispersive than that collected from the soil profile outside piping region. The
dispersion rate in Kerala is found to be relatively low, still it causes piping erosion.
iv
Stabilization of dispersive soils at the piping region has been suggested using lime at
the end of thesis work. Stabilization results on the sample collected from piping region
of Kannur district shows that the optimum percentage of lime to be added to reduce
dispersion potential is 1%. Above that percentage, the results shows an increasing
trend in dispersion potential.
