This study deals with the effect of wastewater on some physical, chemical and
consolidation properties of clayey soil and investigates the effect of wastewater flow
beneath buildings’ and structures’ foundations due to; breaking of wastewater pipes,
the permeation of sewage water in to the soil, or its flow on the land that hasn’t been
constructed yet.
Soil samples have been taken from the University of Technology site at a depth (1–
1.5) m and the preparation of samples were in two manners: the first by taking
undisturbed samples which have been flooded with wastewater that allowed to
permeation and flow through soil sample, the second, by taking disturbed samples
saturated with wastewater to ferment.
The soil that used in this study was silty clay with low plasticity (CL-ML) and the
result of this study which lasted for (10) months showed an increase in the chlorides and sulphates ions during the first months and then decreased, it has been noticed an
increase in the concentration of carbonates ions along the period of study and an
increase in organic matter due to wastewater nature.
The results of soil- wastewater interaction showed an increase in liquid limit, plastic
limit and plasticity index for both undisturbed and disturbed samples and the specific
gravity of soil decreased due to wastewater chemical contents. The void ratio has been
increased and preconsolidation pressure decreased which may be attributed to the
dissolution of soluble salts and the influence of carbonate bonding that may be broken
when subjected to load. Also, the results showed an increment in the ability of soil to
be compressed when soil compression index (Cc) increased and soil swelling index (Cr)
increased, too.