Abstract
Expansive soils are found in numerous regions of the world explicitly in arid and semiarid zones. These soils expand when absorbed moisture and shrink when released water. Such soil is viewed as a characteristic risk for infrastructures due to the shrink and swell behavior. These soils become more problematic when lightly or moderately loaded structures are built on them. The swelling and shrinkage in these soils chiefly happen due to the presence of montmorillonite minerals. The mineralogical and swell behavior of foundation soils is playing a vital role in the overall stability of a structure. These parameters are often ignored in the geotechnical report writing stage specifically in small projects, due to which, the durability and service life of the facilities are reduced and the maintenance cost is increased. To mitigate the potential damages in structures constructed on expansive soil, it is necessary to assess the mineralogical and swelling characteristics of expansive soil. The current study aims to determine the geotechnical, mineralogical, and swell behavior of the local expansive soils. Based on the results, the Karak soil has the highest plasticity index (PI) of 37% with a clay fraction of 28%, while the D.I. Khan soil has the least PI of 23% with a clay fraction of 17%. Similarly, Karak’s soil contained a higher percentage of montmorillonite (Rp = 8.9%). The maximum values of swell pressure, swell potential, and 1D deformation are 280 kPa, 12.5%, and 1.92 mm for the Karak soil, 6.45% 150 kPa, and 1.38 mm for D.I. Khan soil, and 10.5%, 245 kPa, and 1.64 mm for Kohat soil, respectively. This concludes that Karak’s soil has high plasticity and swell characteristics than Kohat and D.I. Khan soil. The swell characteristic of expansive soils increases with the increase in the percentage of the fine specifically the clay fraction. Furthermore, the Karak soil is more critical than Kohat and D.I. khan soil for lightly loaded structures.
Highlights
Expansive soil is a typical soil that goes through enormous volume changes after changing the water content. e volume changes in such soils can be developed as an expansion or as a shrinkage. is soil swells and shows an increment in the volume when its water content is increased, while volume is reduced considerably upon the reduction in their moisture content
For proper characterization and classification of expansive soils, basic geotechnical tests were conducted comprising consistency limits, specific gravity, wet sieve analysis, sedimentation analysis, and standard proctor tests. e mineralogy and morphology were studied through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis while the swelling behavior and deformation were assessed with the help of conventional odometer tests
An experimental study has been conducted to investigate the geotechnical, mineralogical, and swelling behavior of local expansive soils. For this reason, disturbed samples were collected from three sites of expansive soils
Summary
Expansive soil is a typical soil that goes through enormous volume changes after changing the water content. e volume changes in such soils can be developed as an expansion or as a shrinkage. is soil swells and shows an increment in the volume when its water content is increased, while volume is reduced considerably upon the reduction in their moisture content. E structure like boundary walls, one to three-storied houses, pavements, pathways, highways, underground facilities of water, etc., is subjected to severe distress when placed over or under expansive soil. In Pakistan, many areas are covered with expansive soils which have caused intense damages to various types of structures, such as cracking of single and double storied houses, lifting of floor slabs, and cracking of boundary walls as evident from Figure 1 [13]. E main objective of this study is to assess precisely the geotechnical, mineralogical, and swelling behavior of local expansive soil for the subsequent utilization in design parameters For this purpose, representative samples were collected from Karak, Kohat, and D.I. Khan areas in Khyber Pakhtoon Khwa (KPK) province, Pakistan, and assessed for the required characteristic
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
