Research Article Comparative Study on the Field- and Lab-Based Soil-Water Characteristic Curves for Expansive Soils Bakht Zamin , 1 Hassan Nasir, 2 Muhammad Ali Sikandar, 1 Waqas Ahmad, 3 Beenish Jehan Khan , 1 Mahmood Ahmad , 4 and Muhammad Tariq Bashir 1 1 Civil Engineering Department, CECOS University of IT and Emerging Sciences, Peshawar, Khyber Pakhtunkhwa 25000, Pakistan 2 Water and Sanitation Services Peshawar, (WSSP), Peshawar, Pakistan 3 National Centre of Excellence in Geology (NCEG), Peshawar, Khyber Pakhtunkhwa 25000, Pakistan 4 Department of Civil Engineering, University of Engineering and Technology Peshawar (Bannu Campus), Bannu 28100, Pakistan Correspondence should be addressed to Bakht Zamin; bakhtzamin82@gmail.com Received 28 March 2022; Revised 15 April 2022; Accepted 19 April 2022; Published 2 May 2022 Academic Editor: Jianping Sun Copyright © 2022 Bakht Zamin et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Expansive soils are problematic and viewed as a potential hazard for buildings and structures due to swell and shrink phenomena. e damaging effect of these soils is strongly correlated with the soil-water characteristics of expansive soils present in the shallow depth. e seasonal wetting-drying cycle is vital in fluctuating moisture content in the surficial soils. As such, soils remain unsaturated most of the time due to high absorption capacity. erefore, it is crucial to assess them as unsaturated soil, and the soil-water characteristic curve (SWCC) is an essential tool for measuring unsaturated soils’ mechanical and hydraulic properties. e main objective of this study was to establish both field- and lab-based SWCCs for the expansive soils and compare them for determining the possible difference between them. For this purpose, eight sites of expansive soils were selected for sampling and in situ testing. ese sites include three locations of Karak, three locations of Kohat, and two locations of D.I areas. Based on the experimental results, Karak’s expansive soil indicated a high suction value of 705 kPa, while D. I Khan’s soil showed the least suction equal to 595 kPa. e comparison of field and lab SWCCs for the potential sites presented a close agreement in the matric suction values beyond the air entry values (AEVs), particularly in the residual suction zones. It was also concluded that for expansive soils, the field- and lab-based SWCCs are comparable beyond the AEVs. e established curves can be successfully utilized to assess local expansive soils in the framework of unsaturated soils. 1. Introduction Expansive soils are typical soils, which swell and shrink more than ordinary soils, due to which these soils are considered a potential hazard for engineering buildings and structures [1]. Expansive soils can cause severe damage and distortion if not adequately treated [2]. Buildings and structures, which are more susceptible to deformations, include single-story buildings, pavements, canal linings, slab-on-grade members, water channels, and underground pipelines [3]. us, nu- merous techniques and materials have been introduced recently for stabilizing problematic soils including the work of [4, 5] to restore the buildings and stabilize the soil beneath after being deformed due to various natural soil aspects including the swelling-shrinkage behavior [6, 7]. e main cause of the undesirable behavior of expansive soil is the current limited state of knowledge and practice, as soil mineralogical changes and unsaturated parameters of expansive soils are not frequently taken into consideration in the analysis [8, 9]. As problematic soils are near the natural surface level (NSL), the swell and shrink phenomena are more critical in the surficial depth, approximately 3 meters. e detrimental effect of expansive soils is closely related to the soil-water characteristic of the surficial soil layer exposed to the seasonal wetting-drying cycles. Furthermore, the moisture content in the shallow depth is more critical Hindawi Advances in Civil Engineering Volume 2022, Article ID 6390442, 9 pages https://doi.org/10.1155/2022/6390442