Civil Engineering and Architecture 10(1): 388-394, 2022 http://www.hrpub.org DOI: 10.13189/cea.2022.100133 The Identification of the Existence of Dispersive Soil on the Soft Soil for Dam Filling Material Lusmeilia Afriani 1,* , Ryzal Perdana 2 1 Faculty of Engineering, Universitas Lampung, Indonesia 2 Department of Educational Science, Universitas Lampung, Indonesia Received September 12, 2021; Revised November 29, 2021; Accepted January 16, 2022 Cite This Paper in the following Citation Styles (a): [1] Lusmeilia Afriani, Ryzal Perdana , "The Identification of the Existence of Dispersive Soil on the Soft Soil for Dam Filling Material," Civil Engineering and Architecture, Vol. 10, No. 1, pp. 388-394, 2022. DOI: 10.13189/cea.2022.100133. (b): Lusmeilia Afriani, Ryzal Perdana (2022). The Identification of the Existence of Dispersive Soil on the Soft Soil for Dam Filling Material. Civil Engineering and Architecture, 10(1), 388-394. DOI: 10.13189/cea.2022.100133. Copyright©2022 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Abstract Dispersive clay soils are highly erodible, even under standing water conditions. Dispersive clay soils are easily eroded both on the surface and in landfills, despite their high plasticity index and ability to be passed by water flows at low velocities. Dispersive soil will cause a variety of problems in dams and water structures, including the potential for seepage patterns in the embankment material, which can trigger piping, compromising the stability of the water structure. Dispersive soils occurring in many parts of the world are easily erodible and deflocculated in water, posing serious problems for stability of the earth and earth-retaining structures. Earth dams constructed on dispersive soils have sustained internal and external soft soil damage. The purpose of the current study was to identify the predetermine of dispersive clay soil as a filling material for the Way Sekampung Dam in Indonesia. Pinhole and Crumb tests were carried out to determine the dispersity of the original soil. This study analysed 17 undisturbed soil samples collected from 17 different locations throughout the study area. The research findings indicate that there is no evidence of dispersive soil distribution in the samples studied. According to the Pinhole and Crumb tests, all soil samples have ND-1 and 1 status, respectively. These findings are supported by laboratory test results which indicate that the soil content with a diameter greater than 0.005 mm is always less than 12% for each sample. In addition, another test revealed that the permeability value of all tested clay samples was not too low (around 10 -2 to 10 -4 ), indicating that they did not possess the properties of dispersive clay, which had a very low permeability value (around 10 -6 to 10 -7 ). In general, the clay surrounding the dam site is free from dispersive properties and is therefore safe and suitable for use as a dam filling material. Finally, these findings will be beneficial for dam constructions to understand the possibility of dispersive soil causing significant issues that require attention in geotechnical engineering. Keywords Identification, Existence, Dispersive, Soil, Dam Filling 1. Introduction Every type of structure, including buildings, embankments, and dams, is generally constructed using the same procedures [1], [2]. For instance, any structure must be built on soil that is capable of bearing the loads above it. If the ground cannot withstand the vertical and horizontal forces generated by the loads above it, the building's construction will fail [3]. To avert this failure, either the structure must be relocated or the soil stabilised [4]. On the basis of these facts, it can be stated that soil is a critical component of any construction project. The soil ground is the area on which a building is constructed while also supporting the construction load [5]. When constructing a structure, we always strive to obtain suitable soil for the building's foundation. However, not all soils live up to our expectations. Certain areas deposit softer soils, such as clay. Clay is composed of