Contact angle of soil minerals A molecular dynamics study.pdfVIP

Computers and Geotechnics 75 (2016) 48–56 Contents lists available at ScienceDirect Computers and Geotechnics journal homepage: /locate/compgeo Research Paper Contact angle of soil minerals: A molecular dynamics study Chao Zhang a, Zhen Liu a,?, Peng Deng b a Department of Civil and Environmental Engineering, Michigan Technological University, Houghton, MI 49931, USA b Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA article info Article history: Received 29 June 2015 Received in revised form 15 January 2016 Accepted 17 January 2016 Available online 10 February 2016 Keywords: Contact angle Wettability Molecular dynamics Soil minerals Unsaturated soil mechanics abstract In this paper, molecular dynamics was employed to study the wetting behavior of soil minerals. The basic concepts and methodologies of molecular dynamics were brie?y summarized. A speci?c modeling and simulation procedure was presented to study the contact angles of solids using molecular dynamics. This procedure was employed to simulate the contact angles of three minerals, which are common in sand and silt fractions, i.e. a-quartz, orthoclase and muscovite. The simulated contact angle was 29 for a-quartz; 36 for orthoclase; and 116 for muscovite, which shows good agreement with the reported experimental or numerical results and thus substantiates the feasibility and accuracy of the proposed method. The simulation results also reveal that the contact angles of these minerals are considerably larger than zero and quite different from each other. Published by Elsevier Ltd. 1. Introduction Wettability of soil minerals is of critical importance in many aspects of geotechnical engineering, petroleum engineering, and soil science. Contact angle is a major indicator for wettability which could be measured experimentally. According to Young [1], the contact angle is a result of interfacial equilibrium and could be expressed as a function of interfacial sur