Investigating the effect of overburden on the erodibility of gypsum and anhydrite layers

Document Type : Research Paper

Authors

1 Department of Geotechnics, Qazvin Branch, Islamic Azad University, Qazvin, Iran

2 Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran

3 Department of Civil Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran

Abstract

The presence of soluble layers in the foundation of important structures such as dams, bridges and high-rise buildings, in case of being left untreated, may cause severe problems. These layers may easily be dissolved due to contact with groundwater flow, causing some cavities in the soil and settlement of the structure which in severe conditions may highly damage or ultimately lead to failure of the structure. Since nearly all studies carried out on soluble layers so far, have been concentrated on different factors influencing the solubility of the layers under free field conditions, the effect of overburden which roots from the weight of the structure may have an important and influential role in the phenomenon in many engineering projects. Therefore, to fill the gap in past studies on this topic, investigating the effect of overburden on the rate and types of solubility of the susceptible layers is of great necessity and importance. In the present study, the effect of overburden pressures on solubility and erosion of soluble layers has been assessed and investigated. The circulation tests on cubical gypsum samples taken from a mine in Semnan province, west of Tehran, have been carried out. At the same time, they were subjected to different overburden pressures in a new apparatus developed for this study. Cylindrical holes of different initial diameters from 6.5 to 14.75 mm. were cut in the center of samples for the flow passing through and the final diameters of the holes were measured after the electrical conductivity of the flow getting stable during the circulation test. Different flow rates, different overburden pressures and different diameters of holes have been examined and the electrical conductivity was monitored during circulation continuously. Based on the testing results, for relatively large initial hole diameters (eg: 9 & 12.5 mm.), the electrical conductivity decreases as the overburden increases. For greater hole diameters the rate of decreasing the electrical conductivity decreases and nearly becomes constant by increasing the overburden. Nevertheless, the variations of electrical conductivity get an unspecific trend by increasing the initial hole diameter and the overburden pressure.

Keywords

[1] O. Al-Rawi, S. Ghannam, and H.R. Al-Ani, Dissolution of gypseous rocks under different circumstances, Jordan J. Civil Engin. 5 (2011), no. 3, 357–379.
[2] V. Barberini and L. Burlini, High-strain deformation tests on natural gypsum aggregates in torsion, Geol. Soc. Special Pub. 245 (2005), no. 4, 277–290.
[3] F.G. Bell, Geotechnical properties of some evaporitic rocks, Bull. Int. Assoc. Engin. Geo. 24 (1981), no. 2, 137–144.
[4] W. Blum, Creep of crystalline materials: experimental basis, mechanisms and models, Material Sci. Engin. 319 (2001), no. 1, 8–15.
[5] C. Caselle, S.M.R. Bonetto, and D. Costanzo, Crack coalescence and strain accommodation in gypsum rock, Frattura Integrit`a Strutt. 14 (2020), no. 52, 247–255.
[6] S. De Meer and C.J. Spiers, Creep of wet gypsum aggregates under hydrostatic loading conditions, Tectonophysics 245 (1995), no. 4, 141–173.
[7] S. De Meer and C.J. Spiers, Influence of pore-fluid salinity on pressure solution creep in gypsum, Tectonophysics 308 (1999), no. 8, 311–330.
[8] A.M. Farid and Gh. Habibagahi, Dissolution-seepage coupled analysis through formations containing soluble materials, J. Engin. Mech. 133 (2007), no. 6, 713–722.
[9] D. Hong, M. Fan, L. Yu, and J. Cao, An experimental study simulating the dissolution of gypsum rock, Energy Explor. Exploit. 36 (2018), no. 4, 942–954.
[10] A.N. James, Solution parameters of carbonate rocks, Bull. Int. Assoc. Engin. Geo. 24 (1981), no. 6, 19–25.
[11] A.N. James and I.M. Kirkpatrick, Design of foundations of dams containing soluble rocks and soils, Quart. J. Engin. Geo. 13 (1980), no. 3, 189–198.
[12] A.N. James and A.R.R. Lupton, Gypsum and Anhydrite in foundation of hydraulic structures, Geotechnique 28 (1978), no. 3, 249–272.
[13] E. Karacan and I. Yilmaz, Geotechnical evaluation of Miocene gypsum from Sivas (Turkey), Georech. Geolog. Engin. 18 (2000), no. 2, 79–90.
[14] W. Liang and X. Yang, Experimental study of mechanical properties of gypsum soaked in brine, Rock Mech. Min. Sci. 53 (2012), 142–150.
[15] E. Liteanu and C. Spiers, Influence of pore fluid salt content on compaction creep of calcite aggregates in the presence of supercritical CO2, Chem. Geo. 265 (2009), no. 2, 134–147.
[16] T. Meng, M. Xiangxi, Z. Donghua, and Y. Hu, Using micro-computed tomography and scanning electron microscopy to assess the morphological evolution and fractal dimension of a salt-gypsum rock subjected to a coupled thermal-hydrological-chemical environment, Marine Petrol. Geo. 98 (2018), no. 6, 359–367.
[17] W.D. Yu, W.G. Liang, Y.R. Li, and Y.M. Yu, The meso-mechanism study of gypsum rock weakening in brine solutions, Bull. Engin. Geo. Envir. 75 (2016), no. 1, 359–367.
Volume 15, Issue 12
December 2024
Pages 131-141
  • Receive Date: 22 May 2023
  • Revise Date: 26 June 2023
  • Accept Date: 09 July 2023