Deterioration of shear strength parameters of limestone joints under simulated acid rain condition. (November 2020)

• Record Type: Journal Article
• Authors: Basu, Arindam; Ram, Bikash Kumar; Nanda, Nirmal Kumar; Nayak, Sushil Subhadeep
• Is Part Of: International journal of rock mechanics and mining sciences. Volume 135(2020)
• Publication Date: 2020-11
• Subjects: Limestone -- Joints -- Acid rain condition -- Shear strength parameters; Rock mechanics -- Periodicals; Soil mechanics -- Periodicals; Mining engineering -- Periodicals; Roches, Mécanique des -- Périodiques; Sols, Mécanique des -- Périodiques; Technique minière -- Périodiques; 624.151305
• DOI: 10.1016/j.ijrmms.2020.104508
• Languages: English
• ISSNs: 1365-1609

Abstract

Abstract: Deterioration of shear strength parameters of carbonate joints under the influence of acid rainwater is a serious concern in rock engineering. Considering this, limestone specimens with planar joints (i.e. joints having roughness coefficient <5) collected from the Lanjiberna limestone mine (in the state of Odisha, India) were investigated. Depreciation of shear strength parameters of the joints concerning short-term exposure to a simulated typical acid rain (i.e. pH 4 solution) condition was evaluated. A total of 24 direct shear tests were performed on natural limestone joints and their degraded equivalents. Both peak shear strength and peak friction angle of a degraded joint are found to be less than those of its natural counterpart. The drop in peak friction angle is found to be 8–10% and 14–19% due to submergence of the joints in pH 4 solution for 5 days and 10 days, respectively. It was ascertained that the deterioration of the asperity strength due to the short-term exposure of the planar joint surfaces to the pH 4 solution overrides the effect of insignificant macroscopic change of the surface roughness caused by solution induced micro-cavities and hence, controls the degradation of the shear strength parameters.