Investigation of Petrographic and Geo Mechanical Characteristics Of Wargal Limestone, Nammal Gorge, Western Salt Range, Pakistan

Abstract

The estimation of rock mass strength is a key parameter in geotechnical engineering which is used in the design of geotechnical structures like tunnels, dams and slopes. Mechanical characterization was carried out on Wargal Limestone from Nammal Gorge, Western Salt Range to find out its potential to utilize it as construction and aggregate. To determine the mechanical behaviour of Wargal Limestone different tests were performed like UCS, PLT, UTS and SRH. ISRM and ASTM suggested procedures were followed while performing all these tests. Cores were extracted from the bulk samples and these tests were performed on those cores. Along with these mechanical tests, water absorption and specific gravity was also determined. Microscopic studies were performed to study the thin sections of Wargal Limestone. All of the results were correlated to investigate the effect of petrographic properties on mechanical behavior of studied rock. Average values were calculated against all the mechanical tests. Specific gravity was calculated with an average value of 2.64% and an average for Water Absorption is 0.49%. The results of UCS vary from 42.60 Mpa to 57.35 Mpa with their mean value of 51.50 Mpa. Similarly results for SRH range from 41 to 58 and its mean value is 50.93. UTS values range from 10.24 MPa to 14.64 MPa and have a mean value of 12.51 Mpa and PLT ranges from 4.31 MPa to 5.37 MPa while its mean value is 4.89 MPa for the studied samples. Microscopic study of the Wargal Limestone reveals the occurrence of calcite, quartz, bioclasts and pyrite in the studied samples and indicates that average calcite content is 79.8%, average quartz percentage is 9.6% and average bioclast content is 7.8%. Results show that the Wargal Limestone from Nammal Gorge, Western Salt Range fall within standards specifications limits and can safely be used for various construction projects.