Instantaneous nondestructive evaluation of elastic modulus by using knocking ball test on sedimentary and metasedimentary rock slope

• Published in: Measurement: Journal of the International Measurement Confederation
• Main Author: Razali M.; Ismail M.A.M.; Nagendran S.K.; Zainal Z.; Kawano K.; Date K.; Yokota Y.
• Format: Article
• Language: English
• Published: Elsevier B.V. 2023
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85176319633&doi=10.1016%2fj.measurement.2023.113774&partnerID=40&md5=9dd9ebc6ee4cd4f34367d812ddc476e1

The elastic modulus of rock masses is a critical parameter for many engineering applications. However, in situ measurement of the elastic modulus can be challenging and time-consuming. This study established a new in situ method to measure the elastic modulus of rock masses, enhancing prior technology using Hertz's theory. The method involves using a knocking ball, which strikes the rock surface with a spherical steel hammer, providing an instantaneous measurement. The knocking ball method was tested on a variety of rock types, and the results showed a significant correlation (R2 > 0.8) between the elastic modulus of the knocking ball (Ekb) and the in situ uniaxial compressive strength (UCS-Schmidt). The knocking ball method overcomes the limitations of the Schmidt hammer by offering rapid, direct, and multipoint measurements. The knocking ball method is non-destructive, handheld, and easy to use, making it ideal for use in field applications. © 2023 Elsevier Ltd