RQD stands for Rock Quality Designation and is a measure of the quality of rock core obtained from drilling or sampling. RQD is expressed as a percentage and is calculated by dividing the total length of sound rock core pieces over a specified length by that specified length, and multiplying by 100.
An RQD value of 50% means that 50% of the rock core pieces obtained from drilling or sampling are sound and suitable for use in engineering calculations. This value indicates that the rock mass is moderately fractured and may require some support measures, but is still considered suitable for certain engineering applications.
In general, higher RQD values indicate better quality rock and lower levels of rock mass deformation and fragmentation, while lower RQD values indicate poorer quality rock and higher levels of rock mass deformation and fragmentation. RQD is one of the many factors that are considered when assessing the suitability of a rock mass for a particular engineering application, along with other factors such as rock strength, rock mass rating, and geological structures.
Comments