Rock quality designation index (RQD) The Rock Quality Designation index (RQD) was developed by Deere (Deere et al 1967) to provide a quantitative estimate of rock mass quality from drill core logs. RQD is defined as the percentage of intact core pieces longer than 100 mm (4 inches) in the total length of core.

Rock Quality Designation (RQD) is a measure of quality of rock core taken from a borehole. RQD signifies the degree of jointing or fracture in a rock mass measured in percentage, where RQD of 75% or more shows good quality hard rock and less than 50% show low quality weathered rocks.

RQD 即岩石 质量 指标, 指每次进尺中等于或大于10cm的柱状岩芯的累计长度与每个钻进回次进尺之比 (以百分数表示) 。 RQD 由美国人迪尔 (Deere [4] ) 提出的, 被广泛地应用于评价岩体的完整性, 并作为岩石质量分级的一项重要指标。 RQD 值国外应用较多, 我国从80 年代开始引用了这一评价指标, 经过了十几年的实践, 取得了一些成果, 但也发现存在着许多的问题, 无论是对其概念的理解, 还是应用的认识都有较大的不足 [1]。 从RQD 本身的指导意义看, RQD 是一个衡量岩石质量 …

ROCK QUALITY DESIGNATION (RQD) Developed by Don U. Deere in 1964 Significantly expanded by Deere , et al in 1967 A useful index for determining rock quality from core recovery RQD= Length of “sound” core > 10 cm (4 in) X 100 Total Core Run Length

The correct procedure for measuring RQD is illustrated in Fig. I. The RQD index is an index of rock quality in that problematic rock that is highly weathered, soft, fractured, shcarcd, and jointed is counted against the rock mass. Thus it is simply a measurement or the percentage of "good" rock recovered from an interval or a borehole.

4.2 Rock Quality Designation (RQD) e stability of rock masses. Using the RQD-value, five rock classes are define (A-E) as shown in Table 1. RQD was originally defined from drill cores as follows: “RQD is the sum of the length (between natural joints) of all core pieces more than 10 cm long (or core diameter x 2) as a percentage

Download scientific diagram | Procedure for measurement and calculation of Rock Quality Designation (RQD) (Deere and Deere, 1988) from publication: Most used rock mass classifications for...

2024年9月4日 · Rock Quality Designation (RQD) is an important measure in geotechnical engineering used to assess the quality and fracturing of rock masses. It is calculated as the percentage of rock core pieces longer than 10 cm (4 inches) relative to the total drilled length.

RQD (Rock quality designation ) signifies the degree of jointing or fracture in a rock mass measured in percentage, where RQD of 75% or more shows good quality hard rock and less than 50% showed low quality weathered rocks.

2024年6月26日 · Rock Quality Designation (RQD) measures the quality of rock cores from boreholes by calculating the percentage of core pieces longer than 10 cm. It helps assess rock mass integrity, with higher RQD values indicating better quality rock with fewer fractures, and lower values indicating more fractured, poorer quality rock.