Rock Quality Designation

Bieniawski (1974, 1989) maintained that the uniaxial compressive strength of rock material the rock quality designation the spacing, orientation and condition of the discontinuities and groundwater inflow were the factors that should be considered in any engineering classification... 

Rock quality designation RQD 1. Where RQD is reported or measured as < 10 (including 0), a nominal 3... 

Documentation of sampling and coring depths, types, and lengths (e.g., sample type, blow count [for driven samples], and sample length for soil samples core run, recovery, and Rock Quality Designation (RQD) for rock cores) as well as in situ test depths and lengths... 

Reese (1997) proposed a procedure to calculate p-y curves for rock using basic rock and rock mass properties such as compressive strength of intact rock q. Rock Quality Designation (RQD), and initial modulus of rock E-. A description of the procedure is presented in the following. 

Rock Quality Designation (RQD) An indication of the fractured nature of rock determined by summing the total length of core recovered counting only those pieces which are 4 inches or more in length and which are hard and sound. RQD is expressed as a percentage of the total core ran. 

The rock quality designations (RQD the total length of solid core pieces that have individual lengths more than 10 cm, measured axially between discontinuities) of both the moderately and the intensely fractured zones are nearly 0%. Each fracture and fractured zone has been characterized to determine its length, width and continuity and the nature of the filhng minerals. These different zones have different types of wall rock alteration. The distributions of fractured zones are shown in Fig. 4. 

Fig. 4. Rock Quality Designation data (RQD the total length of solid core pieces that have individual lengths more than 10 cm, measured axially between discontinuities) for each borehole.

Castner turned his interest to gold extraction, which required high-quality sodium hydroxide. Castner developed a three-chambered electrolytic cell. The two end chambers contained brine and graphite electrodes. The middle chamber held water. The cells were separated excepted for a small opening on the bottom, which contained a pool of mercury that served as the cell s cathode. When current flowed through the cell and the cell was rocked, sodium reduced from the brine came into contact with water in the middle cell to produce a sodium hydroxide solution. As Castner built his mercury cell, Kellner was working on a similar design. Rather than compete with each other, Castner and Kellner joined forces to establish the Castner-Kellner Alkali Company to produce sodium hydroxide, which competed with soda ash and potash as an industrial base, and chlorine, which was used primarily to make bleach. 

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