As we know that rocks are different from other engineering materials due to its irregular structure containing cracks, folds, joints and bedding planes. These type of rocks may the damage structure and reduces its life. For finding type of structure of rocks, we use Rock Quality Designation method.
RQD provide the basic information which an engineer have keep into mind while designing the building, its foundations and calculation of the depth of foundations to provide proper strength and durability of building. It is also used to give warning of the weakness of rock .
Rock Quality Designation (RQD) is modified core recovery percentage method which indirectly depends upon cracks,fractures present in the rocks.It was introduced 1960's. It is defined as percentage of recover the core from a drill hole.In these process we drill a hole on testing ground over a definite depth.Then we recover the core and calculate the percentage of recovery.of rocks. Sometime while drilling, placing or handling the core, it breaks into any parts. These fresh cut parts are joined together and counted as a single piece. The pieces or parts which is less than 100 mm are the neglected.
RQD =(sum of heights of core recover from drill hole×100)/total depth of drill hole
As below example, a hole is drilled upto 60 inches but for these particular case the total recovery was 50 inches and after the modified the net recovery was 34 inches. Thus the value of RQD is 57% for these particular case and rock belong to fair section.
RQD is not only sufficient to get adequate knowledge of rock as it does not take the joint orientation, tightness, continuity, and gouge material into account. RQD's input should use along with other geographical knowledge of rock.
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Shear force and Bending moment Diagram
COMPRESSIVE STRENGTH OF BRICK
RQD provide the basic information which an engineer have keep into mind while designing the building, its foundations and calculation of the depth of foundations to provide proper strength and durability of building. It is also used to give warning of the weakness of rock .
Rock Quality Designation (RQD) is modified core recovery percentage method which indirectly depends upon cracks,fractures present in the rocks.It was introduced 1960's. It is defined as percentage of recover the core from a drill hole.In these process we drill a hole on testing ground over a definite depth.Then we recover the core and calculate the percentage of recovery.of rocks. Sometime while drilling, placing or handling the core, it breaks into any parts. These fresh cut parts are joined together and counted as a single piece. The pieces or parts which is less than 100 mm are the neglected.
RQD =(sum of heights of core recover from drill hole×100)/total depth of drill hole
As below example, a hole is drilled upto 60 inches but for these particular case the total recovery was 50 inches and after the modified the net recovery was 34 inches. Thus the value of RQD is 57% for these particular case and rock belong to fair section.
RQD is not only sufficient to get adequate knowledge of rock as it does not take the joint orientation, tightness, continuity, and gouge material into account. RQD's input should use along with other geographical knowledge of rock.
Shear force and Bending moment Diagram
COMPRESSIVE STRENGTH OF BRICK
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