Geotechnics And Applied Geology

Geotechnics And Applied GeologyStructural Geology

Prepared By: Guided By:Shuaib Kohee (151100106079)Wahedullah Ehsas (151100106080)Ehsanullah Aydin (151100106078)

Prof. Mital Mistery

Content Strike and DipOutcrop Folds Faults Joints

IntroductionStructural geology is the study of the factors such as origin, occurrence, classification, type and effects of various secondary structures like folds, faults, joints, rock cleavage and are different from those primary structures such as bedding and vesicular structure, which develop in rocks at the time of their formation.

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StrikeIts defined as the direction of a line formed by the intersection of a bedding plane and a horizontal plane.Its always at right angle with the true dip direction.It is a horizontal line on a surface of rock beds.

Dip It means slope or inclination.The angle of inclination of a bedding plane with horizontal plane is called amount of dip.The direction along which the inclination of the bedding plane occurs, is called dip direction.So dip is expressed both as amount and direction.The direction angle is measured with clinometer.The direction is measured with a compass.

OutcropThe exposure of rock beds on the ground surface is called outcrop.In mountain and sub-mountains its easily visible.

Folds When a set of horizontal rock layers are subjected to compressive force, undulation or bends curvatures developed in the rock layers. These bends are called folds.

Classification Of Folds Based on different principles, it can be classified.Its classifications are:Based on upward and downward bendingBased on position of the axial plane Based on degree of compressionBased on mode of occurrence Based on position of fold axisBased on behavior with widthMiscellaneous folds

Based on upward and downward bendingIt can be classified as:Anticlines Synclines

Based On Position of the axial plane It can be classified as:Symmetrical Asymmetrical Overturned Fan folds Recumbent folds Isoclinals folds

Based On Mode Of Occurace It can be classified as:Anticlinorium and synclinorium Dome and basin

Based On Position Of Folds AxisIt can be classified as:Plunging folds Non-Plunging folds

Faults A fault may be defined as a fracture surface along which relative movement of adjacent blocks has taken place.

Classification Of FaultsIt can be classified as following basis:On the basis of apparent movement of the fault blocksOn the basis of amount of the dip of fault On the basis of attitude of the fault On the basis of the direction on the net slipOn the basis of their mode of occurance

On The Apparent Movement On the basis of up or downward motion of the hanging wall or the foot wall the following classifications are:Normal fault Thrust fault Transcurrent fault Vertical fault

Normal and thrust faults

Transcurrent and vertical faults

Based On Attitude Of The Folds It can be classified as:Strike faults Dip faults Oblique faults

Based On The Direction of the net slip It can be classified as below:Dip slip faultsStrike slip faultsOblique slip fault

Based on Mode of OccurrenceIt can be classified as below:Horst faultsParallel faults Radial faultsEnchelon faultsStep faults

Radial fault

Echelon fault

Step fault

JointsWhen rock masses are subjected to tensional compression forces, regular or irregular fractures develop in them. Such fractures along which there has been no relative displacement are called joints.

Classification of JointsBased on attitude and geometry:It can be divided into below categories:Strike joints Dip joints Oblique joint

Classification of JointsBased on Origin:It can classified as below:Tension joints Shear tension

Tension joints They are produced due to tensile or stress force in the rocks, either during their formation or after their formation.It can classified as below:Columnar joints Mud cracks Mural joints

Shear Joints They are formed by shearing force stresses, which tend to slide one part of the rock against the other.

References :Geotechnics and applied geology (DR. R.P Rethaliya)www.wikipedia.com

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