The spatial position of the rock stratum determines its occurrence factors, including the strike, dip and dip angle of the rock stratum (Figure). The strike of rock stratum is the direction where the rock stratum intersects the horizontal plane. When measuring, the bottom of the long side of the compass is close to the rock stratum. When the bubble of the circular level is in the middle, read the degree pointed by the north or compass, which is the required hitting direction. The dip angle of rock stratum refers to the direction in which the downward maximum dip line of rock stratum is projected on the horizontal plane. When measuring? Point the northern section of the compass in the downward inclined direction of the rock stratum, and lean the short side of the southern end against the rock stratum. When the circular bubble is in the center, read the reading indicated by the compass, that is, the required trend. The dip angle of stratum refers to the maximum angle between stratum and imaginary horizontal plane, which is called true dip angle. The true dip angle can be measured along the true dip line of the layer. If the dip angle measured along other dip lines is less than the true dip angle, it is called apparent dip angle. When measuring, stand the compass sideways so that the long side of the compass is close to the stratum, wave the adjustable wrench outside the chassis with the middle finger of the right hand and move the compass along the stratum at the same time. When the bubble of the tubular level is centered, the maximum degree pointed by the inclinometer pointer is the true dip angle of the stratum.

Formation occurrence factors and their measurement methods