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The Hallade method, devised by Frenchman Emile Hallade, is a method used in track geometry for surveying, designing and setting out curves in railway track. [1] It involves measuring the offset of a string line from the outside of a curve at the central point of a chord. In reality, string is too thick to provide a clear reading and breaks ...
Curvature is usually measured in radius of curvature.A small circle can be easily laid out by just using radius of curvature, but degree of curvature is more convenient for calculating and laying out the curve if the radius is as large as a kilometer or mile, as is needed for large scale works like roads and railroads.
Road curves are irregular bends in roads to bring a gradual change of direction. Similar curves are on railways and canals. Curves provided in the horizontal plane are known as horizontal curves and are generally circular or parabolic. Curves provided in the vertical plane are known as vertical curve.
Total stations are the primary survey instrument used in mining surveying. A total station is used to record the absolute location of the tunnel walls, ceilings (backs), and floors, as the drifts of an underground mine are driven. The recorded data are then downloaded into a CAD program and compared to the designed layout of the tunnel.
In topographic surveying, to determine slope to horizontal distance calculation, contour tracing and relative heights. [9] In forestry, for tree height measurement. [10] In mining and mine safety inspection, to measure the grades of haulage roads. [11] In geology, in measurements of rock outcrops and fault scarps. [12] [13] [14]
In horizontal curves, the cross slope is banked into superelevation to reduce steering effort and lateral force required to go around the curve. [1] All water drains to the inside of the curve. [ 2 ] If the cross slope magnitude oscillates within 1–25 metres (3–82 ft), the body and payload of high (heavy) vehicles will experience high roll ...
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Traverse networks involve placing survey stations along a line or path of travel, and then using the previously surveyed points as a base for observing the next point. Connected survey lines form the framework and the directions and lengths of the survey lines are measured with an angle measuring instrument and tape or chain. [2]