Section II Applications of Measurements 2. Earthwork كميات الحفر و الردم 1 1 1

Profile Leveling القطاعات الطولية To collect data about topography along a reference line. Mainly to compute volumes of cut and fill الحفر و الردم for a proposed linear structure, such as: highways, railroads, transmission lines, canals. Then the best route can be chosen. The result: elevations at definite points (stations) along a reference line, usually the center line. 4

Field Procedures Profile leveling 7

First a backsight at a BM is observed. Then, a number of intermediate sights are observed at the locations needed, do not have to be at equal distances. When the distance becomes too long, or readings become hard to observe, a turning point نقطة دورا ن is constructed. You cannot keep the backsight distance equal to the foresight distance. Elevation computation: Elevation of line of sight (LS) = EBM + BSBM. Elevation of any intermediate point = ELS - ISIP. Elevation of point at FS = ELS - FSPOINT Handle new level positions as in differential leveling, construct a turning point and knowing BS and FS readings, compute a new elevation of line of sight. 9

Intermediate sight (IS) Example Point Backsight (BS) مؤخرة Intermediate sight (IS) متوسطة Foresight (FS) مقدمة Elevation of line of sight (HI)  منسوب خط النظر Elevation BM 09 1.573   20.00 1 1.472 2 1.718 3 1.352 1.551 4 1.181 5 1.492 6 2.101 1.212

Intermediate sight (IS) Answer Point Backsight (BS) مؤخرة Intermediate sight (IS) متوسطة Foresight (FS) مقدمة Elevation of line of sight (HI)  منسوب خط النظر Elevation BM 09 1.573   20.00 1 1.472 2 1.718 19.885  3 1.352 1.551 4 1.181 5 1.212 1.492 6 2.101 21.573 20.101 21.374 20.022 20.193 21.094 19.882 18.993

Drawing and Using Profiles Drawn using a software now. To manually draw a profile and compute earthwork: Assume the horizontal axis is the distance and the vertical axis is the elevation. Use a larger scale for the elevation than the scale of the distance, usually 10 times larger. Draw the design line at the proposed grade الميل . Compute the areas of cut and fill. Multiply area by width to get volumes. Gradient الميل (percent grade) is the rise or fall in m per 100. 10

Horizontal scale 1: 2500 Vertical scale 1: 250 1 m 10 m Horizontal scale 1: 2500 Vertical scale 1: 250 11

Example Point Distance (m) Elevation (m) A 0.0 115.0 B 100 117.2 C 200 The table below shows ground elevations along the centerline of a proposed pipeline. If the bottom of the trench to be excavated is at elevation (+115m) at point (A) and slopes -1%, and the the trench is 2m wide, compute the volumes of cut and fill. {Answer is given in lecture} Point Distance (m) Elevation (m) A 0.0 115.0 B 100 117.2 C 200 116.0 D 300 112.0 E 400 110.5 F 500 110.0

Borrow-Pit Method الميزانية الشبكية Not suitable for linear features, very useful for construction sites. The site is divided into equal squares. Elevations are then measured at the corners of the grid الشبكة , which are given names that correspond to the corner coordinates in the grid, ex: 3-D, 4-A, etc. Then heights of cut or fill (hij) over design elevation are computed. Where is the height at the intersection of axes i with axis j, then: V =  (hijn) A yd3 4*27 The idea is to multiply each height by the number of complete squares it is common to (n), the product is then multiplied by (A/4) where A is the area of one of the squares ( ) 12

The volume on any square, or part of a square is equal to the average height(elevation difference) at the corners, times the area. To compute the volume: 1- draw a line between the cut and the fill areas 2- compute the total volume of all the complete cut squares, do the same for the fill, use the previous formula 3- Compute the incomplete squares separately and add them to the squares. 4- Compute the difference between the cut and the fill., pay attention to the expansion factor. 13

A B C 1 hA1 hB1 hC1 V1 = A * (hA1 + hB1 + hA2 + hB2) / 4 V2 =A * (hB1 + hC1 + hB2 +hC2) / 4 2 hA2 hB2 hC2 V3 = A* (hA2 + hB2 + hA3 +hB3) / 4 hA3 hB3 3 Total volume V = A* {(hA1 + hB1 + hA2 + hB2) / 4} + A* {(hB1 + hC1 + hB2 +hC2) / 4} + {A*(hA2 + hB2 + hA3 +hB3) / 4} = (hA1 +2 hB1 + hC1 + 2 hA2 + 3 hB2 + hC2 + hA3 + hB3) / 4

Example Corner A-1 B-1 C-1 D-1 A-2 B-2 C-2 Height +3.1 +2.8 +2.0 +4.0 The table below shows the heights of cut and fill in meters at the corners of a 20m grid. Compute the volume of soil to be imported or disposed. Assume 25% expansion factor for the fill. ( + is cut, - is fill) Corner A-1 B-1 C-1 D-1 A-2 B-2 C-2 Height +3.1 +2.8 +2.0 +4.0 +2.2 +1.5 Corner D-2 A-3 B-3 C-3 D-3 A-4 B-4 Height +1.2 +2.0 +1.7 +1.0 0.0 +1.5 +0.8 Corner C-4 D-4 Height 0.0 - 3.00