![]() The co-ordinates may be written in the determinant form irrespective of the signs. The area of the section is calculated from these notes by coordinate method. The numerator denotes cutting (+ve) or filling (-ve) at the various points, and the denominator their horizontal distances from the centre line of the section. The notes regarding the cross-section are recorded as follows: In this case, the transverse slope of the ground is not uniform but-has multiple cross-slopes as is clear from the figure. In this case, the transverse slope of the ground is not uniform. when the area in filling is greater than that in cutting, the equations 12.3 and 12.4 are used for finding the areas in filling and cutting respectively. When filling extends beyond the centre line i.e. In this case the ground is sloping transversely, but the slope of the ground intersects the formation level such that one portion of the area is in cutting and the other in filling (part cut and part fill). In this case, the ground is sloping transversely, but the slope of the ground does not intersect the formation level. In this case the ground is level transversely. the horizontal distances from the centre line to the intersections of the side slopes with the original surface.įormulae for the dimensions of the cross-sections of cutting and filling for the above cases are given below and should be verified by the readers as exercises. W 1 and W 2 = the side-widths or half breadths i.e. the vertical distances from formation level to the intersections of the side slopes with the original surface. ![]() The following are the various cross-sections usually met with whose areas are to be computed: It is the common practice to calculate the volumes as straight as mentioned above and then to apply the correction for curvature to them.Īnother method of finding curved volumes is to apply the correction for curvature to the areas of cross-sections, and then to compute the required volumes from the corrected areas from prismoidal formula. ![]() ![]() ![]() When the centre line of the project is curved in plan, the effect of curvature is also taken into account specially in final estimates of earthwork where much accuracy is needed. The indirect method being simpler is more commonly used. In the indirect method, the volume is firstly calculated by trapezoidal formula and the prisomoial correction is then applied to this volume so that the corrected volume is equal to that as if it has been calculated by applying the prisomoidal formula directly. The prismoidal formula can be used directly or indirectly. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |