梯田基线设计与简易放线法

梯田基线设计,多采用经验法,等高等宽不好兼顾,“大弯就势,小弯取直”往往只能定性,不能量化,由此设计出的梯田埂线,难以得出最佳梯田断面。如根据地形图等高线走向趋势,选择代表地面走向的等高线,通过概化分析,以数学函数式表达等高线,使其横贯坡面切割等高线为最少,以此作为梯田地埂基线,由其函数对应值,在实地进行坐标放线,即可做到等高布设、等宽兼顾和“大弯就势,小弯取直”定量化,既满足机械作业对曲率半径的要求,也避免了施工时的大切大垫。

Base Line Design of Terraced Land and Simplified Method of Staking out in the Field

The Design of terraced field base line mainly adopted empirical method, which could not take account of both same height and Same width. "Parallel with the tendency at large bend and straight up at small bend" may be used as a qualitative guide but not quantitative. Optimized cross section of the terraced field can not be obtained by this design principle. The base line in the design of a terrace may be determined by selecting the contour which represents the tendency of the ground surface based on the tendency of contours on the torpogrophy map and using an appropriate mathematical function to express the contour line accord-ing to the generalized analysis in order to get least number of intersections of the cross section with the con-tours. Using this contour as the bank line of terraced field and staking out insitu by coordinates, not only both the same height and same width may be considered, but also the guideline of "parallel with the tenden-cy at large bend and straight up at Small bend" may be satisfied. On the one hand, requirement of a proper radius of curvature for operation of machineries could be satisfied, on the other hand, unnecessary large amount of excavation and fill could be avoided.