引言河床,无衬砌渠道以及灌溉沟槽,都趋于近似不变的抛物线型。所以,无衬砌渠道一开始就按抛物线型施工,能使其在水力学上有较大的稳定性。由于沿渠道横断面的边坡通常小于水面处发生的最大允许滑坡,因此,抛物线渠道实际上也较为稳定。妨碍采用抛物线渠道的因素之一,是设计和施工理论上的困难。然而,小型抛物线沟渠能用抛物 INTRODUCTION River beds, unlined channels, and irrigation trenches tend to be approximately parabolic. Therefore, the unpaved channel parabolic construction from the very beginning can make it more stable in hydraulics. Parabolic channels are actually more stable due to the fact that the slope along the channel cross-section is usually smaller than the maximum allowed landslide at the water surface. One of the factors hindering the adoption of parabolic channels is the theoretical design and construction difficulties. However, small parabolic trenches can be parabolic