【摘要】 <正> 无障碍物存在的平坦、均一和坚硬的地表,一般是不易引起风沙(雪)流沉积的,因此,进行各种地形条件下的下导风工程实验是十分必要的。实验仅以公路、铁路线上所遇到的各种地形条件来进行。更多还原

【Abstract】 Under - leading fence is a permanent or semi-permanent eugireering measure . It can redistribute flow energy of the boundary layer where is located the fence so that the resistance caused by fluid seperation on the topographic surface can be surmounted and the deposition of sand or snow drift can be weakened and eliminated. It can also cause strong vortex movement between the fence and dune or snow near the fence so as to disperse and check the harms from sand (or snow) encroachment. To construct a good under - leading fence, the local conditions must be conbined in an optimal way with the protection demands.The penetration coefficient of the fence between 0.4- 0.5 will be better. The inclination angle of the fence is the same as the plane experiment, described in part I, but it must be rectified by the angle of slope.It is required that the design of under - leading fence should be combined wite the measures for stablizing, blocking, transporting and transmitting sands and a better effect will be gained by doing so.更多还原