一般净跨径在2～3米,设计水头差2～4米的小型涵闸,绝大部分采用螺睫启闭机。为使启闭没备的丝杆(螺旋杆)减轻锈蚀,通常把胸墙布置在丝杆外侧(外海边),以免丝杆受海水浸溅。而胸墙底的安置高程,原则以内河的最高洪水位为准。胸墙的断面形式,常见有宽阔式和薄壁式两种,如图1-a、1-b。这两种胸墙形式的不同,促使闸门极承受外力差距很大。一般薄壁式胸墙的闸门板受力,主要考虑静压力,浪压力及漂浮物的撞击力等,进行计算配筋(这里指钢筋砼闸门),可策安全;但宽阔式胸墙的闸门板,它所受外力,在各 The general net span of 2 to 3 meters, the design head 2 to 4 meters of small culvert, the vast majority of snail hoist. To make the opening and closing of the screw (screw rod) to reduce corrosion, usually the chest wall is arranged outside the screw (outside the sea), so as to avoid the screw immersion by seawater. The placement of chest wall at the end of elevation, the principle of the highest flood within the river shall prevail. Breast wall section form, common wide and thin-walled two, as shown in Figure 1-a, 1-b. The difference between the two forms of chest wall, prompting the gate withstand a great gap between external forces. Generally thin wall chest wall of the gate board stress, the main consideration of static pressure, wave pressure and the impact of floating objects, etc., to calculate the reinforcement (here refers to reinforced concrete gates), may be safe; however, wide chest wall of the gate plate, It suffered external forces