为什么下水道井盖是圆的?

2025-03-07 06:30:53
推荐回答(5个)
回答1:

井盖为什么是圆的?

回答2:

  盖子下面的洞是圆的,因为圆柱形最能承受周围土地的压
  力。而且,下水道出入孔意味着要留出足够一个人通过的
  空间,而一个顺着梯子爬下去的人的横截面基本是圆的。
  所以圆形自然而然地成为下水道出入孔的形状。一些方形
  洞口上也会看到方形的盖子。这种盖子比入口大,周围有
  横档。通常这种盖子是金属质地,非常重。我们可以想象
  一下,两英尺宽的方形洞口,1到1.5英寸宽的横档。为了让
  井盖掉进去,需要抬起一端,然后旋转30度,这样它就不
  受横档的妨碍了,然后再将井盖与地平线成45度角,这时
  转移的重心才足以让井盖掉下去。而圆的就没有这样的顾
  虑。从工程学的角度来看,井盖的形状完全取决于它要覆
  盖的洞口的形状。
  1.节省材料
2.方便运输
3.方便安装
4.美观
5.受力均匀
  6.盖子和井口都是圆的,所以盖子掉不下去。
其他的形状
  容易掉下去的这牵涉到圆形和方形(包括正方形、长方
  形、菱形等各类四边形)在井盖上的实际运用问题。
井盖
  上随时有车辆行人经过,使用圆形,主要是考虑到圆形的
  井盖通过其圆心的每条直径长度都是一样的,这样如果井
  盖被经过的车辆轧起时,因为不论如何轧起,其直径都会
  比下面的井口略宽,井盖不会掉到井口里去。
而如果采用
  方形,因为方形的对角线明显长于其每条边长,这样的井
  盖被轧起时,很容易沿井口的对角线方向掉进井中,造成
  安全隐患。
也许有人会问,如果井口做成圆形或明显小于
  井盖,方形的井盖就不会掉进井中。这里就牵涉到一个材
  料的最大利用和节约的问题。井口的使用取决于井口的大
  小,如果非要在上面按个面积远远大于井口的方形井盖,
  那么材料的利用和实用价值自然没有直接使用圆形的井盖
  更有效,既节约井盖的材料,也保证了井口的安全。

回答3:

根据圆的定理,同圆半径相等设计的。我们知道加水道井口主要有三部分组成,井口上沿、井口下沿和井盖。井口直径大于井盖直径,这就保证了在任何角度都可以将井盖放入井口,这样就减轻了人们的劳动强度;同理井口下沿直径小于井盖直径,这样的可以保证在任何角度,井盖都不会掉入井下。

回答4:

圆的面积小呀

回答5:

井盖为什么是圆的?

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