关于涵洞明暗划分的讨论.rar

关于涵洞明暗划分的讨论

公路桥涵设计手册《涵洞》（人民交通出版社出版发行；1993年5月，第一版；2001年4月第一版第4次印刷）第三页中指出：“涵洞按洞顶填土情况可以分为明涵和暗涵两类。明涵是指洞顶不填土的涵洞，适用于低路堤，浅沟渠；暗涵是指洞顶填土大于50cm的涵洞，适用于高路堤、深沟渠。”
这里所说的“洞顶填土”高度是指洞顶至路面顶最薄处的高度。
明涵只在涵洞顶做路面的面层。
对于低等级公路，洞顶填土大于50cm时能够在涵顶将路面结构层（包括面层、基层、底基层）完整的做出来。而对于高等级公路，路面结构层一般都大于50cm，因此50cm高的洞顶填土高度无法将路面结构层完整的做出来。
所以，对于涵洞明暗的划分应当这样规定：明涵是指只在洞顶做路面面层的涵洞；暗涵是指洞顶至路面顶的最小高度大于路面结构层总厚度的涵洞。
也就是说，能够在涵洞的洞顶将路面结构层完整
Discussion on the division of light and dark culvert

Highway Bridge Design Manual "culverts" (People's Transportation Publishing House; in May 1993, First Edition; in April 2001 the first edition 4th printing) the third page states: "culvert by filling in top condition can be divided into two categories Ming Han and culvert. Ming Han is the top of the cave does not fill the culvert, for low embankments, shallow ditches; culvert is the top of the cave fill and culverts greater than 50cm, for high embankment, deep ditch. "
Here "top of the cave fill" high is top of the cave to the top of the thinnest surface height.
Ming Han only do road culvert top surface.
For low-grade highways, and the roof can fill more than 50cm in the culvert when the top layer of the pavement structure (including the surface layer, the grassroots, sub-base) complete to make it. As for the highway, pavement layer is generally greater than 50cm, 50cm high so high you can not fill in top layer of pavement structure integrity to make it.
Therefore, the division of light and shade for the culvert should be such that: Ming Han is only in the top of the cave to do pavement surface culverts; dark road culvert is the top of the cave to the top of the minimum height is greater than the total thickness of pavement layer culverts.
That is, to the top of the cave in the culvert would be complete pavement layer