在顶点两侧的内弧面上仍然有尖端的拱。

An arch having cusps in the intrados on either side of the apex.

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当鼠洞垮塌卸料时，落下的材料常常在出料口上方变得致密而形成拱弧。

While some material may discharge as the rat hole collapses, falling material often gets compacted over the outlet and forms an arch.

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有水平拱背和水平的内弧面的互相支撑的拱石的拱。

An arch with mutually supporting voussoirs that has a straight horizontal extrados and intrados.

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