实践证明，悬拱法是不稳定岩层中平巷掘进的有效施工方法。

The practices showed that the suspension arch method of drifting is an effective way of drifting in unstable strata.

youdao

实践证明，悬拱法是不稳定岩层中平巷掘进的有效施工方法。

The practices showed that the suspension arch method of drifting is an effective way of drifting in unstable strata.

youdao