A.邊支撐邊開(kāi)挖 B.先支撐后開(kāi)挖 C.兩端對(duì)稱同步支撐 D.先淺后深分層支撐
A.3 B.6 C.10 D.15
A.長(zhǎng)度 B.間距 C.抗拔力 D.外露長(zhǎng)度