單項選擇題當(dāng)圈梁遇洞口中斷,所設(shè)置的附加圈梁與原圈梁的搭接長度L應(yīng)滿足()

A.L≤2h且≤1000mm
B.L≤2h且≤1500mm
C.L≥2h且≥1500mm
D.L≥2h且≥1000mm