Floor and pit moulder地面和地坑制模工
floor drainage pit地板排水孔
floor arch pit机器座坑
Under-floor Deep Pit Manure Storage地下深坑储粪坑
floor arch drainage pit地面疏水坑
pit floor drainage地板排水孔
open pit floor edge下部境界线
impact loading to pit floor底坑地面冲击载荷
water bursting in pit floor矿坑底板突水