短語詞組短語advance arch -crown strengthening 拱頂超前加固cracks of arch -crown 頂拱裂縫underground powerhouse arch -crown 地下廠房頂拱arch crown block 拱頂石arch crown concrete 拱頂混凝土arch crown cantilever method 拱冠梁法arch crown beam profile 拱冠梁剖面Arch crown subsidence 拱頂下沉cracks of arch crown 頂拱裂縫arch crown settlement 拱頂沉降 返回 arch crown