Abstract：The land section with long distance in water-bearing unfavorable geological condition of Xiamen Xiang¢an subsea tunnel under construction was performed by center cross diagram(CRD) method. In order to ensure both safety and efficiency of construction，a study based on both numerical calculation and displacements measured in field was carried out. The arch-crown subsidence of CRD under different excavation sequences of headings and the distribution proportion of each heading excavation were discussed. Both calculation and field measured results indicated that，about 40% arch-crown subsidence was caused by excavation of heading 1；the arch-crown subsidence vs. time normally was in a shape of uplifted steps with a final stable value. An integral subsidence of tunnel less than 10% of final value occurred after primary lining was completed. Closing the inverted arch as soon as possible could greatly reduce the final subsidence. The space between border upon headings should be well controlled normally not more than 10–15 m，and the temporary inverted arch should be installed as soon as possible to form the lining structure.
