Abstract: The construction excavation support monitoring data of 29 metro stations in Suzhou City that using the diaphragm wall plus internal support were collected and statistically analyzed in order characterize the deformation of the deep excavation support system. The statistical data indicate that: 1) the maximum lateral deflection of the supporting structure, δ_hm, falls into the range between 0.13% H_e and 0.67%H_e with an average deflection value of 0.32%H_e, where H_e is the excavation depth; 2) The measured maximum deflection falls into the range from H_e-5 (meters) to H_e+3 (meters); 3) the maximum ground subsidence behind the supporting structure, δ_vm, is within a range between 0.07%H_e and 0.7%H_e with an average of 0.26%H_e; the horizontal influence zone of the ground subsidence is approximately 4.5H_e; 4) The ratio of ground vertical deformation behind the supporting structure over lateral deflection at the supporting structure, δ_vm/δ_hm, is between 0.346 and 1.54. 

Key words: metro subways, deep excavations, diaphragm wall, deformation during excavations, statistical analysis