5.3.6 Relation betweenδH（max）andδV（max）
In general，the maximum ground surface settlementδV（max），can be estimated by referring to the value of the maximum wall deflectionδH（max）.From the data of case histories reported by Mana and Clough（1981），Ou et al.（1993），and Hsieh and Ou（1998），the relationship between maximum wall deflection and maximum ground surface settlement can be obtained as
Long（2001）analyzed the effect of different support types onδvmax andδhmax.It was found that there is a variable response in the ratio ofδvmax andδhmax between different support types and ground conditions.The findings of Long（2001）are summarized in Table 5.2.This shows that，as the soil conditions deteriorate，the ratio ofδvmax／δhmax changes from less than 1 to greater than 1.Long（2001）did not quantify the relationship between support stiffness and ground movements，despite identifying the possibility that existed.Long（2001）suggested that there is a linear relationship between H andδvmax andδhmax once classification of different ground conditions has been made，though this was not proven in terms of statistical significance.He also identified that there is an increase inδhmax with a decreasing FoS against basal heave，confirming the conclusions of the earlier study by Clough and O’Rourke（1990）.
Table 5.2 Findings of Long（2001）for magnitudes of ground movement based on split database
Based on the cases by Long（2001）using the same variables.In total，389 case studies have been compiled，with 235 from the database constructed by Long（2001），and 154 cases added by Holmes et al.2019，dating from 2002 to 2016.The database is attached in the Appendix I.It should be noted that only the propped or anchored excavation case studies from the database of Long（2001）were included.