The compression coefficient in settlement calculation for vacuum preloading is based on the oedometer test
but the stress state in ground for vacuum preloading is different from oedometer test
the results of settlement calculation is unreasonable used parameter from oedometer test. The theoretic analyses in elastic condition
compression test by trixail apparatus with automatic controlled stress that can simulate the stress path in vacuum preloading
and field monitoring in project of vacuum preloading are presented. The ratio of isotropic to one dimensional consolidation in elastic condition under same load
compression coefficient from trixial test and oedometer test are discussed. Settlement results of field monitor and calculation show above consideration is reasonable.