Abstract: soft dredger fill in Tianjin Binhai New Area of Lingang industrial zone is investigated by means of common vertical drainage board, improved vertical drainage board and improved transverse drainage board to take low vacuum pre-pressing test. The low vacuum pre-pressing of common vertical drainage board showed that in 28 days the strength of surface soil is up to 10 kPa. But the strength of soil in the middle part is still low. It is hard in both sides but soft in the middle. The low vacuum pre-pressing test of improved vertical drainage board showed that in the first 10 days soil strength increasing was similar to the common vertical drainage board. Later the soil strength increased significantly faster than the common drainage vertical board, in 28 days the strength of surface soil clamed to 12 kPa, the intensity of middle part was improved, but the overall uniformity was still poor. The low vacuum pre-pressing test of improved transverse drainage board showed that in 28 days the surface soil clamed to 11 kPa. The soil strength growth was slower than the improved vertical drainage board, but the strength of middle soil and uniformity were better than the improved vertical drainage board. The above test results are analyzed using the FEM simulation software, and compared with calculated settlement and pore water pressure, the improved vertical drainage board calculation result is found in good agreement with experimental data, improved transverse drainage board is a little poor, but it can basically reflect the low vacuum preloading soil settlement and pore water pressure in the process of value.

Key words: soft dredger fill, low vacuum pre-pressing, common vertical drainage board, improved vertical drainage board, improved transverse drainage board, numerical simulation