Abstract: The improvement effect of using the prefabricated vertical drains with surcharge preloading method to treat the soft soils are presented in this paper. Combined with a soft soil improvement project in Jiangmen City, the monitoring data of surface settlement, extensometer results, pore water pressure and other monitoring information were analyzed. The research results show that: (1) It is unreasonable to use a single settlement rate to determine the results of the improvement, and it is necessary to comprehensively consider a variety of deformation indicators. (2) In the range of 2~12 meters below the ground surface, the compression rate of each soil layer is 6.36~9.56%, and the compression amount accounts for 62.4% of the total settlement. The maximum compression rate is 6 meters below the ground, not at the ground surface. (3) At the end of preloading stage, the dissipation rate of excess pore pressure is close to zero, but there is still residual pore pressure at a deeper level. The research results of this paper can provide a valuable reference basis for the design of regional soft foundation.

Key words: Soft Soil Monitoring, Soft Improvement Effect, Consolidation Settlement, Excess Pore Water Pressure