Abstract:According to geologic characteristics,the vacuum preloading with prefabricated vertical drain(PVD) method was adopted to treat the soft soil in the intertidal zone. The test results show that the groundwater level in the consolidation zone decreases 2.98–4.17 m,and decreases only 0.78,1.04 m at the distances 8,12 m away from the outer boundary of the consolidation zone. Negative pore water pressure at the different depths along the PVD is similar,about 90% of vacuity under the membrane;and its transmission depths are more than 13 m. But the negative pore water pressure in the soft soil is smaller,which is decided by the geologic characteristics of the soft soil. Physico-mechanical properties of the soft soil are improved greatly after being consolidated,for which the water content decreases 10%–20%,the unit weight increases 10% and the void ratio decreases 10%–30%. The shear strengths of the soft soil are also improved greatly. The average strength of the soft soil in the middle of the consolidation zone with PVDs can increase 73%–75% and continues to increase when the soft soil is placed for certain time after being consolidated by vacuum preloading,which will increase averagely about 0.6%/d. This is to say,the vacuum preloading method can also be applied to the treatment of the soft soil in the intertidal zone.