(State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China)
Abstract：The silt in the Yellow River Delta mainly belongs to the quaternary deposits. Based on the in-situ drilling test，pressuremeter test(PMT)，dilatometer test(DMT) and laboratory test，the mechanical properties of silt are studied. Laboratory test results show that there are many special characteristics of silt soil，such as the homogeneous particle size(grain sizes of silt centralized in 0.075–0.005 mm)，poor gradation and little clay content in the silt，therefore，it is hard in compaction. In addition，the porosity of the silt is very high，which leads to large compressibility. The results of PMT demonstrate that the allowable bearing capacity of foundation in the Yellow River Delta is 300 kPa. In addition，the critical edge pressure of silt increases with the depth，and decreases in the depth greater than 13.0 m. The quantitative relationship between modulus of lateral pressure test and depth is also presented. Moreover，the suggested value of modulus of lateral pressure test is 1 800 kPa in the Yellow River Delta. As for DMT，the results reveal that most strata in the area belong to silt ones except for some rock flour or silt clay in some layers. Then，the changes of static lateral pressure coefficient K0 and horizontal stress index KD with depth are studied. Finally，the relationship between dilatational modulus ED and compression modulus Es is discussed；meanwhile，the variations of ED and Es with depth are analyzed.
