Abstract: Through laboratory tests on mudcake and soil between bored piles in mud,clay and silt in Hangzhou,the influence of mudcake on shaft friction and the difference between mudcake and soil between bored piles were studied.In addition,by using laboratory tests on mud mixed with cement grout,the improved effect on mudcake with cement grout was analyzed.It was shown that compared with soil between bored piles,mudcake had high moisture content,high void ratio,high compressibility,low friction and shear strength.Mudcake was weaker than the pormer and became a weak layer between pile and soil and reduced the shaft friction of piles.Grouting could evidently improve mudcake.