For the slant problem of large diameter cylinder piers on the sea due to remained mud interlayer between the enrockment bedding and bedrock

a new remedy method is put forward and designed. It is extruded sand-gravel column with sleeve valve grouting

formed by pouring sand-gravel into boring hole

aiguille extruding them into the soft clay interlayer and enrockment

then grouting with sleeve valve. The inspection results after construction indicate that the diameter of pure sand-gravel column in mud and silt reaches 55 to 82 cm

the boring core sample strength of grouting column reaches 4.3 to 11.4 MPa at 28 days. Now the remedy project is completed for 1 year

the good state of large diameter piers shows that the suggested method is very successful.