In judgment of liquefaction of saturated soils during engineering practice,the author thinks that when cal- culating the depth of standard penetration point,the depth should start with the primitive landform floor before level- ling;water level for discontinuous multi-bedded strata with possible liquefaction should be calculated respectively according to water depth in bed.

The pile foundation is an important component of the offshore jacket platform,the penetration depth of which imposes vital influence on the cost and security of the platform.

To identify saturated sand liquefaction,according to present regulations standard penetration test is used and complemented with static cone test,while shear wave velocity test can be used in areas where have experienced.

On the basis of a large amount of laboratory simulation test in large medium tank and field in-situ tests,we set up relationship between the indexes of cone penetration test and standard penetration test and engineering properties.

Both standard penetration test and ultrasonic wave test are important methods in-site tests.

The stratum ranges that suitable for standard penetration test and heavy-duty dynamic sounding test are different.

Authors made some tests including standard penetration on cement-soil piles, drilling for core and in-door compression without lateral confinement to accurately evaluate the construction quality of these cement-soil agitation piles.

By analysis comparatively of the in?situ testing data, the relation among foundation s bearing capacity of swelling soil in Hefei, moisture content in nature, data of the static cone penetration testing and standard penetration testing is proposed.

Through analysis and compute on 29 item inestigating engineering s data of SPT,weight-type DPT and CPT in saturation sandy soil that they were in Beihai city,The author has setted up the relation formula of groundwater correct for SPT:N=N +4.