Abstract: Based on different types of groundwater and its characteristics, the impaction of of vadose zone water, diving water as well as confined water and their preventive measures are analyzed. The results show that the vadose zone water and diving water's impaction is mainly caused by seepaging Through the cut-off pile,good results can be received; and the confined water is mainly caused by the irnpaction of sudden foundation chung. The traditional preventive method (river drainage, deep well water and so on) and their disadvantages are analyzed. In the study of new ways, we studied the Mechanical properties of unsaturated soils under the condition of flexibility based on spherical particles loose accumulation of the most idealized model show that there are two main damage modes, bending and shear damage. The materials mechanicsare applicated to calculate separately the minimum riser h and h_min, through theoretical analysision we know that, as long as change the value of maximum bending moment the thickness could be reduce to the minimum by adopting additional plates.