safe thickness
2.Through theexperiments and study of the adsorption effect of soil particle on rainwaterpollutant, the saturated-unsaturated soil water movement model and pollutanttransportation model are established, and the purification ability of soil aquiferwith some thickness to the infiltration rainwater is estimated by applyingmathematic equation of solute movement and transportation in soil. Consequenlty, the soil relative safe use time of aquifer with various depthpolluted by heavy metals such as Hg, Cr, Cd, Pb and degradative pollutantssuch as NH4-N, COD is calculated.
3.The tower of the second step ship lift is composed of 2 pairs of separate leading barrels with plane dimension of upstream and downstream barrels being 40. 95m × 10m and 34m ×10m,respectively ,and thickness of wall 83cm. Finite element calculation and verification by plaster modelling have shOWn that the stiffnes and strength meet the requirements and safe operation can be quaranteed.
