For this purpose,the difficulties such as the way of power line patrol,water resistance,washing technology and hotline maintenance technology are solved,in which the critical salt density method is applied in water washing especially.

Through measurement and analysis the critical density of Kerner s non-linear model, the propagation speed of the wide moving jam and the unimpeded velocity of Greenshields s model are obtained.

Different from the typical evaluation index-level of service,this paper adopts critical density ratio to evaluate the operation condition of urban highway basic sections,which synthetically reflects the requests of both road managers and users.

The experimental results showed that there was a critical density for transition to detonation at certain confinement condition.

It was showed that,when the concentration of dosed NaCl solution reached the critical salt concentration,there would generate the phenomenon of particles releasing in sand column;in mixed salt solution,the existence of molar percent of Ca2+ would inhibit the .

The results indicate that critical salt concentration and critical flow rate exit on the saltwater-freshwater interface.

With horizontal seepage experiments,this paper analyzes the critical salt concentrations(CSC)of the different cations,by examining such solutions as NaCl,KCl,LiCl,NH_4Cl,CaCl_2 and MgCl_2,which can cause the particle release of water sensitivity of porous media.

The correlation and regression analyses were done between the indexes of germination,growth and vigor and salinity,through which the critical concentrations of E.