Analysis On Embankment Durability Of Qiantang River

Qiantang river is the biggest river in Zhejiang province. It is faced with flood tidewater and typhoons for its specific geography position. The embankment of Qiantang river plays an important role in resisting flood and ensuring circumjacent region's security and stabilization. For the embankment design, its durability must insure its service life of 50-100 years, except for its safety and applicability. In this paper, the embankment durability of Qiantang river is studied by theory analysis and experimental investigation on in-site inspection. The main research works included:Summarizing the durability of hydraulic concrete construction affected by environmental water.The results of Xiasha embankment durability inspection indicated that the calcium leaching was the main factor of affecting the durability of embankment.Diffusing and dissolubility equations were derived from aqueous calcium distribution law, and formulations of concrete porosity and effective diffusion coefficient, based on Fick's second law. Finite difference method was engaged to obtain the cumulative calcium leached, whick could be used as a guideline for evaluating the durability failure of embankment of Qiantang river.Three calcium leaching experiments were designed to approve that both reducing temporary degree of hardness of environmental water and enhancing calcareousness concentration in void-water speeded up the process of calcium leaching. Compared with experimental data, the theory model was proved to be available, which could be used to evaluate the condition of calcium leaching from embankment concrete of Qiantang river.Theory calculation indicates that after a hundred years, the distance of corrasion front will be 1.63cm and cumulative calcium leached will reach 2.5 percent of the entire calcium content, which is under the proposed data of 10 percent. The method of calculating cumulative calcium leached fills the blanks of this field of our countryonly having experimental investigation and experience formula calculation. The theory quantitatively proves the durability embankment of Qiantang river.