Suitability evaluation of offshore sea sand mining based on subjective and objective weighting method

With the rapid development of China's economy, the demand for sand and gravel resources is increasing year by year. Among the many kinds of sand and gravel resources, sea sand is widely used in the construction industry, chemical industry and other fields because of its rich reserves and wide use. However, in recent years, there are many extensive problems in the development of the sea sand industry. Unreasonable mining not only leads to a large loss of state-owned resources, but also causes a series of environmental problems. After ascertaining the sea sand resources, in order to determine whether the sea sand is suitable for mining, this paper takes pollution impact, social factors, development difficulty, coastal impact and submarine slope stability as evaluation indexes, and uses subjective weighting method (analytic hierarchy process) and objective weighting method (structural entropy weight method) to calculate the index weight respectively. Through the game theory, the two are combined to obtain the combined weight of the index, and the natural breakpoint method is used for superposition analysis to obtain the sea sand mining suitability zoning map, and the offshore sea area of Guangdong Province is analyzed as an example, and the scientificity and rationality of the evaluation results are verified in combination with the actual sand mining project.