Evaluation of geologic bearing capacity of coastal zones taking coastal area of Laizhou Bay as an example

Abstract

The estuarine and coastal vulnerability around the world is increasing day by day, due to climate warming and sea level rise. And the resource-environmental pressure, caused by population expansion, also has been increasing. In a word, human interventions have caused lots of irreparable damages to the sensitive ecosystems in estuarine and coastal regions. Therefore, to carry out evaluations about ecological state and environmental bearing capacity is of great significance for environmental protection, as well as resource utilization. In this study, we constructed an indices system, which was based on a PSR model, to be used for the geologic bearing capacity assessment in coastal zones. There is no doubt that determination of indices weights is very important in the evaluation process, even it is a key factor restricting the ecological evaluation accuracy. Based on the above, we proposed a new weight determining method by fusing non-structural fuzzy number weighting and triangular fuzzy number weighting in the basis of the theories of fuzzy mathematics and named it as unstructured triangular fuzzy number weight determining method. In this new method, judgment matrix is used to calculate the relative importance among those indices included in the evaluation system with unstructured binary tone operators and rules of triangular fuzzy number. Therefore, this new method accords with the cognitive law of decision makers from macro to micro, and that three different experience attitudes (pessimistic, neutral, and optimistic) are fully considered can make the one-sidedness caused by a single attitude be avoided effectively. In addition, a new consistency test method entitled hierarchical sorting consistency test method was proposed to check the consistency of judgment matrix. This study took the coastal area around Laizhou Bay in Shandong Province of China for example and assessed the geologic bearing capacity here. The results indicate the geologic bearing capacity here is gradually increasing from the coast to the inland, and that the proposed weighting model is effective for eco-geological environment evaluation.