生态位适宜度变权法在高速铁路临时用地复垦适宜性评价中的应用——以京沪高铁常州段典型制梁场为例

针对高速铁路临时用地复垦技术难度大、复垦效果不好及传统土地复垦适宜性评价中权重确定主观性等问题,尝试采用生态位适宜度变权方法,应用生态位基本原理,计算高速铁路临时用地复垦生态位适宜度指数,在此基础上识别出非均衡评价因素的优劣性,对其中劣性因素进行变权处理,用以突出限制性评价因素的制约作用,并以京沪高铁常州段典型制梁场为例进行实证分析。研究结果表明研究对象的农用地方向复垦因其破坏严重而适宜性较低,主要限制因素表现为桩基础密度、保存耕作层厚度、平均挖损深度等;建设用地方向的复垦适宜性较高,综合适宜复垦方向为建设用地。评价结果与现实状况较为吻合,评价结果较为客观。对此,建议在高速铁路临时用地使用过程中加强土地破坏防控,调整现行政策中模糊之处,允许临时用地后续利用方式多样化,以提高土地综合利用效益。

An Application of the Variable Weight Method Based on Ecological Niche-Fitness to Reclamation Suitability Evaluation for Land Temporarily Used for High-Speed Railway Construction: A Case Study in Beijing-Shanghai High-Speed Railway Changzhou Section

Reclamation of land used temporarily for high-speed railway construction remains a challenge because of a variety of difficulties in technique and uncertainties in its effects. General methods for land reclamation suitability evaluation seem to fall short of somewhat subjective in the determination of the weights of factors. The variable weight method based on ecological niche-fitness is a weight determination method originating from ecological theory. It is of a significant advantage in substantially mitigating subjective intervention. In the study, the method was used to quantify the niche-fitness of land temporarily used for high speed-railway construction, with the objective to identify the unbalanced factors and deal with factors that are not robust in evaluation. A penalty function was introduced to increase the weights of the restraints in a systematic manner. The temporary land of Beijing-Shanghai high speed-railway Changzhou section was investigated. In the variable weight method, weights of evaluation indexes vary obviously. The weights of factors, e.g., pile foundation density, plough horizon thickness, and the average digging depth, were increased greatly after the change was made, whereas some other factors were decreased accordingly. It was indicated that the major restraints for farmland reclamation are the pile foundation density, the plough horizon thickness, as well as the average digging depth. Likewise, the major restraints for construction land reclamation involved the complete degree of infrastructure and population density of service zone. Evaluation results of the reclamation suitability showed that the typical temporary land LC-01 was seriously damaged. To that end, the reclamation suitability for cultivated land was relatively low, suggesting a value of the reclamation suitability of only 0.347. The construction land was relatively high, with a value of 0.870. Compared with general weight-based evaluation methods which resulted in values of the reclamation suitability index of 0.615 for farmland and 0.915 for construction land, respectively, the results from the variable weight-based evaluation appear to be more objective and reasonable. In terms of the synthetic results, it was suggested that the land temporarily used for high-speed railway construction was converted into construction, which was generally in accord with reality. It is proposed that the follow-up utilization of temporary land for high-speed railway construction should be more diversified and consequently certain policies should be adjusted. The ecological niche-fitness based variable weight method is a combination of basic ecological theories and land sciences. It has been proved to be effective, and may also perform well in other studies associated with land evaluation.