1、 翻译部分 英文原文 Sensitivity analysis for the GIS-based mapping of the ground subsidence hazard near abandoned underground coal mines Abstract Ground subsidence around abandoned under-ground coal mines can cause much loss of life and prop-erty. We analyze factors that can affect ground subsidence around a
2、bandoned mines in Jeongahm in Kangwon-do by sensitivity analysis in geographic information system (GIS).Spatial data for the subsidence area, topography and geology and various ground engineering data were col-lected and used to make a factor raster database for a ground subsidence hazard map. To de
3、termine the impor-tance of extracted subsidence-related factors, frequency ratio model and sensitivity analysis were employed. Sen-sitivity analysis is a method for comparing the combined effects of all factors except one. Sensitivity analysis and its verification showed that using all factors provi
4、ded 91.61% accuracy. The best accuracy was achieved by not consid-ering the groundwater depth (92.77%) and the worst by not considering the lineament (85.42%). The results show that the distance from the lineament and the distance from the drift highly affected the occurrence of ground subsidence, a
5、nd the groundwater depth, land use and rock mass rating had the least effects. Thus, we determined causes of ground subsidence in the study area and this information could help in the prediction of ground subsidence in other areas. Keywords GIS Abandoned underground coal mine Ground subsidence Frequ
6、ency ratio Sensitivity analysis Korea Introduction Coal industry has played a major role in the development of the Korean economy since the 1960s. However, the coal industry began to decline from the end of the 1980s because the oil price fell globally. There were 173 coal mines in 1988 in Jeongseon
7、, Kangwon-do, the largest coal mining region in Korea. However, valueless coal mines were abandoned after the implementation of coal industry rationalization action by Korean government. Today, no coal mines are in operation. In the abandoned coal mines in Jeongseon, environmental pollution, having
8、never been considered a future problem at the time the mines ceased operating, is on the increase. Heavy metals in wastewater from coal mines and muck reaching rivers and soil is a serious problem. In particular, most abandoned coal mines are in mountain ranges and their damage to the environ-ment i
9、s not widely known. Ground subsidence due to an underground coal mine is a hazard to human life as well as to property such as railways, roads, houses and buildings. In addition, it is difficult to completely recover an area of subsidence and rehabilitation is expensive. Moreover, most countermeasur
10、es for ground subsidence are simply rein-forcements after ground subsidence has already occurred. Therefore, it is necessary to have a systematic prediction and management plan for an area of ground subsidence.There have been many studies on the prediction of ground subsidence locations and how to d
11、ecrease related damage. Methodology In general, to predict ground subsidence it is necessary to assume that subsidence occurrence is determined by sub-sidence-related factors, and that future subsidence will occur under conditions that are the same as those for past subsidence according to the relat
12、ive frequency concept of probability theory. On this basis, the relationship between areas where subsidence has occurred and subsidence-rela-ted factors can be distinguished from the relationship between areas without past subsidence and subsidence-related factors. In this work, the spatial relation
13、ships between subsidence locations and each subsidence-related factor were analyzed using the frequency ratio which is one of the probability models. The frequency ratio is the ratio of the area where subsidence has occurred to the total study area, and is also the ratio of the probability of subsid
14、ence occurrence to no occurrence for a given attribute. In the case of subsidence occurrence, if the subsidence event is denotedB and a given factors attribute is denoted D, then the frequency ratio of D is the ratio of the conditional probabilities of B . Therefore, the greater this ratio, the stro
15、nger the relationship between subsidence occurrence and the given factors attribute. The frequency ratio was calculated for each factor type or range that had been identified as significant with respect to causing ground subsidence. The ratios were used for calculating the ground subsidence hazard i
16、ndex (GSHI) and mapping. There have been a few studies carried out on ground subsidence hazard evaluations using the frequency ratio and a GIS； for example, Kim et al. ( 2006) introduced the analysis of ground subsidence hazard and summarized many ground subsidence hazard evolution studies. Diagrams
17、 presented in Fig.4 show the steps for calcu-lating the frequency ratio: (a) finding locations of groundsubsidence, (b) representing cells of class 1 for factor A and (c) describing the area of spatial overlap for areas of subsidence and areas of class 1 for factor A. In the present example in which
18、 the study area comprises 64 cells, there are 23 ground subsidence cells and 19 cells that are of class 1 for factor A. There are 12 cells of subsidence that are also cells of class 1 for factor A. The percentages for subsidence area with respect to class 1 for factor A and the entire domain are 52.
19、17 and 29.69%, respectively. Therefore, the frequency ratio of class 1 for factor A is 52.17/29.69% = 1.76. Sensitivity analysis Sensitivity analyses show how a solution changes when the input factors are changed. If the selection of a factor results in a relatively large change in the outcome, then
20、 the out-come is said to depend on that factor. Sensitivity analysis quantifies the uncertainty of each factor. The factors that have the greatest impact on the calculated subsidence hazard map can therefore be identified. Sensitivity analyses model behavior by determining the rate of change in the
21、model output as parameters or input data are varied, thus giving an understanding of how changes in the inputs influence the output. Such analyses explain how inputs affect the output and quantify the strengths of the inputs from the variations in the output. Sensitivity analysis has been applied in
22、 a variety of studies. Arhonditsis and Brett (2005) introduced process formula-tions and sensitivity analysis for a complex eutrophication model of Lake Washington, USA. Joo et al. ( 1998) repre-sented the sensitivity of the leachate level to reduce the high leachate level in landfill. Sensitivity a
23、nalysis has been applied to landslide susceptibility hazard mapping (Lee and Talib2005). In the present study, the sensitivity analyses were conducted to determine factors involved in ground subsidence. To extract subsidence-related factors, the fre-quency ratio model and sensitivity analysis were e
24、mployed. The sensitivity analysis compared the effects of all factors except one. Data Many studies have identified important factors that con-tribute to ground subsidence around coal mines (e.g.Waltham 1989； Coal Industry Promotion Board 1997), including the depth and height of mine cavities, excav
25、ation method, degree of inclination of the excavation, scope of mining, structural geology, flow of groundwater and the mechanical characteristics represented by the rock mass rating (RMR). In this study, locations of ground subsidence and factors governing the occurrence of ground subsidence were c
26、ol-lected in a vector-type spatial database and then repre-sented on a grid using the ArcGIS software package. The spatial database is shown in Table 1 . The database included a 1:5,000 ground subsidence map, 1:50,000 geological map, 1:5,000 topographic map, 1:5,000 land use map, 1:1,200 mine tunnel
27、 map, borehole data and satellite imagery with 1 m resolution. The site Jeongahm was chosen for investigation in this study. Reliable accuracy of the spatial database is indispensable in a GIS environment. For this reason, accurate maps authorized by national organizations such as the Coal Industry Promotion Board for ground subsidence, the National Geographic Informa-tion Institute for topography and
