Informatics Publishing Limited

Yan Liu ¹, Xianjin Huang ¹, Taiyang Zhong ¹, Guangjie Luo ², Ran Yu ¹, Li Li ¹

Affiliations
1 School of Geographic and Oceanographic Sciences, Nanjing University, 163 Xianlin Street, Nanjing, 210023 Jiangsu Province, CN
2 Institute of Agro-Ecological and Rural Development, Guizhou Normal University, Guiyang 550018, Guizhou Province, CN

Abstract

Unexploited land change is a main driver of regional eco-environment change. Through an integrated technique of geographic information system (GIS), remote sensing (RS), and global positioning system (GPS), the authors attempted to address this topic by examining unexploited land conversion in Guiyang City in Guizhou province in southwestern China as a case study, as well as looking at the effect of policies in land use from 1996 to 2010 in the same area. Results showed that: Agricultural development of unexploited land was encouraged from 1996 to 2000, and a progression conversion process with direct and indirect transformations overlaid was formed by unexploited land → arable land + unexploited land → forest land and grass land → arable land. The conversion management of unexploited land was enhanced, unexploited land occupied for construction was controlled, and the area of unexploited land converted to forest land and grassland showed an upward trend from 2000 to 2006. Local government was encouraged and supported in exploring construction and use of unexploited land, and achieved the maximum value by converting unexploited land to construction land, as a result we see the area of forest land and grassland decreased from 2006 to 2010.

Keywords

Unexploited Land Change, Guiyang City, Eco-Environment, Land Type Classification.

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Yan Liu ¹, Xianjin Huang ¹, Taiyang Zhong ¹, Guangjie Luo ¹

Affiliations
1 School of Geographic and Oceanographic Sciences, Nanjing University, 163 Xianlin Street, Nanjing, Jiangsu Province 210023, CN

Abstract

Urbanization is regarded to be one of the most important factors driving land use change. In this paper, through an integrated technique of RS, GIS and GPS, unexploited land conversion has been unveiled from 1996-2010 in Guiyang and further examination has been made on the impact of urbanization on unexploited land change. And based on the adjustment of Markov process, land use transition probability and CLUE-S parameters, many scenarios of unexploited land changes in the study area have been simulated. It is found that: (1) the unexploited land in Guiyang has experienced complex changes due to the rapid social and economic change since 1996. It showed a declining trend generally and was reduced from 74.33 km² in 1996 to 65.72 km² in 2010, a reduction of 8.61km² in 14 years. It has a close relationship with the rapid development of urbanization. (2) The urbanization comprehensive parameter (k) showed growth from 2.91% to 4.78% after urbanization development indicators were standardized during 1996-2010. (3) Regression analysis was used to unveil the relationship between urbanization and unexploited land. There was a significant correlation between them, which proved that the urbanization is one of the dominant factors to lead to exploited land change. (4) The unexploited land will show a significant decreasing trend in the coming 20 years, the conversion-out area will be larger than the conversion-in area in three scenarios and the gap will be widened gradually year by year. During multi-scenario simulations, unexploited land area decrease in ecological protection scenario is most prominent, the proportion of unexploited land converted to construction land in economic development scenario is the largest, and the area of grass land becoming unexploited land in unchanging trend scenario is the largest.

Keywords

Unexploited Land, Karst Areas, Guiyang City, Urbanization.

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Yun-Fei Ma ¹, Hao Qin ², Chun-Mei Zheng ³, Ming-Bin Wang ³, Ke-Zhi Song ³, Yan Liu ³, Wan-Tao Ding ⁴, Xiao-Jin Li ⁵, Tong-Shun Wang ³, Ting-Peng Zhang ³

Affiliations
1 College of Information and Electrical Engineering, China Agricultural University, Beijing-100083, CN
2 Beijing Canbao Architecture Design Institute, Beijing-100000, CN
3 School of Civil Engineering, Ludong University, Yan'tai-264025, CN
4 Research Center of Geotechnical and Structural Engineering, Shandong University, Ji’nan-250061, CN
5 School of Civil Engineering, Shandong Jianzhu University, Ji'nan-250101, CN

Abstract

The elastic-plastic problem for a circular pressured tunnel with liner is furthermore investigated. A new mechanical model to model the construction sequence of the tunnel structure is applied. Based on the linear Mohr-Coulomb yield criterion, for the case that the yield range is in the surrounding rock is dealt with. With consideration of boundary conditions along the internal and external boundaries of the liner and the interface between the elastic and yield regions, the stress solutions for the total field, and the relations to determinate the support pressure and the yield radius are given. Also, the confinement of the liner to the surrounding rock and the effect of the internal pressure on the surrounding rock pressure and the yield range are considered in the above-mentioned analyses. Numerical results indicate that the internal pressure has the same action as the support. And that with the increase of the relative liner rigidity the support pressure is increased. However, the radial displacement along the tunnel wall and the yield radius may decrease with increasing the relative liner rigidity. Moreover, when the surrounding rock is in elastic-plastic state, the variation ranges of the internal pressure, the support pressure, the radial along the tunnel wall and the yield radius decrease with increasing the relative liner rigidity. The presented solutions contain previously known result as the special cases, for example, classical Fenner's solution.

Keywords

Tunne, Elastoplasticity, Liner, Mohr-Coulomb Yield Criterion.

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