Security evaluation and measures of land arrangements in Sichuan seismic region

Earthquake and secondary geological disasters damaged 129 500 hm2 farming land, 114 500 hm2 construction land and 22 701 villages in Wenchuan County, Sichuan Province, thus reconstruction of land arrangements after earthquake is very arduous. Land arrangements are the effective measures for implementation of reconstruction after disasters, and the security evaluation of land arrangements are the foundation of rearrangement and reuse of land after disasters. In this paper, factors of security evaluation of reconstructed the land arrangements of seismic region post-disaster were analyzed. Distance away from the earthquake fault zone, type of rock soil body, angle of terrain slope and relative high altitude were selected for influence factors of land arrangements security evaluating. According to the possibility of the disasters happen, the influence factors were divided into different danger ranks. Taking single-factor superposition method evaluation, the Sichuan seismic region was divided into high-risk areas, warning areas and general warning areas. The land arrangements high-risk danger area, in which the distance was less than 200 m away from the Longmen mountain earthquake fault zone, the relative high altitude was more than 500 m, and the terrain slope was more than 25°, mainly constitutes of rock mass stave or soft with hard interaction and so on easy slippery gneiss. The land arrangements warning area is within the earthquake fault zone 200-500 m, the relative high altitude was 200-500 m, the terrain slope was 15°-25°, mainly constitutes of the diluvial level or the soft with hard interaction and so on easy slippery gneiss. The land arrangements general warning area, in which was 500 m apart from the earthquake fault zone, the terrain slope was less than 15°, and the relative high altitude was less than 200 m. This paper put forward the objective and measures of land consolidation post-disaster.