摘要
甘肃永靖黑方台为一典型的黄土台塬,该处黄土具有较强自重湿陷性,长期大水漫灌作用下,厚层黄土自重湿陷后导致严重地面沉陷灾害。然而,至今台塬地面沉陷的时空特征及发展趋势尚不清楚。本文依据2007年～2011年的InSAR测量数据,分析了黑方台地面沉陷特征及其发展趋势,基于黄土湿陷特征指标,估算了台塬剩余沉陷量。研究发现,黑方台地面仍处于沉陷之中,但是各处沉降幅度不一,目前区内形成12个沉陷中心,新源村附近沉陷最大(120.4mm),77%以上区域的年均沉降量小于10mm。随着黄土地层经历多次减湿-增湿循环以及黄土层内潜水位的不断上升,沉降速率将更加缓慢,估测台塬剩余沉陷量不大于0.687m,小于台塬沉陷总量3%。
Heifangtai is a kind of typical loess terrace in loess area of northwest China,where loess is sensitive to water and is of nature of hydro-collapse. Due to flood irrigation for more than 30 years,a severe land subsidence has occurred in the area on its ground. However,little has learned about how long and how much the land subsidence is going to be. Based on monitoring data during the period between 2007 and 2011 obtained using InSAR,trend of the land subsidence in the area was analyzed in this paper followed by estimation of the residual subsidence. It was found that the land in the area is still subsiding,whereas amount of subsidence varied in different sections. There have been 12 subsiding sections,among which the greatest subsidence had been recorded up to 120. 4mm in the monitoring period. However,about 77% of the entire area was subsiding with an annual rate less than 10mm,suggesting subsidence in the area has been very slow. Regarding that hydro-collapse of the loess in the area becomes much weaker when it experiences more cycles of wetting and drying,it is believed that both rate and amount of the land subsidence will be much lesser. It is estimated that residual hydro-collapse of the loess in the area will be not greater than 0. 687m,which is less than 3% of total amount of hydro-collapse of the loess could be.
出处
《中国地质灾害与防治学报》
CSCD
2013年第4期108-114,共7页
The Chinese Journal of Geological Hazard and Control
关键词
黑方台
黄土湿陷
灌溉
INSAR
Heifangtai
hrdro-collapse of loess
irrigation
InSAR
