西安市地面沉降探讨

本文在讨论西安市地面沉降特征的基础上,论述了西安市地下水开采量、承压水位变化与地面沉降三者之间在时间和空间上的对应关系,初步认定大量开采地下水是地面沉降主要原因。典型水准点沉降量与邻近自备井承压水位变化相关分析表明,两者间相关性极强。经综合分析市区地貌、第四系地质、工程地质和水文地质特征并进行工程地质分层后,可确定出市区地面沉降的第一和第二主要压缩层。据地面沉降与承压水位下降值回归方程所预测的地面沉降发展趋势表明,西安地面沉降今后还会继续发展,将对西安城市建设产生严重影响,故应采取相应治理措施。

AN ANALYSIS OF THE CAUSE AND DEVELOPMENT OF THE LAND SUBSIDENCE IN XI'AN

After analysing the features of the land subsidence in Xi'an, the paper preliminarily determines that the overextraction of ground water is the main cause of the land subsidence in Xi'an on the basis of the corresponding relations of ground water output, the piezometric water level changes and the land subsidence of time and space.The correlation analysis between the subsidence amount of the typical bench mark and the piezometric water level changes that the wells provided for oneself shows that the correlation between them is very close. The returning equations between the subsidence magtitude and the piezometric water level changes are established. On the basis of analysing the regional geological condtions in Xi'an, the paper evalutes the urban district geomorphic features and the Quaternary features. In this paper the author makes the engineering geological layering and the geological framework zoning, thus for the city's urban districts determining the main compressing layers. That the land subsidence of Xi'an aggravates the development of its gound fissures is proved by discussing their relations.At the present pumping water rate, the result obtained by forecasting subsidence with the returning equations shows that the ground surface of Xi'an will subside continuously, and the ground fissures will be aggravated. So,the corresponding harness measures should be taken to control the land subsidence of Xi'an