漳州地下热水开采与地面沉降预测

据福建省漳州市漳州地热详查报告(1988年),漳州市城区地热田孔隙热水水位降深1.16 m~5.0 m(平均4.41 m),允许开采热水资源5 410.08 m3/d,但目前的开采量为883.20 m3/d,仅占16%,若全部开采,势必引起地面沉降。根据漳州地热田水位降深段内土体浮力消失,相应自重应力增加而引起压缩变形原理,预测漳州地热田平均水位降深4.41 m引起的地面沉降值,Ⅰ级阶地为3.85 cm~8.66 cm,按有关地热田沉降资料研究,沉降差超过2.0cm时,地下水泥管道将会破裂。因此,漳州孔隙热水资源全部开采可能引起地面沉降,导致局部建筑物开裂,影响安全使用。

Prognoses of Possible Land Subsidence Brought on by Extraction of Geothermal Resources in Zhangzhou City, Fujian Province

Based on the Detailed Report of Geoheat Survey in Zhangzhou City of Fujian Province,in Zhangzhou City the hydrotherm water table in the apertures is 1.16m5.0m in drawdown(on an average 4.41m) and allowable extraction of hydrothermal resource is 410.08 cubic meters per day,but the produced quantity of thermal water is 883.20 cubic meters per day,accounting for the 16 percent of allowable extraction reserves.The full extraction will tend towards land subsidence.According to the principle of compression deformation,it is inferred that the 4.41-meter mean water drawdown in the Zhangzhou geothermal field can bring on land subsidence of 3.85-8.66 centimeters in the I-grade terrace.Referring to some research data of land subsidence,over 2.0 centimeters of differential settlement can result in the rupture of underground concrete ducts.Therefore,it is considered that full extraction of aperture thermal water resources in Zhangzhou City may be cause to land subsidence and brings about the local cracking of some buildings,which can greatly effect on the safety of the buildings.