清徐县地裂缝活动与地下水开采定量关系

摘要

Long-term over-exploitation of groundwater in QingXu,Shanxi Qrovince has caused serious land subsidence,and has induced and exacerbated earth fissures in basin edge.Through analyzing the characteristics of groundwater withdrawal and earth fissures development,the relation between changes in ground-water levels and earth fissure have been found.The persistent motion of Jiaocheng fault caused considerable differences between the two sides of the fault plane.Excessive exploitation of ground-water caused a significant decline in confined water ta-ble and succeeding differential subsidence.Qre-existed fault planes as a macro-structure plane in the soil body have caused concentration of differential subsidence and accelerated the earth fissure activities.Base on the earth fissure mechanism,combined with drilling and hydrogeological profile data,a numerical model has been build.The model results well explain the characteristics of earth fissure.Through this simulation the mechanism of QingXu earth fis-sure has been verified.The simulation is useful in forecasting earth fissure trend.%地下水长期超采使山西省清徐县产生了严重的地面沉降，在边山地区甚至诱发和加剧了地裂缝灾害。通过对清徐县地下水开采和地裂缝发育特征分析发现两者有很好相关性。结合地裂缝发育区的地质环境，分析认为交城断裂的持续活动使断层两盘的地层岩性及厚度具有相当大的差异，在过量开采地下水导致承压水位大幅度下降，两盘地层发生差异沉降。先存断裂作为土体中的宏观结构面，差异沉降沿此面集中发生，造成了上部地裂缝的出现与活动的加剧。根据地裂缝的成因机制，结合钻孔和水文地质剖面资料，建立了适用于洪积扇地面沉降的计算模型。计算结果很好地解释地裂缝的活动特征，为进一步明确地裂缝的成因、预测地裂缝活动趋势提供了参考。