裂隙发育地层中超深工作井开挖对周边地下水位的影响

Influence of Excavation of Ultra-Deep Working Well on Groundwater Level in Fractured Formation

结合广东一底部为裂隙发育地层的超深大直径工作井建设工程,通过现场监测、现场试验和数值分析三种方法,清晰的展现了工作井周边地下水水位随基坑开挖的变化过程,由此揭示了该特殊地质条件下工作井开挖对周边地下水水位变化的影响规律:基坑的开挖降水破坏了区域原有的水力平衡,地下水水位下降速率随其施工进程变化;透水层会使水位变化范围变大并影响周边建筑物安全。对于有裂隙发育地层的复杂地质条件,在开挖过程中应加强对地下水水位的监测,并及时做好防渗与加固等措施。

Based on the construction of a ultra-deep and large-diameter working well in a fractured formation at the bottom in Guangdong province,three methods of field monitoring,field test and numerical analysis were used.It clearly showed the change process of groundwater level around the working well with the excavation of foundation pit,therefore,the influence of the excavation of the working well on the groundwater level in the surrounding area could be revealed.The excavation and precipitation of the foundation pit destroy the original hydraulic balance of the area,and the rate of groundwater level decrease changes with the construction process.The pervious layer might enlarge the range of water level change and hence affect the safety of surrounding buildings.For the complicated geological conditions of fractured strata,the monitoring of groundwater level should be strengthened in the process of excavation,and the measures of seepage control and reinforcement should be taken in time.