The natural flow field of groundwater is slow at Binhai New Area in Tianjin, which leads to the decrease of heat exchange efficiency of ground source heat pump. To solve this problem, pumping wells around the buried pipe were arranged to accelerate the flow rate of groundwater. Pumping would improve heat exchange efficiency and make ground subsidence. Our aim is to find a method to improve heat exchange and reduce ground subsidence. Based on previous researches, the periodic alternately pumping and recharging method was designed. Through field test and physical model test, the water level in pumping well, recharging well, observation holes, and pore water pressure and subsidence at different points were monitored and analyzed. The results show that the periodic alternately pumping-recharging method makes smaller subsidence than that of conventional pumping methods. It is feasible to apply it to ground source heat pump project in Tianjin. At a reasonable flow rate, period, and pumping-recharging mode, subsidence is small or even negligible. In addition, the pore water pressure and subsidence in aquifer and aquitard have different characteristics. The clay layer is mainly plastic deformation. With the process of pumping and recharging, the plastic deformation becomes smaller and smaller. The sand layer presents both elastic and plastic deformation. With the process of pumping and recharging, the plastic deformation becomes smaller and smaller, and tends to have elastic deformation gradually. Additionally, when the flow rate is large enough, soil particles in aquitard below the aquifer move to the aquifer with the seepage force caused by drainage.

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抽水补给引起地面沉降的试验研究

天津滨海新区地下水的自然流场较慢，导致地源热泵的换热效率下降。为了解决这个问题，在埋管周围布置了抽水井以加快地下水的流量。抽水将提高热交换效率并使地面沉降。我们的目标是找到一种改善热交换并减少地面沉降的方法。在先前研究的基础上，设计了周期性交替抽水和补水的方法。通过现场测试和物理模型测试，对抽水井，补给井，观测孔，孔隙水压力和沉降在不同点的水位进行了监测和分析。结果表明，与传统的抽水方式相比，周期性的交替抽水方式沉降量较小。将其应用于天津地源热泵项目是可行的。在合理的流量，周期和抽水-补给模式下，沉降很小，甚至可以忽略不计。另外，含水层和阿奎塔尔中的孔隙水压力和沉降具有不同的特征。粘土层主要是塑性变形。随着泵送和充电的过程，塑性变形变得越来越小。沙层既有弹性变形，也有塑性变形。随着泵送和充电的过程，塑性变形变得越来越小，并且趋于逐渐具有弹性变形。此外，当流量足够大时，