随着城市地下空间的利用率不断提高，地下大型构筑物成为区域地面沉降发展不可忽视的影响因素。为了揭示群桩基础对抽水型地面沉降的影响机理，文章开展了物理模型试验，分析了桩间距和桩的平面布置方式对土层孔压和沉降的影响。试验结果表明，桩间距和桩布置方式影响群桩阻挡渗流和阻碍土体沉降的效果，从而影响地面沉降发展。较小的桩间距和梅花形布置方式具有较大的面积置换率和较长的渗流路径，对水流和土体沉降的阻挡效果显著。因桩群的阻挡作用，抽水时位于群桩和抽水井之间区域的地下水难以得到及时补充，孔压下降明显，沉降梯度也较大。

With increasing utilization of urban underground spaces, large underground structures have clear influence on the
development of regional land subsidence. To reveal the mechanisms for the effect of pile group foundations on pumping-induced land subsidence, physical model tests were conducted in this paper and the effects of pile spacings and pile arrangement patterns on pore water pressure and soil subsidence were analyzed. The experimental results indicate that pile spacing and layout have effects on the hindrance of pile groups to water flow and soil subsidence. Smaller pile spacings and checkerboard arrangements result in higher area replacement ratios and longer seepage paths, effectively obstructing seepage and soil subsidence. Owing to the blocking of pile group, groundwater in the zone between the pile group and a pumping well is hardly replenished when pumping, causing the pore water pressure to decline obviously and the gradient of subsidence to increase.