Palaeo-geographical conditions control the sedimentological and hydrological heterogeneity within the upper aquitard and late Pleistocene aquifers beneath Kolkata. Such complexity at Bowbazar was unmapped prior to the Tunnel Boring Machine (TBM) of East-West metro project which hit the local aquifer at 14 m depth. This led to development of cracks in tens of buildings due to land subsidence; few of which collapsed immediately, and some stood in such a precarious position to be eventually razed. Mass evacuation was undertaken from the area. This paper assesses the local hydrogeological conditions and hydrostatic pressure of the aquitard-aquifer system that caused the disastrous land subsidence.

中文翻译：

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加尔各答东西地铁项目在建隧道中透水层孔隙水渗漏导致地面沉降

古地理条件控制着加尔各答下方的上透水层和晚更新世含水层内的沉积学和水文异质性。在东西方地铁项目的隧道掘进机 (TBM) 击中 14 m 深度的当地含水层之前，鲍巴扎尔的这种复杂性是未绘制的。由于地面沉降，这导致数十座建筑物出现裂缝；有的立马倒塌，有的站在如此岌岌可危的位置，最终被夷为平地。从该地区进行了大规模疏散。本文评估了导致灾难性地面沉降的弱透水层-含水层系统的当地水文地质条件和静水压力。