Abstract

Recently, many of the world’s major river deltas have been sinking, making them increasingly vulnerable to floods and storm surges, salinization and permanent inundation. For the Yellow River delta, annual subsidence rates of several to dozens of centimeters have been reported in the past few years. The extraction of a considerable amount of groundwater due to continuous pumping is suggested as the main driver of the groundwater depression cone. Despite its scale and severity, methods to quantify subsidence are scarce. We introduce a soil mechanics approach to quantify subsidence due to the compaction of soft soil. The largest reduction in soft soil thickness, which is more than 2.6 m, occurred in the salt field area to the north of the Yellow River. Furthermore, by estimating the primary consolidation of soft soil, the subsidence caused by groundwater exploitation is quantified. In the coastal area of the delta, due to excessive exploitation of shallow underground brine resources, the maximum accumulated subsidence is as high as 2 m. Since the natural consolidation of these deltaic sediments has ended, if the current groundwater exploitation intensity is maintained, major subsidence disasters, such as subsidence depressions and ground fissures, will occur.

摘要

最近，世界上许多主要的三角洲都在下沉，使其越来越容易遭受洪水和风暴潮，盐碱化和永久性洪水的侵袭。对于黄河三角洲，过去几年的年沉陷率据报道达到几厘米至几十厘米。建议将由于连续抽水而抽取的大量地下水作为地下水压降锥的主要驱动力。尽管其规模和严重性，但尚无量化沉降的方法。我们引入了一种土壤力学方法来量化由于软土的压实引起的沉降。在黄河以北的盐田地区，最大的软土厚度减少超过2.6 m。此外，通过估算软土的初步固结，对地下水开采造成的沉降进行了量化。在三角洲的沿海地区，由于浅层地下盐水资源的过度开采，最大沉降量高达2 m。由于这些三角洲沉积物的自然固结已经结束，因此，如果保持目前的地下水开采强度，将发生沉陷和塌陷等重大沉陷灾害。