Groundwater Level Change Management on Control of Land Subsidence Supported by Borehole Extensometer Compaction Measurements in the Houston-Galveston Region, Texas
Groundwater Level Change Management on Control of Land Subsidence Supported by Borehole Extensometer Compaction Measurements in the Houston-Galveston Region, Texas
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DOI：
10.3390/geosciences9050223
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发表时间：
2019-05-01
期刊：
影响因子：
2.7
通讯作者：
Fang, Zheng N.
中科院分区：
文献类型：
--
作者：
Liu, Yi;Li, Jiang;Fang, Zheng N.
1979 年，休斯敦-加尔维斯顿地区出现了高达 3.05 m 的地面沉降，这主要是由于 1937 年至 1979 年间 Chicot 和 Evangeline 含水层中的弱透水层的非弹性压实所致。这两个含水层中的弱透水层的预固结压力水头不断更新，以响应地下水位的降低，而地下水位的降低又是由于地下水位不断增加而导致的。 0.57 至 428 万米(3)/天。这次地面沉降是在没有对地下水位变化进行任何管理的情况下发生的。然而，1979年至2000年期间恢复地下水位的管理通过将地下水抽取率从4.3减少到300万立方米/天，成功地将非弹性压实从1980年代初期的约40毫米/年减少到2000年左右的零。大约从1937年到2000年，非弹性固结作用持续了大约63年，导致该地区出现地面沉降危险。通过地下水位恢复管理，地表有所回升。本文发现，在对两个含水层地下水位进行管理的同时，13个钻孔引伸计站位置出现或倾向于出现由于伪恒定二次固结率导致的每年0.08至8.49毫米的沉降。自2000年以来，该趋势被认为保持稳定。二次固结引起的沉降超出了任何地下水位变化管理方案的控制范围，因为它是由两个含水层的地质历史覆盖压力引起的。自 1971 年以来，从 13 个引伸计收集的压实测量结果不仅成功证实了控制地面沉降的地下水位变化管理的必要性，而且还首次得出休斯敦-加尔维斯顿地区第四系和第三系含水层系统中发生二次固结沉降的实证结果。
As much as 3.05 m of land subsidence was observed in 1979 in the Houston-Galveston region as a result primarily of inelastic compaction of aquitards in the Chicot and Evangeline aquifers between 1937 and 1979. The preconsolidation pressure heads for aquitards within these two aquifers were continuously updated in response to lowering groundwater levels, which in turn was caused by continuously increasing groundwater withdrawal rates from 0.57 to 4.28 million m(3)/day. This land subsidence occurred without any management of changes in groundwater levels. However, the management of recovering groundwater levels from 1979 to 2000 successfully decreased inelastic compaction from about 40 mm/yr in the early 1980s to zero around 2000 through decreasing groundwater withdrawal rates from 4.3 to 3.0 million m(3)/day. The inelastic consolidation that had existed for about 63 years roughly from 1937 to 2000 caused a land subsidence hazard in this region. Some rebounding of the land surface was achieved from groundwater level recovering management. It is found in this paper that subsidence of 0.08 to 8.49 mm/yr owing to a pseudo-constant secondary consolidation rate emerged or tended to emerge at 13 borehole extensometer station locations while the groundwater levels in the two aquifers were being managed. It is considered to remain stable in trend since 2000. The subsidence due to the secondary consolidation is beyond the control of any groundwater level change management schemes because it is caused by geo-historical overburden pressure on the two aquifers. The compaction measurements collected from the 13 extensometers since 1971 not only successfully corroborate the need for groundwater level change management in controlling land subsidence but also yield the first empirical findings of the occurrence of secondary consolidation subsidence in the Quaternary and Tertiary aquifer systems in the Houston-Galveston region.