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江阴河塘地裂缝最早为发生于1995年的局部小裂纹,持续活动时间已有12年,目前已趋缓。其平面展布特征为走向NE20°、线状延伸长达500m的地裂缝带,由主裂缝及主裂缝NW侧的宽约20～60m的凹陷带构成,主裂缝处形成高约20～30cm的陡坎,在凹陷带内一般发育有规模较小的地面裂纹。浅地震勘探及钻探证实,在地裂缝发育处存在隐伏基岩山脊,其走向与地裂缝一致,地裂缝的空间分布与隐伏基岩山脊线基本一致,山脊最浅埋深约64m,山坡坡度约12°～15°,隐伏山体西侧松散盖层一般厚度为140～150m。隐伏基岩面隆起及其所控制的第四系松散层厚度及结构差异是地裂缝发育的空间乃至时间特征的基础,是控制因素;深层地下水的长期超量开采所导致的地层压缩或固结是地裂缝形成的主导因素,该地裂缝正是基岩隆起带地层差异压缩所形成的差异地面沉降的结果。据估算,其发育深度可达基岩隆起的最浅处,实际上已发展成为小断层。
The ground fissure in Jiangyin Hetang was the first local small-scale crack that occurred in 1995 and has been in continuous operation for 12 years and has now slowed down. Its plane distribution features a ground fissure zone extending to NE20 ° and a linear extension of 500m. It is composed of a main depression and a depression zone with a width of 20 to 60m on the NW side of the main crack, with a height of about 20-30cm Steep ridge, the development of a generally small crater in the depression of the ground cracks. Shallow seismic exploration and drilling confirmed that there are hidden basement rock ridges in the development of the fissures, which are consistent with the ground fissures. The spatial distribution of the fissures is basically consistent with the ridge line of the buried base rock. The shallowest depth of the ridge is about 64m, 12 ° ~ 15 °, the thickness of the loose cover on the west side of the hidden mountain is 140 ~ 150m. Hidden bedrock uplift and the controlled thickness and structure of the Quaternary loose layer are the basis for the spatial and even temporal characteristics of ground fissure development and are the controlling factors. The formation compression or consolidation caused by long-term over-exploitation of deep groundwater Is the dominant factor in the formation of ground fissures as a result of the differential ground subsidence caused by the differential compression of bedrock uplift strata. It is estimated that the depth of its development up to the bedrock uplift of the shallowest, in fact, has developed into a small fault.