自然因素对天津市地面沉降影响分析

摘要

As now well known, the main factor to cause surface subsidence in the Tianjin Municipality is strata compression caused by groundwater exploitation. In fact, natural factors caused surface subsidence also has a certain proportion in total subsidence measure-ment. They include tectonic movement, earthquake activity and under-consolidated soil distributed in large area. The paper has dis-cussed geological environment setting related to surface subsidence in Tianjin, and analyzed natural factors caused surface subsidence one by one. Finally have found that the surface subsidence measurement in Cangxian uplift and Central Hebei depression is 1.41~1.53mm/a, in Huanghua depression 1.90~2.15mm/a, municipality average 1.5mm/a. During the time interval before and after earth-quake occurred, is the maximum impacting period of the earthquake caused surface subsidence measurement. The distribution area of under-consolidated soil in Tianjin (the first marine bed) to the east of outer ring road, soft soil caused average subsidence measurement is 1.0mm/a. The study has certain reference significance for surface subsidence controlling works.%众所周知，引起天津市地面沉降的主要因素是地下流体的开采导致的地层压缩。实际上，自然因素引起的地面沉降在总沉降量中也占有一定比重。引起天津市地面沉降的自然因素包括构造运动、地震活动以及欠固结土的大面积分布。论述了天津市与地面沉降相关的地质环境背景，并对引起地面沉降的自然因素逐一分析。构造运动引起地面沉降量在沧县隆起、冀中坳陷构造单元为1.41～1.53mm/a，在黄骅坳陷为1.90～2.15mm/a，全市平均1.5mm/a；地震发生前后时间段内，是地震导致地面沉降量变化影响最大的时期；天津市欠固结土（第一海相层）分布区（外环线以东）软土引起平均沉降量1.0mm/a。该研究对地面沉降的防治工作起到一定的参考价值。