层状盐岩中天然气地下储存库地表沉降分析

摘要

To study the rule of surface subsidence of natural gas underground storage cavern in bedded salt under the change of internal pressure and the effect of overlying strata, the predictive method of surface subsidence based on the numerical simulation method was proposed. The surface subsidence rule of one natural gas underground storage cavern in bedded salt during operation was analyzed with the predictive method. The analysis results show that the surface subsidence is expressed as a typical funnel shape curve in each storing stage with the subsidence mainly concentrated on the very top of the storage. The surface subsidence increases with time. The subsidence rate is relatively large in the early stage and tends to be stable gradually after a time of operation. The surface subsidence rate varies in each storing operation stage. The rate is relatively smaller in the early stage, larger in the active stage and then turns to be smaller gradually in the decline stage. In the actual project, numerical method can be used to predict the surface subsidence first and the subsidence monitoring of pre-existing buildings should be strengthened.%为了研究层状盐岩中天然气地下储存库在内压变化和覆岩压力作用下的地表沉降规律,提出了基于数值模拟的地表沉降预计方法,并对某层状盐岩天然气地下储存库在运营过程中的地表沉降规律进行了预计分析.分析结果表明,在储存库的各个阶段,地表沉降均呈现出典型的漏斗状曲线,沉降主要集中在储存库正上方；地表沉降随时间的增长而变大,开始时地表沉降增大速率比较大,储存库运营一段时间后,地表沉降慢慢趋于稳定；地表沉降速率在储存库运营的各个阶段是不同的,开始阶段沉降速率相对比较小,活跃阶段沉降速率比较大,衰退阶段沉降速率逐渐变小.实际工程中,可先采用数值方法对地表沉降进行预测计算,并加强对既有建(构)筑物的沉降监测.