地铁区间隧道暗挖法施工因预降水而诱发地表沉降分析

为了预测地铁区间隧道暗挖法施工前预降水诱发的地表沉降量,依据群井降水作用下含水层水位降低、土体有效应力变化的过程,建立了单元土体固结压缩模型;基于有效应力原理和一维固结压缩理论,得到了含水层水位降深、土体压缩系数及初始孔隙比与隧道上方地表沉降量的关系。其预测结果可用于评价地面道路、建(构)筑物稳定性,为现场施工提供指导参考。最后通过工程实例验证以上分析过程的合理性。

Analysis of Ground Settlement Induced by Pre-precipitation in Metro Tunnel Construction by Covered Excavation Method

In order to predict the ground settlement induced by pre-precipitation before the covered excavation of subway tunnel,a unit soil consolidation compression model is established,based on the aquifer water level lowering process and the soil effective stress changing under the effect of group well dewatering,Then,according to the effective stress principle and one-dimensional consolidation compression theory,the relationship between the water level depth drop in the aquifer,the soil compressibility and the initial void ratio,thus the ground settlement above the tunnel is obtained.The prediction results can be used to evaluate the stability of ground road and buildings,providing guidance for the site construction.Finally,the rationality of above-mentioned analysis process is verified by practical engineering examples.