新立副井井塔不均匀沉降分析

Analysis on unequal settlement of auxiliary shaft tower in Xinli

通过对新立金矿副井井塔的沉降观测数据和沉降曲线的观察分析,发现井塔出现了不均匀沉降现象,进而对产生不均匀沉降的相关因素进行研究分析,得到了引起不均匀沉降的原因主要有冻结壁的融化造成的冻土融沉、荷载偏心(承载中心与荷载中心不重合)和地下水疏降造成的地面沉降。副井井筒表土段施工采用了冻结法施工技术,由于在海水条件下,冻结温度场低,冻结壁范围大,而冻融速度慢,使得融沉周期较长。冻结法施工结束后,冻土产生缓慢的融沉效应,而且副井井塔基础采用摩擦型灌注桩,因此,冻土的融沉效应使得井塔产生不均匀沉降,它引起的沉降量占到总沉降量的69.5%,是造成不均匀沉降的最主要原因。

By observing and analyzing on the observational settlement data and the settlement curves for the auxiliary shaft tower in Xinli Gold Mine, the unequal settlement appeared at the shaft tower is found. The reasons to cause the unequal settlement is analyzed, which include the thawing settlement of the frozen soil caused by the melting of the frozen wall, the load eccentricity and the surface subsidence caused by pumping groundwater. The freezing method is used in the shaft construction at the topsoil section. It makes the thawing settlement cycle long, because of the low freezing temperature field, the large range of freeze walls and the slowing freeze-thaw speed under sea water conditions. After the freezing method construction, the frozen soil caused the slow thaw settlement effect, and the shaft tower adopted the friction pile foundation. So the thawing settlement effect of the frozen soil resulted in the unequal settlement of the shaft tower. The settlement from the thawing effect is about 69.5% of the total settlement, and the thawing settlement of the frozen soil is the main reason to cause the unequal settlement.