乌鲁木齐泥沙地层盾构隧道地表横向沉降参数反演分析

Back Analysis on Lateral Surface Settlement Parameters of Shield Tunnel of Sediment Stratigraphy in Urumqi

针对乌鲁木齐地铁1号线新疆大学—二道桥区间盾构隧道沿线近距离侧穿匝道桥扩大基础时的沉降问题,基于实际地层条件和地表沉降监测数据,结合最小二乘法和Peck理论公式拟合出某典型断面的实测地表沉降槽曲线,得到相应的地表最大沉降值Smax以及沉降槽宽度i等拟合结果,进而反演分析地表沉降槽宽度系数K和地层损失率η并给出建议值。结果表明:土压平衡盾构机穿越某泥沙地层断面时,运用Peck公式可以拟合沉降趋于稳定时的地表横向沉降槽曲线,地表沉降槽宽度系数K介于0.260~0.320,均值约0.297,地层损失率η介于0.210%~0.560%,均值约为0.352%。

Aiming at the settling problem of Urumqi Metro Line 1, Xinjiang University--Erdaoqiao interval shield tunnel passing alongside the expanded foundation of ramp bridge at close distance, this paper based on the actual formation condition and monitoring data of surface subsidence, combined with least square method and Peck formula, fitting the actual measured surface settlement curves of a typical section, getting the corresponding maximum surface settlement Smax and width of settlement i and inversion analyzing the width coefficient of the surface subsidence K and the loss ratio of the stratum η and giving the recommended value. The results show that when the earth pressure balance shield machine crossed a sediment section, the lateral surface settlement curve could be fit by the Peck formula when the transverse settlement was stable, the width coefficient of the surface subsidence K is 0. 260 - 0. 320, the average value is about 0. 297, the ground loss rate η ranged from 0. 210 % to 0. 560 % and the average value is about 0. 352 %.