小曲线半径叠落盾构隧道近接施工安全控制研究

Study on Safety Control of Adjacent Construction of Overlapped Shield Tunnel with a Small Radius of Curve

小曲线半径叠落盾构隧道近接施工风险较高,其安全控制是工程界亟待解决的难题。依托某叠落盾构工程,通过数值模拟,研究了夹层土注浆、架设内部钢支撑等措施的可行性,据此提出合理的控制方案,并结合现场监测数据对安全控制效果进行评价。研究结果表明:相比于无加固措施方案,夹层土注浆加固能够提高夹层土的强度,有效减小管片上浮,架设内部钢支撑能减小管片水平变形,两种方案结合能够有效保持断面形状;管片拱顶竖向变形和水平净空收敛变形的最大值分别为7.02 mm和2.74 mm,均小于变形控制标准值;现场采用夹层土注浆和架设内部钢支撑的联合措施是合理和可行的。

The risk of the adjacent construction of overlapped shield tunnel with a small radius of curve is relatively high,so its safety control is of great importance in the industry.Based on the case of an overlapped shield tunnel project,the feasibility of control measures such as interlayer soil grouting,erection of internal steel supports,etc.was studied through numerical simulation,and a reasonable control scheme was proposed accordingly.In addition,the effect of safety control was evaluated according to the data of on-site monitoring.The study results showed that,compared with the scheme without reinforcement measures,the reinforcement through interlayer soil grouting could increase the strength of interlayer soil and effectively reduce the floating of segments,while the erection of internal steel supports were could reduce the horizontal deformation of segments.The combination of these two schemes could effectively maintain the shape of the section,and the maximum values of vertical deformation of segment crown and convergence deformation of horizontal clearance were 7.02 mm and 2.74 mm respectively,both of which were less than the standard value of deformation control.Therefore,the combined use of interlayer soil grouting and erection of internal steel supports on site was reasonable and feasible.