水下盾构隧道施工管片上浮控制

Segment-up control in underwater tune construction by shield

以天津地铁3号线13标段盾构穿越新开河为背景,研究了盾构穿越河底粘土层、粉质粘土层条件下的管片上浮控制问题.研究结果印证了粘土、粉质粘土地层条件下注浆扩散跨过渗透注浆阶段,直接进入压密注浆阶段的结论;同时表明：在河底土层为粘土、粉质粘土地层条件下,管片上浮以局部管片上浮为主,局部管片上浮控制的决定性因素为壁后注浆动态上浮力和连接螺栓抗剪力,控制局部管片上浮的根本性方法是控制壁厚同步注浆压力.笔者还提出,盾构穿越新开河河底时,控制管片上浮的注浆压力不超过0.25 MPa,实际注浆压力为0.15~0.20 MPa,并在实践中取得了良好效果.

Base on tunnel building by shied under Xinkai River water of the part marked 13 of Tianjin Metro Line 3,segment-up-control has been studied when shield is passed along clay-bearing and silty clay layer under water.The results show that filled ground behind line will stride over permeation diffusing phase,and go into phase of post-compactions,part segment-up is the most possible thing of tunnel line-up when tunnel under river in clay-bearing and silty clay layer constructed by shield,and final factors of segment-up are flotage from injection sress on time and shear resistance of joint bolts,the essentional measure of segment-up control is controling injection stress on time.Propositional injection stress parameter（less than 0.25 MPa） has been put forward,this ensues that segment-up dos＇t arise,the true value is 0.15~0.2 MPa.