青岛胶州湾海底隧道涌水断层全断面帷幕注浆技术研究

Study of full-face curtain grouting on water-burst fault F_(4-4) subsea tunnel in Qingdao Jiaozhou bay

青岛胶州湾海底隧道F_(4-4)断层破碎带,受构造影响严重,围岩破碎,岩体强度低,出水量大,拱顶自稳能力差,在极端地质条件下存在突水的高风险,施工风险极大.基于这种情况,通过现场试验确定了全断面帷幕注浆技术参数,主隧道注浆加固区范围为隧道开挖轮廓线外5m;上断面周边注浆扩散半径为1.5m,下断面注浆扩散半径为2m;注浆终孔间距为3.5m;水灰比为1:1的超细水泥;注浆压力为3～4MPa;施工工艺选用前进式注浆.最后采用全断面帷幕注浆技术方案和措施在青岛胶州湾海底隧道右线主洞穿越F_(4-4)断层的设计和施工中得到了成功的应用.通过检查孔检验,注浆效果良好,达到了开挖要求.全断面帷幕注浆技术对类似工程具有一定的借鉴与指导意义.

The fault crashed zone F4-4 of the Qingdao Jiaozhou Bay subsea tunnel, is seriously influenced by the earth construction. And the stave rock, which has low intensity existence together with the high hydraulic pressure, is bad for the stability, so the possibility of water-burst under violent geological condition is high, and the construction risk is enormous. The full-face curtain grouting technical parameters was determined by on-site test. The main tunnel area grouting reinfforcement was 5 m away from the tunnel excavation contour lines. The grouting proliferation radius of the upper cross-section was 1.5 m, and the proliferation grouting radius of the lower cross-section was 2.0 m. The grouting endpoint radius was 3.5 m, and the water-cement ratio was 1 ： 1, and the grouting pressure was 3 - 4 MPa. The advancing grouting was used in eoustruetion technology. Finally, the full-face curtain grouting plan and measure was successfully applied in the design and construction in the right line of the Qingdao Jiaozhou Bay subsea tunnel for passing through the No. F4-4 fault. This full-face curtain grouting has significance to similar project.