盾构在高水头粉土粉砂及淤泥地层始发时易出现各种安全事故，工程上常采用地表注浆、地层冻结 等方法预先对始发端地层进行加固处理。结合杭州望江路盾构隧道地层特点，提出一种三轴搅拌桩、高压 旋喷桩及局部垂直冻结相结合的联合加固方法，并系统介绍该方法加固参数的确定和加固效果评价。现场 检测表明，各项条件均满足设计要求，盾构顺利始发，以期为类似工程提供借鉴。

Accidents are likely to occur when shield tunnels are launched in high water head and silty strata. Surface grouting, freezing, and other methods are often used to pre-strengthen the initial strata at the shield launching hole. Combined with the strata characteristics in the Wangjiang road tunnel, this study proposes a combined ground improvement of triaxial mixing piles, high-pressure jet grouting piles, and partial vertical freezing. This paper introduces the determination principle of the reinforcement parameters and effect evaluation. Field tests showed that all conditions met the design requirements. The tunnel was launched successfully and can be used as a reference for similar projects.

U455.49