风积砂地层隧道导向水平旋喷桩超前加固与预留核心土台阶法施工技术

Application of Horizontally-oriented Rotary Jet Grouting Pile and Bench Construction Along Reserved Core-soil Technology in Aeolian Sand Strata Tunnel

为解决风积砂地层隧道施工难题,提出了风积砂地层隧道施工的导向水平旋喷桩超前支护技术和先行施作仰拱边墙结合部预留核心土台阶法开挖技术,前者的技术关键是导向技术,后者的技术关键是上下台阶施工长度、上下核心土临时加固质量以及两侧墙角仰拱结合部快速跟进时机。通过现场工艺试验、数值模拟以及工程施工实践表明:采用水平旋喷桩超前支护与预留核心土台阶法联合施工,能有效控制风积砂地层的变形,确保施工安全和施工进度。

To solve these problems, it was proposed to use advanced support technology with horizontally- oriented rotary jet grouting piles and the excavation method of pre-construction of the inverted arch-side walls junctions with reserved core-soil bench. The key technology for the former is the orientation technology, and for the latter are the construction lengths of the upper and lower benches, the mass of the upper and lower core soil for temporary strengthening and accurate follow-up timing for the inverted arch- side walls junction construction. Field testing, numerical simulation and construction practice show that the deformation of the aeolian sand can be controlled effectively and the construction safety and construction progress were successfully guaranteed.