全断面砂层土压平衡盾构掘进渣土改良技术试验研究

Experimental Study on Improvement Techniques of Muck in the Tunnelling of Whole-section Sand Strata Soil Pressure Balance Shield

针对西安地区全断面砂层特点,以膨润土与黄土等土体改良材料,对各类砂土进行了土体改良试验,研究土压平衡盾构砂层施工渣土改良材料配比参数,并结合西安地铁二号线一期工程运动公园站～北客站盾构隧道下穿全断面砂层工程实例对试验结果进行了验证。试验结果及工程实践表明:膨润土与黄土混合泥浆对各类砂层渣土具有较好的改良效果,提高了砂层渣土流塑性,解决了土压平衡盾构在西安地区全断面砂层中出土不畅、土压难以建立等施工难题,为同类工程积累了经验。

According to the characteristics of whole-section sand strata in Xi’an area ,the experiments of soil mass improvement were conducted by using bentonite ,loess and other soil mass improvement materials to study the ratio parameters of muck improvement materials in soil pressure balance shield tunnels .The experimental results were verified by the case study of shield tunnel of the first-stage construction of Xi’an Metro Line 2 which runs through the whole-section sand strata ,from Sports Park Station to Beike Station .The experimental results and engineering practice indicate that mixed slurry of bentonite and loess has a great improving effect on muck of all kinds of sand strata ,flow plasticity is also improved in the sand strata .Thus solve construction problems such as difficult unearthing in the shield tunnel and establishment of soil pressure in whole-section sand strata of Xi’an area .This will provide referential guidance to similar projects .