【作者】 程盼盼； 徐前卫； 李谷阳； 李晓亮；

【Author】 CHENG Panpan;XU Qianwei;LI Guyang;LI Xiaoliang;Key Labiratory of Road and Traffic Engineering of Ministry of Education,Tongji University;Five Iron Group Electric Service City Link Engineering Co.,Ltd.;

【机构】 同济大学道路与交通工程教育部重点实验室； 中铁五局电务城通公司；

【摘要】 碴土改良是盾构在砂卵石地层中掘进必不可少的一项辅助措施。为确保北京地铁天桥-永定门外区间隧道在砂卵石中顺利施工,开展了一系列碴土改良研究。首先,通过分析砂卵石土样的颗粒级配特征,并综合考虑经济性及环保要求,选取泡沫和膨润土为碴土改良剂;随后,为配制出特定性能的改良剂,对改良材料的性能进行了试验研究,最终确定了产生试验所用改良剂的试验条件;再后,以室内坍落度试验为主,在选定膨润土体积添加比为7%的情况下,得出泡沫添加剂最优配比为45%~60%;最后,将室内研究成果应用于实际工程,从现场改良土状态、坍落度值及掘进参数三个方面说明碴土改良取得了较好的效果,从而表明室内试验研究成果具有一定的实用价值,可为类似无水砂卵石地层碴土改良方案制订提供参考。更多还原

【Abstract】 It is essential to condition the soil when shield tunneling in sandy pebble stratum.The interval tunnel from the Tianqiao Station to the Outside of Yongdingmen Station of Metro line 8 in Beijing city is mainly constructed in sandy pebble stratum.In order to ensure the safety and high efficiency of tunneling,a series of research on soil conditioning was carried out.Firstly,the foam and bentonite slurry were chosen as the soil additives based on comprehensive consideration of soil particle size distribution,construction cost and environment effect;Secondly,the influential factors of the properties of the foam and bentonite slurry were tested,and then the additives with specific properties were produced for the subsequent experiments;Thirdly,through soil slump tests,the optimum addition ratio of the foam was set about 45%to 60%under the condition that the injection ratio of bentonite slurry was 7%;Finally,the laboratory optimization results were applied to the practical engineering and the soil conditioning achieved an ideal result in terms of the muck performance,the value of conditioned soil slump and the tunneling parameters.These research results can provide some reference for soil conditioning in similar engineering.更多还原