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土压平衡盾构在隧道施工中,特别在地铁区间隧道施工中已经得到广泛应用。土压平衡盾构主要适用于粘性土地层开挖,其在砂土地层的掘进过程中通常会遇到掌子面土压平衡难以形成、螺旋出土器无法正常排土、刀盘扭矩过大及刀具磨损过快等一些问题。最有效的解决方法是使用泡沫等添加剂对土体进行改良,但是目前工程施工现场添加剂的使用尚存在一定的盲目性。文章首先通过自制的试验室发泡装置生产泡沫,并对泡沫的性能与发泡剂溶液浓度的关系进行研究,为有效使用泡沫提供依据,并通过一系列试验研究泡沫对砂土的改良效果,得到适合土压平衡盾构施工的优化泡沫掺入比。
Earth pressure balance shield in the tunnel construction, especially in the subway tunnel construction has been widely used. Earth pressure balance shield is mainly applied to the excavation of cohesive soil strata. During the process of sand stratum excavation, the earth pressure balance is usually difficult to form, the earth excavated by screw can not be properly drained, the cutter torque is too large, Tool wear too fast and some other problems. The most effective solution is to use foam and other additives to improve the soil, but there is still some blindness in the use of additives at the construction site. In this paper, firstly, the foam was produced by a self-made laboratory foaming device, and the relationship between the performance of the foam and the solution concentration of the foaming agent was researched to provide the basis for the effective use of the foam. Through a series of experiments, The optimized foam incorporation ratio is obtained for the construction of EPB shield.