膨润土及黏土用于地铁盾构渣土性能改良的分析与研究

Analysis and research on bentonite and clay used for improving the performance of metro shield muck

哈尔滨地铁3号线沿江车站区间采用土压平衡盾构法施工,因为盾构渣土内摩擦角大,流动性差,压缩效应不能完全止水,且工程要求作为支撑介质的渣土应具有良好的塑性变形、较小的内摩擦角和渗透率。为保证工程质量和进度,需对哈尔滨地铁3号线盾构渣土进行改良,分别利用纯膨润土,暗挖区间开挖出的废黏土掺加一定比例膨润土改良粉细砂、细砂、粗砂等渣土。研究显示掺加废黏土后的膨润土浆液黏性较好,能够满足实际现场需要,既节约了膨润土的使用量,又能够利用其他施工现场开挖的废黏土,起到经济环保的作用,同时为现场施工提供一定的技术参考,取得了较为有意义的成果。

The construction of Harbin Metro Line 3 along the river is constructed by the earth pressure balance shield method.Because the internal friction angle of the shield muck is large,the fluidity is poor,the compression effect cannot completely stop the water,and the muck must have plastic deformation,small internal friction angle and permeability that should be a good support for the supporting medium.In order to ensure the quality and progress of the project,the shield muck of Harbin Metro Line 3 needs to be improved.In this study,pure bentonite is used,and the waste clay excavated in the excavation interval is added.The waste clay is mixed with a certain proportion of bentonite to improve the fine sand.coarse sand and other muck.Studies have shown that the bentonite slurry after adding waste clay has good viscosity and can meet the actual site needs,which saves the use of bentonite,and can use the waste clay excavated at other construction sites to play an economic and environmental protection role.The construction provides a certain technical reference and has achieved more meaningful results.