纳米材料对顶管法施工触变泥浆减阻性能影响及浓度优选研究

顶管法施工具有设备少、工序简单、工期短、造价低等优点，被广泛应用于城市涵管、管廊等工程中。触变泥浆是顶管施工中重要的润滑减阻剂，其减阻性能的好坏对顶管施工特别是长距离、大断面顶管工程的顺利进行至关重要。论文使用膨润土触变泥浆为基础泥浆，质量配比为膨润土：羧甲基纤维素钠（CMC）：无水Na₂CO₃：水=80 ： 2 ： 3 ： 920，并选择纳米ZnO、纳米SiO₂、纳米Al₂O₃ 3种纳米材料作为添加剂，通过测试泥浆密度、pH、六速黏度、滤失、泥饼黏附系数和析水率等指标的变化，确定最优纳米材料类型并优选配比浓度。结果表明：浓度为2%纳米SiO₂触变泥浆的减阻性能最好，比基浆减阻性能提升约14%。本文研究成果可为提高长距离、大断面顶管施工中触变泥浆的减阻性能提供一定借鉴，对纳米材料在触变泥浆中的应用具有一定参考作用。

EFFECT OF NANOMATERIALS ON DRAG REDUCTION PROPERTY OF PIPEJACKING THIXOTROPIC MUD AND OPTIMIZATION OF CON-CEN-TRA-TION STUDY

Pipejacking construction has many advantages, such as needing less equipment, simple working procedure, shorter construction period and low cost, etc. Pipejacking construction has been widely used in urban culvert pipes, alure and other projects. Thixotropic mud is an important lubricant in pipejacking and it's very essential for a long-distance and large-section pipejacking project. This paper used bentonite thixotropic mud as base mud, which mass ratio is bentonite:CMC:anhydrous sodium carbonate water=80:2:3:920. Nano-ZnO, nano-SiO₂ and nano-Al₂O₃ were selected as additive. Through measuring the mud density, pH, six-speed viscosity, filter loss, mud cake adhesion coefficient and drainage rate, the optimum of nanomaterial and its concentration were determined. The conclusion is as follows:the drag reduction property of the thixotropic mud with the concentration of 2% nano-SiO₂ is the best, which is about 14% higher than that of base mud. The conclusion can provide some reference for improving the drag reduction perperty of thixotropic mud in long-distance and large-section pipejacking construction, and provide some reference for the application of nanomaterials in thixotropic mud.