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.