9.Study on the performance of xanthan gum-modified rectangularpipe jacking dragreducing mud

Abstract:

To improve the performance of dragreducing mud in rectangular pipe jacking construction and to overcome the shortcomingsof conventional muds—such as high fluid loss,low viscosity,and poor filter cake quality—bentonite was chosen as the base material,with xanthan gum incorporated as a modifier. A singlevariable experimental approach was employed to investigate the effects of bentonite,soda ash,sodium carboxymethyl cellulose (CMC),and xanthan gum on mud properties. The optimized mud demonstrates broadapplicability in sandy,silty,and silty clay ground conditions commonly encountered in rectangular pipe jacking projects. Results showthat xanthan gum markedly increases mud viscosity and thixotropy,reduces fluid loss,and enhances filter cake thickness. The optimalformulation consists of 10% bentonite,0. 4% soda ash,0. 8% CMC,and 0. 5% xanthan gum. Compared with mud used in actualfield applications,the optimized formulation achieved the following improvements:fluid loss decreased from 15 cm 3 to 9 cm 3 in minutes(a 40% reduction);filter cake thickness increased from 1. 5 mm to 2. 5 mm (a 66% improvement);and funnel viscosity rose from80 s to 101. 35 s (a 26% increase). These results offer valuable guidance for designing and optimizing dragreducing mud formulationsin similar rectangular pipe jacking applications.

Keywords: pipe jacking;dragreducing mud,xanthan gum;filtrate loss;singlefactor experiment;mud modification