The Fenhe Bridge pile foundation along Menghua Railway has such characteristics as large diameter, great borehole depth and complicated stratum. Many problems have been encountered in the construction such as borehole shrinkage, higher-than-standard settlements, rebar cage dislocation. By careful analysis and exploration, the method of mud preparation, the treatment measures of borehole shrinkage in expansive soil, and the effective tools to prevent dislocation of rebar cages have been developed for drilling in loose sand layers with rotary drilling rig, which not only ensured the construction quality, but also reduced the cost, achieving some social and economic benefits.