The Study On Treatment Of Waste Drilling Mud Of Railway Bridge

In order to reduce the impacts which waste mud put on environment during railway bridge construction, the rheological properties of waste drilling mud of Beijing-Shanghai high-speed railway construction were studied based on the experiments. The particle diameter of boring mud carried out by drilling mud and the sedimental velocity of boring mud with the minimum diameter were calculated, in order to provide reasonable suggestions for the design of a sedimentation tank. Then the conditions of waste mud treatment including effective flocculant, additive method and optimum dose were determined, and the process was designed. After that, the treatment conditions and process were proved to be reliable in field test. The main conclusions are as follows:-The pseudoplastic fluid model was suitable to describe drilling mud, and the linear relation between the Marsh funnel viscosity and the apparent viscosity measured by the rotational viscometer was existed.-The calculated results of the particle diameter and the sedimental velocity of the boring mud corresponded with the situations observed in construction site.-Anionic polyacrylamide (PAM) was effective to the treatment of waste drilling mud, and the way adding PAM in powder was applicable. For the clay waste mud, the treatment process included adding PAM, mixing, stirring, discharging supernatant fluid, and backfilling the sediment. For the ardmorite waste mud, the solid-liquid separation would be efficient only if the pH was adjusted to 5.5-6.5 before adding PAM, and the sediment need to be dewatered by centrifugal before backfilled.-The concentrations of COD and SS of the supernatant fluid meet the second grade standard of Integrated wastewater discharge standard, and AM would not have unfavourable impacts on environment and organism. The test of plant showed that PAM was not harmful to the growth of wheat. The treatment process was safe to entironment.