Development and durability performance of high density cement slurry filled with drilling method for shaft sinking
In order to improve the filling and replacement effect of the first section of high wall in deep and large drilling shafts in western China,it was proposed to use high density cement slurry as a new type of wall filling material.Firstly,through comparative experiments,barite powder was selected as the weighting agent and magnesium aluminum silicate as the suspension agent.Then,orthogonal experiments and range analysis were used to analyze the effects of water cement ratio,barite powder,magnesium aluminum silicate,and expansion agent dosage on the density,initial setting time,flowability,and compressive strength at 3 and 28 days of high density cement slurry.The optimal mix ratio of high density wall filling material was determined using the comprehensive balance method as cement:water:barite powder:magnesium aluminum silicate∶expansion agent∶water reducing agent=1∶0.55∶0.5∶0.03∶0.025∶0.015.Through comparative experiments with sulfate solution erosion of commonly used cement slurry filling materials,it is shown that high density cement slurry filling materials have reliable durability performance.Finally,the hydration products and microstructure of the optimized weighted cement slurry at 3 d and 28 d were analyzed by XRD and SEM,revealing its superior impermeability and durability mechanism.The research results provide a new type of cement slurry material with high density,high strength,low permeability,and good durability for the back wall filling of deep and large shaft drilling in western China.
mine in western Chinadeep and large shaft drillingbackwall fillinghigh specific gravitymix ratio
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