Research on performance of early-strength tailings-based shield tunnel grouting material
The effects of three types of tailings sand(tin,pyrite,and lithium)replacing river sand on the workability,stability,and mechanical properties of shield grouting materials were studied.The change law in the performance of tailings-based grouting materials under the influence of early strength agents was investigated and the the microscopic mechanism was analyzed by SEM.Research has shown that tailings sand reduces the fluidity,consistency,and setting time of shield grouting materials,lowers its workability,reduces its bleeding rate,increases its stone formation rate,and improves its stability.Compared with natural river sand,the 28 day compressive strength of shield grouting materials using tin tailings sand,pyrite tailings sand,and lithium tailings sand increased by 14.62％,0.84％,and-25.21％,respectively.Compared to natural river sand,when using tin tailings sand,sulfur iron tailings sand,and lithium tailings sand,the 3-day compressive strength of grouting materials with early strength agent increased by 52.78％,55.56％,and 28.33％,respectively.The hydration products of shield grouting materials are mainly hydrated calcium silicate gel and a small amount of needle like ettringite.The incorporation of sulfoaluminate early strength agents can further reduce pores,increase the formation of ettringite,and improve early strength.
万方数据
维普
