黏土水泥膏浆流变性能及其对灌浆的影响

黏土水泥膏浆性能优越,可广泛用于土木、水利等工程的防渗堵漏和基础加固,其流变性能对灌浆工程施工及灌浆效果有重要影响。利用Brookfield+R/S流变仪对其流变参数进行测试,研究固化剂掺量、温度及时间等因素对流变性能的影响。结果表明:膏浆的黏度及屈服应力均随时间增大;固化剂掺量为水泥质量的1.0%左右时的膏浆为Herschel-Bulkey流体,并且具有触变性,防渗堵漏效果最佳;温度在5～40 ℃之间,温度影响膏浆的黏度及屈服应力,但不影响膏浆的流型,温度越高,黏度越大,28 ℃下的屈服应力最大。室内灌浆模拟试验及抗冲试验,证明其扩散距离可控,抗水冲释性能强,与纯水泥膏浆相比,初始屈服应力及黏度更大,触变性可控,浆体的稳定性更好。黏土水泥膏浆是含水及大孔隙地层、松软地层等复杂地层灌浆防渗堵漏的优选材料。

Rheological Properties of Plaster Slurry of Clay-cement andIts Influence on Grouting Engineering

Plaster slurry of clay-cement can be widely used in seepage and leakage prevention and foundation strengthening in civil and hydraulic engineering.Its rheological properties have important influence on the construction and performance of grouting projects.The influences of curing agent's content, temperature, and time on the rheological properties of clay-cement plaster slurry were researched by testing the rheological parameters through Brookfield+R/S rheometer.Results revealed that 1) the viscosity and yield stress of the slurry increased with time;2) when the dosage of curing agent reached about 1.0% of cement mass, plaster slurry had optimum anti-seepage performance and belonged to Herschel-Bulkey fluid;3) at temperature ranging from 5-40 ℃, temperature had impact on the viscosity and yield stress of the slurry, but had no effect on the fluidity, and the higher temperature led to larger viscosity, and in the meantime yield stress reached its maximum at 28 ℃.Through indoor grouting simulation test and anti-scour test, clay-cement plaster slurry was verified to have good water-dilution resistance and controllable diffusion range.Compared with pure cement slurry, clay-cement plaster slurry has larger initial yield stress and viscosity and better stability with controllable thixotropy.It is a preferred material for the seepage prevention in grouting of complex strata such as water-bearing and large-porosity strata as well as loose and soft strata.