注浆扩散与浆液若干基本性能研究

Research on diffusion of grouting and basic properties of grouts

浆液流型、流变参数的时变性、可灌性、塑性强度和可重复注浆性是影响浆液扩散的基本性能。试验表明,各种浆液分别属于三种不同流型;水泥基浆液在注浆过程中流型不变;浆液粘度的时变性规律符合指数函数。研制了平板裂隙注浆装置进行试验,结果表明,普通水泥浆的最小可灌裂隙宽度并非 0.18 mm 或 0.2 mm。在重复注浆时,后注浆液克服先注浆液的粘聚力,在流道中间冲开新通道继续注入,而不是推动先注浆液向前整体移动。“塑性强度”概念可以推广到一般浆液,用这一指标可以预知浆液的可注期。基于以上试验研究成果,尤其是粘度时变性规律,建立了稳定性浆液注浆扩散模型。

Row pattern, time-varying behavior of rheological parameters, groutability, plastic strength and re-groutability of grouts are properties influencing the diffusion of grouts. Test result indicates that the flow pattern of grouts can be classified into three types, namely Newtonian fluid, Bingham fluid and Power law fluid. The time-varying behavior of grouts conforms to exponential function, and the flow pattern of cement-based grouts does not change during grouting. Grouting and back grouting tests are conducted with a simulation grouting device, verifying that the minimal groutable breadth of fissures are not 0.18 mm or 0.20 mm but changeable with different water-cement ratio, and the grouts can force a new way in the flow path during back grouting as long as the pressure of back grouting is larger than the cohesion of grouts previously injected into the fissures, rather than push them forward as a whole. In addition, the concept of plastic strength is proposed to predict groutability period of grouts. Based on these achievements, especially on time-varying behavior of viscosity of grouts, the author develops a grout diffusion model.