基于流体时变性的隧道劈裂注浆机理研究

Fracture grouting mechanism in tunnels based on time-dependent behaviors of grout

水泥复合浆液流变参数的时变性对注浆扩散范围计算值影响很大。基于宾汉体流变方程和平板裂缝理想平面流模型,推导了考虑流体时变性的土体劈裂注浆扩散半径计算公式。由公式可知,土体劈裂压力、裂隙宽度、浆液流速、流变参数的时变性是影响扩散半径的重要因素。计算分析了劈裂注浆过程中劈裂压力随缝隙宽度的变化以及流变参数对扩散半径的影响规律。结果表明,忽略流体时变性注浆扩散半径计算值明显偏大,会给注浆工程设计带来隐患。结合厦门机场路隧道全风化花岗岩地层注浆试验,发现水泥复合浆液劈裂注浆加固效果良好,扩散半径理论计算值基本符合工程实际;研究成果对风化花岗岩地层劈裂注浆的设计和施工具有一定的指导意义。

The rheological parameters of cement-based grout is time-dependent,which has an important influence on building grout diffusion model.Based on the assumption of Bingham fluid and narrow plate model of grouting diffusion,a formula for calculating the diffusion radius in soil is developed considering the time-varying behaviors of grout.It shows that the grouting diffusion radius of Bingham fluid is related to the grouting pressure difference,gap width,flow velocity and time-dependent behaviors of rheological parameters.The law of fracture pressure of grouting is affected by the gap width notably,and the rheological parameters of grout play a key role in computing the diffusion radius.So it is unreasonable to neglect the time-dependent behaviors of grout in computing the diffusion radius.Based on the grouting tests on strong-weathered granite tunnel in Xiamen Airport,the application of the formula of grouting diffusion has proved to be successful in practice.Furthermore,some available results are gained,beneficial to the design and construction of fracture grouting in strong-weathered granite.