富水砂卵石地层动水注浆模型试验

Model Test of Dynamic Water Grouting in Water-Rich Sandy Gravel Stratum

在富水砂卵石地层注浆治理中,由于浆液扩散规律不明导致突涌水及坍塌事故频发。注浆模型试验是研究浆液扩散规律的有效手段。以北京地区富水砂卵石地层为研究对象,自主设计了动水注浆模型试验,基于均匀设计法研究了水泥浆在注浆压力、水流速度、水灰比和地层渗透系数共同影响下的浆液空间分布形态及扩散规律。结果表明:浆液在富水砂卵石地层中呈椭球状、球状或柱状形态渗透扩散;多元线性回归分析发现,注浆压力、地层渗透系数、水流速度、水灰比与浆液扩散距离是幂指数函数关系;单因素分析发现,地下水阻碍了浆液逆水流向和垂直水流向的扩散距离。在此基础上,提出了注浆孔布置的建议。

Water inrush and collapse accidents occur frequently due to the unclear diffusion law of the grouts when grouting in water-rich sandy gravel stratum.Grouting model test is an effective method to study the law of grout diffusion.Taking the water-rich sandy gravel stratum in Beijing as the research object,a model test of dynamic water grouting was independently designed.Based on the uniform design method,the spatial distribution and diffusion of cement grout under the influence of gouting pressure,water flow velocity,water-cement ratio and stratum permeability coefficient were studied.The results show that:The grout diffused in an ellipsoid,spherical or columnar shape in water-rich sandy gravel stratum,which is a typical seepage diffusion.Multiple linear regression analysis found that the grouting pressure,stratum permeability coefficient,water flow velocity,water-cement ratio and grout diffusion distance were exponential function relationships.The single factor analysis found that the groundwater hindered the diffusion distance of the grout in the couner-current and vertical water-flow directions.On this basis,some suggestions on the arrangement of grouting holes were put forward.