考虑浆-土参数动态变化的砂卵石土柱面渗透注浆机制研究

Study on Mechanism of Cylindrical Seepage Grouting Considering Dynamic Change of Slurry-soil Parameters in Sandy Gravel Soil

基于FLAC3D fish语言实现考虑浆液和砂卵石土参数动态变化的渗流场与应力场耦合下注浆扩散过程模拟,研究浆液在砂卵石土中柱面渗透扩散机制,并研究地层渗透系数K、浆液水灰比W/C及注浆压力P等注浆参数变化对浆液扩散半径L的影响,并将注浆参数应用于浅埋暗挖隧道工程,基于现场工程施工检测结果验证本文注浆参数的合理性;研究结果表明:考虑浆液、土层参数的动态变化的流固耦合作用数值模拟方法可以很好地分析砂卵石土中浆液扩散过程。在注浆前期较小一段时间内扩散半径随时间增加而增大的幅度明显大于后期且扩散半径存在极限值;渗透系数K为0.20,0.40cm/s时,K变化对扩散半径L影响最为明显;在水灰比W/C为0.8~0.9时,W/C变化对扩散半径L影响最为明显,W/C为0.8~0.9可作为注浆时水灰比控制的范围;提高注浆压力对注浆前期浆液扩散速率有较大的促进作用,注浆压力宜控制为1.0~2.0 MPa。

Based on FLAC3 D fish language,the simulation of grouting diffusion process coupled with seepage field and stress field considering the dynamic change of slurry and sandy pebble soil parameters is realized;The mechanism of slurry diffusion diffusion in sand and gravel soil is studied and the influence of permeability coefficient K,slurry water cement ratio W/C and grouting pressure P of grouting parameters on the diffusion radius L of slurry is studied; The grouting parameters are applied to shallow buried tunnel engineering,and the rationality of the grouting parameters is verified based on the field construction test results;The results show that considering the dynamic coupling of fluid and soil parameters,the numerical simulation method can well analyze the slurry diffusion process in sandy soil;In the earlier period,the radius of diffusion of sand and gravel soil increases with the increase of time,and the amplitude is obviously larger than that of later period,and the limit of diffusion radius exists; When the permeability coefficient K is 0. 20 ~ 0. 40 cm/s,the influence of K variation on the diffusion radius L is the most obvious;water cement ratio of 0. 8 ~ 0. 9 can be used as control water cement ratio in sandy pebble stratum; Increasing the grouting pressure has a great influence on the diffusion rate of grout at the early stage of grouting,and the grouting pressure should be controlled from 1 to 2 MPa.