公路软粘土层注浆试验分析及效果评价

Experimental Analysis and Effect Evaluation of Grouting in Soft Clay

为了分析在公路工程中软粘土层的注浆加固效果,针对黄石市兴富一级公路的软基路段注浆处理工程,借助室内试验、数值模拟计算和理论分析等方法,进行了注浆方案设计及处治效果分析。通过抗压试验和直剪试验,分析了3种水泥掺入比方案及其试样的抗压强度和抗剪强度参数变化规律,确定合适的配合比。利用Comsol软件进行多孔介质的流体渗流模拟,得到了不同注浆压力下的浆液扩散半径,确定了注浆半径和注浆压力参数。运用FLAC3D数值软件计算路基的应力场与变形场。结果表明:随着水泥掺入比的增加,试件无侧限抗压强度和粘聚力也随之提高,注浆扩散半径随着注浆压力增加而增大,软土层注浆加固后形成了较好的复合地基整体作用。确定最终采用水泥掺入比为2.5%的浆液、注浆压力为0.8 MPa、单孔扩散半径为130 cm的设计方案。施工完成后现场进行了标准贯入度试验,测试结果显示该方案具有良好的加固效果。

In order to analyze the grouting reinforcement effect of soft clay in highway project,the grouting project of soft clay subgrade of Xing-Fu first class highway was taken as an example. The methods of laboratory test,numerical simulation and theoretical analysis were adopted to the design grouting scheme and to study the treatment effects. Through the unconfined compression test and direct shear tests,samples of compressive strength and change rule of sheering strength parameter with three kinds of cement mixing ratio were studied and the suitable mixing ratio was determined. The model of porous media fluid seepage simulation was made by using Comsol software,the cement slurry diffusion radius under different grouting pressure was calculated and the grouting radius and grouting pressure parameters were confirmed. The FLA3 D software also was applied to calculate the stress field and deformation field of roadbed. The results showed that the unconfined compressive strength and cohesion of the samples increased with cement mixing ratio rising,and the cement slurry diffusion radius amplified with increase of grouting pressure. Finally,the cement mixture ratio 2. 5%,the grouting pressure 0. 8 MPa and 130 cm single-hole diffusion radius were adopted. After completion of construction,the standard penetration test was carried out on site and the test result showed a great reinforcement effect.