考虑化学反应的高聚物压密劈裂注浆仿真研究

Simulation study on polymer compaction fracture grouting considering chemical reactions

考虑浆液化学反应原理,综合运用扩展有限元理论、修正剑桥模型和高聚物浆液膨胀力计算模型,建立了模拟高聚物在土体中压密劈裂注浆动态过程的二维仿真分析方法。通过模型试验验证了所提出方法的适用性,进而分析了浆液膨胀力、浆脉形态、土体孔隙比随时间变化规律及注浆孔埋深、土体断裂韧度对浆脉扩展过程的影响。结果表明:受高聚物化学反应进程驱动,在浆液与土体耦合作用下,浆液膨胀力初期随时间近似呈线性增长,达到峰值后快速下降并趋于稳定;浆脉长度和宽度发展速度不同步,裂缝启裂至二次扩展阶段,浆脉长度基本保持不变,宽度线性增大,裂缝二次扩展后,浆脉长度近似线性增大,而宽度增长速率趋缓;受浆液挤密作用影响,裂缝两侧一定范围内土体孔隙比显著降低,沿垂直于裂缝面方向,距注浆孔中心越近,孔隙比越小;孔隙比随时间整体呈下降趋势,随着裂缝的扩展和后期膨胀压力的下降,紧邻裂缝面两侧土体孔隙比有一定恢复,随后趋于稳定;随着注浆孔埋深和土体断裂韧度的增加,浆脉长度逐渐减小,宽度不断增大,两者变化速率基本保持不变;浆脉扩展稳定时间随埋深的增大而提前,随断裂韧度的增大而延后。

Based on the chemical reaction principles of slurry,a two-dimensional simulation method for polymer fracture grouting in soil was developed using the extended finite element method(XFEM),the modified Cam-clay model,and the calculation model for polymer slurry expansion force.The serviceability of this method was confirmed.The study then examined the temporal changes in slurry expansion force,slurry vein morphology,and soil void ratio,while also exploring the influence of grouting hole depth and soil fracture toughness on the expansion process of slurry veins.The results indicate that the expansion force of the slurry increases initially due to the chemical reaction process of polymers,peaks,and then rapidly decreases to stabilize under the interaction of slurry and soil.The development rates of vein length and width are asynchronous:the vein length remains relatively constant while the width linearly increases from crack initiation to the second expansion stage.Subsequent to the second crack expansion,the vein length linearly increases,and the width growth rate tends to slow down.The slurry squeezing effect significantly reduces the soil void ratio in a specific range on both sides of the crack.Perpendicular to the crack surface,the void ratio decreases closer to the center of the grouting hole.Over time,the void ratio decreases.As the crack expands and the expansion pressure decreases later on,the soil’s void ratio on both sides of the crack surface partially recovers and then stabilizes.With increasing grouting hole depth and fracture toughness,the slurry vein length gradually decreases while the width continuously increases,with the change rate of the two remaining relatively constant.The stability time of slurry vein expansion advances with increasing burial depth and delays with increasing fracture toughness.