Abstract: Based on the foundation condition associated with Zunyi to Bijie section , HangRui highway in Guizhou Province , China , three foundation treatments including gravel pile reinforcement , cement fly-ash gravel (CFG) pile reinforcement , and gravel pile combined with CFG pile reinforcement , were studied by finite element software PLAXIS. The simulation models were developed to compute the displacement and the stress of pile-soil. And the reinforcement effect and economic benefit of these three treatments were then compared. The results indicate that the maximum vertical displacements are O. 569 m for gravel pile , 0.056 m for gravel pile combined with CFG pile and O. 035 m for CFG pile. The maximum horizontal displacements are O. 317 m, 0.069 m and 0.054 m, respectively. And the costs are 11216.08 RMB , 9776.08 RMB and 8480.27 RMB , respectively. It indicates that the CFG pile performs best , but the gravel pile combined with CFG pile is the most econonllC

Key words: gravel pile strengthening foundation, CFG pile strengthening foundation, gravel pile and CFG pile combined to reinforce foundation

摘要： 以杭瑞高速公路贵州遵义一毕节段软土地基处理工程为依托，针对碎石桩加固、CFG 桩加固以及碎石桩与 CFG 桩联合加固三种不同软土路基加固形式，利用PLAXIS 有限元软件建立数值模拟模型，计算位移、桩间土应力， 对比分析了三种方法的加固效果及经济性。研究表明:碎石桩加固、组合桩加固、CFG 桩加固三种加固地基的最大 坚向位移分别为0.569 ， 0.056 ， 0.035 m; 最大水平位移分别为0.317 ， 0.069 ， 0.054 m; 造价分别为8480.27 ， 9776.08 ， 11216.08 元。说明CFG 桩加固效果最好，而组合桩加固地基具有经济优势。

关键词: 碎石桩加固地基, CFG 桩加固地基, 碎石桩与CFG 桩组合加固地基