孟加拉吉大港盾构隧道碎石桩液化处置效果评价

The Evaluation of Liquefaction Disposal of Gravel Piles in Shield Tunnel of Chittagong, Bangladesh

饱和砂土地基液化处置方案效果评价至关重要,关系到液化处置方案的有效性和经济性,可以实现设计方案最优化。孟加拉吉大港盾构隧道存在地基地震液化问题,须采取有效的液化处置措施才能确保工程的安全性。从机理上分析了碎石桩液化处置的优势,提出了合理的液化处置方案。而且在定性分析的基础上,对该项目的地基碎石桩液化处置效果进行数值分析与评价:利用有限差分程序FLAC3D,分别建立碎石桩加固前和加固后的三维动力计算模型,通过计算分析液化处置前后的超孔压比、超静孔隙水压力、抗浮特性等,定量评价液化处置效果。研究表明该碎石桩液化处置方案效果明显,各方面抗震特性均有效提升。

The evaluation of the effect of the liquefaction disposal scheme of saturated sand foundation is very important. It is related to the effectiveness and economy of the liquefaction disposal scheme, and the design scheme can be optimized. There is a ground liquefaction problem in the shield tunnel of Chittagong, Bangladesh. Effective liquefaction measures must be taken to ensure the safety of the project. This paper analyzes the advantages of liquefaction disposal of gravel piles from the mechanism and proposes a reasonable liquefaction disposal plan. On the basis of qualitative analysis, the numerical analysis and evaluation of the liquefaction effect of the base gravel pile is carried out. By using the finite difference program FLAC3 D, the three-dimensional dynamic calculation model of the gravel pile before and after reinforcement is established. The liquefaction disposal effect is quantitatively evaluated by the excess pore pressure ratio, the excess pore water pressure, and the anti-floating property before and after the liquefaction treatment. The research shows that the liquefaction disposal scheme of the gravel pile has obvious effects, and the seismic characteristics of all aspects are effectively improved.