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以京沪高速铁路液化土地基加固为背景,采用数值分析方法,通过各级加载情况下地基路基加固前后液化区域分布及超静孔隙水压力变化规律的分析,对水泥粉煤灰碎石桩(CFG桩)桩-网结构地基加固饱和粉土地基进行抗液化性能研究。研究表明,未加固饱和粉土地基在加载加速度大于0.2g时,几乎全部液化;加固后饱和粉土地基在加速度幅值为0.1g时,加固区以外的饱和粉土地基面附近有小面积的液化,随着加载加速度的增大,加固区以外的饱和粉土地基面积液化进一步加大,并逐渐向桩间土发展,当加速度幅值达到0.4g时,路基发生完全液化;超静孔隙水压力随加载加速度幅值的增加而增大。CFG桩桩-网结构地基能够有效地抑制超静孔隙水压力的上升,从而提高地基的抗液化能力。
Taking the reinforcement of liquefied soil foundation of Beijing-Shanghai high-speed railway as the background, numerical analysis method is adopted to analyze the distribution of liquefaction area before and after liquefaction under subgrade loading and the change rule of excess pore water pressure under various loading conditions. Study on liquefaction resistance of saturated silt foundation by pile - net structure foundation. The results show that almost all of the unconfined saturated silt foundation is liquefied when the loading acceleration is greater than 0.2g. When the acceleration of saturated silt foundation is 0.1g, the area of saturated silt surface outside the reinforcement zone is small Liquefaction. With the increase of loading acceleration, the liquefaction of saturated silt ground outside the reinforcement zone further increases and gradually develops into the inter-pile soil. When the acceleration amplitude reaches 0.4g, the subgrade liquefies completely; Pressure increases with increasing loading amplitude. The foundation of CFG pile-net structure can effectively restrain the increase of excess pore water pressure and improve the liquefaction resistance of foundation.