强夯法加固铁路松软土地基现场试验研究

Field Test Study on the Reinforcement for the Saturated Soft Soil Foundation of Railway Using the Dynamic Consolidation

结合强夯法加固铁路饱和松软土地基的现场测试试验,研究强夯过程中地层孔隙水压力的增长和消散规律、孔隙水压力的空间分布特征、地表位移和地层深处沉降的变化规律以及加固后的地基承载力。结果表明,强夯荷载作用下,孔隙水压力的影响范围可以达到水平距离4.75m和深度6m,在第1遍和第2遍强夯作用后经过约4～6d,孔隙水压力消散率能达到90%以上;同时,土层较深处的沉降量也十分显著,在第1遍强夯荷载作用后,3.8m深处的沉降量可以达到10.7cm。因此,用强夯法加固饱和松软土地基可行,加固后的地基承载力特征值可达240kPa。

Combining with the field tests of reinforcement for the saturated soft soil foundation of railway using the dynamic consolidation,this paper analyzes the development and dissipation laws of the pore pressure in strata,the distribution characteristics of the pore pressure in space,the surface displacement and the change law of the settlement in the deep strata during the dynamic consolidation,as well as the variation of the bearing capacity after the reinforcement. Test results show that the affecting scope of the pore pressure is 4.75 m in the horizontal direction and 6 m in the vertical direction under the dynamic loading. The dissipation ratio reaches to more than 90% after 4～6 d of the first and second stages of the dynamic loading. In the meantime,the settlements in deep soil layers are also very obvious. For example,the settlement in the depth of 3.8 m is 10.7 cm after the first stage of the dynamic loading. Hence,the effect of the dynamic consolidation method used for this kind of saturated soft soil foundation is feasible and the eigenvalue of the bearing capacity of the reinforced ground can reach to 240 kPa.