侧限固结时应力比对粗粒土变形的影响

粗粒土侧限变形特性是量化港口填料在不同荷载作用下沉降的重要依据。基于12组不同应力比侧限固结试验,得出侧限条件下加卸荷次数及应力比对粗粒土应变增量的变化趋势,建立粗粒土应变及塑性应变计算模型,并在二维及三维空间下验证了所建模型合理性。结果表明,堆载应力在土体中存在最大影响深度;当应力比相同时,侧限条件下应变增量及塑性应变增量与增量荷载数值无关。粗粒土受荷载循环作用时应变及塑性应变随应力比增大均呈指数函数变化,且其界限应力比处于2. 124～2. 461。建议在港口施工填筑时对地基上部进行多次强夯加固处理,营运阶段应控制最大堆载量并均匀平铺堆场,以降低填筑区的不均匀沉降量。

Effect of stress ratio on deformation of coarse grained soil under lateral consolidation

The lateral deformation characteristic of coarse grained soil is an important basis for quantifying the settlement of port filling under different loads.Based on 12 sets of lateral confinement tests with different stress ratios,we obtain the changing trend of loading and unloading times and stress ratios on strain increment of coarse grained soil under lateral confinement condition,establish the calculation models of strain and plastic strain of coarse grained soil,and verify the rationality of the models in two-dimensional and three-dimensional space.The results show that there is a maximum depth of influence of surcharge stress in soil.When the stress ratio is the same,the strain increment and plastic strain increment under the lateral limit condition are independent of the incremental load value.The strain and plastic strain of coarse grained soil change exponentially with the increase of stress ratio,and the limit stress ratio is between 2.124 and 2.461.It is suggested that the upper part of the foundation should be strengthened by dynamic consolidation for many times during the construction and filling of the port,the maximum heap load should be controlled and the stacking yard should be evenly paved in the operation stage so as to reduce the uneven settlement of the filling area.