黏性土中桩侧后注浆单桩抗压承载性能室内模型试验研究OA北大核心CSTPCD

The post-grouting technique can effectively improve the soil performance against disturbance and break the mud crust around the bored pile.Most of the researches on post-grouting focused on pile tip,while the pile side grouting is rarely involved,which affects its further application.To study the influence of pile side grouting volume on the compressive load behavior,an model test was carried out on the basis of the post-grouting technique of the field pile test.The test results show that,when the load is at a high level,the bearing capacity of the pile with 2 L and 3 L grouting volumes are 18.2% and 66.0% greater than that of the pile with volumes of 1 L,respectively.The increased rate is positively correlated with grouting volume,and the settlement of pile top can be greatly reduced.The axial force of the post-grouting pile decreases rapidly near the position of grouting,and the axial force near the tip of post-grouting pile is relatively low in the whole loading process.The post-grouting pile demonstrates the characteristics of the friction piles.The cement grout diffuses upward and downward from the grouting position,and the diffusion heights are both about 14 times the pile diameter for this model test.The pile side resistance of the post-grouting pile increases significantly in the range of the grout diffusion stage,and the increasing trend is more obvious the closer to the grouting point.