包裹碎石桩在粉质黏土地基中的承载特性研究

为了探究包裹碎石桩对粉质粘土地基的加固效果，本文基于模型试验和数值模拟方法，对包裹碎石桩与传统碎石桩复合地基承载力特性进行了研究，并分析了碎石模量、碎石内摩擦角和土工格栅刚度等参数对包裹碎石桩复合地基承载及变形的影响。结果表明：传统碎石桩复合地基在荷载小于20kPa时，沉降增大不明显。当荷载大于30kPa时，沉降迅速增大，复合地基失稳破坏；在一定的粒径范围内，相同级配下，碎石粒径越大，碎石桩整体变形越小，承载能力越高；包裹碎石桩的碎石模量在高应力状况下，对复合地基沉降的影响效果较为明显。当桩土模量比大于30时，其对复合地基的沉降影响逐渐减弱；增大碎石内摩擦角能有效增大桩土应力比，并提高桩身应力传递效率。随着内摩擦角的增大，复合地基的沉降逐渐减小，在高荷载水平下，其影响效果更加明显；土工格栅的包裹能减少复合地基沉降，但影响程度有限，当包裹刚度J>1000kN/m时，对沉降的影响逐渐减弱。

Model test and Numerical Simulation Study of Silty Clay Ground Reinforced by Geosynthetic Encased Stone Columns

In order to explore the reinforcement effect of wrapped gravel pile on silty clay foundation, based on model test and numerical simulation method, the bearing capacity characteristics of wrapped gravel pile and traditional gravel pile composite foundation are studied, and the effects of gravel modulus, gravel internal friction angle and geogrid stiffness on the bearing capacity and deformation of wrapped gravel pile composite foundation are analyzed. The results show that when the load of traditional gravel pile composite foundation is less than 20KPa, the settlement increase is not obvious. When the load is greater than 30KPa, the settlement increases rapidly and the composite foundation is unstable and damaged; Within a certain particle size range, under the same grading, the larger the particle size of the gravel, the smaller the overall deformation of the gravel pile and the higher the bearing capacity; The gravel modulus of wrapped gravel pile has obvious effect on the settlement of composite foundation under high stress. When the pile-soil modulus ratio is greater than 30, its influence on the settlement of composite foundation gradually weakens; Increasing the internal friction angle of gravel can effectively increase the pile-soil stress ratio and improve the stress transfer efficiency of the pile. With the increase of internal friction angle, the settlement of composite foundation decreases gradually, and its effect is more obvious at high load level; The wrapping of geogrid can reduce the settlement of composite foundation, but the influence is limited. When J>1000kN/m, the influence on the settlement is gradually weakened.