This paper presents an experimental study of shaking table tests on two geosynthetic encased stone columns (GESC) composite foundation models with different geosynthetic encasement stiffness to investigate the influence of geosynthetic encasement stiffness on the shear reinforcement effect. The reduced-scale GESC composite foundation models were designed according to the similitude relationships by scaling the model geometry, geosynthetic encasement stiffness, and input motions for shaking table tests in a 1 g gravitational field. The GESC composite foundation models were constructed using poorly graded sand, gravel, and geotextile encasement, and then were excited using a series of sinusoidal input motions with increasing peak acceleration. The acceleration amplification factors for the GESC composite foundation model with higher geosynthetic encasement stiffness are larger than those of the lower geosynthetic encasement stiffness model due to the increased stiffness of the composite foundation. The higher geosynthetic encasement stiffness composite foundation has smaller settlements and lateral displacements under the same input motions compared to the lower geosynthetic encasement stiffness composite foundation. The incremental geosynthetic encasement tensile strains increase with increasing input acceleration for both models. The longitudinal tensile effect of geosynthetic encasement plays an important role on the shear reinforcement mechanism of GESC.

本文通过对两种不同土工合成材料围护刚度的土工合成材料围护石柱（GESC）复合地基模型进行振动台试验研究，研究土工合成材料围护刚度对抗剪加固效果的影响。缩小比例的 GESC 复合地基模型是根据相似关系设计的，通过缩放模型几何形状、土工合成材料围护刚度和 1 g重力场中振动台试验的输入运动。GESC 复合地基模型使用级配较差的沙子、砾石和土工织物包裹物构建，然后使用一系列峰值加速度。由于复合地基刚度的增加，具有较高土工合成材料围护刚度的 GESC 复合地基模型的加速度放大系数大于较低土工合成材料围护刚度模型的加速度放大系数。与较低土工合成材料围护刚度的复合地基相比，在相同输入运动下，较高土工合成材料围护刚度的复合地基具有较小的沉降和侧向位移。对于两个模型，增量土工合成材料包裹拉伸应变随着输入加速度的增加而增加。土工合成材料围护结构的纵向拉伸效应对GESC的抗剪加固机制起着重要作用。