饱和软黏土地基单桩基础水平荷载模型试验研究

Model Test and Study on Single Pile in Saturated Soft Clay under Lateral Static Load

通过自制的水平加载装置对饱和软黏土和砂黏土地基中嵌固式单桩基础开展水平静载模型试验研究,主要研究了单桩基础的水平承载力和变形特性。试验发现:(1)桩身最大弯矩出现在土表下5倍桩径附近,当水平荷载较小时(小于45 N),桩周土处于弹性变形阶段,当水平荷载较大时,桩周上部土体开始进入塑性阶段,并出现明显的裂纹;(2)桩周土最大抗力发生在泥面下3倍桩径位置处,并随着外荷载增大土抗力也增大,但当外荷载增大到一定程度时,土抗力不再继续增大;(3)API规范推荐的p-y曲线与试验值相比偏于保守,表现为极限土抗力偏小。

Lateral static loading model test was conducted on buih-in single pile foundation in saturated soft clay and sandy clay with self-made loading device, studying the horizontal bearing capacity and deformation characteristics of this single pile foundation. It was found that, （1）the maximum bending moment of pile body occurs at the place about five-fold pile diameter below the soil surface, the soil around is in the elastic deformation stage when the lateral load is relatively small （less than 45 N）, and the upper soil around has been in the plastic stage when the lateral load is larger with cracks significantly; （2） the maximum soil resistance occurs at the place three-fold below the surface soil, the resistance will increase with the external load, however, not to increase any more when the external load increases to certain extent; （3）compared with the test result, the API recommended p-y curve is relatively conservative, showing a relatively small ultimate soil resistance.