土体空间变异性是影响桩基承载性能的主要来源之一,研究其对桩基承载性能的影响具有重要的工程实用价值,但目前考虑空间变异性的静载试验研究较少。因此本文提出一种可以考虑土体水平与竖向空间变异性的室内小尺寸单桩静载试验方法。以考虑砂土含水率的空间变异性为例,首先,自主设计与制作了可以划分不同区域的模型箱,用来填充不同含水率的砂土;然后,基于Karhunen-Loeve展开法建立随机场模型,获得模型箱内不同区域的含水率分布。最终按所需含水率配制与填充砂土模型并在中心安装小尺寸模型桩,进行竖向荷载下的静载试验,进一步获得模型桩的荷载–沉降曲线。通过对比不同随机场模型下的静载试验结果,发现空间变异性对桩基承载性能具有不可忽视的影响。
Spatial variability of soil is one of the main sources that affect the bearing performance of pile foundation. It is of great engineering practical value to study the effect of spatial variability of soil on the bearing performance of pile foundation. However, there are few researches on the effect of spatial variability on the bearing performance of pile foundation using the static load test. Therefore, this paper proposes a static load test method for small size single pile which can consider the spatial variability of soil in both horizontal and vertical directions. Taking the spatial variability of moisture content of sand as an example, firstly, a model box which can be divided into different areas is designed and fabricated independently to fill sandy soil with different moisture content. Then, a random field model is established based on Karhunen-Loeve expansion method, and the water content distribution of different regions in the model box is obtained. Finally, the sand model was prepared and filled according to the required moisture content, and the small size model pile was installed. The static load test under vertical load was carried out, and the load-settlement curve of the model pile was further obtained. By comparing the static load test results under different random field models, the influence of sands spatial variability on the bearing capacity of pile foundation is analyzed.
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