钙质砂地区桩基的横向承载特性

Hu Haibo, Luo Lina, Lei Gang, Guo Jin, He Shaoheng, Hu Xunjian, Guo Panpan, Gong Xiaonan

Research Center of Coastal and Urban Geotechnical Engineering, Zhejiang University, Hangzhou 310058, China.

College of Railway Engineering, Guangzhou Railway Polytechnic, Guangzhou 510430, China.

Materials (Basel). 2022 Sep 5;15(17):6176. doi: 10.3390/ma15176176.

Reviewing literature revealed that the studies on the bearing characteristics of pile foundations mainly focuses on clay, ordinary sand, loess, saline soil, and other areas. However, few studies on the bearing characteristics of the pile foundation in calcareous sand were conducted. Besides, existing traditional studies ignored the variation of soil compression modulus with depth, and the effect of void ratio on the transverse bearing characteristics of the pile foundation in a calcareous sand area were not well understood. In response of these problems, this study conducted a theoretical investigation on the transverse bearing characteristics of the pile foundation in a calcareous sand area. The transverse bearing characteristics of the pile foundation were derived based on the Pasternak foundation model and the Winkler foundation model, incorporating the heterogeneous distribution of compressive modulus with buried depth. The calculation results of the Pasternak foundation model are closer to the observed results than the Winkler foundation model. Therefore, the following research on the transverse bearing characteristics of the pile foundation in the calcareous sand area adopts the Pasternak foundation model. Then, the effects of the pile length, pile diameter, pile elastic modulus, horizontal load, bending moment, and void ratio on the transverse bearing characteristics of the pile foundation in a calcareous sand area were thoroughly analyzed. Furthermore, the difference between the transverse bearing characteristics of the pile foundation in a calcareous sand area and a quartz sand area was discussed. Results show that the horizontal displacement of the pile top in a calcareous sand area is greater than the quartz sand area under the same conditions.

文献综述表明，关于桩基承载特性的研究主要集中在黏土、普通砂土、黄土、盐渍土等领域。然而，针对钙质砂中桩基承载特性的研究较少。此外，现有的传统研究忽略了土压缩模量随深度的变化，且对钙质砂地区桩基横向承载特性中孔隙比的影响了解不足。针对这些问题，本研究对钙质砂地区桩基的横向承载特性进行了理论研究。基于帕斯特纳克地基模型和文克尔地基模型，考虑压缩模量随埋深的非均匀分布，推导了桩基的横向承载特性。帕斯特纳克地基模型的计算结果比文克尔地基模型更接近实测结果。因此，后续对钙质砂地区桩基横向承载特性的研究采用帕斯特纳克地基模型。然后，深入分析了桩长、桩径、桩弹性模量、水平荷载、弯矩和孔隙比对钙质砂地区桩基横向承载特性的影响。此外，还讨论了钙质砂地区与石英砂地区桩基横向承载特性的差异。结果表明，在相同条件下，钙质砂地区桩顶的水平位移大于石英砂地区。