软黏土中静压沉桩引起的侧向挤土位移分析

Lateral Displacements of Ground Caused by Piles Installation in Soft Clay

摘要:

将软黏土中桩体贯入过程看作不排水条件下圆柱孔的扩张.弹性和塑性区分别采用小应变和大应变理论，考虑传统超固结比与各项同性超固结比的不同，推导了修正剑桥模型土中单桩挤土位移的解析解；并与文献离心模型试验结果进行了比较，验证了理论解答的可靠性.在此基础上，采用叠加原理对排桩的侧向挤土位移进行了估算，并分析了沉桩数目、桩间距、预钻孔孔径以及土体超固结比对侧向挤土位移的影响规律.研究结果表明，随着沉桩数目的增加，挤土影响范围增大；当桩间距、预钻孔孔径增大时，挤土位移快速减小；土体超固结比增加时，侧向挤土位移略有增加，但总体影响不明显.

Abstract:

By taking the pile penetration as the expansion of a cylindrical cavity under the undrained condition and assuming small strain deformation in the elastic region and large strain deformation in the plastic region, the lateral displacement of ground due to a single pile installation is derived in modified Cam clay critical state soil. Meanwhile, the difference between the traditional overconsolidation ratio and the isotropic overconsolidation ratio is taken into account. Comparison between the predicted and the measured values from literature verifies the validity of the present solution. Furthermore, the proposed solution is developed to estimate the lateral displacements due to a single row of piles based on the assumption that superposition is applicable to the displacements. The effects of the number of piles, space of two adjacent piles, prebored hole and the overconsolidation ratio (OCR) on the calculation of displacements are conducted. The results show that the value of the displacement increase with the increasing piles number, and decreases with the increasing space of two adjacent piles and radius of prebored hole. The increase of OCR also leads to increase of displacement, however, that is not pronounced.