Optimization and reinforcement effect analysis of vertical drain in a soft soil foundation treatment
某软土地基处理排水板优化及加固效果分析

摘要

真空预压塑料排水板在沿海地区的软土地基处理中广泛应用，塑料排水板长度和间距的确定是平衡软土地基处理效果与工程造价的关键。本文基于某沿海地区软土地基处理工程，提出了实际工程中塑料排水板长度和间距的选取及优化设计方法。首先，采用规范法计算初步确定塑料排水板长度；其次，基于PLAXIS 2D数值模拟分析塑料排水板长度和间距对地基沉降量及沉降速率的影响，提出优化设计参数；最后，通过现场实测分析塑料排水板设计优化后的加固效果。结果表明：优化后的排水板长度为10m~11m，比原设计排水板长度减短36.8%~39.6%，经济造价节约了近30%。排水板的合理间距在0.8m~1.8m范围内，随着排水板间距增加，固结速率逐渐减小，但趋于稳定的沉降值基本一致。排水板优化加固后软土地基的最终沉降量约为55.39cm，与数值计算沉降量61.57cm相差约10.03%，十字板平均剪切强度较未处理前增加约82.94%。该研究结果为软土地基处理工程中排水板优化设计提供了有效指导。

Abstract

The prefabricated vertical drain (PVD) with vacuum preloading is widely used in soft soil treatment in coastal areas. The length and spacing of PVD are the key parameters affecting the reinforcement effect and construction costs. Based on a soft soil treatment project in coastal area, this paper puts forward the selection and optimal design method of the length and spacing of PVD. Firstly, the length of PVD is preliminarily determined according to the issued standard. Secondly, the influence of the length and spacing of PVD on the final settlement and settlement rate of the foundation is analyzed based on PLAXIS 2D numerical simulation, and the optimal design parameters are proposed. Finally, the reinforcement effect of PVD after design optimization is finally analyzed through the field measurement. The results show that a reasonable optimized length of the PVD is 10m~11m in this project. Compared with the original design, the length of PVD is reduced by 36.8%~39.6%, and the construction cost is saved by 30%. The reasonable spacing of the PVD is in the range of 0.8m~1.8m. With the increase of the spacing of the PVD, the consolidation rate decreases gradually, but final settlement values tend to be the same. The final settlement of the soft soil foundation after treatment is about 55.39cm, which shows a deviation of about 10.03% from the numerically calculated settlement of 61.57cm. The average shear strength from vane shear tests increases about 82.94% for the soft soil foundation after treatment. The results provide effective guidance for the optimal design of PVD in soft soil treatment.