摘要
桩网复合地基填土性质与土拱效应发挥程度直接相关,而传统土拱模型并不能有效反映填土黏聚力对桩土应力计算结果的影响。在Hewlett极限状态空间土拱效应分析基础上,采用填土综合内摩擦角指标完成空间土拱拱顶及拱脚位置处单元土体应力极限状态分析,考虑桩间土应力非均匀分布与被动土压力发挥程度的影响,得到桩网复合地基桩体荷载分担比解析表达式。研究结果表明:填土黏聚力显著提高路基填土土拱效应,复合地基设计应考虑填土黏聚力的有利影响;桩间土应力并非均匀分布,通过非均匀分布系数折减后,可有效提高弹性工作状态的桩体荷载分担计算结果;考虑被动土压力发挥程度的计算结果并不合理,应分别由桩顶和拱脚土体应力极限状态确定对应的桩体荷载分担比,取较小值为最终桩体荷载分担比结果。
Pile efficacy related to the soil arching is directly influenced by the backfill soil properties, but conventional soil arching model fails to reflect the internal mechanisms such as soil cohesion. In this study, comprehensive internal friction angle is applied for the critical stress situation analysis of the soil arch top and toe based on Hewlett Model. Meanwhile, the uneven distributed soil stress between piles and the effecting degree of the passive earth pressure are both considered to establish the analytical equation of pile efficacy. The new soil arch model outputs indicate that backfill soil cohesion can greatly improve the calculated pile efficacy and it is more reasonable to consider the effect of soil cohesion. Soil stress between piles is of uneven distribution, and the calculated pile efficacy will also increase if the uneven coefficient is taken into consideration during the calculation process. As the pile efficacy determined by the effecting degree of passive earth pressure is not as good as expected, it is more reasonable to apply the original Hewlett model, and the smaller one of the two is taken as the soil arching final pile efficacy.
出处
《铁道标准设计》
北大核心
2015年第5期16-23,共8页
Railway Standard Design
基金
中国铁路总公司科技研究开发计划项目(2014G003-B)
