桩网结构路基承载特性的现场试验研究.pdf

第31 卷第12 期 岩 土 力 学 Vol.31 No.12 2010 年12 月 Rock and Soil Mechanics Dec. 2010 文章编号：1000－7598 (2010) 12 －3793 －08 桩网结构路基承载特性的现场试验研究 张 良，罗 强，陈亚美，裴富营 （西南交通大学土木工程学院，成都 610031 ） 摘 要：为了考察路堤荷载作用下桩网结构路基桩土间的荷载分担与传递、垫层筋带拉力的组成与分布，选择某新建铁路桩 网结构路基试验工点进行了现场试验，测试了地基变形、路堤基底压力、孔隙水压力、桩身轴力和格栅拉力等数据。测试数 据表明：①地基沉降以压密下沉为主，路基结构稳定，软土较厚一侧地基变形较大；②当桩、土间沉降差与桩间净距的比值 为5.93%时，土拱效应完全发挥，之后增加的路堤荷载完全由桩承担；③桩间土竖向附加应力在加固区内沿深度呈K 型分布； ④筋带拉力沿路基横向呈 M 型分布，软土较厚一侧拉力较大；⑤筋带拉力由路堤荷载作用下的桩间筋带张力与路堤横向滑 移引起的筋带拉力两部分组成，设计筋带时二者均需考虑。 关 键 词：桩网结构路基；现场试验；荷载分担与传递；筋带拉力；土拱 中图分类号：TU 472 文献标识码：A Research on bearing behavior of pile-net structure subgrade based on field test ZHANG Liang, LUO Qiang, CHEN Ya-mei, PEI Fu-ying (School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China) Abstract: Field tests were conducted at a pile-net structure subgrade working point of a certain new railway to investigate the load sharing and transfer between piles and soil in pile-net structure subgrade, also the composition and distribution of tensile force in cushion. In which the deformation of foundation, the pressure at the bottom of embankment, the pore water pressure, the axial force of pile shaft, and the tensile force in grid were tested. We can get the results as follows. Firstly, compaction subsiding is major component of foundation settlement, indicating the subgrade is stable. The thicker the soft soil, the larger the foundation deformation. Secondly, the soil arch exerts fully when the ratio of settlement difference between pile and pile-inter soil to piles net distance is 5.93%. The subgrade load raised later will undertaken by pi