摘要
基于复杂海相沉积深厚软基处理情况,设置监测断面,埋设相关监测仪器,对桩-网复合地基上部路堤填土施工过程中地表沉降、深部分层沉降、桩土应力、孔隙水压力、土工格栅伸长量等的变化进行观测分析研究。在加载初始阶段,桩间土应力和桩顶土应力都有一个快速升高的历程,但桩间土应力增大的速率要小于桩顶土应力;在一定填土高度时,极值出现于桩间土,随之产生的"土拱效应"会使两桩中心处的土应力大于四桩中心处的土应力值;孔隙水压力随填土高度的增加上升得并不明显,荷载的变化对浅部孔隙水压力的影响较大,对深部的孔隙水压力影响则较小;地基分层沉降的速率与路堤填土的速率呈正相关,沉降量的大小与地层深度和地层特征有关;随着填土高度的增加,土工格栅的拉伸位移量亦增加,且桩间土处的土工格栅的拉伸率及所承受的拉力均要大于桩顶处。
Based on the treatment of complex marine sedimentary deep soft soil foundation, monitoring sections and in- struments were selected and buried for measuring and analyzing surface settlement, layered settlement, lateral displace- ment, earth pressure on piles and soils, and stretching of the geogrid during filling construction of pile - net composite foundation. At the beginning of uploading, earth pressure on soil among piles and the top of the piles increase abruptly, but the rate of change of the pressure on the top of the piles is larger than that on soil among piles. When the filling rea- ches a certain height, the earth pressure on the soil between the piles reaches a maximum value, which leads to soil arc- hing. In this phenomenon, the pressure on the soil in the center of four piles becomes smaller than the pressure between two piles. The layered settlement of the foundation is directly proportional to the filling height, and it is relevant to the foundation depth and the properties of the corresponding stratum ; The tension displacement of the geogrid increases with the increasing filling height, and both the tension ratio and the tension force on the soil between piles are larger than that on the top of the pile.
出处
《高速铁路技术》
2015年第6期26-31,共6页
High Speed Railway Technology
基金
国家自然科学基金项目(41172260
41372292
51108393)
关键词
桩-网复合地基
现场监测
大面积深厚软土
复杂海相
承载性状
沉降变形
pile - net composite foundation
field monitoring
large area deep soft soil
complex marine facies
bearingbehavior
settlement deformation
