摘要
选用碎石、圆砾和砂3种填料,以及5种不同强度的聚丙烯土工编织布套筒,制备成15组尺寸为?300 mm×600mm,填料压实度?=0.9的土工织物散体桩,对桩体进行单轴压缩试验,以研究不同填料土工织物散体桩在轴向荷载作用下的强度特性。研究结果表明:不同填料桩体在单轴压缩下具有不同的破坏模式,碎石填料局部刺破编织布套筒形成较大破口,圆砾填料致套筒横向筋丝断裂、纵向筋丝分离,而砂填料致套筒横向筋丝断裂较均匀且无明显破口。桩体强度与筋材和填料强度均呈正相关关系,3种填料桩体轴向应力–应变曲线在加载初期因填料受到初始压密而略有上凹,而后近似线性增长至桩体强度,峰值强度后呈现应变软化现象;综合本文试验数据及前期所做的单轴、三轴压缩试验数据,修正了桩体强度理论计算公式,得到的桩体强度修正值与试验值吻合较好。
15 samples of geosynthetic-encased stone columns(GESCs) with a dimension of φ300 mm×600 mm and degree of compaction of 0.9 are made using three types of fills of crushed stone, pebble and sand and five different strength woven sleeves made of polypropylene geotextiles. The uniaxial compression tests are performed on the samples to investigate the characteristics of strength of GESCs. The results show that different failure modes happen to the GESC body with different fills under uniaxial compression. The crushed stone can partly puncture the woven sleeves to produce obvious holes and pebble is extruded to break the transverse polypropylene slices, while the longitudinal slices are separated. The sand evenly breaks the transverse slices with no obvious holes on sleeves. The strength of the GESC body has a positive relationship with the strength of the sleeves and the fills. The stress-strain curve of GESC body at preliminary loading stage is mildly concave down due to the initial densification, then increases linearly up to the peak stress, and subsequently decreases, showing strain-softening characteristics. Based on the present data and those of uniaxial and triaxial compression tests carried out by the authors before, the theoretical formula for the strength of the GESC body is amended, and the results of the modified formulas are proved to be in good agreement with the experimental ones.
作者
陈建峰
花嘉嘉
冯守中
CHEN Jian-feng;HUA Jia-jia;FENG Shou-zhong(Department of Geotechnical Engineering,School of Civil Engineering,Tongji University,Shanghai 200092,China;Wuhan Guangyi Transportation Science and Technology Co.,Ltd.,Wuhan 430074,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2019年第1期148-153,共6页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(41572266
41772289)
关键词
土工织物散体桩
单轴压缩试验
应力-应变曲线
桩体强度
填料
geosynthetic-encased stone column
uniaxial compression test
stress-strain curve
strength of GESC
fill
