湛江组结构性黏土触变性对群桩承载力时效性的影响  

Effect of Thixotropy of Structural Clay in Zhanjiang Group on Timeliness of Bearing Capacity of Pile Groups

作　　者：汤斌 亢佳帅 姚正 TANG Bin;KANG Jia-shuai;YAO Zheng(Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,China)

机构地区：[1]桂林理工大学广西岩土力学与工程重点实验室,桂林541004

出　　处：《武汉理工大学学报》2021年第1期61-67,共7页Journal of Wuhan University of Technology

基　　金：国家自然科学基金(41867035);广西省自然科学基金(2020GXNSFAA297199);广西岩土力学与工程重点实验室项目(2016-A-01)

摘　　要：对7套不同桩材、桩间距、桩长的模型群桩基础进行不同休止时间(0d、7d、14d、28d、60d、90d)的桩周土十字板剪切试验和桩基静载试验,探究桩周土抗剪强度和桩基承载力随休止时间的变化,揭示湛江组结构性黏土触变性对群桩承载力时效性的影响规律。结果表明:湛江组结构性黏土的抗剪强度随休止时间增加而增长,相同休止时间情况下,桩周土触变强度比率随桩材弹性模量、桩间距、桩长的增大而减小;群桩的荷载沉降曲线呈明显的陡降型,具有明确的破坏荷载,群桩的极限承载力具有明显的实效性,相同休止时间情况下,极限承载力随桩材弹性模量、桩长和桩间距增大而增大;桩基承载力时效性系数与桩材、桩间距和桩长有关,相同休止时间情况下,桩材弹性模量和桩间距越小,承载力时效性系数越大,桩长越长时,承载力时效性系数越小;湛江组结构性黏土触变强度比率与桩基承载力时效性系数呈对数函数关系。Seven sets of model pile group foundations with different pile materials,pile spacing and pile length were subjected to cross plate shear test and pile foundation static load test with different resting time(0 d,7 d,14 d,28 d,60 d and 90 d)to explore the variation of shear strength of soil around pile and bearing capacity of pile foundation with resting time.The influence law of thixotropy of structural clay in Zhanjiang Formation on the timeliness of bearing capacity of pile group is revealed.The results show that the structural shear strength of clay in zhanjiang group increase with the increase of resting time,same inactivity time cases,ratio of pile soil thixotropic strength with the pile material elastic modulus,pile spacing,pile length and decreases;The ultimate bearing capacity of pile group has obvious effectiveness.Under the same resting time,the ultimate bearing capacity increases with the increase of elastic modulus of pile material,pile length and pile spacing.Pile foundation bearing capacity coefficient of timeliness and piling pile length,pile spacing,and related,resting time same case,pile material elastic modulus and the smaller the pile spacing,the greater the coefficient of bearing capacity of timeliness,the longer the pile length,the smaller the coefficient of bearing capacity of timeliness;The thixotropic strength ratio of structural clay in Zhanjiang Formation has a logarithmic function with the time-effectiveness coefficient of pile bearing capacity.

关 键 词：湛江组结构性黏土 群桩 模型试验 触变性 时效性 

分 类 号：TU473.1[建筑科学—结构工程]