摘要
能量桩工作过程中,桩体受温度变化影响会产生热变形,进而引起桩周土体的循环剪切作用,弱化地基承载力,给桩基的正常使用带来风险。由于传统直剪仪无法模拟能量桩工作过程中的温度变化,因此对桩-土接触面力学特性受温度影响的变化规律研究较少。对传统直剪仪进行改造,使其可以改变剪切试样温度;所用土体从重庆某施工现场取样,开展不同温度变化下桩-土接触面的室内土工直剪试验,分析单次温度变化和循环温度变化对桩-土接触面力学性能的影响,并对温度影响下桩-土接触面力学特性与土体力学特性的差异进行比较。结果表明,能量桩-土接触面的抗剪强度受温度影响较大;随着温度的升高,能量桩-土界面摩擦角和黏聚力先减小后增大;低法向应力下温度循环对桩-土接触面力学特性影响较大,而高法向应力下温度循环对桩-土接触面力学特性影响不显著;土体的抗剪强度、黏聚力和摩擦角随温度变化规律与桩-土界面类似。
In the working process of energy pile,the pile body will produce thermal deformation influenced by temperature change and induce cyclic shear action on the soil around the pile,which would weaken the bearing capacity of the foundation and bring risks to the normal use of the pile foundation.Because the traditional direct shear apparatus could not simulate the temperature variation of the pile and soil in the working process of energy piles,there was limited research on the mechanical properties of the pile-soil interface affected by the temperature.In this paper,the traditional direct shear apparatus was modified to adjust the temperature of soil samples.The soil used in this test was sampled from a construction site in Chongqing,and the geotechnical direct shear tests of pile-soil interface under different temperatures were carried out.The effects of single and cyclic temperature variation on the mechanical properties of the pile-soil interface were analyzed.Meanwhile,the difference between the mechanical properties of pile-soil interface and soil was compared.The results showed that the shear strength of pile-soil interface was influenced significantly by the temperature.With the increase of temperature,the friction angle and cohesion of the pile-soil interface would firstly decrease and then increase.Temperature cycles had a great influence on the mechanical properties of pile-soil interface under low normal stress,while it had no significant influence under high normal stress.The variations of shear strength,friction angle and cohesion of the soil influenced by temperature was similar to those of pile-soil interface.
作者
陈志雄
甘丰嘉
王成龙
彭宸
丁选明
CHEN Zhixiong;GAN Fengjia;WANG Chenglong;PENG Chen;DING Xuanming(College of Civil Engineering,Chongqing University,Chongqing 400045,P.R.China;Academy of Dazu Rock Carvings,Chongqing 402360,P.R.China;Chongqing Bureau of Geology and Minerals Exploration,Chongqing 401121,P.R.China)
出处
《土木与环境工程学报（中英文）》
CSCD
北大核心
2024年第3期16-23,共8页
Journal of Civil and Environmental Engineering
基金
国家自然科学基金(51908087)
中央高校基本业务费(2021CDJQY-042)。
关键词
能量桩
剪切特性
桩-土接触面
温度变化
energy pile
shear behavior
pile-soil interface
temperature variation
