摘要
为探究粗糙度和土体相对密实度对砂土-混凝土桩接触面力学特性的影响规律,利用大型直剪仪开展了不同粗糙度、相对密实度下的砂土-混凝土接触面直剪试验,分析了粗糙度、相对密实度对砂土-混凝土接触面的剪切应力-切向位移、峰值剪切强度、割线摩擦角、归一化摩擦系数的影响.研究结果表明:密砂的剪切应力-切向位移曲线在光滑接触面下呈轻微软化型,随粗糙度增加,软化越明显;松砂的剪切应力-切向位移曲线始终呈硬化型.界面峰值剪切强度随法向应力增加呈非线性增长,土体相对密实度越大,非线性越明显.接触面割线摩擦角随法向应力增加呈指数衰减,而由于剪切强度增量较小,导致接触面峰值摩擦系数随法向应力增加呈幂函数衰减.存在临界粗糙度I_(cr),当I>I_(cr)时,接触面峰值摩擦系数和归一化割线摩擦角不再随粗糙度增大而增加,而是呈减小趋势.
To investigate the effect law of surface roughness and soil relative density on the mechanical properties of sand-concrete pile interface,a series of sand-concrete interface tests with various surface roughness and soil relative densities were conducted by the large-scale direct shear apparatus.This study investigated the influence of roughness and soil relative density on shear stress-horizontal displacement,peak shear strength,secant friction angle,and normalized friction coefficient.The results showed that in the case of the smooth interface,the shear stress-horizontal displacement curves of the dense sand sample illustrated a slight softening response,and softening response became remarkable as the roughness increased.The curves of the loose sand sample showed a hardening response.Moreover,the peak shear strength of the interface increased nonlinearly with the increase of normal stress.And the greater the soil relative density,the more obvious the nonlinearity.The secant friction angle of the interface decayed exponentially with increasing normal stress.However,the peak friction coefficient decreased as a power function with the increasing normal stress due to the smaller shear strength increment.Additionally,there existed a critical value of roughness I_(cr),such that the peak friction coefficient and normalized secant friction angle no longer increased as the roughness increased and turned to decrease when I exceeded I_(cr).
作者
陈琛
冷伍明
杨奇
徐方
魏丽敏
CHEN Chen;LENG Wuming;YANG Qi;XU Fang;WEI Liming(School of Civil Engineering,Central South University,Changsha 410075,China;MOE Key Laboratory of Engineering Structures of Heavy Haul Railway,Central South University,Changsha 410075,China;Hunan Tieyuan Civil Engineering Testing Co.,Ltd,Changsha 410075,China)
出处
《湖南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2022年第11期225-236,共12页
Journal of Hunan University:Natural Sciences
基金
国家自然科学基金资助项目(51978672,51878671)
中南大学研究生创新项目(2017zzts159)
杭枢指合(2021)92号
湖南铁院土木工程检测有限公司开发课题。
