考虑粗糙度的黏性土-结构接触面力学特性试验

发布时间：2018-04-13 20:14

本文选题：黏性土 + 接触面粗糙度　；参考：《四川大学学报(工程科学版)》2015年04期

【摘要】：为深入研究粗糙度对黏性土与结构接触面的相互作用及影响,基于对灌砂法的修正,提出了一种测定土-结构接触面粗糙度的方法。针对试验自制混凝土试块的半圆凹槽状粗糙表面和其他学者设计的齿形粗糙表面,使用修正后的灌砂法、常规灌砂法和试验常用的峰谷距测定法测定其粗糙度,并进行对比。利用大型直剪试验仪对红黏土-混凝土试块接触面进行直剪试验,定量分析了粗糙度对接触面剪切破坏、变形等的影响,并探讨了粗糙度的影响机理。结果表明:针对接触面粗糙度的测定,修正后的灌砂法比常规灌砂法或峰谷距测定法有效;接触面剪切破坏满足摩尔-库伦剪切破坏准则;粗糙度对接触面摩擦角影响不大;接触面抗剪强度和黏聚力的增长速率随粗糙度的增大而降低;随着粗糙度的增大,接触面黏聚力增大且逐渐趋近红黏土的黏聚力,此时剪切破坏可能发生在接触面上或接触面附近的土体内;随着法向应力的增大,临界粗糙度减小且粗糙度对接触面抗剪强度的影响降低;粗糙度较小时,接触面剪切破坏后出现较为明显的应力跌落现象。
[Abstract]:In order to study the interaction and influence of roughness on the interface between clay soil and structure, a method for measuring the roughness of soil-structure interface is proposed based on the modification of sand filling method.Aiming at the semi-circular grooved rough surface of the concrete test block and the tooth shape rough surface designed by other scholars, the roughness was measured by the modified sand filling method, the conventional sand filling method and the peak-valley distance measurement method, and compared with each other.The direct shear test on the interface of red clay and concrete was carried out by using a large direct shear tester. The effects of roughness on shear failure and deformation of contact surface were quantitatively analyzed, and the influence mechanism of roughness was discussed.The results show that the modified sand filling method is more effective than the conventional sand pouring method or peak-valley spacing method in measuring the roughness of the contact surface, the shear failure of the contact surface meets the Moll-Coulomb shear failure criterion, and the roughness has little effect on the friction angle of the contact surface.The increasing rate of shear strength and cohesive force of contact surface decreases with the increase of roughness, and with the increase of roughness, the cohesive force of contact surface increases and gradually approaches the cohesion of red clay.In this case, shear failure may occur on or near the contact surface. With the increase of normal stress, the critical roughness decreases and the influence of roughness on the shear strength of the contact surface decreases.The phenomenon of stress drop appears after shear failure of contact surface.
【作者单位】：中南大学土木工程学院;天津市市政工程研究院;
【基金】：国家自然科学基金资助项目(51378514)
【分类号】：TU411

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