【摘要】 钻孔灌浆土钉的抗拔承载力直接影响着边坡以及挡土墙等支挡结构的稳定与安全.抗拔承载力主要来自钉体与周围土体之间的摩阻力,而界面处的粗糙情况更是影响摩阻力的关键因素之一.以往的研究并未把粗糙度的概念引入到土钉拉拔研究中.本研究提出了一种具有工程可操作性的新型土钉模型,通过在钉体表面制作不同尺寸的偏直角三角形螺纹来改变钉体表面的粗糙度.通过定义一个更为合理的表观粗糙系数,并建立表观粗糙度系数与表观摩擦系数的关系,提出了考虑土体剪胀作用与土钉制作方式而产生的装配后应力,以及表观粗糙度参数的钻孔灌浆土钉拉拔承载力的计算模型.最后,通过有限元分析软件A B A Q U S模拟粗糙土钉的室内拉拔试验,系统地研究了表观粗糙度对土钉极限抗拔承载力的影响.通过数值模拟结果表明,在钉体表面制作规则螺纹,可以显著提升钉体极限抗拔承载力;土钉极限抗拔承载力与表观粗糙角并非是线性关系.更多还原

【Abstract】 Pullout resistance of cement-grouted soil nails is a key factor affecting the stability of slopes, retaining walls and other retaining structures. The pullout resistance mainly comes from the friction at the interface between the nail body and the surrounding soils, which is influenced by many factors, while the roughness condition is a critical one. Past studies only focus on how the roughness condition affect the interface friction between the soil and different materials. In this study, a new type of soil nail which can be easily applied in engineering practice is proposed. By varying the configuration of buttress thread on the surface of soil nail, we can get different surface roughness. A reasonable surface roughness factor was also defined by applying soil mechanics theories. Then the relationship between the surface roughness factor and the coefficient of apparent friction is established quantitatively. The numerical simulation shows that by manufacturing different sizes of buttress thread on the surface of soil nail, the pullout capacity of soil nail can be improved significantly. The relationship between the limit pullout capacity of soil nail and the surface roughness factor is nonlinear.更多还原