颗粒粒径对粗粒土-混凝土接触面剪切特性影响试验研究

Effects of Particle Size on Shear Behavior of Interface Between Coarse-grained Soil and Concrete

为研究颗粒粒径对粗粒土与混凝土结构接触面剪切力学特性的影响,进行3不同粒径范围（2.36-4.75mm、4.75-9.5mm、13.6-16mm）均匀粒径组粗粒土与两种不同混凝土接触面（光滑和粗糙）大型直剪试验,研究粗粒土粒径对接触面剪切强度的影响规律.试验结果表明：随粒径的增大接触面剪切应力-剪切位移曲线从剪切软化型逐渐向剪切硬化型发展.光滑接触面剪切强度随粗粒土平均粒径的增大几乎呈线性增大;而粗糙接触面剪切强度在平均粒径达到7.13mm后,其增大速率逐渐变小.相同法向应力下粗糙接触面剪切强度明显高于光滑接触面.摩尔库伦强度指标分析表明：粒径的增大显著提高了接触面的表观黏聚力;但对接触面内摩擦角的影响不明显.

A series of large direct shear tests were performed to study effects of particle size on shear behavior of coarse-grained soil-concrete interface,three types of uniformly coarse-grained soil（ 2. 36 - 4. 75 mm、4. 75 - 9. 5 mm、13. 6 -16 mm） and two different concrete surface（ smooth and rough） were used in this study. The results show that the shear stress-shear displacement curves of interface develop from strain softening to strain hardening with increasing particle size. The shear strength of smooth interface increases almost linearly with mean particle size of coarse-grained soil; The rate of increase in shear strength of rough interface diminishes when mean particle size of coarse-grained soil is greater than 7. 18 mm. The shear strength of rough interface is significantly larger than that of smooth interface under a specific normal stress. The increasing particle size can remarkably increase the apparent cohesion of interface,but has little influence on internal friction angle of interface.