粉细砂与混凝土接触面强度影响因素显著性分析

Analysis of the Influencing Factors on the Strength of the Contact Surface Between Fine Sand and Concrete

土与混凝土接触面剪切强度是研究土与混凝土接触面力学特性的重要参数,是解释土与混凝土相互作用问题的理论基础,为探究含水率、干密度及法向应力对粉细砂与混凝土接触面剪切强度的影响,开展不同含水率、干密度及法向应力工况下粉细砂与混凝土接触面直剪试验研究。结果表明:三种试验因素对粉细砂与混凝土接触面剪切强度影响的主次顺序为法向应力>含水率>干密度;粉细砂与混凝土接触面剪切应力-剪切位移关系曲线在低法向应力下表现出应变软化特性,在高法向应力下呈现出应变硬化特性;粉细砂与混凝土接触面在高法向应力下形成一定厚度的剪切带,且剪切带厚度和面积随着法向应力的增加而增大;在一定干密度下,粉细砂-混凝土接触面剪切强度在不同法向应力作用下随含水率的增大呈现先增大后减小的趋势,在粉细砂最优含水率附近接触面剪切强度达到极大值,且这种变化趋势随法向应力的增大而愈发显著。

Soil and concrete interface shear strength is of great importance for studying the characteristics of soil and structural mechanics parameters,interpreting the interaction between soil and concrete problems of theoretical basis,and exploring the moisture content,dry density and the normal stress conditions on the strength of silty sand and concrete interface,the influence of normal stress in different moisture content,dry density and the quick direct shear test under the condition of research.The results show that the primary and secondary influences of the three test factors on the shear strength of the contact surface of fine sand-concrete are the normal stress,moisture content,dry density.The shear stress-shear displacement curves of the contact surface of fine sand and concrete show strain softening under low normal stress and strain hardening under high normal stress.The contact surface of fine sand and concrete forms shear zone with certain thickness under high normal stress,and the thickness and area of the shear zone increase with the increase of normal stress.At a certain dry density,the shear strength of the contact surface of fine sand-concrete increases first and then decreases with the increase of water content under different normal stresses,and reaches the maximum value near the optimal water content of fine sand-concrete,and this change trend becomes more and more significant with the increase of normal stress.