The shear properties of carbonate sand and structure interface are of significance for the engineering construction. The parallel paper (Rui et al. in Acta Geotech, 2020) focuses on the monotonic behavior of the interface between carbonate sand and steel. In this paper, by a series of shear tests on the interface between carbonate sand and steel, the evolutions of interface strength during cyclic interface shear were investigated. Further, the influences of cyclic amplitude, particle size, surface roughness and normal stress on the sand–steel interface shear behavior were discussed. Using a kind of transparent ring, the particle movements near the interface were observed to explain the mechanism during cyclic interface shear. The experimental results show that the shear zone appears near the interface, and is mainly composed of crushed fine particles and original particles. With lower steel roughness condition, the volume contraction is dominant in cyclic interface shear, while the dilation and contraction occur alternatively for higher roughness, which leads to higher interface shear strength. Compared with monotonic shear, the thickness of shear zone after cyclic shear is relatively small. Cyclic interface shear can lead to more fine particles, but less is embedded into the interface. It is found that under cyclic shearing, the interaction between particles and steel is enhanced, which is the main factor for promoting the interface strength, so interface strength in cyclic shear is higher than that in monotonic shear.

碳酸盐砂的剪切特性和结构界面对工程建设具有重要意义。平行论文（Rui等人，Acta Geotech，2020年）着眼于碳酸盐砂与钢之间界面的单调性。通过对碳酸盐砂与钢之间的界面进行一系列剪切试验，研究了循环界面剪切过程中界面强度的变化。此外，还讨论了循环振幅，粒度，表面粗糙度和正应力对砂钢界面剪切行为的影响。使用一种透明的环，观察界面附近的粒子运动，以解释循环界面剪切过程中的机理。实验结果表明，剪切带出现在界面附近，并且主要由粉碎的细颗粒和原始颗粒组成。在较低的钢粗糙度条件下，体积收缩在循环界面剪切中占主导地位，而膨胀和收缩在较高的粗糙度下交替发生，从而导致较高的界面剪切强度。与单调剪切相比，循环剪切后的剪切带厚度较小。循环界面剪切可产生更多的细颗粒，但嵌入界面的颗粒较少。研究发现，在循环剪切作用下，颗粒与钢之间的相互作用得到增强，这是提高界面强度的主要因素，因此循环剪切作用的界面强度高于单调剪切作用。扩张和收缩交替出现，以获得更高的粗糙度，从而导致更高的界面剪切强度。与单调剪切相比，循环剪切后的剪切带厚度较小。循环界面剪切可产生更多的细颗粒，但嵌入界面的颗粒较少。研究发现，在循环剪切作用下，颗粒与钢之间的相互作用得到增强，这是提高界面强度的主要因素，因此循环剪切作用的界面强度高于单调剪切作用。扩张和收缩交替出现，以获得更高的粗糙度，从而导致更高的界面剪切强度。与单调剪切相比，循环剪切后的剪切带厚度较小。循环界面剪切可产生更多的细颗粒，但嵌入界面的颗粒较少。研究发现，在循环剪切作用下，颗粒与钢之间的相互作用得到增强，这是提高界面强度的主要因素，因此循环剪切作用下的界面强度高于单调剪切作用下的界面强度。但接口中嵌入的内容较少。研究发现，在循环剪切作用下，颗粒与钢之间的相互作用得到增强，这是提高界面强度的主要因素，因此循环剪切作用的界面强度高于单调剪切作用。但接口中嵌入的内容较少。研究发现，在循环剪切作用下，颗粒与钢之间的相互作用得到增强，这是提高界面强度的主要因素，因此循环剪切作用的界面强度高于单调剪切作用。