Effects of Interface Morphology on the Shear Mechanical Properties of Sand–Concrete Interfaces

Abstract

The morphology of the contact surface between cast-in-place engineering structures and soil is generally random. Previous research focusing on the shear mechanical properties of soil–concrete interfaces has predominantly concentrated on the role of interface roughness by constructing regular concrete surface types, largely neglecting the potential impact of the roughness morphology (i.e., the morphology of the concrete surface). In this study, concrete blocks with the same interface roughness and different roughness morphologies were constructed based on the sand-cone method, including random rough surface, triangular groove surface, rectangular groove surface, trapezoid groove surface, and semicircular groove surface. A series of direct shear tests were conducted on the rough and smooth sand–concrete interfaces, as well as on natural sand. Through these tests, we examined the shear mechanical behavior and strength of the sand–concrete interfaces, and analyzed the underlying shear mechanisms. The results showed that: (i) the interface morphology had little effect on the variation in the shear stress–displacement curve of sand–concrete interfaces, and it had a significant influence on the shear strength of the interfaces; (ii) under the same normal stress, the shear strength of the sand–concrete interfaces with a random rough surface was the greatest, followed by the triangular groove surface, while the shear strength of the rectangular groove surface proved the lowest; (iii) the shear strength of the sand–concrete interfaces with the same roughness was affected by the size of the contact area between the concrete plane and the sand, that is, a larger contact area correlated with a decrease in shear strength. It can be concluded that the shear strength value of a sand–concrete surface with the triangular groove is the closest to the shear strength of a random rough interface. By gaining a deep understanding of the effects of different contact surface morphologies on shear strength and shear behavior, significant insights can be provided for optimizing engineering design and enhancing engineering performance.

Investigation of the Shear Mechanism at Sand-Concrete Interface under the Influence of the Concave Groove Angle of the Contact Surface

“…As depicted in Figure 6, at an angle θ of 18°, the initial contact force chains are significantly influenced by the sawtooth geometry, forming an "arch" structure at the tips of the sawteeth. The force distribution on the zigzag surface is In the course of the shearing experiment, elements 1 ⃝ 2 ⃝ 3 ⃝ 6 ⃝ are held stationary, while elements 4 ⃝ 7 ⃝ 8 ⃝ 9 ⃝ 10 ⃝ are displaced to the right at a steady pace of 1.2 mm/min, thereby simulating the direct shear interaction between "sawtooth contact interfaces" and "sand particles". The model assumes that the sand particles act as rigid spheres while maintaining a constant density of 2.0 g/cm 3 .…”

“…In the academic sphere, the term Buildings 2024, 14, 1452 2 of 14 "roughness" is frequently employed to characterize structural surfaces, which are typically classified into two categories: "regular-type" and "random-type". Scholars have studied the excitation effect of structural textures, such as periodic rectangular surfaces, trapezoidal surfaces, triangular surfaces, wave textures, and snake textures on the interfacial shear strength through various types of interface shear experiments [4][5][6]. They have investigated the shear failure behavior of interfaces such as soil-concrete, soil-steel, soil-geosynthetic membrane, etc., [7][8][9].…”

Analyzing cyclic shear behavior at the sand–rough concrete interface: An experimental and DEM study across varying displacement amplitudes

“…23,24 However, these parameters are primarily applied to regular surfaces while engineering practice often deals with surfaces that possess irregular shapes. Various methods have been proposed to assess the roughness of irregular surfaces, including the sand cone method, sand replacement method, and sand-pouring method 25,26 But in the preparation of experimental materials, researchers commonly create regular surface test blocks using acquired roughness values. 27 Therefore, it is necessary to investigate the influence of irregular surfaces on the shear behavior of the soil-structure interface, which is in line with the engineering practice.…”