Laboratory Investigation of Shear Behavior of High-Density Polyethylene Geomembrane Interfaces

Abstract

As a product of polymeric materials, geomembranes (GMs) are widely used in engineered systems as impervious barriers due to their low permeability. In this study, a large-scale composite shear test apparatus was developed to investigate the shear behaviors of various GM interfaces. A series of direct shear tests were conducted on GM–soil, GM–geotextile, and GM–concrete interfaces. Two types of high-density polyethylene (HDPE) GMs, a smooth GM and a textured GM, were used to evaluate the effect of GM-texturing on the shear properties of these interfaces. Based on the experimental data, the friction angles and adhesions of GM interfaces were calculated using the Mohr–Coulomb criterion. Test results describing the behavior of GM–soil and GM–geotextile interfaces from the current study were then compared with results from previous studies. The test results are shown to verify the reliability of the new large-scale composite shear apparatus. In addition, this paper presents preliminary experimental results of the GM–concrete interface shear tests.

Effects of soil and geomembrane types on interface and shear strength behaviour

“…The interface friction angles (uncured) were compared with the results obtained in the literature and are summarised in Table 5. In this study, the friction angles of the GM-soil interfaces were consistent with the results of Fleming et al [21], Frost et al [23], Cen et al [37], and Stark and Santoyo [50]. It was also evident that the friction angle of the coarse-grained soil was greater than that of the fine-grained soil.…”

“…The interface friction angles of the coarse and angular soils are higher, as listed in Table 4. It has been determined that soils with different morphological properties (roundness and sphericity) can affect the internal friction angle [23][24][34][35][36][37]. The internal friction angle increased as the particle size increased because larger particles required more friction force to roll and reach the sliding state after the lock was released at the peak [36,38,39].…”

“…Crush sand and crushed gravel were less spherical, less rounded, and less regular than river sand and gravel, respectively. These angular sand particles can easily plough and form deeper grooves, providing higher interface friction angles [23,24,36,37,42]. Studies have also reported that higher interfacial friction angle values are obtained at higher dry densities because more soil particles are in contact with the surface of the GM, resulting in an increased contact area, and therefore, increased interface shear strength [21,24,43].…”

Research on the interface characteristics of coal gangue with different geosynthetic reinforcements

“…TIWARI and SATYAM's [18] large-scale direct shear and unconfined compressive strength tests on the interaction at the interface between the subgrade, polypropylene fibers, triaxial geogrids, and biaxial geogrids revealed that the shear strength of the reinforced subgrade increased by 177% with the addition of bi/triaxial geogrids and polypropylene fibers. CEN et al [19] developed a large-scale composite shear test apparatus to study the shear behavior of various geomembrane interfaces, observing higher peak shear stresses and shear displacements on textured geomembrane-soil interfaces compared to smooth ones. ZHANG et al [20] conducted a series of direct shear tests to reveal the shear mechanism of the concrete-HDPE material interface, finding that the interface exhibited evident strain-softening behavior during shearing, with shear strength linearly increasing with normal stress.…”

Effects of the Preparation Conditions and Reinforcement Mechanism of Polyvinyl Acetate Soil Stabilizer

“…Adding reinforcement material to soil is internationally considered as an effective method to improve soil properties (i.e., strength performance, permeability behavior, and erosion resistance) [1,2,3,4,5,6]. In general, the reinforcement material is divided into two types, namely, physical reinforcement material and chemical additives.…”