Study on Geocell-Sand Interface Characteristics Based on Large-Scale Stacked Ring Shear Test

Abstract

Geocell is a new type of three-dimensional geosynthetics which can provide stronger side limit constraint and friction for the soil, form a flexible structure with the soil, and effectively reduce soil settlement and deformation. It is widely used in engineering construction. At present, there are few studies on the reinforcement mechanism and geocell-sand interface characteristics, and the soil deformation under prototype conditions cannot be fully studied. Through the self-developed DW1280L electro-hydraulic servo direct shear pull-out test system, the interfacial shear characteristics of prototype geocells of different heights under different normal stress conditions were studied. The shear stress, axial displacement and horizontal displacement of stacked rings under different shear conditions were monitored to analyze the influence of geocells of different heights on the reinforcement effect and strain law. The analysis of test results shows that the shear strength parameters of the geocell-sand interface are greater than those of pure sand. With the increase of geocell height, the cohesion of the geocell-sand interface gradually increases, the internal friction angle increases less, and the influence range of reinforcement gradually increases. Under different normal stress conditions, the reinforced soil exhibits a state of first shear shrinkage, then shear expansion, and then tends to stabilize. The change in axial displacement is negatively correlated with the magnitude of normal stress. Comparative analysis shows that the geocells near the horizontal loading position play a reinforcing role first when subjected to load. As the experiment progresses, the geocells at other locations gradually play a reinforcing role. The test results can provide a test basis for the application and theoretical research of geocell in practical engineering.