Geogrid-reinforced structures are extensively adopted in various engineering fields. At present, the influence of boundary conditions was not considered in design methods, bringing hidden dangers to the safety of the structure. In the current study, a series of pullout tests were carried out on high-density polyethylene (HDPE) geogrid-reinforced coarse sand. The magnitude and growth pattern of pullout resistance and the variation laws of interfacial shear strength indexes under four types of boundary conditions were analyzed. Additionally, the boundary reduction coefficient (BRC) was introduced to establish the relationship between rigid and flexible boundary for the design of the structure. The tests results showed that the boundary conditions cannot be ignored in the design of structures, especially in the front. When the normal loading was up to 120 kPa, the BRC-top and BRC-positive could be taken as 0.9 and 0.5, respectively, and verified by fitting results. The boundary conditions affected the pullout resistance, while the vertical loading corresponding to the maximum pullout resistance was not related to boundary conditions. Investigating the interaction of the geogrid–soil under different boundary conditions can help to improve the understanding of the behavior of reinforced soil structure, and to achieve a more efficient and economical design.

In this paper, a model of torque dependence of critical current in a Bi2223/Ag composite concentric cylinder is analyzed. Based on the hypothesis of planar section and elastic linear strengthening constitutive theory, the relation between torque and shear strain is firstly obtained. Then a linear weakening relation between critical current density and shear strain are put forward. Finally the effects of the applied torque together with the mechanical properties of superconducting core on the degradation behavior of critical current are calculated and discussed. The results and conclusions should be helpful to the application of superconducting materials subjected to elastic–plastic torsional deformation.

The dynamic compaction method is an important method for roadbed compaction treatment. Due to its simple procedure, quick construction speed, material saving, low cost, and excellent effect, it is an extremely important procedure in the roadbed construction with gravel soil. By analyzing the structure of the embankment, structural characteristics of the gravel fill and the the engineering stress characteristics of the subgrade in the mountainous area, the macroscopic and microscopic reinforcement mechanisms of the dynamic compaction is analyzed by using three waves transfer procedure. The results show that the various waves do positive to the gravel-filled foundation in the mountainous area. However, the way of contribution is different. The analysis should be focus on the effect of dynamic consolidation, which is the result of the synergistic action of three waves. Based on the Ping-zan highway project, the details of the test and the operating process have been introduced. Also, references for roadbed dynamic compaction reinforcement construction under similar conditions have been provided.