Combining field test research with finite element numerical analysis, this paper studies the mechanical behavior of pile-supported reinforced embankments in soft soil areas. We analyze and compare the variation law of load transfer efficacy at the subgrade center, the right side of the centerline, and the road shoulder; the variations of the load sharing ratios of the soil arching effect and the load sharing ratios of the membrane effect; and the load variation law of wide subgrade cross-sections. Then, the model calculation results are compared with the calculation results of the five theoretical methods and the applicability of the various methods is evaluated. The results show that: increasing the pile length, pile cap width, and embankment height and reducing the pile spacing will increase the pile load transfer efficacy; pile cap width has the greatest influence on the load transfer efficacy; regarding the variation law of the load sharing ratios of subgrade cross-sections, the load-sharing ratio of the soil arch effect at the shoulder is smaller than that at the center of the subgrade, indicating that the deformation of the geogrid at the shoulder is large and the membrane effect is significant; and, regarding the load variation law of subgrade cross-sections, from the subgrade center to the shoulder direction, the pile load transfer efficacy decreases gradually and the load transfer efficacy at the shoulder decreases significantly.

China generates substantial construction and demolition (C&D) waste, owing to rapid urbanization. However, the resource utilization rate of C&D waste remains low. This work is devoted to promoting the application of C&D waste in reinforced soil structures. In this research, the physical and mechanical properties of C&D waste recycled aggregate, biaxial geogrids and triaxial geogrids were first clarified. Then, a series of pullout tests were carried out based on the large-size pullout test setup. With the help of macroscopic indicators, including pullout resistance, horizontal displacement and interface friction coefficient, the effects of normal stress, pullout rate and reinforcement type on the characteristics of the reinforcement–C&D waste recycled aggregate interface were clarified. The test results show that normal stress has the greatest influence on pullout resistance. The pullout rate has the lowest effect on pullout resistance. In addition, the interface effect between the triaxial geogrid and the C&D waste recycled aggregate is more significant than that in biaxial geogrid–C&D waste recycled aggregate. The interface friction angle of triaxial geogrids is 18.1% higher than that of biaxial geogrids (11.6° vs. 9.82°), correlating with an enhanced particle interlocking mechanism.

In this paper, the load-transfer mechanism and settlement behaviors of the pile-supported reinforced embankment are reviewed by laboratory model tests, and a series of finite element method (FEM) modellings are conducted to analyze the soil-arching geometry and embankment deformation patterns of the pile-supported reinforced embankment. The results show that: the embankment load distribution is significantly impacted by the filling cohesion because of the effect of cohesion on the interaction between particles. The soil pressure difference between the center and corner of the pile caps decreases with the increase of filling cohesion. The pile-subsoil stress ratio decreases with the increase of filling cohesion. The embankment deformation behavior and soil-arching geometry are less affected by the change in filling cohesion compared with the influence of pile spacing. That may because of the fact that although the cohesion of the embankment filling has been increased, the granular material’s properties have not been fundamentally changed. Pile-subsoil different settlement decreases with the increase of embankment filling cohesion, and the different settlement at the mid-span between four piles decreases by 4.09% and 6.34%, respectively, as filling cohesion increases from 0 kPa to 11 kPa and 25 kPa. The height of the soil-arching crown decreases with the increase of filling cohesion, and the height of the soil-arching crown between horizontal adjacent piles decreases by 3.85%, 7.69%, and 9.62%, as filling cohesion increases from 5 kPa to 15 kPa, 25 kPa and 45 kPa. The rate of decrease in soil-arching height gradually decreases with increasing cohesion. The height of the soil-arching between the horizontal adjacent piles is about $1.0 \left(s-a\right)$. The height of soil arching between the diagonal adjacent piles is about $1.0\sqrt{2 }\left(s-a\right)$. The differential settlement at the same height inside the embankment decreases with the increase of filling cohesion, and the height of the equal settlement plane is basically the same as the height of soil arching.

Facing the challenges in field monitoring of the mechanical response of geogrids in asphalt pavements, this study integrated two types of Fiber Bragg Grating (FBG) sensors, unarmored and armored, into geogrids using the pillar-stitching technique on industrial warp-knitting production lines. The integrated FBG-geogrid systems were comprehensively evaluated in both wound and flattened configurations, enabling the selection of a sensor type suitable for industrial production. After precise strain calibration, a full-scale field damage test was performed during the construction of the Qu-Gang Expressway in Hebei Province, China. The results demonstrate that the helical steel armor layer significantly enhances the mechanical durability of the FBG sensor. Specifically, the armored sensor maintained stable optical transmission over its entire 60-m length, with an average performance retention rate of 98.86% in the flattened state. Moreover, a strong linear correlation was established between the wavelength shift of the armored FBG sensor and the tensile strain of the geogrids. In contrast, the unarmored FBG sensor underwent irreversible shear deformation during production and contained at least two breakpoints. Additionally, a protection scheme employing fiberglass-reinforced silicone rubber on the hot side and standard silicone rubber on the cold side effectively shielded the sensors from high-temperature and compaction loads during asphalt paving. Consequently, the proposed FBG-geogrid integration method and the corresponding field protection strategy provide technical support for the real-time monitoring of geogrid performance in asphalt pavements and have significant engineering value.

The tensile performance of geocells depends on the mechanical responses of both cell walls and junctions. Three commercial geocells, liquation-welded polypropylene (LW), injection-molded polyester (IM), and ultrasonic-welded high-density polyethylene (UW), were examined through tensile testing, macroscopic observation, and scanning electron microscopy of cell-wall fracture surfaces. Five configurations were used: cell-wall tension, junction-inclusive tension, and junction seam, shear, and split tests. The cell-wall peak strengths of LW, IM, and UW were 143.03 ± 4.43, 185.61 ± 7.96, and 39.42 ± 2.41 kN/m, respectively. Including a junction changed the strengths by +28.99%, −59.79%, and −23.76%. The LW and IM cell walls lost load rapidly after the peak. UW exhibited necking and extended post-yield deformation. SEM revealed microfibrillar bundles in LW, a smooth layered surface in IM, and dense drawn microfibrils in UW. Under junction-inclusive tension, LW tore near the raised-tab edge, IM cracked through the ligaments between the holes, and UW fractured at a weld-wall boundary. LW provided the highest seam and shear strengths of 66.16 ± 4.20 and 146.02 ± 8.46 kN/m. IM provided the highest split strength of 158.55 ± 10.34 kN/m. UW showed lower junction strengths but reached 343.09 ± 13.72% rupture strain under shear. Under seam and shear loading, LW failed near the tab-wall transition, while IM fractured from hole edges. UW failed within the weld region under seam loading and at a weld-wall boundary under shear loading. Under split loading, failure occurred at the heat-fused interface in LW, the molded body in IM, and the central weld in UW.