This study aims to evaluate and compare the carbon emissions and reduction strategies of two different slope construction methods—concrete slope protection and ecological sprayed-soil slope protection—using a life-cycle assessment (LCA) approach. The research focuses on identifying key carbon emission sources throughout each stage of the construction, from material production to transportation, construction, and maintenance, with a particular emphasis on the ecological benefits of vegetation in reducing carbon footprints. Results indicate that the ecological slope protection scheme significantly outperforms the concrete scheme, reducing total carbon emissions by 667.21 tons. Furthermore, the ecological solution, due to its carbon sequestration capabilities, is projected to achieve carbon neutrality within 3.66 years after completion, offering a net carbon sequestration benefit of 2422.97 tons over its lifecycle. Optimization strategies across various stages—material production, transportation, construction, and maintenance—further reduce emissions by 56.8%, underscoring the potential for ecological slope protection to contribute to sustainable construction practices. This study not only provides valuable insights into low-carbon construction methods but also highlights the importance of integrating ecological and engineering technologies to meet global carbon reduction goals.

While the longitudinal pre-embedded holes in a reinforced concrete column have a variety of beneficial functions during the whole life of the building, they have certain negative influences on the mechanical properties of the column. To investigate the influences of longitudinally pre-embedded holes on the mechanical properties of reinforced concrete (RC) columns, numerical simulations were conducted using the finite element software ABAQUS 2021 to analyze the effects of various parameters, including hole diameter, concrete strength, stirrup ratio, and slenderness ratio, on the mechanical behavior of RC columns under axial pressure. The results show that the presence of longitudinally pre-embedded holes reduces the load-bearing capacity of the columns. Furthermore, when the hole diameter exceeds 75 mm and the concrete strength is over C35, the failure mode of the columns shifts from axial compression failure to shear failure at the bending section of the pre-embedded hole. Increasing the stirrup ratio effectively enhances the ductility and load-bearing capacity and avoids brittle failure, whereas the influence of slenderness ratio variations on the column’s bearing capacity is negligible. These results provide a theoretical basis for the safe design of longitudinally pre-embedded hole columns in green buildings, effectively balancing the requirements between structural lightweight design and load-bearing performance.

In the newly developed hybrid prefabricated RC-steel structure (SS) foundation pit bracing system, the main braces are the main load-carrying components, which are assembled from standardized prefabricated reinforced concrete beam segments (referred to as beam segments). To facilitate assembly, beam segments are equipped with beam sleeves and beam-end connection holes. The holes at the end of the beam can cause stress concentration problems, while the beam sleeve has a reinforcing effect on the end of the beam segment. To investigate the influence of beam-end holes and beam sleeves on the compressive mechanical properties of beam segments, a numerical simulation study was conducted. Taking the beam segment (specification: 4500 mm × 700 mm × 800 mm) used in a certain foundation pit support project as the research object (i.e., specimen), Abacus software was first used to build parameterized models of beam segments with holes and beam sleeves using the concrete damaged plasticity model (CDP) and the steel double-line strengthening model. Then the influence of three factors, namely end face friction coefficient, beam-end holes diameter, and beam sleeve thickness, on the axial compression performance of the beam segment specimens was studied. The results indicated that the axial compressive capacity of specimens without a beam sleeve decreased with increasing hole diameter; the axial compressive bearing capacities of specimens with hole diameters of 35 mm, 40 mm, and 45 mm were 13,300 kN, 12,500 kN, and 12,300 kN, respectively, which are 11.3%, 16.7%, and 18% lower than the compressive bearing capacity of specimens without holes (15,000 kN). When both a beam sleeve and holes were present, the holes had a negligible influence on the compressive capacity, while the beam sleeve played a decisive role. The compressive bearing capacity increased with greater beam sleeve thickness; the peak bearing capacities of the specimens with beam sleeves 5 mm, 10 mm, and 15 mm thick were 16,200 kN, 16,500 kN, and 17,600 kN, respectively. As the end face friction coefficient decreased from 0.6 to 0.1, the location of maximum compressive damage shifted toward the end face of the beam segment, and the area of maximum concrete damage gradually migrated toward the hole locations. The study demonstrates that the confinement effect of the beam sleeve can compensate for the weakening effect caused by the holes and confirms that the designs of holes in beam segment ends and in the beam sleeve can meet safety requirements.

To overcome the inherent drawbacks of cast-in-place reinforced concrete bracing—such as long construction periods and difficult demolition—as well as the relatively high construction cost of steel structure bracing, while fully incorporating the respective technical advantages of these two traditional support systems, this paper proposes a novel hybrid prefabricated reinforced concrete (RC)–steel structure foundation pit bracing system. In order to investigate the overall bearing capacity variation in the standard components of this structure under complex external forces in foundation pits, a numerical model was established using the finite element software ABAQUS. The study examines the trend of the axial compressive bearing capacity of a single standard beam segment as the steel thickness of its external stiffening sleeve varies, as well as the effects of eccentric loading, oblique loading, and the presence or absence of auxiliary supports on the structural bearing capacity of multi-segment beam assemblies. The numerical analysis results show that the bearing capacity of a single beam segment exhibits a strong correlation with the variation in sleeve thickness, and a fitting curve of compressive strength as a function of thickness was derived. For the multi-segment assembly, an increase of 1 mm in the load eccentricity in the Y and Z directions reduces the ultimate peak load by approximately 20.95 kN and 23.94 kN, respectively; in the XY and XZ planes, an increase of 1° in the eccentric angle of the oblique load reduces the peak ultimate bearing capacity by about 6.02 kN and 9.67 kN, respectively. Auxiliary supports have a relatively minor influence on the structural bearing capacity. This research thoroughly explores the bearing capacity of the prefabricated steel–concrete composite and steel structure foundation pit bracing under complex working loads, providing strong support for engineering design and demonstrating broad application prospects.

This study proposes a design method for near-slope roads along multi-level slopes that integrates excavation requirements and post-construction ecological restoration through sprayed eco-protection. Firstly, the design principles and procedural steps for near-slope roads are established. The planar layouts of multi-level slopes are categorized, including mixing areas, turnaround areas, berms, and access ramps. Critical technical parameters, such as curve radii and widths of berms and ramps, as well as dimensional specifications for turnaround areas, are systematically formulated with corresponding design formulas. The methodology is applied to the ecological restoration project of multi-level slopes in the Huamahu mountainous area, and a comparative technical-economic analysis is conducted between the proposed design and the original scheme. Results demonstrate that the optimized design reduces additional maintenance costs caused by near-slope roads by 6.5–8.0% during the curing period. This research advances the technical framework for multi-level slope governance and enhances the ecological design standards for slope protection engineering.