A laboratory‐scale model test is conducted to improve the understanding of the effects of thermal cycles on the mechanical behavior of energy piles. The model pile is composed of cement mortar and dry sand with a relative density of 30% is used for the model ground. After applying the working load to the pile head, the pile is subjected to three thermal cycles with a magnitude of 15^°C. The measured temperature response and mechanical behavior are analyzed and used to validate the proposed numerical approach. In the numerical analysis, the temperature variation due to thermal cycles is calculated using uncoupled heat transfer analysis. Then, the computed temperature field is used as the boundary condition in the sequence stress analysis. A series of numerical sensitivity analyses are carried out using the sequentially coupled method to investigate the long‐term performance of energy piles under different soil and pile head restraint conditions. The numerical results suggest that the restraint condition at the pile head plays an important role in the mechanical response of energy piles. The ultimate pile resistance after thermal cycles does not decrease significantly. The accumulation of settlement of the free head pile and the reduction in the axial force of the restrained head pile should be considered in the design.

In road construction, a large number of excavated soils need to be treated with stabilizers. The addition of superabsorbent polymer (SAP) can improve the road performance of these stabilized soils. In order to predict roadbed deformation, dynamic triaxial tests were carried out on cemented soil containing SAP to investigate its resilient and plastic strain behavior. The effects of SAP content, cyclic stress ratio, and loading frequency on cement-stabilized soils with SAP were analyzed combined with the number of cycles. This study demonstrates how these influencing factors effect the resilient strain, dynamic elastic modulus, and accumulated plastic strain, which are crucial to better understanding the strain behavior of cement-stabilized soil with SAP. The results show that SAP can significantly improve the brittle failure characteristics and dynamic strength of cement-stabilized soil. Soil with higher SAP content possesses smaller accumulated plastic strain; with the increase in the cyclic stress ratio, the dynamic elastic modulus decreases significantly, whereas the accumulated plastic strain has the opposite trend. In addition, the lower frequency produces larger cumulative axial strain.

The process of road construction is often accompanied by a large number of excavation work, and most of the excavated soil has poor engineering performance and needs to be transported away. It has the significance of environmental protection and cost saving to treat the excavated soil as pavement materials. The aim of this study is to present laboratory experiments into the mechanical properties, engineering properties, and microstructure of excavated soil stabilized by ordinary Portland cement (OPC) and superabsorbent polymer (SAP). Laboratory experiments were performed to determine unconfined compressive strength (UCS), compactness, durability after wetting and drying cycles, drying shrinkage, and California bearing ratio (CBR). Apart from these, X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were used for the microstructure analysis to understand the impact of SAP on cemented excavated soil. It shows that SAP can effectively improve the strength and the compaction of cemented excavated soil with good durability. Although SAP will reduce the CBR value of cemented excavated soil, it still meets the requirements of engineering acceptance. Microscopic analysis shows that SAP absorbs water in the cemented excavated soil and plays a filling role.

In arid and semi-arid areas, soil is blown up by the wind because of its loose structure. Wind erosion causes soil quality and fertility loss, land degradation, air pollution, disruption of ecological balance, and agricultural and livestock losses. Consequently, there is an immediate imperative for methods to mitigate the impacts of wind erosion. SICP (soybean urease-induced carbonate precipitation) has emerged as a promising biogeotechnical technology in mitigating wind erosion in arid and semi-arid regions. To enhance bio-cementation efficacy and treatment efficiency of SICP, aluminum chloride (AlCl₃) was employed as an additive to strengthen the SICP process. Multiple SICP treatment cycles with AlCl₃ additive were conducted on Tengger Desert sand specimens, with the specimens treated without AlCl₃ as the control group. The potential mechanisms by which AlCl₃ enhances SICP may have two aspects: (1) its flocculation effect accelerates the salting-out of proteinaceous organic matter in the SICP solution, retaining these materials as nucleation sites within soil pores; (2) the highly charged Al³⁺ cations adsorb onto negatively charged sand particle surfaces, acting as cores to attract and coalesce free CaCO₃ in solution, thereby promoting preferential precipitation at particle surfaces and interparticle contacts. This mechanism enhances CaCO₃ cementation efficiency, as evidenced by 2.69–3.89-fold increases in penetration resistance at the optimal 0.01 M AlCl₃ concentration, without reducing CaCO₃ production. Wind erosion tests showed an 88% reduction in maximum erosion rate (from 1142.6 to 135.3 g·m⁻²·min⁻¹), directly correlated with improved microstructural density observed via SEM (spherical CaCO₃ aggregates at particle interfaces). Economic analysis revealed a 50% cost reduction due to fewer treatment cycles, validating the method’s sustainability. These findings highlight AlCl₃-modified SICP as a robust, cost-effective strategy for wind erosion control in arid zones, with broad implications for biogeotechnical applications.

The Nanjing Circumvallation has been severely damaged due to natural factors, human interference, and urban expansion. Restoring this edifice serves not only as a preservation of historikcal and cultural values, but also as an advancement towards sustainable urban development. This research proposes an environmental ethical decision-making model (EEDM) grounded in sustainable urban development indicators. The model is then applied to the restoration of the Nanjing Circumvallation. Based on feedback from the research trial section, the renovation of the Circumvallation trial segment, guided by the EEDM, effectively embodies the core principles of sustainable urban development. By extending this model to the entire restoration project, it is feasible to achieve a harmonious balance between heritage preservation and urban sustainability. This methodology offers a novel framework for the restoration of similar heritage sites, ensuring the concurrent achievement of conservation and sustainable development goals. Furthermore, this approach holds considerable promise for fostering sustainable urban progression.