In this study, the effects of polypropylene fibre content and length on the mechanical properties of municipal solid waste incineration (MSWI) bottom-ash-mixed (BA-mixed) clay soil were investigated through triaxial tests. By varying the fibre length and content, the stress-strain relationship and strength characteristics of polypropylene fibre-reinforced soil were analysed under different confining pressures. The main stress difference and shear resistance of polypropylene fibre-reinforced BA-mixed soil were discussed. The law of strength variation was used to analyse the reinforcing mechanism of fibres during the process of soil shearing. The results demonstrate that the strength and deformation resistance of polypropylene fibre-reinforced soil are significantly enhanced when compared with the original soil and pure BA-mixed soil. With the fibre content increases, the internal friction angle of the reinforced soil increases slightly, whereas the cohesion of the reinforced soil increases significantly. The sample can reach the maximum strength and have the best reinforcement effect when the control polypropylene fibre length is 2.5 cm, and fibre content is 0.3%.

The geotechnical properties, chemical reaction mechanisms, and microstructure evolution of alkali-activated fly-ash-stabilised construction and demolition waste (C&D) and the main components recycled concrete aggregate (RCA) and clay brick (CB) were investigated in this study. The alkali activator was a composite solution of sodium hydroxide and water glass. XRD, FTIR, SEM, and UCS testing methods were used to analyse the properties and mechanisms of the alkali-activated fly-ash-stabilised C&D and main single-component RCA and CB. The test results demonstrate that using alkali-activated fly ash in stabilising C&D improves the UCS of the material significantly. When C&D is mixed with fly ash at a mass ratio of 60/40, its UCS reaches 37 MPa at 28 days, which is much higher than the strength requirement of cement-stabilised soil mixture and meets the strength requirements of inorganic binder stable materials for road base and sub-base layers. C-A-S-H and N-A-S-H (where N = Na₂O, A = Al₂O₃, C = CaO, S = SiO₂, and H = H₂O) generated by the alkaline activation have several similarities with cement hydration products and also show high cementing ability. Alkali-activated fly ash improves the strength and stability of C&D as a roadbed filler and has prospective applications in road engineering.

Recently, soil reinforcement using arranged or randomly distributed fibers has attracted increasing attention in geotechnical engineering. In this study, polypropylene (PP) fibers with three lengths (6, 12, and 24 mm) and three mass percentages (0.5%, 1%, and 1.5%) were used to reinforce a coal fly ash soil (FAS) mixture. Unconsolidated, undrained triaxial tests were carried out in order to study the mechanical properties of the polypropylene fiber-reinforced FAS mixture and evaluate the impact of fiber on the shear strength of the FAS mixture. It is found that the fiber length of 12 mm could significantly improve the shear strength of the polypropylene fiber reinforced FAS mixture, and little effect is shown on the shear strength while using a fiber length of 24 mm. Additional fibers enhance the energy absorption capacity of the FAS specimens and therefore the highest energy absorption capacity occurs when the fiber content is 1% and the fiber length is 12 mm. The peak deviator stress enhances impressively with the addition of polypropylene fiber. The impact of fiber on the peak deviator stress is the largest when fiber content is within 1.0%. The fiber length has little effect on the peak deviator stress when it exceeds 12 mm.

The ice accumulation on the surface of the stay cable of the bridge is a frequently identified problem that threatens the safety of bridge traffic. Therefore, it is important to investigate the ice accumulation on the stay cable under different conditions. To understand the distribution characteristics and variation rules of ice, this study analyzed the effects of ambient temperature, cable inclination angle, and diameter on the ice accumulation of the high-density polyethylene (HDPE) stay cable. The results show that the ambient temperature significantly affects ice formation in the lower part of the stay cable. Low temperature facilitates the formation and growth of icicles, while larger size and inclination angle of the stay cable inhibit the icicle growth. When the inclination angle of the cable is less than 60°, icicles easily form at the bottom of the cable. Smaller-diameter cables are more likely to accumulate icicles at the bottom.

It is well known that geomembranes frequently and easily fail at the seams, which has been a ubiquitous problem in various applications. To avoid the failure of geomembrane at the seams, photocuring was carried out with 1~5% photoinitiator and 2% carbon black powder. This geomembrane can be sprayed and cured on the soil surface. The obtained geomembrane was then used as a barrier, separator, or reinforcement. In this study, the direct shear tests were carried out with the aim to investigate the interfacial characteristics of photocured geomembrane–clay/sand. The results show that a 2% photoinitiator has a significant effect on the impermeable layer for the photocured geomembrane–clay interface. As for the photocured geomembrane–sand interface, it is reasonable to choose a geomembrane made from a 4% photoinitiator at the boundary of the drainage layer and the impermeable layer in the landfill. In the cover system, it is reasonable to choose a 5% photoinitiator geomembrane. Moreover, as for the interface between the photocurable geomembrane and clay/sand, the friction coefficient increases initially and decreases afterward with the increase of normal stress. Furthermore, the friction angle of the interface between photocurable geomembrane and sand is larger than that of the photocurable geomembrane–clay interface. In other words, the interface between photocurable geomembrane and sand has better shear and tensile crack resistance.

This study employed triaxial compression tests to investigate the deformation characteristics and damage evolution of construction and demolition waste (C&D) stabilized with alkali-activated fly ash (FA). Furthermore, the study explored the mechanisms of microcracks initiation, propagation, and the stress-strain behavior of stabilized C&D under varying stress conditions. A strain-softening damage model was employed to investigate the mechanism of damage evolution in the specimens. The test results revealed that the internal damage process of the stabilized recycled concrete aggregate (RCA) exhibited five stages: elastic recovery, damage initiation, damage acceleration, damage deceleration, and damage completion. The confining pressure had a significant influence on the deformation characteristics of the specimens. Additionally, the deformation characteristics of the stabilized C&D and rock materials exhibited remarkable similarities. By employing a model of rock strain softening and intrinsic structural damage the damage evolution trends and the equation of the intrinsic structure of the main component RCA-FA. The results demonstrated a good agreement between the test data and the predictions of the proposed constitutive model.