The surge in the number of cars has generated enormous numbers of waste tires in recent years. How to utilize the waste tires in engineering construction in an environmentally friendly way is a problem that China and many other countries have to tackle. In this study, the dynamic response of a retaining wall reinforced with combined waste tires and geogrid was experimentally investigated. The simulated dynamic vehicle load was exerted by a self-developed loading system. The performance of the combined waste tire and geogrid reinforcement for a retaining wall system was compared with that of systems reinforced with biaxial geogrid, geocell, and waste tire. The accelerations and vertical earth pressures at selected locations within the model and deformations of different reinforced retaining walls subjected to simulated dynamic vehicle loads were measured. The test results demonstrated that the combined waste tire and geogrid reinforcement enhanced the dynamic performance and stability of the retaining wall. Furthermore, the influences of tire spacing, vehicle speed and loading magnitude on the dynamic responses of the reinforced retaining wall system also were examined. The findings drawn from this study along with the derived correlations likely will benefit both relevant engineering practice and the recycling of waste tires.

As a shallow geothermal energy development technology, energy pile contributes to sustainable development. The seepage effect has a positive effect on the heat transfer performance of the energy pile, and the heat transfer efficiency of the energy pile can also be improved by optimizing the operation strategy. Combined with the structural characteristics of the deep-buried energy pile, the heat transfer characteristics of the deep-buried energy pile are analyzed under continuous and intermittent operation conditions, and the effect of seepage on the heat transfer performance is further investigated under the intermittent operation mode. The results show that the long-term operation of the deep-buried energy pile will reduce its heat exchange performance and aggravate the heat accumulation phenomenon inside the pile body, and the intermittent operation can maintain a higher instantaneous heat exchange rate (HER) in the long-term operation compared with the continuous operation. Considering the energy demand, when the intermittent ratio is 5, the average HER of the pile body only decreases by 68.93 W, and the overall energy efficiency of the pile body is improved by 7.7%. Combined with the operating effects of different intermittent ratios, the optimal range of the circulating medium flow rate for deep buried pipe energy piles should be selected from 1.0 m³/h to 1.2 m³/h. Groundwater seepage can weaken the degree of heat accumulation inside the DBP-EP piles and improve the overall heat exchange efficiency of DBP-EP, and combined with the intermittent operation mode will be able to further alleviate the DBP-EP heat buildup. The two factors promote each other and have a positive impact on the piles, positively affecting the soil’s long-term heat exchange.

Distributed optical fiber sensors based on Brillouin scattering are emerging as valid alternatives for monitoring the health of civil structures and applications in geological engineering. The measurements are made by establishing a correlation between fiber strain and temperature in the frequency shift of Brillouin backscattered light induced by a monochromatic light pulse. The monitored strain consists of two parts: stress strain and temperature strain. This article presents an application of Brillouin optical time domain reflectometry in measuring stabilizing pile deformation over time. In the process of pile construction, the hydration heat of cement raises the temperature of the pile, thus causing errors in pile strain monitoring. So, the effect of temperature on strain should be considered. A finite element model built on the basis of monitoring objects and their geological environment is proposed to eliminate the influence of hydration heat on pile strain. The results indicated that the changed temperature resulting from hydration takes approximately three months to reach the same level as the ground temperature, in agreement with the monitoring results. The magnitude of the relative strain caused by hydration temperature was on the order of 10−4 microns and should be considered in the three-month monitoring data after the construction of piles. Factors that may affect calculation accuracy are discussed on the basis of the experimental and numerical results.

Deeply buried pipe energy pile (DBP-EP) offers the capability to harness geothermal energy from significantly deeper subterranean layers than those available inside buried pipe energy pile (IBP-EP). Despite its potential, there is a notable scarcity of research on the thermomechanical behavior of DBP-EP. This study meticulously observed the thermal variations in the soil surrounding the DBP-EP, the mechanical response of the pile itself, the earth pressure at the pile toe, and the displacement occurring at the pile’s top during the heating phase across various operational conditions. The findings show that for every 1 °C increase in inlet temperature, the temperature difference between the inlet and outlet increases by about 0.27 °C. The method of load application at the pile top during heating markedly influences the frictional resistance along the pile’s sides. Furthermore, When the pile top load rises from 0.26 kN to 0.78 kN, the observed vertical load at the pile foot decreases by 2.2–8.51%. This indicates that the increase in the pile top load reduces the downdrag effect on the sandy soil near the pile toe. This reduction subsequently diminishes the impact of vertical loads on the pile toe. Notably, after continuous operation for 8 h, the rate of increase in pile top displacement for DBP-EP shows a decline. Additionally, for every 1 °C rise in the inlet water temperature, the final displacement at the pile top diminishes by approximately 0.03‰D. This research endeavors to furnish a robust theoretical foundation for the structural design and practical engineering applications for DBP-EP.

This paper presents an investigation on the compatible deformation characteristics of double-row stabilizing pile based on field monitoring using brillouin optical time domain reflector. The research focuses on the influence factors of coordinate deformation. The deformation of piles under the thrusting force was monitored by using distributed optical fiber sensing technology. A method based on grey correlation theory was introduced to overcome the deficiency of data from pile monitoring. The results show that the advantages of the technology can be fully utilized to obtain sufficient continuous deformation data of pile in a short period of time. In addition, the information, such as parameters used in the theory and numerical analysis, geotechnical force distribution form between pile bents, is not necessarily required. The present study can be used to analyze monitoring data for coordination deformation characteristics of double-row piles, which provides confidence for working status assessment and demonstrates the potential for further application.