The soil dielectric constant model reflects the relationship between the volumetric water content and the dielectric constant. The ground penetrating radar (GPR) could quickly, precisely and non-destructively obtain the water state of the soil layers. A reasonable and reliable dielectric constant model is of great significance for predicting, monitoring and exploring water migration in soils. Taking Yunnan laterite as an example, this study comprehensively considered the key physical factors (dry density, water content, temperature) of the in situ laterite dielectric properties. The dielectric properties and the influencing factors of laterite has been discussed with the laboratory tests by reshaping laterite, and the dielectric constant model was finally proposed to evaluate the natural water state of the laterite. The results show that the relative dielectric constant of laterite increases gradually with the increasing volumetric water content, dry density and temperature respectively. The water content is the most important influencing factor, secondly followed by temperature and dry density. The dielectric constant model of laterite was built based on the influence of dry density and temperature on the relationship between the relative dielectric constant and volumetric water content. The proposed multivariate model has a good prediction effect on the water content of laterite, and the prediction effects compared with other existing models are as follows: Multivariate model, Zhao model, Malicki model, Zhou model, Topp model, Liao mode and Herkelrath model. This model could be applied to evaluate the plastic limit index and the liquid limit index using the relative dielectric constant, and then finally estimate the soft and hard state grades of laterite. This study could provide a reference for the construction of laterite dielectric constant models in different regions, and a convenient way for the estimation of the laterite water content state and engineering categories.

According to the results of the physical model tests, the failure plane of an anaclinal layered rock slope was a linear‐type plane at an angle above the plane normal to the discontinuities, and the failure mode of rock strata was bending tension. However, the shear failure occurred near the slope toe, the effects of the cohesion of the discontinuities on the stability of the slope, and the contribution of tangential force to cross‐section axial force were neglected in such studies. Moreover, none of the experts had developed a rigorously theoretical method for determining the angle between the failure plane and the plane normal to the discontinuities. This paper was initiated for the purpose of solving the problems described above. With the cantilever beam model and a step‐by‐step analytical method, an optimization of the analytical method for determining the flexural toppling failure plane based on the limit equilibrium theory was developed and the corresponding formulations were derived. Based on the present computational framework, comparisons with other studies were carried out by taking a slate slope in South Anhui in China and a rock slope facing the Tehran‐Chalus Road near the Amir‐Kabir Dam Lake in Iran. Furthermore, the sensitivity analyses of the parameters used in the calculation process of the failure angle of the slate slope in South Anhui in China were performed. The results demonstrated that the failure plane and the safety factor of the stability obtained with the presented method were credible, which verified the proposed method. The dip angle of the slope, the dip angle of the rock stratum, and the friction angle of the discontinuities were the controlling factors for the overall failure of the slate slope in South Anhui in China.

The failure mechanism of hard anti-inclined bedded rock slopes with the possibility of undergoing flexural toppling is very complex so that it is difficult to effectively perform their stability assessment. In this study, an attempt was made to accurately predict the stability factor and the failure surface of such slopes: establishing a new failure zone model and developing a limit equilibrium method based on this model. In this model, the failure zones of such a slope were divided strictly according to the failure mechanisms of the rock layers. In the presented method, the failure surface was considered to be a bilinear-type surface as observed in field investigations and laboratory tests, and the non-dimensional parameter indicating the position of application of the interlayer force was revised by deriving the distribution and the equivalent substitution of interlayer force. Then, a comparative study on Yangtai slope was performed to prove the presented method, and the effect of the non-dimensional parameter on the stability was also investigated. The results reveal that the presented method can accurately determine the failure surface and precisely evaluate the slope stability factor. In addition, the presented method has higher predictive accuracy compared with other analytical methods. With the decrease of the non-dimensional parameter, the stability of the slope is reinforced, but the larger landslide with more serious damage effect will occur if the slope undergoes the overall failure.

This study extended a hybrid immersed boundary-lattice Boltzmann method (IB-LBM) to analyze the hydrodynamic and thermodynamic behaviors of a fluid heat exchanger (FHE) with an asymptotic tube configuration. The effects of Reynolds number (Re), superheat levels, porosity, and cylinder arrangements on temperature and flow velocity were primarily examined. Several thermodynamic parameters were introduced as metrics to evaluate the thermal efficiency of the FHE. The results revealed that the Re significantly influenced the hydrodynamic and thermodynamic behaviors of the FHE. Pressure drops increased with higher Re, while the rapid decline in average heat flux was attributed to reduced conductive heat transfer caused by decreasing temperature difference. Moreover, superheat levels directly impacted the outlet temperature but primarily affected the frequency of flow velocity fluctuations. The average flow frequency, determined through the fast Fourier analysis, helps avoid resonance with the structure's natural frequency, thereby preventing potential structural failures. Additionally, five different porosity and cylinder configurations were analyzed to evaluate their impact on thermal performance of the FHE. The findings from this research provide valuable insights for enhancing the thermal efficiency of the FHE.

Mohr–Coulomb (MC) strength criterion has been widely used in many classical analytical expressions and numerical modeling due to its simple physical calculation, but the MC criterion is not suitable for describing the failure envelope of rock masses. In order to directly apply MC parameters to analytical expressions or numerical modeling in rock slope stability analysis, scholars established a criterion for converting Hoek–Brown (HB) parameters to equivalent MC parameters. However, the consistency of HB parameters and equivalent MC parameters in calculating critical acceleration of slope needs to be further explored and confirmed. Therefore, HB parameters are converted into equivalent MC parameters by considering the influence of slope angle (1# case and 2# case when slope angle is not considered and slope angle is considered respectively). Then, the lower-bound of finite element limit analysis is used for numerical modeling, and the results of calculating critical acceleration using HB parameters and equivalent MC parameters are compared, and the influence of related parameters on the calculation of critical acceleration is studied. Finally, the influence of different critical accelerations on the calculation of slope permanent displacement is further analyzed through numerical cases and engineering examples. The results show that: (1) In the 1# case, the critical acceleration obtained by the equivalent MC parameters are significantly larger than that obtained by the 2 #case and the HB parameters, and this difference becomes more obvious with the increase of slope angle. The critical acceleration obtained by the 2# case is very close to the HB parameters; (2) In the 1# case, slope height is inversely proportional to ΔAc (HB_(Ac)− 1#_(Ac)), and with the increase of slope height, ΔAc decreases, while in the 2# case, the difference of ΔAc (HB_(Ac) − 2#_(Ac)) is not significant; (3) In the 1# case, the sensitivity of the HB parameters to ΔAc is D > GSI > m_i > σ_ci, but in the 2# case, there is no sensitivity-related regularity; (4) The application of HB parameters and equivalent MC parameters in slope permanent displacement is studied through numerical cases and engineering examples, and the limitations of equivalent MC parameters in rock slope stability evaluation are revealed.