Expansive soils are widely distributed in tropical and subtropical regions and are highly sensitive to moisture variations, posing significant challenges to slope stability. Rainfall infiltration alters the hydro-mechanical behavior of expansive soils, increasing the risk of landslides and slope failures. Understanding the infiltration dynamics under different slope conditions is therefore essential for improving slope stability management and disaster mitigation. To investigate the mechanisms governing the long-term stability of steep expansive soil slopes, this study designed and constructed a multi-slope combination model test box. Model experiments were conducted on rainfall-induced expansive soil slopes with varying gradients to analyze the interaction between surface runoff and seepage under different rainfall conditions. The results demonstrate that slope gradient plays a crucial role in the rainfall infiltration process. As the slope gradient decreases, the time required for runoff initiation increases, and rainfall infiltration becomes the dominant process, while runoff plays a secondary role. This effect is more pronounced at lower slope gradients. Furthermore, as the slope gradient increases, the variation in soil moisture content decreases, and the influence of rainfall on deeper soil layers is reduced. Beyond a certain threshold, further increases in slope angle result in a diminished effect on enhancing surface runoff and limiting infiltration. Additionally, steeper slopes exhibit a slower rise in soil moisture content during rainfall events. The results also indicate that as the slope gradient increases, the depth of soil affected by rainfall becomes shallower, and the migration speed of the wetting front decreases. The findings of this study provide valuable insights into slope hydrodynamics and serve as a scientific basis for sustainable slope management and soil conservation in expansive soil regions.

Expansive soil poses significant challenges for engineering due to its susceptibility to swelling and shrinkage. This study aims to explore effective methods for improving its mechanical properties using single alkaline activators, single slag, and their combination. Laboratory experiments were conducted to evaluate the unconfined compressive strength (UCS) and analyze curing mechanisms through X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results demonstrate that all three treatments enhance soil strength, with the combination of alkali-activated slag being the most effective, followed by the single alkaline activator and single slag. Optimal dosages were determined as 15% for the activator and slag individually and 15% activator combined with 20% slag, yielding the densest structure and highest UCS. The activator’s modulus of 1.5 was found to be optimal, and strength improved further with extended curing time. A microscopic analysis revealed that alkaline activation formed gel-like substances and dense needle-like structures, while slag generated CaCO₃ and Ca(OH)₂. The combination produces a synergistic effect, creating substantial amounts of C-S-H, C-A-S-H gel, and dense needle-like structures, which enhance soil compactness and strength by binding particles and filling voids. These findings provide insights into the curing mechanisms and offer practical solutions for improving expansive soil in engineering applications.

Peripheral primitive neuroectodermal tumors (PNETs) constitute very rare and aggressive malignancies. To date, there are no standard guidelines for management of peripheral PNETs due to the paucity of cases arising in various body sites. Therapeutic approach is derived from Ewing sarcoma family, which currently remains multimodal. Our study retrospectively analyzed 86 PNET patients from February 1, 1998 to February 1, 2018 at Peking Union Medical College Hospital with an additional 75 patients from review of literature. The clinicopathologic and treatment plans associated with survival was investigated. Surgery, chemotherapy, female sex, small tumor size, no lymph node metastasis, R0 surgical resection, (vincristine + doxorubicin + cyclophosphamide)/(isophosphamide + etoposide) regimen, and more than 10 cycles of chemotherapy were associated with improved overall survival in univariate analysis. Surgery, more than 10 cycles of chemotherapy, and small tumor size were independent prognostic factors for higher overall survival. Our data indicates that multimodal therapy is the mainstay therapeutic approach for peripheral PNET.

Recent years have seen the rise of the ‘processual approach’ in media ritual studies, which focuses on the making of media rituals through various ‘ritualised actions’ rather than assuming them as isolated events distinctive to ordinary broadcasting. This article advances this line of argument by shedding light on a previously less-discussed form of ritualised action: the ritualised casting. It examines how the character of ‘rural migrant’ has been staged in the 28-year history of China Central Television’s Spring Festival Gala and how the casting of this ‘social outsider’ served as a dynamical strategy in the process of ritualisation of the Gala. The case study demonstrates a persistently central position of the image of ‘rural migrants’ in the Gala in the past 21 years, yet the scripting of this ritual subject varied as the agendas and crises of ritualisation shifted. This ritualised casting not only delivered a self-replicating effect that made the success of the Gala as natural and desired, but also, it exhibited a power to converge the media’s categories with other social categories, which further legitimised the ritual authority of the Gala as a mediated centre in the festival space of the Chinese New Year.

To simulate the influence of rainfall on the internal forces of expansive soil slope retaining structures, an approximate calculation method for the humidity stress field of expansive soil is proposed in this study. Considering both rainy and non-rainy conditions, on a high expansive soil slope, a numerical model is constructed for a combining supporting structure, which is composed of upper and lower anti-sliding piles and anchor rods/cable frames. Furthermore, the distribution of internal forces in the retaining structure is studied, and design optimization is performed. The research findings reveal that the bending moment profile along the longitudinal axis of the lower anti-sliding pile demonstrates a distinctive “W” pattern, which is characterized by initial reduction, following augmentation, a subsequent reduction, and final amplification. In contrast, the upper anti-sliding pile experiences an ascending trend, followed by a descending trend, and then a subsequent ascending trend. Interestingly, the introduction of rainfall grants an escalation in both the shear force exerted along the entire length of the upper and lower anti-sliding piles and the bending moment encountered by the lower anti-sliding pile. The determination of the internal force distribution of the expansive soil slope retaining structures under different conditions, using the proposed calculation method, provides a further optimization in their design.

The evolution of the crystal structure and mechanical behavior of Ca-montmorillonite (Ca-Mnt) under varying degrees of hydration is crucial for understanding its swelling properties. The objective of the present study was to investigate systematically the microstructural changes and stress–strain response of Ca-Mnt through molecular dynamics (MD) simulations, supplemented by experimental validation. By employing stress–strain hysteresis curves, the equivalent damping ratio was characterized by quantifying the impact of hydration on energy dissipation. The results indicated that, within the investigated hydration range, the absolute value of the mean H ₂ O–Mnt interfacial interaction energy decreased with increasing hydration; as the water content increased from 300 mg _water per g _clay to 420 mg _water per g _clay , the average interfacial energy was reduced by ~2.65 eV Å ^–2 . Hydration had a significant influence on the mechanical properties of Ca-Mnt, particularly in the Z -direction, in which the tensile strength decreased, whereas the compressive strength increased with greater degrees of hydration. The stress–strain hysteresis curves shifted progressively to the right as hydration intensified, demonstrating pronounced non-linearity and energy dissipation characteristics. The equivalent damping ratio initially decreased and then increased with increasing degrees of hydration, highlighting the dual effect of hydration on energy dissipation. This study validates the reliability of the simulation results and provides theoretical insights for understanding the hydration-induced expansion mechanisms of montmorillonite and its engineering applications.