Current Issue : July-September Volume : 2026 Issue Number : 3 Articles : 5 Articles
The determination and evaluation of severity rating of soil is an important part of the research on the engineering properties of water-repellent soil. It is still difficult to accurately obtain the soil water-repelling rate in essence, and there are a lot of influencing factors. In this paper, the severity rating of sandy soil hydrophobized by dichlorodimethylsilane (DMDCS) was obtained by different water-repellent detection reagents. The change laws and influencing factors of drop penetration time were obtained. It is shown that the change laws of drop penetration time of sandy soil detected by water-insoluble organic matters, acid, alkali, salt, and strong oxidants were similar to the water’s, which are not considered to be the water-repellent detection reagents. The water drop penetration time (WDPT) of sandy soil by glutaraldehyde solution is much less than the water’s. Moreover, the detection sensitivity is enhanced and the accuracy is improved. The detection standard and evaluation system of glutaraldehyde drop penetration time (GDPT) method are put forward accordingly. In this new system, “moderate-strong,” “strong,” and “serious” are added to perfect the system of water-repelling rate. The study will be helpful to improve the existed evaluation system of waterrepelling rate....
Grouting diffusion range is the key to evaluate the grouting effect. In this study, a theoretical model of noncohesive sediment erosion damage was established, and the main parameters affecting erosion were qualitatively analyzed. Secondly, based on the computational fluid dynamics (CFD)–discrete element method (DEM) coupling method, the effect of grouting pressure and nozzle diameter on the diffusion mechanism of slurry was studied. The findings reveal a distinct evolution in the grouting process. Initially, during the early stages of grouting, the scour hole expands, accompanied by pronounced horizontal crack development. As grouting progresses, more vertical cracks emerge, indicative of a transition from jet grouting to fracture grouting. Notably, the cross-sectional shape of the grouting area resembles a “bell-shaped,” while horizontally it appears round or oval. The axial diffusion depth increases with the increase of injection pressure and increases first and then decreases with the increase of nozzle diameter. Notably, the optimal process parameters can be achieved when either the injection pressure or nozzle diameter is held constant. Under specific simulation conditions, such as a grouting pressure of 20 MPa, the optimal nozzle diameter is determined to be 2.5 mm. These findings offer valuable insights for enhance our understanding of the grouting mechanism....
Prefabricated components are an integral part of the prefabricated construction. One of the main challenges in seismic regions is developing constructible connections between prefabricated components that can withstand inelastic cyclic deformations. This study introduces a novel type of joint designed to connect prefabricated concrete columns and beams while effectively transferring bending moments and shear forces. To assess the seismic performance of the proposed joint, three reinforced concrete frame specimens were designed: a prefabricated concrete frame incorporating the novel joint, another using a grouted corrugated duct joint, and a third comprising a cast-in-place (CIP) concrete frame. Quasi-static cyclic tests were performed on all three specimens. The results indicate that the frame utilizing the novel joints demonstrated superior seismic performance, exhibiting high drift capacity with minimal damage. These findings suggest that the novel joints are safe, reliable, and suitable for application in seismic zones....
To address the disturbance and damage to the surrounding rock and retaining piles caused by blasting excavation in deep foundation pits, the vibration response and cumulative damage under multiple blasting events were investigated through numerical simulations. Based on the deep foundation pit project associated with Huicheng Road Station on the Qingdao Metro, ANSYS/ LS-DYNA software was used, combined with the complete restart technique to simulate the multiple blasting excavation process. The vibration response and propagation trends, as well as the damage characteristics of the surrounding rock and retaining piles, were investigated. The results show that the vibration velocity of the strongly weathered rock layer of the surrounding rock in the deep foundation pit decreases in an approximately exponential manner down the height of the foundation pit. However, due to the elevation-amplification effect, the vibration amplitude first decreases and then increases. The vibration velocity on the blasting side of the retaining piles is dominated by the component in the direction of propagation of the blasting stress wave. The vibration velocity at the top of the pile is low, but the vibration frequency is high. The maximum peak vibration velocities of the surrounding rock and retaining piles are both located near the blasting excavation surface. The higher the peak vibration velocity, the larger the degree of damage. Therefore, it is necessary to optimize the blasting parameters in a timely manner and implement vibration isolation measures to control the blasting vibration velocity and enhance the stability of the foundation pit....
Current bridge design codes stipulate that prefabricated T-beam bridges must include intermediate diaphragms, with spacing not exceeding 10 m. However, the construction of these diaphragms entails extensive overhead work, elevated safety risks, and significant challenges in quality control. Therefore, safely and reliably reducing or even eliminating the use of intermediate diaphragms offers a promising approach to enhancing construction efficiency and quality. This study focuses on conventional T-beam bridges and investigates the structural function and mechanical mechanisms of intermediate diaphragms through a combination of theoretical analysis, finite element simulations, and scaled model testing. Load effects in both longitudinal and transverse directions were evaluated for girder systems with and without diaphragms to assess their structural function and the mechanism behind longitudinal cracking in bridge decks. Key findings include: (1) Under current transverse load distribution theory, intermediate diaphragms affect longitudinal force response by ~10%, with limited influence on overall bridge design. (2) Diaphragms enhance load-sharing among girders. Removing them increases the maximum vertical deflection by 13.5%, while longitudinal load changes remain minimal. However, the maximum transverse tensile strain in the deck slab increases by ~1.1–1.4 times. (3) Intermediate diaphragms reduce nonuniform deflection between beams, effectively decreasing the indirect transverse internal force in the bridge deck and cumulative tensile stress, which helps prevent longitudinal cracking. Enhancing deck slab stiffness can improve vertical shear resistance at the wet joint, reduce nonuniform deflection, and enable the design of T-beam bridges without intermediate diaphragms....
Loading....