最新刊期
- 摘要：To achieve the dual objectives of “solid waste resource utilization” and “using waste to treat hazards,” this study systematically investigated the improvement effects of two methods—sole marble waste powder and composite marble waste powder-xanthan gum—on the engineering properties of Nanning expansive soil. The expansion and strength characteristics of the modified expansive soil were evaluated through free swell ratio tests and direct shear tests, respectively, to determine the optimal dosage of each improvement material. Additionally, scanning electron microscopy tests were conducted to reveal the microscopic mechanisms of the improvement. The experimental results showed that: (1) The addition of sole marble waste powder effectively reduced the free swell ratio of the expansive soil, but soil strength decreased with increasing dosage. When the dosage reached 25%, the expansion inhibition effect was significant, and the strength degradation trend stabilized. (2) On the basis of 25% marble waste powder, the addition of xanthan gum significantly improved the cohesion and internal friction angle of the modified soil. At a xanthan gum dosage of 1.5%, the strength parameters reached their peak values while the expansiveness remained within a controllable range. (3) Marble waste powder primarily inhibited the expansive deformation by altering the particle gradation and mineral composition of the soil, while the gel matrix formed by xanthan gum effectively filled soil pores, enhanced particle bonding, and formed dense aggregates, thereby improving soil strength. Considering all factors, the material ratio of 25% marble waste powder and 1.5% xanthan gum was determined to be the optimal scheme for the composite improvement of expansive soil.关键词：expansive soil;marble waste powder;Xanthan gum;swelling characteristics;strength properties6|7|0更新时间：2026-05-12
- 摘要：To address the challenges of dense stacking, mutual occlusion, and the difficulty of deploying heavy deep learning models on edge devices in prefabricated beam yard rebar inventory scenarios, this paper proposes a lightweight dense rebar cross-section detection method named LPR-YOLO, based on YOLOv8n. Firstly, the method reconstructs the backbone network of YOLOv8n using Ghost modules, which replace standard convolutions with cheap linear operations to significantly reduce model parameters and computational redundancy while maintaining feature extraction effectiveness. Secondly, the Convolutional Block Attention Module (CBAM) is integrated into the neck network to enhance the model's focus on key rebar cross-section features from both channel and spatial dimensions, effectively suppressing complex background noise and lighting interference. The experimental results show that LPR-YOLO achieved an mAP@0.5 of 94.8%, which is a 2.2% improvement compared to the original baseline model, while the model parameters and GFLOPs were reduced by 1.3M and 3, respectively. LPR-YOLO also demonstrates excellent generalization ability under complex conditions such as strong light interference and mud occlusion.关键词：rebar counting;attention mechanism;YOLOv8;lightweight network;Ghost module0|0|0更新时间：2026-05-11
- 摘要：Prefabricated bridge piers are widely adopted for their high construction efficiency and environmental benefits. However, complex terrain and restricted construction space in mountainous regions severely constrain the transportation and hoisting of large precast segments. To address this, a three-segment precast segmental pier system utilizing a hybrid connection of “grouted sleeves and prestressed tendons” (PSC-GSPT) is proposed. Relying on the Chongqing North Ring Interchange Renovation Project, 1:5 scale specimens were fabricated. Quasi-static tests compared the seismic performance of PSC-GSPT and a cast-in-place (CIP) pier, followed by numerical simulations analyzing the influence of prestressing parameters. Results indicate that, due to the addition of unbonded prestressed tendons, the PSC-GSPT exhibited increases of 28.6% in peak load, 41.3% in ultimate displacement, and 20.7% in displacement ductility compared to the CIP pier. Despite a slightly lower equivalent viscous damping ratio, cumulative energy dissipation increased by 27%, accompanied by significantly smaller residual displacement and good post-earthquake recoverability. Parametric analysis suggests that to prevent premature yielding and ensure ductility, a central layout for prestressed tendons is preferred, with the initial prestress level controlled within 30% to 50%. The study confirms that PSC-GSPT possesses excellent seismic performance, meets requirements for seismic fortification zones, and holds significant engineering application value.关键词：precast segmental bridge pier;grouted sleeve;prestressed tendon;hybrid connection;seismic performance1|0|0更新时间：2026-05-11
- 摘要：The development and rational utilization of aeolian sand as subgrade material is of great significance for the construction of transportation projects in desert areas. Existing research mainly focuses on the description of macroscopic deformation phenomena of aeolian sand subgrade fillers, lacking quantitative criteria for the "dynamic instability critical state" of this special poorly-graded material, and the macroscopic deformation mechanism under dynamic loading is still unclear. Through indoor dynamic triaxial tests combined with PFC3D discrete element simulation, based on the evolution law of cumulative plastic strain rate, a dynamic stability critical criterion based on the b value for aeolian sand subgrade fillers was proposed; from the perspective of force chain network evolution, the microstructure response mechanism of aeolian sand under different deformation modes (stable type, critical type, and failure type) was clarified. The results show that confining pressure and dynamic stress amplitude respectively regulate the plastic deformation of aeolian sand subgrade through lateral constraint strengthening and load increment effect, among which low confining pressure causes particle structure instability under dynamic stress, and high dynamic stress directly leads to aggravated deformation. The parameter b value determination criterion established based on the fitting curve of cumulative plastic strain rate with the number of loading cycles can accurately identify the type of plastic deformation behavior of aeolian sand subgrade fillers (failure type/stable type/critical type). The evolution process of the force chain field of the three types of plastic deformation behaviors shows differences at the microscale: in the failure type condition, the dense concentration of axial strong force chains leads to rapid deformation; in the stable type condition, stable force transmission paths are formed through uniformly distributed strong and weak force chains, enhancing the anti-deformation ability; in the critical type condition, there is a phenomenon of strong force chain fracture and weakening, and the force chain system is not in equilibrium, still posing a risk of failure.关键词：road engineering;aeolian sand;subgrade fill material;dynamic deformation characteristics;dynamic triaxial test;discrete element simulation15|2|0更新时间：2026-05-06
- 摘要：Landslide-generated impulse waves pose a significant secondary hazard in reservoir areas. Current risk assessments often prioritize extreme water levels and rely on deterministic values for key landslide kinematic parameters, which may lead to an incomplete understanding of the full hazard spectrum. This study aimed to investigate the characteristics of impulse waves from the potential collapse of the Jianchuandong rocky cliff (Chongqing City, China) under a representative normal water level, and to quantify the sensitivity of wave predictions to the coefficient of restitution (COR) and coefficient of friction (COF). A three-dimensional fluid-solid coupling numerical model was established using FLOW-3D software. The simulation incorporated a general moving object for the rock mass and the fractional area/volume obstacle representation method for interface tracking. The impulse wave process under a 162 m water level was simulated, and a one-at-a-time sensitivity analysis was performed by varying the COR and COF by ± 20%. The results showed that the collapse generated an impulse wave with a maximum amplitude of 27.4 m, evolving through distinct generation, propagation, run-up, and dissipation phases. The sensitivity analysis revealed that the COF dominantly controlled the minimum free surface elevation (relative sensitivity coefficient, RSC, approximately –1.27 for a –20% change), whereas the COR primarily governed the maximum rock mass velocity (RSC approximately –0.52 for a –20% change). In contrast, the maximum wave height was notably insensitive to these parameter variations. This study concludes that wave hazard assessments must account for the representative operational water levels and the asymmetric, metric-specific sensitivities of key uncertain parameters.关键词：reservoir;impulse waves;rocky cliff collapse;hazard assessment;numerical simulation14|15|0更新时间：2026-04-26
- 摘要：This study aims to investigate the molecular mechanism by which γ-Aminopropyltriethoxysilane(APTES) undergoes amino protonation, bridges anions, and complexes Cu2+ to form the APTES+–SO42-–Cu2+ ternary complex in acidic environments, so as to address the technical issue of secondary Cu2+ release from MgO-carbonation-stabilized copper-contaminated soil under long-term acid rain stress. Based on density functional theory, quantum chemical calculations were performed via Gaussian software to reveal the thermodynamic mechanism of APTES hydrolysis and self-condensation, as well as the adsorption and complexation mechanism of Cu2+ under varying acidic conditions. The existence of the ternary complex was further validated by infrared spectral calculations. Long-term leaching tests were conducted to comprehensively evaluate the release law of Cu2+ under different pH values and leaching intensities, which validated the long-term immobilization characteristic of amino protonation bridging on Cu²⁺. The test results showed that when the pH of the acidic leachate decreased from 5.5 to 4, the cumulative release of Cu²⁺ decreased instead of increasing, and the release amount was only 1/20 to 1/27 of that in the unstabilized soil. The triple-driven molecular mechanism of APTES-MgO synergistic stabilization and the proposed stabilization method can realize efficient and long-term stabilization of copper-contaminated soil even under extreme acid rain conditions, which can be applied to the green remediation practice of heavy metal-contaminated soils.关键词：copper-contaminated soil;carbonation;γ-Aminopropyltriethoxysilane(APTES);acid rain;molecular mechanism89|117|0更新时间：2026-04-10
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Performance and mechanism of UV-US-Fenton advanced oxidation for high-salinity organic wastewater AI导读
摘要：To address the problems of high reagent consumption, poor reaction selectivity and high-salinity inhibition in conventional treatment of high-salinity organic wastewater, this study constructed a pilot-scale ultraviolet-ultrasound/Fenton (UV-US-Fenton) advanced oxidation system. Using conventional Fenton, ultrasound-Fenton (US-Fenton), and ultraviolet-Fenton (UV-Fenton) as control processes, the treatment performance, spectral variations, and molecular transformation mechanisms of dissolved organic matter (DOM) in high-salinity wastewater were explored via spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Results showed that the UV-US-Fenton process exhibited the optimal degradation performance, with COD and TOC removal rates reaching 73.84% and 70.62% under optimal operating conditions, respectively. It significantly reduced the ultraviolet absorbance and completely removed various fluorescent components. The DOM component analysis revealed that 13,595 DOM molecules were detected in the raw water, with CHON and CHONS as the dominant subtypes. After UV-US-Fenton treatment, up to 7,189 DOM molecules were removed in total. The modified aromatic index (AIₘₒd) and double bond equivalent (DBE) of the effluent DOM decreased to 0.217 and 5.911, respectively, while the oxygen-to-carbon ratio (O/C), nominal oxidation state of carbon (NOSC), and hydrogen-to-carbon ratio (H/C) increased to 0.50, 0.156, and 1.358, respectively. The aromaticity and unsaturation degree of the system were significantly reduced. Oxygen addition reaction was the dominant reaction in the UV-US-Fenton process, which could significantly enhance the transformation of nitrogen-containing functional groups.关键词：high-salinity organic wastewater;fenton process;dissolved organic matter (DOM);Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS);molecular transformation63|110|0更新时间：2026-04-09 - 摘要：Continuous deterioration of reservoir bank rock under periodic water level fluctuations is a key factor triggering slope instability. Unfortunately, this poses significant challenges to the long-term safe operation of hydropower projects in mountainous regions. Conventional rock reinforcement methods are prone to damaging the reservoir's ecological environment. Microbial-induced carbonate precipitation (MICP), a widely recognized technology in geotechnical engineering, offers low-carbon, environmentally friendly benefits and minimal disturbance to geomaterials. However, research on the application of MICP to reinforce fractured rock masses in reservoir banks remains relatively scarce. This study focused on rock within the water-level fluctuation zone of the Three Gorges Reservoir Area. Three MICP treatment methods—MICP precipitation, active bio-slurry, and rock powder-amended grouting method (RPGM)—were employed for microbial reinforcement of fractured rock samples. Based on micro-CT scanning and laboratory permeability tests, a multi-scale evaluation method was proposed to quantitatively assess the effectiveness of various MICP methods in improving pore-filling in fractured rock. The results demonstrated that MICP technology effectively reduced the permeability of fractured rock, achieving surface-filling rates exceeding 60%. Notably, the RPGM method yielded the optimal reinforcement effect, achieving a fractured surface filling rate of up to 92.6%, with 90.7% of the pores identified as isolated. Moreover, the permeability of rock reinforced by RPGM was reduced by one order of magnitude compared to the MICP precipitation methods.关键词：microbial-induced carbonate precipitation (MICP);fractured limestone;water-level fluctuation zone;X-ray CT scanning;seepage simulation123|124|0更新时间：2026-04-08
- 摘要：High concentrations of nitrate ions (NO
- 摘要：To promote the resource utilization of shield muck and low-carbon construction, this study proposes a novel approach combining Microbial-Induced Magnesium Oxide Carbonation (MIMC) technology with 3D printing to fabricate shield muck-based materials for building structures. Tests were conducted using shield muck as the base material and microbially carbonated magnesium oxide as the cementitious agent. By adjusting the magnesium oxide content (0%, 5%, 10%, 20%) and the sand-to-binder ratio (0.5, 1.0, 1.5), the flow performance of the printing mortar and the anisotropic strength characteristics of the printed blocks were systematically evaluated. The microstructural differences of specimens under various material ratios were analyzed using scanning electron microscopy. The results show that the magnesium oxide content significantly affects fluidity and strength. The mortar flowability increases with the content of the hydrolyzed liquid; under the same hydrolyzed liquid content, the flowability first increases and then decreases as the magnesium oxide content rises. The highest strength is achieved at a 20% magnesium oxide content, and the strength follows a power function relationship with increasing magnesium oxide content. The sand-to-binder ratio has no significant effect on the strength. The 3D printed specimens exhibit negligible anisotropy in strength along the X, Y, and Z directions. Mold-cast specimens show higher strength due to compaction and densification. Microstructural analysis reveals that magnesium oxide content promotes the formation of magnesium carbonate hydrate crystals and improves their morphological regularity and distribution density.关键词：shield tunneling muck;microbial carbonized magnesium oxide;3D printing;strength;anisotropy48|53|0更新时间：2026-03-31
- 摘要：Traditional mositure-buffering materials are prone to mold growth under prolonged exposure to warm and humid conditions, posing risks to both human health and building durability. To address this limitation, this study developed four antibacterial moisture-buffering composites by incorporating nano-TiO2 or ZnO into palygorskite-based (denoted as T-FP, T-WFP, Z-FP and Z-WFP). The synergistic effects of the type of antibacterial agent and the type of fiber on the moisture regulation and antibacterial performance of the material were systematically explored through tests such as moisture-buffering value (MBV), moisture absorption strength and mold coverage, and by using SEM, TEM and other methods to test and analyze the microscopic appearance and physical property parameters of the composite material.Results indicated that nano-zno significantly enhanced the comprehensive performance. Compared to the TiO2 systems, Z-FP and Z-WFP exhibited superior practical MBV (reaching 2.06-2.75 g/(m²·%) under high humidity) and antibacterial efficacy. Notably, Z-WFP demonstrated less than 10% mold coverage and over 90% structural integrity after a 60-day natural mold incubation test, identifying it as the optimal formulation. Further antibacterial tests determined that the optimal mass ratio of palygorskite to nano-ZnO was 4:1. The nano-zno modified material Z-WP-4 has excellent moisture-regulating and antibacterial properties and is suitable for use as a building moisture-regulating coating.关键词：palygorskite composite;moisture buffer value (MBV);antibacterial performance;nano antibacterial agent;synergistic effect59|103|0更新时间：2026-03-24
- 摘要：To address the challenges of strong nonlinearity, large parameter span, and difficulties in training with small samples in seepage parameter inversion for core-wall rockfill dams, a novel parameter inversion method is proposed, integrating logarithmic space Latin hypercube sampling (LHS) with an improved sparrow search algorithm to optimize support vector regression (SVR). The LHS technique is used to generate an initial sample set with high spatial filling and scale balance in logarithmic space. To address the weakness of the standard sparrow search algorithm (SSA) in getting trapped in local optima, a novel Tent chaotic mapping is introduced to enhance the initial ergodicity of the population. Furthermore, a Cauchy mutation strategy is employed to enable individuals to dynamically escape local optima, achieving adaptive optimization of key hyperparameters for SVR. A model is constructed based on the core-wall rockfill dam project of the Shiziping Hydropower Station to perform seepage parameter inversion. Results show that this method has higher prediction accuracy under small sample conditions; the inverted permeability coefficients satisfy the gradient law of the seepage prevention and drainage system; the RMSE between the calculated and measured head values at monitoring points is 1.36 m, with a maximum relative error of 0.120 4% and an average relative error of 0.039%, significantly outperforming machine learning models such as backpropagation (BP) neural networks and random forests.关键词：rockfill dam;seepage;parameter inversion;support vector regression;enhanced sparrow search algorithm70|42|0更新时间：2026-03-24
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Experimental study of underground pipeline acoustic detection method based on big data deep learning AI导读
摘要：In shallow exploration, complex geological conditions, noise interference, and multi-path effects severely hinder traditional seismic methods from acquiring high-resolution images of underground buried objects. To address this challenge, we propose a data-driven neural network-based full waveform inversion (DNFWI) method, which integrates deep neural network signal denoising with pre-trained DeepDenoiser, coupled with a tailored big data deep learning model and optimized neural network architecture. For validating its effectiveness and performance in practical detection, two electric excitation modes—horizontal shear wave (SH-wave) source and vertical source—were designed, and acoustic detection tests were conducted on buried steel oil pipelines in sand formations. By analyzing the collected acoustic signals, key parameters including the sensor transfer function of buried objects, ground properties, surface wave velocity, surface signal time-histories, and power spectra were derived. The imaging results of the two excitation modes were compared using DNFWI. Our findings indicate that the depth attenuation rate is approximately 20-25 dB/m for horizontal excitation and 10-20 dB/m for vertical excitation, with a spatial attenuation rate of ~11 dB/m for surface waves. Notably, SH-wave inversion yields stronger reflected signals due to the larger shear wave impedance contrast with steel pipelines, enabling clearer localization of buried objects and outperforming vertical wave inversion in pipeline positioning. Compared to traditional FWI, DNFWI enhances positioning accuracy by 66.7%, reduces convergence iterations by 59.7%, and shortens computation time by 60.8%.关键词：underground oil pipeline;acoustic detection;big data;deep learning;full waveform inversion66|40|0更新时间：2026-03-21 - 摘要：Soil rebound induced by unloading in deep excavations can generate significant tensile stress in pre-embedded vertical structure components such as engineering piles. In severe cases, it may lead to component fracture and structure instability. To address the limitations of the traditional Geddes stress solution under unloading conditions, this study first reveals the distribution of pile shaft resistance and determines the neutral point position based on numerical analysis, thereby modifying and extending the Geddes additional stress theory. Subsequently, by incorporating soil small-strain stiffness characteristics and the layer-wise summation method, a simplified algorithm for soil rebound which accounts for pile-soil interaction is established. Furthermore, the validity of the simplified algorithm is verified through 3D finite element simulations under both single pile and piles group conditions, and the influence of piles group effects on calculation accuracy is analyzed. The results indicate that the calculated values from the proposed simplified algorithm are slightly larger than the numerical simulation, providing a certain safety margin. The calculation errors for discrepancies primarily attributed to the simplifications of pile shaft and tip resistances. Finally, the simplified algorithm is validated using field measurement data from the V-D excavation of the Beijing Sub-Center Transportation Hub Project. Although the calculated results are approximately 32% larger than the numerical solutions, the overall trend is consistent with the actual engineering model, which suggests that the proposed algorithm offers valuable reference for the design of engineering uplift piles and prediction of soil rebound in similar deep excavations.关键词：unloading rebound;engineering piles;additional stress;three-dimension finite element;small-strain stiffness;single pile-piles group analysis70|54|0更新时间：2026-03-17
- 摘要：Traditional manual inspection tasks are labor-intensive and physically demanding, with potential for missed detections due to subjective factors. This paper addresses challenges in detecting small targets, strong background interference, and inaccurate bounding box localization during surface defect detection in subway tunnels by proposing an improved YOLOv12 model (YOLOv12-BCM). First, a weighted bidirectional feature pyramid network (BiFPN-Concat) replaces the traditional Concat layer to enhance multi-scale feature fusion capabilities. Second, a convolutional attention mechanism (CBAM) is embedded within the Neck network to suppress complex background interference. Finally, a minimum point distance-based bounding box loss function (MPDIoU) optimizes bounding box regression, improving localization accuracy. Validation using tunnel apparent defect images collected by subway tunnel monitoring devices demonstrates that Compared with the original model, YOLOv12-BCM increases mAP50 from 0.761 to 0.799 (+3.8%), Recall from 0.749 to 0.780 (+3.2%), Precision from 0.723 to 0.740 (+1.7%), and F1-score from 0.736 to 0.760 (+2.4%)., respectively, outperforming classic SSD and RT-DETR object detection models. The improved model demonstrates outstanding performance in detecting small-scale defects. Grad-CAM++ visualization analysis further validated the model's accuracy in focusing on defect regions.关键词：subway tunnel;defects detection;computer vision;image acquisition;object detection31|31|0更新时间：2026-03-17
- 摘要：To address the complex construction techniques and poor durability of traditional steel-concrete composite structures, this paper proposes steel concrete columns confined by PVC-CFRP pipes, that is a new type of composite structures with steel sections embedded in PVC-FRP tubes and concrete filled inside. Based on axial compression tests and finite element analysis of nine medium-length concrete columns confined by PVC-CFRP pipes, the influence patterns of slenderness ratio, concrete strength, steel content ratio, CFRP strip spacing, number of CFRP strip layers, and PVC pipe thickness on the axial compression performance of medium-to-long columns are investigated. Results indicate that all specimens failed within the range of 1/4 to 1/2 of the column height, with the failure modes of CFRP strip rupture, PVC pipe fracture, and concrete crushing. As the slenderness ratio and CFRP strip spacing increased, and as concrete strength, steel content, number of CFRP layers, and PVC pipe thickness decreased, the ultimate bearing capacity of specimens gradually decreased. Among which the slenderness ratio has the most sensitive influence. By regressing the quadratic function relationship between slenderness ratio and stability coefficient, a calculation formula for the axial compression bearing capacity of medium-long steel concrete columns confined by PVC-CFRP pipes is proposed. Theoretical calculations showed good agreement with experimental results.关键词：steel concrete columns confined by PVC-CFRP pipes;medium-long columns;axial compression performancel;slenderness ratio;bearing capacity calculation;finite element mode48|53|0更新时间：2026-03-12
- 摘要：To address the issue of limited recovery purity of valuable elements caused by coexisting hardness ions in oil and gas produced water, this study developed a hardness removal technology based on NCP, aiming to achieve efficient separation of hardness ions and high‑purity recovery of valuable elements. Using sodium carbonate/sodium hydroxide as a composite crystallization‑inducing agent, the removal efficiency of calcium and magnesium ions as well as the loss rate of valuable elements were systematically investigated by optimizing pH, dosing ratio, and hydraulic conditions. The results show that under the optimal process parameters, the removal rates of calcium and magnesium ions reached 94.5% and 85.3%, respectively, while the loss rates of valuable elements were all below 20%. Through multi‑dimensional characterization techniques such as XRD, Raman, and SEM‑EDS, the removal mechanism of calcium and magnesium ions was elucidated: they undergo heterogeneous nucleation on the seed surface in the form of calcium carbonate and magnesium hydroxide, respectively, and grow into dense granules. Furthermore, the rough surface structure formed on the granules effectively compensates for the loss of active sites due to particle growth, thereby maintaining the continuous treatment capacity of the system. Mechanistic analysis indicates that under alkaline conditions, the negatively charged seed surface preferentially enriches free calcium and magnesium ions via electrostatic interactions. After adding the crystallization‑inducing agent, a locally supersaturated microenvironment is constructed within the confined region of the seeds, driving the heterogeneous crystallization process.关键词：oilfield produced water;nucleation crystallization pelleting process;calcite;brucite;electrostatic interaction;high-purity recovery62|40|0更新时间：2026-03-03
- 摘要：Current research on anti-slide piles predominantly concentrates on single-row piles reinforcing homogeneous slopes, while the reliability of double-row piles in heterogeneous slopes remains underexplored. To address this research gap, this paper proposes an efficient framework for the reliability analysis of double-row anti-slide pile-reinforced slopes, with explicit consideration of the spatial variability of soil parameters. The framework integrates Sliced Inverse Regression (SIR) for dimensionality reduction, constructs a surrogate model via Multivariate Adaptive Regression Splines (MARS), and subsequently employs Subset Simulation (SS) to quantify the slope failure probability. The efficacy of the proposed framework is validated through two case studies: a slope in Northern Sai Kung, Hong Kong, and a c-φ soil slope, where comprehensive probabilistic stability assessments are conducted. Results indicate that the proposed framework provides a robust and efficient approach for the reliability analysis of double-row anti-slide pile-reinforced slopes considering soil spatial variability. Furthermore, increasing the length of the front-row piles contributes more significantly to enhancing slope system reliability compared to equivalent increases in the rear-row piles. The optimal pile configuration is determined as follows: the front row is installed near the slope toe, and the rear row is positioned in the mid-slope region.关键词：slope reliability;double-row anti-slide piles;optimal pile location;surrogate model;spatial variability53|37|0更新时间：2026-02-25
- 摘要：To elucidate the nonlinear mechanical response and seepage evolution mechanism of surrounding rock during underground excavation, a unified hardening-softening elastoplastic damage-seepage coupled numerical model was established based on the thermodynamic internal variable theory. This model employs a Logistics function to reconstruct the damage evolution equation, enabling a more accurate description of the initiation, accelerated propagation, and saturation stages of damage. A hyperbolic hardening law is introduced to characterize the expansion of the yield surface in the pre-peak hardening stage and its contraction in the post-peak softening stage. Furthermore, an anisotropic permeability model is integrated to simultaneously capture the dual effects of pore compaction and fracture-induced permeability enhancement. The model was implemented via secondary development within the FLAC3D platform, and its reliability was validated against experimental data for stress-strain behavior and permeability. Subsequently, by applying the model to a case study of underground tunnel driving, the excavation-induced responses of the surrounding rock were systematically analyzed: the deformation patterns of arch-shaped subsidence and horizontal convergence were revealed, and the three-dimensional reconstruction characteristics of permeability in space were elucidated, showing significant anisotropic enhancement near the excavation zone while being dominated by compression in other areas. The results demonstrate that the proposed model can accurately simulate the complete process of rock behavior, from elastic deformation and hardening to softening failure, along with its coupled effects with seepage.关键词：elasto-plastic damage;hardening-softening yield;seepage coupling;numerical model41|38|0更新时间：2026-02-25
- 摘要：To enhance the mechanical performance and support-free capability of precast composite slabs during the construction phase, this study proposes a novel truss steel fiber-reinforced concrete composite slab (XUDB slab). Through the synergistic design of materials and structure, its mechanical behavior and enhancement mechanisms were systematically investigated. Focusing on composite slabs with a standard span of 3600 mm, four types of comparative specimens were designed, encompassing traditional reinforced trusses, novel trusses, ordinary concrete, and steel fiber-reinforced concrete. A refined three-dimensional solid finite element model was established using ABAQUS for nonlinear coupled analysis. The results demonstrate that the novel truss system significantly optimizes stress distribution by improving the load transfer path, reducing the peak stress of the main reinforcement at mid-span by 21% and increasing the material utilization rate to 91.7%. The bridging effect of steel fibers effectively suppresses the initiation and propagation of micro-cracks, leading to a 37% reduction in the maximum plastic strain of the XUDB slab and a 26.7% decrease in the peak damage factor. Most importantly, the steel fibers and the novel truss exhibit a significant synergistic effect, jointly forming a dual enhancement mechanism of “fiber bridging - truss load redistribution.” This mechanism successfully transforms the failure mode from traditional “brittle crushing” to “gradient energy dissipation with multiple cores,” thereby reducing the crushing area at mid-span by 33% and decreasing the stiffness degradation rate by 28%. This synergistic mechanism significantly improves the ductility, load-bearing capacity, and support-free capability during the construction phase, providing an important theoretical basis for the optimal design of prefabricated composite slabs.关键词：new truss system;steel fiber-reinforced concrete;finite element analysis;synergistic mechanism;failure mode50|37|0更新时间：2026-02-12
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