This study addresses the reliance on empirical methods in the structural analysis of hinged prefabricated frame beam (HPFM) structures by proposing a theoretically rigorous analytical framework based on the Winkler foundation model. The proposed analytical framework comprises three main steps: (a) The HPFB structure is discretized into individual beam segments supported on a Winkler foundation, based on the locations of anchorage points and hinge connections; (b) A system of linear equations is formulated using static equilibrium and deformation compatibility conditions at both anchorage points and hinge joints. Solving this system yields the distribution of concentrated loads—applied perpendicular to the slope surface at anchorage points—among horizontal and longitudinal beam segments of the cross beams, and simultaneously determines the shear forces transferred through hinge joints to adjacent beam ends; and (c) The deflection and internal forces for each Winkler-supported beam segment are evaluated using the computed loads and beam-end shear forces obtained in the previous step. To evaluate the validity and practical applicability of the proposed framework, a simplified HPFB structure was analyzed in terms of load distribution, beam-end shear forces, deflections, and internal forces. The results were compared with those from a traditional frame beam (TFB) structure under identical conditions to assess differences in mechanical behavior between the two structures. Deformation analysis at both the anchorage points and hinge joints indicates that the proposed analytical framework inherently satisfies deformation compatibility conditions at the anchorage points and hinge joints. Consequently, the results demonstrate improved accuracy compared to those derived from empirical methods. Comparative analysis reveals that, relative to the TFB structure, the HPFB structure exhibits larger deflections near the beam ends and smaller deflections in regions farther away from the beam ends, along with a reduced maximum negative bending moment, an increased maximum positive bending moment, and lower maximum shear forces. These results suggest that the HPFB structure offers improved mechanical performance. A sensitivity analysis was further performed to quantify the influence of the subgrade reaction coefficient on the mechanical behavior of the HPFB structure. As the subgrade reaction coefficient increases multiplicatively, the concentrated loads allocated to the shorter horizontal beam segments and their corresponding beam-end shear forces exhibit a progressive increase. Conversely, the loads assigned to the longer longitudinal beam segments and the associated beam-end shear forces demonstrate a consistent decrease.Variations in beam loading induced by a multiplicative increase in the subgrade reaction coefficient significantly influence beam deflection, yet exert only a minimal effect on both the bending moment and shear force. Consequently, the proposed analytical framework establishes a robust theoretical foundation for the rational design of HPFB structures, diminishing the dependency on empirical approaches and enhancing the reliability of structural performance predictions.

Conventional structural analysis of hinged precast frame beams (HPFB) often relies on a simplified load distribution method that may not fully account for deformation compatibility, potentially affecting result accuracy. To address this limitation, this paper develops a rigorous analytical framework based on the Winkler foundation model. The framework explicitly incorporates soil-structure interaction (SSI) and enforces static equilibrium and deformation compatibility at all structural nodes and hinges, thereby enabling a mechanically consistent prediction of structural responses. A comprehensive comparative analysis with a traditional frame beam (TFB) reveals the unique mechanical behavior of the HPFB system. Key findings demonstrate the HPFB configuration achieves a drastic reduction in maximum negative bending moment (63.5–83.5%) and shear force (7.8–22.8%), while increasing the maximum positive bending moment by 46–62%. This fundamental shift in internal forces occurs in conjunction with a characteristic segmented deflection profile. Sensitivity analysis further indicates that while the subgrade reaction coefficient significantly influences deflection patterns, its effect on bending moments and shear forces remains marginal. The proposed framework provides designers with a robust and theoretically sound tool for the analysis and design of HPFB structures, ensuring performance reliability while addressing limitations observed in current analytical approaches.

The permeability of the ore-bearing layer is an important indicator affecting the in-situ leaching (ISL) of uranium-bearing sandstone, which is related to various factors such as pore shape, distribution, and size. In order to study the effect of pore structure on seepage in low-permeability uranium-bearing sandstone, CT scanning tests were conducted to create a 3D digital core based on scanning images and to calculate the fractal dimension using the box counting dimension method, which integrated fractal theory to define the core samples' pore structure. The permeability prediction was realized based on the porosity-permeability model and the fractal theory model. Results indicated that this type of sandstone is obviously characterized by pore connectivity, large differences in distribution, and strong microscopic inhomogeneity. The pores are dominated by micro- and nano-pores, as well as small pores, accounting for 90%; macropores are few in number, but the diameters of their single pores are large. The distribution of pore structure in this type of sandstone exhibits a good fractal characteristic; the three-dimensional fractal dimensionality is 2.044–2.310. The porosity-permeability model was established, and permeability prediction was realized by combining the fractal theory to provide theoretical support for determining the values of well field parameters in ISL.

Investigating the seepage characteristics of acid leaching solution affected by surfactant in the ore-bearing layer during the in-situ leaching process can be useful for optimizing the process parameters of uranium ore. Three surfactant leaching solutions of different concentrations were prepared respectively for the agitation leaching experiment, from which the best was screened out for seepage simulation experiment using a self-developed multifunctional physical and chemical seepage test device. The influence of surfactant to seepage characteristics of leaching solution were examined based on the seepage flow mechanics and physicochemical seepage theory. Results indicated that trend of seepage characteristics of different leaching solutions were the same in rock samples with similar internal pore architectures in general, both of which were horizontal seepage processes from the unsaturated stage to the saturated stage. While the seepage process of leaching solution added surfactant reached the saturation point of the set flow rate earlier, and the addition of surfactant provided improvement in the permeability coefficient with the largest increase of 29.41% in the saturation stage, the growth of seepage pressure also decreased by up to 22.72%.

Rock masses in underground engineering are usually damaged, which are caused by rock genesis and environmental stress. Studying the constitutive relationship between rock strength and deformation under loading is crucial for the design and evaluation of such scenarios. The new damage constitutive model considering the dynamic change of joint damage was developed to describe the behavior of rocks under loading in this work. First, considering the influence of jointed rock mass structural features in their entirety, the Drucker–Prager criterion and the Hoek–Brown criterion were combined. Second, based on the idea of macro–micro coupling, the calculation formulae of damage variables were derived. Finally, the damage constitutive model of the jointed rock mass was established, and the proposed model was fitted and compared with the test data. Results show that the variation rules for damage value and peak strength are opposite, and the stress–strain is highly sensitive to changes in the parameter s of the model. Moreover, the proposed model can accurately describe the effect of joint deterioration on the entire process of rock mass compression failure, which shows that the damage constitutive models are useful for evaluating the strength characteristics of jointed rock mass in engineering practice.

As a new type of retaining structure, lattice beams with tie-back anchor cables have been increasingly used in slope reinforcement and have achieved improved prevention effects. However, the simplified load distribution method (SLDM) at the node, which is the theoretical basis of internal force analysis for lattice beams, is not perfect at present. An alternative new load distribution method (NLDM) at the node based on the force method for the lattice beam was therefore introduced in this paper. Taking into account the loads acting on other nodes of the beams in both directions and according to the static equilibrium condition and deformation compatibility condition at the nodes, NLDM assigns the loads acting on the nodes to the cross beams and vertical beams, respectively, by constructing and solving a system of linear equations. In order to verify the superiority of NLDM, a case of slope reinforced by a lattice beam was introduced in this paper, and the load distribution of the nodes under the design condition was carried out based on both methods. Then, the deflections at the nodes of the lattice beam resting on the Winkler foundation, loaded with the known loads, were analyzed by the superposition method. The results of the deformation analysis showed that the deflections at the same nodes of the beams in both directions based on NLDM were almost equal, thus demonstrating the superiority of NLDM in terms of deformation compatibility. In addition, a comparative analysis of the theoretical bending moments of the lattice beam under the design and the actual working conditions based on both methods was also carried out. The results of the bending moment analysis showed that the bending moments of the cross beam differed significantly in the middle third of the beam length, while the bending moments of the vertical beams differed significantly at the beam sections where the maximum bending moments are located, and the theoretical bending moments under the actual working condition were in relatively good agreement with the measured values. Consequently, NLDM for the lattice beam was self-consistent in terms of the deformation compatibility at the node, and therefore the introduction of this new method provides an important theoretical basis for the accurate internal force analysis of lattice beams.

Investigating the seepage characteristics of the leaching solution in the ore-bearing layer during the in situ leaching process can be useful for designing the process parameters for the uranium mining well. We prepared leaching solutions of four different viscosities and conducted experiments using a self-developed multifunctional uranium ore seepage test device. The effects of different viscosities of leaching solutions on the seepage characteristics of uranium-bearing sandstones were examined using seepage mechanics, physicochemical seepage theory, and dissolution erosion mechanism. Results indicated that while the seepage characteristics of various viscosities of leaching solutions were the same in rock samples with similar internal pore architectures, there were regular differences between the saturated and the unsaturated stages. In addition, the time required for the specimen to reach saturation varied with the viscosity of the leaching solution. The higher the viscosity of the solution, the slower the seepage flow from the unsaturated stage to the saturated stage. Furthermore, during the saturation stage, the seepage pressure of a leaching solution with a high viscosity was greater than that of a leaching solution with a low viscosity. However, the permeability coefficient of the high viscosity leaching solution was less than that of a low viscosity leaching solution.

To study the influence of damage degree on dynamic characteristics of damaged rock mass, the samples with different damage degrees were obtained by cyclic loading test and then the impact failure test was carried out by a 100-mm diameter split Hopkinson pressure bar (SHPB) device. In addition, the Zhu-Wang-Tang (ZWT) constitutive model was improved to establish the dynamic constitutive model of damaged granite. Results show that when the cyclic upper limit stress (CULS) reached 60% of the compressive strength of rock mass, the Felicity effect was significant and the Kaiser effect basically disappeared. Furthermore, there was obvious compressive strengthening effect of damaged rock mass under impact load, with the increase of the CULS in the early stage, the dynamic compressive strength of granite samples showed an overall decreasing trend. The damage degree had a significant effect on the propagation and energy absorption ability of rock mass, thus affecting its failure characteristics. Eventually, the proposed constitutive model was fitted with the experimental data, which showed that the model could accurately describe the dynamic mechanical properties of damaged granite under impact load.

The instability and failure of engineered rock masses are influenced by crack initiation and propagation. Uniaxial compression and acoustic emission (AE) experiments were conducted on cracked sandstone. The effect of the crack's dip on the crack initiation was investigated using fracture mechanics. The crack propagation was investigated based on stress-strain curves, AE multi-parameter characteristics, and failure modes. The results show that the crack initiation occurs at the tip of the prefabricated crack, and the crack initiation angle increases from 0 & DEG; to 70 & DEG; as the dip angle increases from 0 & DEG; to 90 & DEG;. The fracture strength ������������������ is derived varies in a U-shaped pattern as /3 increased, and the superior crack angle /3 ������ is between 36.2 and 36.6 and is influenced by the properties of the rock and the crack surface. Low-strength, large-scale tensile cracks form during the crack initiation in the cracked sandstone, corresponding to the start of the AE energy, the first decrease in the b-value, and a low r-value. When macroscopic surface cracks form in the cracked sandstone, high-strength, large-scale shear cracks form, resulting in a rapid increase in the AE energy, a second decrease in the b-value and an abrupt increase in the r-value. This research has significant theoretical implications for rock failure mechanisms and establishment of damage indicators in underground engineering.

为研究轻质条板对填充墙RC框架抗震行为的影响,基于ABAQUS构建有限元计算模型并结合前人的实测数据对所建模型进行对比验证.在已验证模型的基础上,通过构建自主研制的新型轻质材料的抗压本构模型,改变条板布置方式、条板厚度和柱轴压比等关键参数,分析这些参数对填充墙RC框架的滞回曲线、刚度退化曲线及耗能能力的影响.结果表明:使用轻质条板填充墙能显著改善RC框架结构的抗震性能;条板竖向布置对承载力、初始刚度及耗能能力的提升有显著效果;条板厚度对框架抗震性能影响不明显;柱轴压比在合理区间内能有效提高结构承载力、初始刚度和耗能能力,但柱轴压比过大时结构抗震性能会被削弱.

工程实际中的岩体常常受到地质构造运动、工程施工及次生应力场等循环荷载作用,表现出与单调荷载不同的力学特性.为了更好地研究循环荷载作用下岩石材料的力学特性,对强度特征、变形特征及破坏特征3个方面进行了总结分析,同时对现有研究的局限性提出了几点建议:在更宽频率范围内研究频率对循环力学特性的影响,从而得出更为准确的结论;将现有的力学理论与数值模拟手段结合起来研究岩石材料的循环力学特性;通过扫描电镜与原位CT扫描等技术深入开展循环荷载下岩石力学特性的微观结构研究,探究岩石材料的失稳破坏机制.

为了对比电子雷管和导爆管雷管两种起爆方式的爆破振动信号,开展了某露天采石矿两种雷管起爆的深孔爆破振动测试.基于小波分析方法和Matlab程序小波工具箱,对爆破振动信号按照频率划分为10个频带,分析各频带能量和峰值质点速度(peak partide velocity,PPV)的分布特征及随爆心距的变化.结果表明:采用电子雷管和导爆管雷管起爆时,90％的爆破振动能量分布在2～6频带(9.77～312.50 Hz)和2～7频带(9.77～625.00 Hz),且PPV分布在3～4频带(19.53～78.13 Hz)和4～5频带(39.06～126.25 Hz),即电子雷管起爆的爆破地震波能量和PPV均向低频带分布,且信号的PPV更小;中、高频带能量大小与段药量成正比,与爆心距成反比;各频带能量占比和PPV大小是反映爆破振动强度的重要指标,采用电子雷管能有效地减少爆破振动.

Self-organizing criticality theory provides a new interpretation for the behaviour characteristics and evolution patterns of disordered and non-linear complex systems. Based on this theory, the law of fracture evolution with different rock types was discussed. Considering the influence of body shape on the failure characteristics, uniaxial compression test and acoustic emission (AE) test were carried out on two rock specimens, i.e. cube and cylinder. The acoustic emission information before and after the self-organized critical point during the evolution of rock fracture was analyzed. According to the distributed of the probability density of AE energy, the spatial positioning of AE event and the AE waiting time, and their critical exponent k, productivity exponent a of after shock distribution, and waiting time distribution exponent delta were analyzed statistically. The results show that the failure processes of both cube and cylinder specimens are self-organization processes from disordered stable state of low energy value to ordered unstable state of high energy value. The body shape has little effect on the self-organization process of its destruction. Comparing with cylindrical specimens, the first phase of cubic specimens from compression to the first critical point of self-organization, volume expansion point, lasts relatively longer, and the self-organization evolution process from the first critical point to the second critical point of self-organization, speak strength point, is also faster. The failure of the cubic specimen is more regular, which is more conducive to failure prediction. Cubic specimen is isotropic in the process of compression, which restricts the development of cracks so the critical index of the whole process of fracture is larger. While the local yield weakening characteristic of cylindrical specimen is obvious, which makes the development of cracks under compression easier and its critical index is smaller. For the productivity exponent alpha of Omori law of rocks with different sizes, the value alpha of the second stage of the self-organization evolution of fracture of cubic specimens is greater than 1, while that of cylinderical specimens is less than 1, indicating that the cube specimens have entered the critical instability state before the second critical point. In the large waiting time range (>0.1 s), the critical exponent of the second stage of self-organization evolution of fracture of specimens with different body shapes is larger than that of the first stage, which is consistent with the fact that the frequency of new cracks increases with the self-organization evolution of fracture.

砌体填充墙作为改变结构受力性能的关键因素,其对框架结构的抗震能力乃至建筑物的安全稳定有着至关重要的作用.围绕砌体填充墙对RC框架结构抗震性能的影响,介绍了砌体填充墙RC框架结构的受力过程和破坏模式,从水平承载力、刚度效应和变形能力三个方面对国内外研究成果展开了分析总结,并根据当前研究现状对框架结构未来的发展方向进行了展望.

基于弹性梁理论,对局部失效缺陷下的二级层级褶皱结构失效机理进行了分析.通过对原结构体系和局部失效后新结构体系的受力分析,归纳总结了结构的六种失效模式.根据各失效模式之间的占优关系绘制了失效机理图,讨论了参数l1/l、θ和α对失效机理图的影响,并基于特定失效序列优化约束,给出了结构轻量化优化列式.通过数值仿真,验证了局部失效后二级层级褶皱结构失效预测的正确性和层级失效序列设计思路的可行性.最后采用3D打印模型进行了验证实验,实验结果与理论解吻合较好.

针对爆破振动引起的一系列危害,采取科学合理的爆破振动控制措施有着重要意义.根据爆破振动衰减理论,从爆源条件和传播途径两个方面分析了爆破振动影响因素,并总结了几种爆破振动控制技术在理论、实验与数值模拟方面的研究情况.结合不同破坏机制下的爆破振动安全判据研究现状,指出现阶段爆破振动研究的发展方向:建立快速、准确的爆破振动优势因素评价系统;利用三维数值模拟方法分析建筑结构易损构件;制订具有人性化的爆破振动安全标准;开发基于无线网络技术的爆破振动智能分析系统.

原地浸出采铀具有生产成本低、环境破坏小和资源利用率高等优点,已成为我国铀矿开发的主要方式.铀浸出率是原地浸出采铀成败的关键问题,最大限度地提高浸出率对铀资源的深度开发具有重要的现实意义.通过以原地浸出采铀关键性指标铀浸出率为研究对象,对铀浸出率的影响因素进行综合分析,得出铀浸出率主要受内在和外在因素影响.内在因素主要有铀矿的结构演化、矿岩的孔隙结构和矿物蚀变等,矿岩结构演化造成孔隙结构的差异,从而导致孔隙度和渗透性变化,最终影响浸出率;矿物蚀变可造成孔隙堵塞,使得渗透率降低,影响浸出效果.外在影响因素主要为铁离子浓度、氧化剂、H2 SO4浓度、表面活性剂和井网参数等生产工艺技术参数,可以添加氧化剂、表面活性剂等来促进溶浸液与铀矿石的充分接触,加快反应速率等来提高铀浸出率.建议进一步研究多孔介质渗流理论和溶浸液渗流数值模拟技术,并开展多因素、多过程、相互耦合作用下外因素对浸出率的影响研究.

将实验室废弃的强度等级为C30混凝土试块经人工破碎后通过筛选得到粒径为20～50 mm的再生粗骨料.为探究科氏芽孢杆菌矿化沉积对再生粗骨料的影响,研制了不同pH条件科氏芽孢杆菌菌液浸泡处理的再生粗骨料.利用科氏芽孢杆菌菌液浸泡处理后的再生粗骨料(取代率选用20％)制备再生骨料混凝土,开展了再生骨料混凝土试件的单轴抗压强度和声发射损伤特征试验,分析了不同pH条件的科氏芽孢杆菌矿化沉积再生粗骨料对浸泡液残余Ca2+浓度、混凝土峰值抗压强度和损伤演化的影响.试验结果表明:科氏芽孢杆菌菌液浸泡处理再生粗骨料后,残余Ca2+浓度随浸泡液pH值的减小而减少,科氏芽孢杆菌菌液浸泡能有效改善再生粗骨料的密实性,且酸性条件下效果最好;再生粗骨料经酸性环境的科氏芽孢杆菌菌液浸泡处理后制备的再生骨料混凝土的峰值强度有明显的提高;在抗压过程中,损伤演化减缓,损伤劣化程度降低,当浸泡液从pH=8到pH=5时,再生骨料混凝土损伤变量逐渐减小且累积损伤明显降低.研究成果可为微生物改良再生骨料的实际应用提供参考.

In the process of in situ leaching of uranium, the microstructure controls and influences the flow distribution, percolation characteristics, and reaction mechanism of lixivium in the pores of reservoir rocks and directly affects the leaching of useful components. In this study, the pore throat, pore size distribution, and mineral composition of low-permeability uranium-bearing sandstone were quantitatively analyzed by high pressure mercury injection,nuclear magnetic resonance, X-ray diffraction, and wavelength-dispersive X-ray fluorescence. The distribution characteristics of pores and minerals in the samples were qualitatively analyzed using energy-dispersive scanning electron microscopy and multi-resolution CT images.Image registration with the landmarks algorithm provided by FEI Avizo was used to accurately match the CT images with different resolutions. The multi-scale and multi-mineral digital core model of low-permeability uranium-bearing sandstone is reconstructed through pore segmentation and mineral segmentation of fusion core scanning images.The results show that the pore structure of low-permeability uranium-bearing sandstone is complex and has multi-scale and multi-crossing characteristics. The intergranular pores determine the main seepage channel in the pore space, and the secondary pores have poor connectivity with other pores. Pyrite and coffinite are isolated from the connected pores and surrounded by a large number of clay minerals and ankerite cements, which increases the diffi-culty of uranium leaching. Clays and a large amount of ankerite cement are filled in the primary and secondary pores and pore throats of the low-permeability uraniumbearing sandstone, which significantly reduces the porosity of the movable fluid and results in low overall permeability of the cores. The multi-scale and multi-mineral digital core proposed in this study provides a basis for characterizing macroscopic and microscopic pore-throat structures and mineral distributions of low-permeability uranium-bearing sandstone and can better understand the seepage characteristics.