单拱大断面偏压隧道衬砌模型试验分析

模型试验方法分析大断面隧道衬砌结构的受力特性是一种比较实用的方法.以单拱四车道隧道为依托,按弹性阶段相似原则进行偏压条件下单孔大断面隧道衬砌破坏的室内模型试验,研究不同围岩条件下,隧道衬砌的破坏机制.试验通过千斤项加载的方式,模拟偏压条件下,不同围岩级别条件下的隧道衬砌的破坏行为,得到隧道模型的围岩及衬砌之间的接触压力,锚杆、衬砌的应力和位移分布.此外,综合模型试验和数值模拟的结果,分析了大断面隧道受到上部偏压荷载作用时,在衬砌内方面的发展规律及特点.     

基于复变函数理论和D-P屈服准则的并行隧道合理间距

综合利用复变函数理论、解析延拓法和Schwarz交替法揭示相邻水平并行隧道的应力分布特征.在此基础上,结合考虑了中间主应力效应的D-P屈服准则建立相邻水平并行隧道力学模型.提出并行隧道塑性区贯穿半径的概念,建立求解方程,并通过数值模拟证明其正确性.采用隧道间塑性区临界贯穿状态下的间距作为隧道合理间距,与数值模拟软件FLAC3D计算得到的围岩位移量和沉降量随间距变化至基本不发生变化时所对应的隧道间距有较高的吻合性,从而表明其作为相邻水平并行隧道合理间距的可行性.      

熔池底吹搅拌的广义相似试验研究

气体搅拌是有色金属冶金与钢铁冶金中常用的一种技术。本文就某冶金工况进行了相似模拟的试验研究，根据试验结果进行有关相似原理的讨论，提出了现象广义相似的观点，即表征现象模型与原型的各特征数并不严格一一对应，而是广义相似。模拟试验中线性相关的各特征数变化范围所覆盖的任何点，其表征的现象均具有广义相似性，因此可以用内插法求定。     

初始温度条件下全尾胶结膏体损伤本构模型

膏体充填料到达采场初始温度不同是矿山存在的普遍现象，不同初始温度条件下膏体力学特性及应力-应变关系直接影响到矿山采充周期及相邻采场开采时贫化指标.通过对初始温度为2、20、35和50℃的硬化膏体进行单轴抗压强度试验，获得不同初始温度下充填体应力-应变演化曲线.根据理论推导和试验结果，建立了不同初始温度下膏体损伤本构模型，通过本构模型参数回归，提出膏体温度-时间耦合损伤本构模型.最后，采用Comsol数值模拟软件，将温度-时间耦合损伤本构模型嵌入solid mechanics模块，对单轴抗压试验进行数值模拟，模拟应力-应变曲线与试验结果较为吻合，验证了所提出本构模型的可靠性.      

熔池底吹搅拌的广义相似试验研究

气体搅拌是有色金属冶金与钢铁冶金中常用的一种技术。本文就某冶金工况进行了相似模拟的试验研究,根据试验结果进行有关相似原理的讨论,提出了现象广义相似的观点,即表征现象模型与原型的各特征数并不严格一一对应,而是广义相似。模拟试验中线性相关的各特征数变化范围所覆盖的任何点,其表征的现象均具有广义相似性,因此可以用内插法求定。     

充填体的分数阶微积分蠕变本构模型及其在FLAC~(3D)中的开发应用

为了更加准确地评估分析充填采矿法中实际矿山充填体矿柱的稳定性,通过在广义开尔文体中引入分数阶黏性元件来模拟胶结充填体蠕变过程,根据试验数据对所得蠕变本构方程利用爬山算法和全局优化法相结合的方式进行参数辨识,并将得到的蠕变本构方程开发进岩土数值分析软件FLAC~(3D)中进行数值计算。计算结果表明,改进后的分数阶蠕变本构方程很好地拟合了试验数据,证明了改进模型及其计算程序的正确性。该成果对矿山矿柱充填及稳定分析具有实际指导意义。     

磷石膏膏体充填体力学特性研究

以贵州开磷集团膏体充填项目为工程背景,磷石膏膏体充填体为主要研究对象,采用室内试验与现场模拟试验相结合,进行磷石膏充填膏体力学特性试验研究。通过测定不同黄磷渣掺量、添加剂掺量和膏体质量浓度下膏体不同龄期（7 d、14 d和28 d）的立方体试块的抗压强度和抗拉强度,分析得到：试块抗压强度随着黄磷渣含量的增加而增加;膏体充填体强度随着膏体质量浓度增大而增强。结合FLAC^3D建立磷石膏膏体充填体力学本构模型并对试验进行数值验证,结果表明膏体充填体变形特性符合摩尔-库仑数值模型。     

冲刷深度对海上风电塔地震动力响应的影响分析

基于某海上风电塔进行现场监测、有限元模拟及室内振动台试验研究，考虑桩-土相互作用并对结构进行精细化数值模拟分析，研究了不同冲刷深度下结构自振周期的变化及不同冲刷深度对结构地震动作用下动力响应的影响规律.现场监测结果表明:6#风机结构受海水冲刷严重，与同时期建造的15#风机相比振动幅度明显，说明冲刷深度对结构的影响不可忽略.数值模拟分析表明:冲刷深度主要影响结构高阶振型，使结构自振周期变长，增幅最大达33%.由于冲刷致使土层对高柔性结构约束减弱，结构将产生大的振动进而导致风机停摆；在遭遇7度罕遇地震时，应立即停止发电工作.室内缩尺振动台试验与数值模拟所得结果的变化曲线较为均匀，趋势上较吻合，充分验证了数值模拟的准确性.      

某露天矿坑内排土场边坡稳定性分析

为分析某露天矿坑内排土场边坡稳定性,先采用极限平衡法中的瑞典法、简化毕肖普法、推力传递法、滑楔法、摩根斯法计算边坡安全系数,然后采用数值模拟软件FLAC~(3D)模拟边坡岩土体的应力及位移的变化规律.通过对所得边坡安全系数、应力及位移结果进行分析可知,该排土场边坡处于稳定状态.     

电解铝阳极焙烧炉模型实验与数值模拟

为降低阳极焙烧炉实炉测试的成本与难度,搭建阳极焙烧炉模型试验平台,采用试验的方法获得了焙烧炉模型内阳极炭块与火道的温升曲线,试验结果表明沿炉体方向火道温度由高到低分布,同时阳极炭块的升温速率呈先提高后下降的趋势。采用CFD数值模拟的方法模拟了焙烧炉模型内的温度分布情况,并获得了四个温度监测点随时间变化的升温曲线。将实验模型与数值模拟结果进行对比,表明数值模拟的结果与实际升温过程基本相符,因此可将模型算法推广到实际应用中去。     

基于RHT模型双孔同时爆破均质岩体损伤的数值模拟

为探究双孔爆破时炮孔间距和额外自由面对爆破过程中爆破损伤的影响,基于RHT（Riedel-Hiermaier-Thoma）损伤本构建立了多组三维数值模型,利用模型损伤云图研究不同爆破条件下的岩石爆破过程,通过自定义变量—有效损伤率的变化探究炮孔周围岩石损伤的时空演化过程。结果表明：随着炮孔间距的增加,岩石有效损伤率逐渐递减,相同截面处的有效损伤率在炮孔间距最小的方案中最大,相邻炮孔间的爆破能量叠加作用随炮孔间距的增大而减弱,合适的炮孔间距可以获得更加理想的爆破效果;岩石有效损伤率随着自由面到炮孔中心处距离的增大而逐渐减小,爆破能量倾向于向自由面方向传播,额外自由面对爆破能量分布的影响随自由面与炮孔间距的增大而减弱。数值模拟结果对研究双孔爆破能量的传递法则具有一定的借鉴意义。     

砂卵石土的剪切流变特性研究

应用RYL-600岩石剪切流变仪对长沙市某边坡砂卵石土试样进行剪切流变试验，分析砂卵石土的剪切流变特性。试验表明正应力越高时，能够引起砂卵石土试件发生剪切流变破坏的剪切应力也随之增高。砂卵石土剪切流变在低于长期抗剪切强度的应力作用下，表现出黏弹特性；在高于长期强度的应力作用下，表现出黏弹塑性。应用五元黏弹性模型与VR黏塑性模型串联得到的黏弹塑性模型对砂卵石土全程流变曲线进行模拟，将拟合结果与试验数据进行分析比较，验证了新模型具有正确性和合理性，这对砂卵石土工程具有重要的指导意义和参考价值。     

动力扰动下深部出矿巷道围岩的变形特征

以冬瓜山铜矿井下900 m深处的出矿巷道作为研究对象，基于“隔一采一充一”阶段凿岩、分段崩落的回采方案，利用FLAC^3D数值模拟软件研究了静动态开挖过程中出矿巷道围岩的变形特征。模拟相关岩体力学参数由三轴压缩及频繁冲击扰动试验数据折减获得，采用Mohr-Coulomb模型进行静态开挖分析，结合Strain-Softening模型进行动态扰动影响模拟分析。研究结果表明：爆破产生的扰动促使围岩变形加剧，但不会改变静态开挖时围岩变形演化的规律；开挖时巷道周边产生应力卸荷现象，且顶板出现拉应力，靠近采场巷道两帮应力离散性大，造成顶板易产生拉伸破坏，靠近采场巷道两帮易发生片帮；结合深部出矿巷道实际稳定情况，推测巷道顶板及靠近采场部位易产生破坏，需加强支护，其余部位稳定性相对较好。     

排土场边坡堆排设计及稳定性分析

排土场作为露天采场剥离废石的堆放场地。其稳定性设计和分析至关重要,也是边坡工程的核心问题,是露天矿组织生产不可缺少的一项永久性工程。以某铁矿排土场为例,根据工程地质情况,对该排土场进行了堆排设计,然后对该堆排设计进行了边坡稳定性数值模拟分析。模拟结果表明：在浸水状态下,排土场边坡处于稳定状态,说明该排土场堆排设计方案具有一定的可行性和合理性,为露天采场的废石堆排提供了一定的指导依据。     

Application of Seismic Refraction Tomography in Karst Terrane

Seismic refraction tomography field data were collected on several bridge foundation sites in Pennsylvania, in close proximity to geotechnical boring locations. Profiles determined from these field measurements were plotted against drilling data, and these comparisons revealed the ability of seismic wave velocities to differentiate overburden soil from rock. In addition, foundation construction data were collected at each of the sites and compared with refraction test results determined prior to construction. In particular, top of rock revealed by an excavation, and pile tip elevations at driving refusal, were compared with refraction test results. From these data it appears that seismic wave tomograms can characterize the soil/rock interface, and that it is possible to predict expected design pile lengths based upon a measured P-wave velocity tomogram. It can be concluded from these site comparisons that geophysical techniques such as seismic refraction tomography can provide important additional information to site characterization for bridge foundations in karst terrane. However, these techniques should not be viewed as a replacement, but should be conducted during design stage site investigation to aid selection of borehole locations and other testing needs.     

FLAC和神经网络在隧道位移反分析中的应用

应用三维有限差分程序FLAC^3D和BP神经网络对隧道位移进行分析,使用正交实验和FLAC^3D正演结果作为样本,用神经网络建立围岩位移与反演参数的映射关系．反演得出了围岩的弹性模量和初始地应力测压系数,并使用FLAC^3D正算验证反演参数的精度．结果表明：可搜索得出反演参数的最优解,实现在隧道围岩中的位移反分析．可将反演结果用于隧道的设计,反演精度满足工程要求．     

Structural Characterization of Hybrid Fiber-Reinforced Polymer-Glulam Panels for Bridge Decks

The structural characterization of hybrid fiber-reinforced polymer (FRP)–glued laminated (glulam) panels for bridge deck construction is examined using a combined analytical and experimental approach. The structural system is based on the concept of sandwich construction with strong and stiff FRP composite skins bonded to an inner glulam panel. The FRP composite material was made of E-glass reinforcing fabrics embedded in a vinyl ester resin matrix. The glulam panels were fabricated with bonded eastern hemlock vertical laminations. The FRP reinforcement was applied on the top and bottom faces of the glulam panel by wet layup and compacted using vacuum bagging. An experimental protocol based on a two-span continuous bending test configuration is proposed to characterize the stiffness, ductility, and strength response of FRP-glulam panels under simulated loads. Half-scale FRP-glulam panel prototypes with two different fiber orientations, unidirectional (0°) and angle-ply (±45°), were studied and the structural response correlated with control glulam panels. A simple beam linear model based on laminate analysis and first-order shear deformation theory was proposed to compute stiffness properties and to predict service load deflections. In addition, a beam nonlinear model based on layered moment-curvature numerical analysis was proposed to predict ultimate load and deflections. Correlations between experimental results and the two proposed beam models emphasize the need for complementing both analytical tools to characterize the hybrid panel structural response with a view toward bridge deck design.     

节理粗糙度对应力波传播及试样破坏影响的颗粒流模拟

为了研究节理粗糙度对应力波传播规律的影响以及粗糙节理试样受应力波作用发生破坏的微观机理,利用基于离散元方法的数值分析软件PFC2D构建了SHPB系统的颗粒流数值模型.在已有SHPB物理试验的基础上对试验中采用的节理试样进行微观参数标定,研究了较低冲击荷载下节理粗糙度对应力波传播的影响规律以及较高冲击荷载下不同形貌节理试...     

Effects of Electroosmosis on Soil Temperature and Hydraulic Head. II: Numerical Simulation

A numerical model to simulate the distributions of the voltage, soil temperature, and hydraulic head during a field test of electroosmosis was developed. The two-dimensional governing equations for the distributions of the voltage, soil temperature, and hydraulic head within a cylindrical domain are derived based on the principles of charge, energy, and mass conservations, Darcy’s law, Ohm’s law, and Fourier’s law of heat conduction. We assumed that the voltage distribution was at steady state, whereas the soil temperature and hydraulic head were at transient states during the test. The simulated domain was segmented with a block-centered finite-difference scheme and the resulting equations were solved numerically with the successive overrelaxation method. The parameters (such as electrical, thermal, hydraulic, and electroosmotic properties of the soil, graphite, and sand) that were required by the model were measured either using core samples or slug tests. The model is able to predict the pattern as well as the magnitude of the voltage profiles observed. The simulated temperatures are similar in pattern and are within 3°C of the values observed in the four casings during 4 weeks of electroosmosis. The changes in the rates of temperature with an increase in energy input predicted by the model are in agreement with the observed changes. The output from the hydraulic head simulations showed that the model could predict patterns of hydraulic head changes in the vicinity of mesh and graphite electrodes. The model, however, underestimated the magnitude of the changes close to the anode. The simulated electroosmotic flow rate of 0.9 L/h is also consistent with the observation of 0.6–0.8 L/h.     

基坑开挖对临近地表沉降影响的分析

采用FLAC-3D软件对某基坑开挖引起的地表沉降进行了数值模拟,计算中采用摩尔库仑及修正剑桥弹塑性模型模拟土体特征,采用结构单元模拟基坑支护结构。通过模拟开挖过程,获得了地表沉降的一些规律,可供工程设计和施工参考。分析表明：土方开挖对基坑周围土体的影响范围约为2.7倍的基坑深度;修正剑桥模型模拟昆明地区典型地基土能取得较好效果。