Application of three-dimensional discrete element face-to-face contact model with fissure water pressure to stability analysis of landslide in Panluo iron mine

1 Introduction Rock slopes usually contain many jointed surfaces such as joint fissure. When subject to water seepage, the jointed surfaces will induce many geologic disasters such as land- slide and mudflow, and these will do great loss to the national economic development. Therefore, it is very important to deeply understand the mechanism of these disasters. Site observations and analysis on the landslide show that water is one of the key factors to induce landslide[1―8]. All methods calcu…     

Experimental and discrete element numerical analysis of side slope instability induced by fissure water underlying impervious bed

1 Introduction The in situ observations and analysis on the landslide events indicate that water is one of the key factors which induce landslide of the mountain mass[1―8]. The mechanism offissure water inducing landslide can be generalized into three aspects: (1) the softening influence of water weakens the strength of materials on the slip surface[9―11]; (2) the cleft water pressure towards the slide slope free face increases sliding force[12―15]; (3) water pressure on the slip surface lo…     

大型水面舰船防护水舱内爆炸的数值模拟

随着反舰武器的发展大型水面舰船舷侧多层防护结构受到更严酷的考验.反舰武器战斗部有可能进入原本设计用来阻拦爆炸破片的水舱内爆炸.针对这种情况,采用MSC.Dytran中的一般耦合计算方法对水舱和空舱内爆炸流场及其对舱壁结构造成的变形与破损进行了数值模拟与分析.     

深部巷道围岩变形试验与数值模拟研究

为了研究深部软岩巷道的变形破坏特性,以淮南矿区某煤矿13-1煤回采巷道为例,在现场调查回采巷道工程概况的基础上,开展了室内深部回采巷道围岩变形特性相似模拟试验,并基于块体离散元法,建立了深部回采巷道围岩的数值模型,模拟了开挖过程中围岩的变形特性。相似模拟试验和数值模拟试验结果表明,深部巷道围岩的典型特征为:巷道底臌量两帮移近量顶板下沉量,巷道不同围岩受开挖扰动的位移影响范围不同,底板为3.5 m,顶板为2.45 m,两帮为5.5 m。     

Exploitation technology of pressure relief coalbed methane in vertical surface wells in the Huainan coal mining area

Exploitation technology of pressure relief coalbed methane in vertical surface wells is a new method for exploration of gas and coalbed methane exploitation in mining areas with high concentrations of gas, where tectonic coal developed. Studies on vertical surface well technology in the Huainan Coal Mining area play a role in demonstration in the use of clean, new energy re-sources, preventing and reducing coal mine gas accidents and protecting the environment. Based on the practice of gas drainage engineering of pressure relief coalbed methane in vertical surface wells and combined with relative geological and exploration en-gineering theories, the design principles of design and structure of wells of pressure relief coaibed methane in vertical surface wells are studied. The effects of extraction and their causes are discussed and the impact of geological conditions on gas production of the vertical surface wells are analyzed. The results indicate that in mining areas with high concentrations of gas, where tectonic coal developed, a success rate of pressure relief coalbed methane in surface vertical well is high and single well production usually great. But deformation due to coal exploitation could damage boreholes and cause breaks in the connection between aquifers and bore-holes, which could induce a decrease, even a complete halt in gas production of a single well. The design of well site location and wellbore configuration are the key for technology. The development of the geological conditions for coalbed methane have a sig-nificant effect on gas production of coalbed methane wells.     

滑动轴承压力分布及动特性系数

为了对滑动轴承的压力分布和动特性进行研究,基于有限差分法求解静态雷诺方程,得出滑动轴承油膜压力的分布情况,分析了油膜压力作用下轴瓦合金层的应力分布情况。通过求解扰动压力微分方程,得出有限宽滑动轴承的动特性系数。研究表明,油膜压力呈三维抛物面分布,在油膜压力峰值处合金层应力最大,在油膜压力梯度最大处应变最大,油膜动特性系数随着偏心率的增大而增大,交叉阻尼近似相等。     

Experimental study on water seepage constitutive law of fracture in rock under 3D stress

The test method and test result of water seepage constitutive law of fracture in rock under 3D stress are introduced. A permeability coefficient formula including the coefficient of fracture connection, normal stiffness, 3D stress, initial width of fracture and Poisson ratio is presented based on the analysis of the test theory and its result.     

Numerical simulation of bistatic scattering from fractal rough surface in the finite element method

By using the Monte Carlo method and numerical finite element approach, bistatic scattering from the fractal and Gaussian rough surfaces is studied. The difference between these two surfaces and their functional dependence on the surface parameters are discussed. Angular variation of bistatic scattering from the fractal surface is very significant, even for fairly smooth surface, whilst scattering from the Gaussian rough surface tends to the specular reflection. The slope of angular variation is linearly related with the fractal dimension. If an electrically-large target is placed over the rough surface, the fractal dimension inverted from bistatic scattering would be reduced. As the surfaces become very rough, scattering from different fractal and Gaussian surfaces would be not identified.     

Distinct element modelling of fracture plan control in continuum and jointed rock mass in presplitting method of surface mining

Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit m...     

Shaking table test and numerical simulation on the effect of reinforcement on the seismic safety of dam slopes

The seismic safety of the reinforcement dam slope is studied through shaking table test and numerical simulation.The dynamic characteristics of dam slopes,failure mechanism,seismic stability,as well as the effect of reinforcement during earthquakes are discussed.An elasto-plastic analysis method (FLAC) is used to simulate the dynamic failure process of the reinforcement dam slope.The change law of permanent displacement of dam slope is studied.The effect of the length and the space of reinforcement on the depth of slip surface and the slope stability are investigated.Good agreement is obtained between the numerical results and those from shaking table tests.The results show that the dynamic failure is a gradual process not at a particular time.With the increase of the reinforcement length or the decreasing reinforcement spacing,the slip surface becomes deeper and thus the slope stability is improved.The reinforcement can obviously enhance the overall stability of slope dam.It can also effectively control the shallow sliding of slope.These researches provide basic data for reinforcement measures design of earth-rockfill dam.     

沿淮淮北地区地表水与地下水相互转化特点实验资料分析

通过对亳县站地下水排井连续20年实验资料的分析,揭示了河网地表水补给浅层地下水以及地下水侧向排泄的规律.     

安徽省地表水资源量的分析计算

文章介绍水资源评价中地表水资源量的计算方法,对我省同步期(1956-2000年)地表水资源量的计算结果进行初步的合理性评价.     

基于偏最小二乘回归法的管网测压点压力宏观模型

测压点压力宏观模型是根据多个泵站的出口压力和流量,预测各测压点压力值的数学模型,可用作水厂调度优化的理论模型。因模型自变量多重相关,普通回归方法难于得到满意的精确度,而偏最小二乘回归法能较好地解决此类问题,通过实例计算、拟合、分析,结果证明用这种方法建立的宏观模型具有较好拟合性。     

Time effect and prediction of broken rock bulking coefficient on the base of particle discrete element method

Bulking characteristics of gangue are of great significance for the stability of goafs in mining overburden in the caving zones. In this paper, a particle discrete element method with clusters to represent gangue was adopted to explore the bulking coefficient time effect of the broken rock in the caving zone under three-dimensional triaxial compression condition. The phenomena of stress corrosion, deformation,and failure of rock blocks were simulated in the numerical model. Meanwhile, a new criterion of rock fragments damage was put forward. It was found that the broken rock has obvious viscoelastic properties. A new equation based on the Burgers creep model was proposed to predict the bulking coefficient of broken rock. A deformation characteristic parameter of the prediction equation was analyzed, which can be set as a fixed value in the mid-and long-term prediction of the bulking coefficient. There are quadratic function relationships between the deformation characteristic parameter value and Talbot gradation index, axial pressure and confining pressure.     

砂层盾构隧道泥水劈裂试验与数值研究

开展砂层盾构隧道泥水劈裂平面模型试验,研究不同覆土厚度条件下的泥水劈裂破坏机制、土体表面竖向位移和土体内部土压力变化规律. 结果显示,劈裂机制为加压泥浆向掘削空间表面砂层渗透形成致密砂层及其表面泥膜（泥膜-砂层结构）,泥膜-砂层结构在泥浆挤压作用下发生拉剪破坏. 劈裂压力随覆土厚度的增加呈近似线性增大. 劈裂扩展从刀盘顶部起始分别呈“斜直线”或“先竖直后斜线”型向上扩展. 基于自主开发的模拟泥水劈裂的有限元计算程序,参照模型试验建立二维数值模型,计算获得与模型试验较一致的劈裂扩展形态以及土体内部竖向位移与水平位移的变化规律. 结果表明,土体竖直向位移主要分布在刀盘上方以劈裂面为边界的“三角形”区域内,土体水平位移主要分布在掘削面土层.     

Improvement of two-dimension AR model and application in simulation on surface profiles of steel plates

The order and parameter estimation is always difficult in two-dimension AR model because the two-dimension Yule-Walker equation does not have the property of uniqueness and identifiability as the one-dimension AR model.This paper provides an AR order estimation method for a two-dimension AR model, and an AR model parameter estimation method on the basis of an autocorrelation function. A simulation example on surface profiles of some kinds of steel plates is given using this improved AR model with positive results.     

基坑底部土体满堂加固模型试验与数值模拟研究

为探究基坑底部土体满堂加固对基坑变形和内力的影响,采用室内模型试验方法,研究了基坑底部土体满堂加固对基坑周围地表沉降、冠梁侧向位移、桩身弯矩以及桩后土压力变化的影响。运用ABAQUS有限元软件对模型试验进行数值模拟,将试验数据与数值计算结果进行对比,并分析了加固土体的水泥掺入比和加固深度对基坑变形的影响。结果表明：满堂加固对降低基坑底部隆起效果最为明显,对降低支护结构侧向位移较为明显,对减小地表沉降不明显;通过极差分析法得出,增加加固土体的弹性模量较增加加固深度对抑制支护桩侧向位移及坑底隆起更为有效;当水泥掺入比超过一定范围后,加固效果没有显著提升,建议在含水率为20%左右的软弱土层地区,水泥掺入比一般为5%~20%;土体的加固深度超过一定范围后,控制基坑变形的效果有所提高,但不明显,建议土体加固深度取0.4~0.45倍基坑深度。     

内错式下分层回采巷道围岩变形破坏机理研究

利用非线性有限元数值计算方法,模拟了上分层回采巷道开挖、上分层回采及下分层回采巷道开挖三个过程,经过分析得出了下分层煤体内应力分布曲线、内错式下分层回采巷道两帮煤体破坏过程及两帮位移分布特征;室内相似材料模拟试验结果显示了底板岩层竖直应力分布规律及采空区上覆岩层破坏形式。     

水箱模型在小流域水文水质模拟中的应用研究

水箱模型也称Tank模型,是应用较为广泛的流域水文模型.模型将复杂的降水径流过程简单概化为流域的蓄水与出流关系进行模拟.针对皂河小流域的降水、径流和水循环等水文特性,建立了4层串联水箱模型,模拟流域的降水径流过程,计算流域径流量,并结合河流水质模型,综合模拟河流流量及主要水质指标变化.结果表明:各项指标的模拟值与实测值吻合较好,说明水箱模型用于小流域的径流模拟较为准确,可与水质模型耦合使用,综合模拟小流域的水文水质变化.     

济南泉域“三水”转化与泉水恢复关系研究

分析了济南泉水动态特征,对济南泉域岩溶水系统“三水”转化的模式进行了划分,认为来自间接补给区河道径流补给减小、直接补给区河道断流入渗能力降低和城市化建设是地下水补给区入渗功能退化和泉水断流的根本原因. 提出利用雨洪水直接补给区补源、控制城区扩展、优化开采布局等泉水保护措施.