共查询到20条相似文献，搜索用时 580 毫秒
1.
The initially designed deposits of the Longdu tailings pool is the mixed tailings of iron ore and covelline. However, the fact that no iron ore tailings have been infused into the pool during its employment directly influenced its stability. By making use of 2D limited meta-softwares, the authors study the seepage features of Longdu tailings pool based on the tested data and material for it. According to first dam penetration, dry slope's length and different atmosphere rainfalls, the seepage field of the tailings pool is analyzed so they can conclude seepage rules for the fine grained tailings pool under different conditions and then study the stability features of the tailings pool. The result shows that change of the deposits gives ill effect on the stability of the pool, and the tailings pool will not run normally if no proper reinforce measure is taken in time. 相似文献
2.
The static stability of a tailings dam is analyzed with a finite element approach, which takes into account the effect of plastic deformation, temperature, saturation and void ratio on the properties of soil materials, the effect of water and soil interaction and the extended Mohr-Coulomb failure criterion. The concept of yield approaching degree is introduced, which is defined as the ratio of the existing equivalent stress to the yield stress taking into account the effects of different influencing factors. The response of the tailing dam subjected to the coupled saturated/unsaturated seepage and deformation is simulated, considering that the dry beach is 100-meter long and the starter dam is jammed, respectively. The important indexes such as the deformation and the phreatic surface of the dam are obtained. The distribution of the yield approaching degree in the whole dam under the given condition is obtained, which can provide not only a general stability assessment of the dam, but also important information to the decision-making for the reinforcement and maintenance of the dam. 相似文献
3.
The technology of splitting grouting for earth dam is one of the important technical measures to improve the quality of dam. However, the consolidation mechanism of slurry in the dam is not clear, which can not evaluate the effects of seepage control of the dam after grouting. Therefore, assuming that the construction technology does not change and with the consideration of interaction between the layout of hole-boring distance and the effects of seepage control, the Mohr-Coulomb Hardening model and fluid-solid coupling method were used to analyze the rule of pore pressure, stress and strain in the dam during splitting grouting based on the finite element simulation. The consolidation mechanics was discussed and stability of the dam was evaluated. 相似文献
4.
流固耦合的多元结构深厚覆盖层透水地基的力学特性 总被引：3，自引：0，他引：3
深厚覆盖层多元结构坝基在渗流过程中各土层力学差异明显,分析时关注的具体问题也不尽相同,需要深入研究。基于比奥固结理论,考虑土体的非线性流变以及土体固结变形过程中孔隙度、渗透系数、弹性模量及泊松比的变化;借助ADINA流固耦合模块来模拟西藏达嘎水电站坝基渗流场与应力场耦合过程,分析各层力学特性及相互作用。研究表明,透水性较强的表层土体是渗流主要通道,也是渗流进出区和沉降变形体现区,应在上游采取措施提高其压缩模量,下游区域增设反滤层和排水设施;坝基中的粉细砂层是坝基沉降的主要原因,对坝基沉降起主导作用,同时应注意其液化特性对坝基的不利影响;坝基中的承压含水土层对下游上部结构产生向上顶托力,若位置较深,则破坏性较小;坝基深部土层对整个坝基的渗流破坏影响较小,但对沉降和渗流量的影响不可忽视;表层砂卵砾石层和粉细砂层的渗透系数相差较小时,土层间不会发生接触冲刷。此外,还发现坝基孔隙水压力在快速衰减阶段被消散,期间土体固结较快。垂直防渗墙能有效降低渗透坡降和渗流量,将坝基沉降变形控制在防渗墙上游区域,但上游坝基变形对防渗墙产生较大的水平推力,应加大防渗墙尺寸或者采用辅助渗控措施。 相似文献
5.
Numerical simulation of seepage field of gas extraction drilling of single bedding of mining-coal bed 总被引：3，自引：0，他引：3
Aiming at the problem of reasonable decorate of coal gas extraction drilling, combining with the initial and boundary condition of borehole extraction, the solid and gas coupling mathematical model of gas seepage of borehole extraction is deduced based on established control equations of seepage field and deformation field. Taking gas extraction of stone coal slit as an example, according to the characteristics of coal seam in the research, the numerical simulation method is used to obtain the distribution rule of gas pressure, coalbed gas permeability, and coalbed gas seepage velocity as well as seam deformation. The effective radius of gas extraction drilling of single bedding about mining-coal bed is determined, which provides the basis for optimum arrangement of gas extraction drilling of single bedding. The results show that the effective radius of stone coal is about 4 m. If the prolonging drilling drainage time is less than 20%, the drilling quantities would reduce by about 50%. 相似文献
6.
Analysis and numerical simulation of fluid-structure coupling of gas drainage from boreholes 总被引：2，自引：0，他引：2
Gas drainage from boreholes is main method of utilization and management of Chinese coal seam gas. As the exploitation depth increases, stress field and other factors on the impact of gas seepage are increasingly apparent. Based on the basis of a series of assumptions of coal seam gas, porosity and permeability equations are described by considering stress, coal seam gas pressure change on the coal produced by deformation of the skeleton. The fluid-structure coupling equations are derived by using the basic theorem of porous media flow and the fluid structure coupling theory. The gas seepage field is simulated and analyzed by using multi-physics coupling analysis software. The effect of gas pressure distribution, different burial depths and different drilling parameters (drainage negative pressure, drilling radius) on gas seepage field is obtained. Analysis of simulation results can provide theoretical guidance for on-site gas drainage. 相似文献
7.
Since the analysis of seepage field with horizontal drain holes and the stability analysis of reservoir banks are very complicated, the application of horizontal drain holes in the engineering control of bank slope is restricted seriously. It is economical and reasonable to add horizontal drain holes to improve the slope stability, so it is of both practical and theoretical significance to research horizontal drain holes. Considering the complication of analysis, the paper introduces a complete set of methods of establishing the model of horizontal drain holes, analyzing the seepage field with horizontal drain holes and analyzing the slope stability after engineering control with horizontal drain holes only in two dimensional condition with a calculation example. The results of numerical analysis show that the slope stability can be improved by adding horizontal drain holes. and the length of the hole has obvious effects on draining compared with the aperture. 相似文献
8.
The foundation pit deformation of a commercial building in Hangzhou is calculated by using calculation method related to foundation pit deformation. The calculation results by m method show that the maximum deformation is 29.2mm and the real maximum deformation is 174.6mm. The deformation character obtained by foundation coefficient method is different from the real deformation. There are lots of factors influencing foundation deformation. According to practical engineering condition, in this study, the influencing factors for soil parameters, bracing condition, condition for insertion of retaining wall into soil and construction speed are determined. The calculation method used is analyzed and modified. Finally, a useful and valid method for calculating foundation deformation is presented, by which the foundation pit deformation in practical project can be forecasted and analyzed. 相似文献
9.
In order to optimize design and operation, it is necessary to calculate accurately hydraulic characteristics large central air-conditioning systems. Simplified Model can not be applied to hydraulic calculation of large pipe network topological structure for its large calculation error. Taking into account the regulating characteristics of terminal branch temperature regulating valve, a direct-return chilled water system is studied, an accurate mathematical model of pipe network hydraulic characteristics has been established and a computer logic algorithm with virtual flow has been given. A direct-return pipe network with ten AHU branches is used as simulation calculation object, the pipe network supply-return water pressure difference is calculated, and also the temperature regulating valve opening and actual flow of each branch are calculated in the condition of different supply-return water pressure difference. The calculated results accord with the natural characteristics of high pressure difference unbalanced for direct-return pipe network. The calculation method can ensure calculation convergence. 相似文献
10.
基于极限平衡理论,以砂土边坡为研究对象,推导了渗流和地震存在时拟静力法和拟动力法边坡安全系数的计算表达式。通过程序求解,与已有算例对比表明,计算结果基本一致,验证了2种方法解析式的合理性。参数分析表明,水位越高,边坡失稳越严重,水力梯度与安全系数基本为线性关系。渗流方向向下时,稳定性随水力梯度的增加而增大;渗流方向向上时,变化规律相反。水平地震加速度系数对稳定性的影响剧烈,竖向地震加速度系数对稳定性影响较小,简化计算可以忽略不计。最终得出拟静力法的解析式,简单、实用,而拟动力法则可以更为全面地考察砂土边坡稳定性随时间变化的特点。 相似文献
11.
Wang Xuan Wu Zeyuan 《保鲜与加工》1990,(3)
In this paper, the permeability of coal, porous rock (sandstone), fractured rock(limestone) varifies with different confining pressure is discussed. Exponential functions between permeability and confining pressure are concluded. As a primary exploratiotion of permeability, it is significant to study coal and rock seepage characteristics and methane emission prediction. It is also useful in mine methane drainage system design. 相似文献
12.
The one-dimensional flow model based on Saint-Venant equation is developed.Then,it is applied to calculate the holistic hydraulic characteristics in the natural condition of the Three Gorges Reservoir in Chongqing region,which is the 500 km-long mainstream beginning at Cuntan and ending at the boundary of Chongqing.Further,the model is applied to predict the hydraulic characteristics of the calculating zone at the time of the second stage of the dam construction(156 m storage level at the dam) and the completion of the project(175 m storage level at the dam).When the reservoir is operated at the storage level of 156m,the river-width of most corss-section increasing 2 times and the cross-section average velocity is reduced by 2/3 compared with these in the natural condition.When the reservoir is operated at the storage level of 175 m,the river-width of most cross-section increasing 2.5 times and the cross-section average velocity is reduced by 3/4 compared with these in the natural condition.The validating result indicates that the model properly reflectes the holistic hydraulic characteristics.This model is an effective tool for the assessment of the environmental impacts of the Three Gorges operated at the different storage level. 相似文献
13.
The Cuplock Template supports system joint initial rigidity and bowl buckle tightening torque was closely linked, with MATLAB applications for the two order and three order numerical fitting between them, found that three order fitting accuracy was higher than two order fitting results. Using ANSYS finite element software to establish the corresponding with the entity model, the changes in simulated nodes hinged, rigid and different initial stiffness condition for supporting system, and the simulation results were compared with the actual bearing capacity of the frame body stability. Find node is hinged and rigid connection simulation results state and actual frame difference. When the simulation results between node tightening torque of the 35N.m~50N.m and the actual time the frame carrying capacity is close, the node for the semi-rigid connection state. In order to show that the semi-rigid joint model can simulate accurately with the actual capacity of the Cuplock Template supports system. 相似文献
14.
不同养殖模式下俄罗斯鲟肌肉营养成分的比较与分析 总被引：1，自引：1，他引：0
为了了解循环水养殖系统养殖条件下鱼类肌肉的营养成分,开展鱼类品质调控研究。本研究比较了循环水养殖系统养殖条件下与池塘拟野生条件下俄罗斯鲟肌肉的常规营养成分、氨基酸和脂肪酸组成,并进行对比评价。结果表明,两种条件下俄罗斯鲟肌肉中一般营养成分不存在显著差异,均检出17种氨基酸,氨酸酸各组成成分含量方面两者无显著差异。氨基酸评分(AAS)和化学评分(CS)结果显示：循环水系统养殖条件下第一限制性氨基酸均为蛋-胱氨酸,赖氨酸在必需氨基酸中评分最高,必需氨酸基指数（EAAI）循环水组高于池塘组。循环水组检出20种脂肪酸,池塘组检出14种脂肪酸,两者脂肪酸总量无明显差异,脂肪酸各组成成份有较大差异,其中二十二碳六烯酸(DHA)循环水组显著高于池塘组。综上所述,循环水养殖系统养殖条件下俄罗斯鲟肌肉的营养价值不低于池塘拟野生条件下的俄罗斯鲟。 相似文献
15.
In order to improve vehicle handling stability,a control system using optimal allocation of yaw moment was designed.The first layer is a linear quadratic regulator (LQR) controller,which optimizes a desired yaw moment to work on the vehicle and calculates reference wheel slip for the target wheel.The second layer of the control system is a PID controller which can track the reference wheel slip rate,and then apply braking torque on the target wheel to make the vehicle stable.Simulations are carried out by using an 8-dof nonlinear vehicle model under different conditions.The simulation results indicate that the designed control system can effectively improve vehicle handling stability. 相似文献
16.
In order to analyze seepage feature and seepage failure mechanisms of seawall under flood infiltration, a numerical model for saturated-unsaturated and unsteady seepage flow analysis considering soil permeability variation with seepage failure process was established. And the corresponding finite element computation program was made. Numerical simulation of flood seepage for typical section of real seawall was carried out by use of the program. The computed results were compared with the measured results of field test, which shows good agreement. Based on the numerical simulation results, it can be seen that flood seepage of seawall is a saturated-unsaturated and unsteady seepage flow process and seepage failure of seawall is caused by long time flood infiltration under large seepage gradient. Therefore, upon the flood infiltration, seepage failure of the seawall is a very complicated process, which involves soil permeability variation with seepage failure process and saturated-unsaturated/unsteady seepage flow. It is questionable to use the steady seepage analysis method to simulate seepage failure process of seawall. 相似文献
17.
By using the method of characteristics, a shock fitting schemes for computation of gas dynamics is proposed and used to simulate the 1-D unsteady open channel flow of sudden dam break. The calculation results are compared with analytic solutions. It is demonstrated that high accuracy, good stability are obtained and good shock-capturing ability is shown. 相似文献
18.
This paper constructs a model of refrigerant thermodynamic properties calculation for simulation of refrigeration and air condition system based on the parametric equations of state of refrigerant. The Visual C++ 6.0 language is used to develop this model, which has a friendly user interface (UI). This program is easy to learn and use and it has reliably function. Compared with the data provided by the standard graphs and tables of refrigerant thermodynamic properties, the calculation results of this model have certain precision and meet the expectative requirements. 相似文献
19.
池塘内循环养殖模式关键工艺参数设计 总被引：3，自引：0，他引：3
为确立科学、合理的池塘内循环养殖模式关键工艺参数范围,运用物质平衡等相关原理,对系统内循环量、养鱼槽体面积与池塘面积比工艺参数进行科学设计,并讨论鱼粪及残饵收集率等基本参数对其影响。结果表明：在水体容积为198m3(22×5×1.8m)、溶氧为6mg/L的槽体中开展养殖密度达100kg/m3大宗鱼类养殖,当鱼粪及残饵收集率为30%时,池塘内循环养殖模式内循环量设计为653.59 m 3/h(约每18min槽内水体交换一次),槽体面积与池塘面积比设计为1.05～1.58%;当鱼粪及残饵收集率为60%,池塘内循环养殖模式内循环量设计为573.11m 3/h(约每21min槽内水体交换一次),槽体面积与池塘面积比设计为1.20～1.80%。需综合考量设定最佳鱼粪及残饵收集率,以降低模式运行能耗。本设计为提升模式技术性能,促进池塘内循环养殖技术发展及广泛推广提供支持。 相似文献
20.
In the temperate climate of northeast Germany, a trade-off exists between water use in agricultural crop production and groundwater recharge which is important for urban water supply, irrigation, forestry and peat protection. The APSIM-Nwheat model was used to analyze the impact of climate change scenarios on deep drainage (DD), the water loss below the maximum root zone as the main source of groundwater recharge, and wheat production for two main soil types. A linear and a nonlinear climate scenario were used in this study: The linear scenario for 2001–2050 was based on a simple linearly modified historical climate record from 1951 to 2000. The nonlinear scenario used the same 1951–2000 historical climate record but combined it nonlinearly with a Global Circulation Model climate scenario for 2001–2050. Simulation results showed different distributions of deep drainage and grain yield with the linear and nonlinear scenarios, but no difference in the 50-year averages. Hence, a linear manipulation of climate records can be as effective for climate change impact studies on deep drainage and grain yield as nonlinearly manipulated climate data, if long-term average changes are of main interest. The simulation results indicated that a trade-off between deep drainage and grain yields can be potentially controlled through N management. However, such control mechanism was more effective under current climate conditions than under future climate and on a better water-holding silt soil compared to a poorer water-holding loamy sand. It is suggested that areas with poor water-holding soils should be managed extensively for groundwater recharge harvesting while better water-holding soils should be used for high input grain production. 相似文献