矿坑人工块体的理论模型     

B.A.谢凯尔巴耶夫 《吉林大学学报(地球科学版)》1989,(3)

文章叙述了充填配料沉陷的形成过程和考虑的影响充填配料压缩性的因素。给出了具有最佳压缩性能的理想充填块体的计算模型。 提出的最优配料压缩性方程式,由已知组成粒级数据,通过选择、计算所需压缩特性的最优配料的成分,有可能解决重要的生产问题。  相似文献   

滕县煤田滨湖煤矿16煤层开采充水条件浅析          下载免费PDF全文

王继芳  韩廷宝  杜显彪  徐然  王娜  李军 《山东国土资源》2016,32(1)

滨湖煤矿16煤开采过程中,曾多次出现涌(突)水现象,影响了矿井的正常生产。全面分析16煤开采的充水条件,才能排查出水患威胁的各种原因,从而制订出合理有效的防治水措施,对保障滨湖煤矿16煤层的安全顺利开采具有重要意义,对滕县煤田其他煤矿16煤的开采也具有重要的参考意义。  相似文献   

Numerical Wave Tank Based on A Conserved Wave-Absorbing Method     

扈喆  唐文勇  薛鸿祥  张晓莹 《海洋工程》2016,(1):137-148

Recently the numerical wave tank has become a widely-used tool to study waves as well as wave-structure interactions, and the wave-absorbing method is very important as its effect on the quality of waves generated. The relaxation method and the derived momentum source method are often utilized, however, the damping weight is constant during calculation and repeated trials are required to obtain an acceptable wave-absorbing effect. To address the above- mentioned issues, a conserved wave-absorbing method is developed. The damping weight is determined by solving the mass conservation equation of the absorbing region at every time step. Based on this method, a two-dimensional numerical wave tank is established by using the VB language to simulate various waves by which the validation of this method is evaluated.  相似文献   

Formation and preservation of open-framework gravel strata in unidirectional flows   总被引：1，自引：0，他引：1  

I. A. LUNT  J. S. BRIDGE 《Sedimentology》2007,54(1):71-87

Open‐framework gravel (OFG) in river deposits is important because of its exceptionally high permeability, resulting from the lack of sediment in the pore spaces between the gravel grains. Fluvial OFG occurs as planar strata and cross strata of varying scale, and is interbedded with sand and sandy gravel. The origin of OFG has been related to: (1) proportion of sand available relative to gravel; (2) separation of sand from gravel during a specific flow stage and sediment transport rate (either high, falling or low); (3) separation of sand from gravel in bedforms superimposed on the backs of larger bedforms; (4) flow separation in the lee of dunes or unit bars. Laboratory flume experiments were undertaken to test and develop these theories for the origin of OFG. Bed sediment size distribution (sandy gravel with a mean diameter of 1·5 mm) was kept constant, but flow depth, flow velocity and aggradation rate were varied. Bedforms produced under these flow conditions were bedload sheets, dunes and unit bars. The fundamental cause of OFG is the sorting of sand from gravel associated with flow separation at the crest of bedforms, and further segregation of grain sizes during avalanching on the steep lee side. Sand in transport near the bed is deposited in the trough of the bedform, whereas bed‐load gravel avalanches down the leeside and overruns the sand in the trough. The effectiveness of this sorting mechanism increases as the height of the bedform increases. Infiltration of sand into the gravel framework is of minor importance in these experiments, and occurs mainly in bedform troughs. The geometry and proportion of OFG in fluvial deposits are influenced by variation in height of bedforms as they migrate, superposition of small bedforms on the backs of larger bedforms, aggradation rate, and changes in sediment supply. If the height of a bedform increases as it migrates downstream, so does the amount of OFG. Changes in the character of OFG on the lee‐side of unit bars depend on grain‐size sorting in the superimposed bedforms (dunes and bedload sheets). Thick deposits of cross‐stratified OFG require high bedforms (dunes, unit bars) and large amounts of aggradation. These conditions might be expected to occur during high falling stages in the deeper parts of river channels adjacent to compound‐bar tails and downstream of confluence scours. Increase in the amount of sand supplied relative to gravel reduces the development of OFG. Such increases in sand supply may be related to falling flow stage and/or upstream erosion of sandy deposits.  相似文献   

西太平洋海山玄武岩的岩石学特征及与上覆富钴结壳的关系     

赵海玲  范忠孝  王成  丁旋  莫兆  李长江  张振国  张静 《现代地质》2007,21(2):352-360

通过对西太平洋海山玄武岩和玄武质火山角砾岩的岩石学特征及其气孔充填物成分变化的研究,讨论了海山玄武岩与上覆富钴结壳的关系。富钴结壳的基岩火山岩主要为碱性玄武岩和玄武质火山角砾岩。碱性玄武岩中气孔充填物为S型和C型,S型和C型气孔充填物不共存在同一个气孔中。S型气孔充填物的物质成分富Si、Fe、K、Mg、Al,Co含量一般为0.17%~0.46%,其成分与碱性玄武岩的组成类似,其物质来源可能与碱性玄武岩有关。C型气孔充填物为O、Ca、C及少量Si、Al、Mg、Fe、K等元素,C型气孔充填物可能与海水中物质的沉积有关。由Si、Al、Fe、Mg、K等元素变化曲线反映出的S型气孔充填物沉积过程与富钴结壳早期的沉积过程具有相似的趋势,说明富钴结壳早期沉积物的物质来源可能与碱性玄武岩有关,富钴结壳物质来源可能是碱性玄武岩和海水共同作用的结果。  相似文献   

新近系热储层回灌井钻探工艺探索   总被引：4，自引：0，他引：4  

曾梅香  李会娟  石建军  赵娜  扬永江  田宗宝 《地质与勘探》2007,43(2):88-92

文章通过对新近系热储层回灌井成井结构进行室内模拟试验,探索了因回灌井自身结构特点不足而造成回灌不畅的原因,初步探讨了适合天津地区孔隙型回灌井的施工工艺及井身结构.  相似文献   

地震作用下立式储液罐罐壁“象足”变形仿真分析   总被引：1，自引：0，他引：1  

范喜哲  郑天心王伟  吴灵宇何雪 《地震工程与工程振动》2007,27(3):104-109

基于ANSYS软件建立了考虑液体晃动和罐底提离立式储液罐有限元模型,分别进行了水平地震和竖向地震作用下罐壁“象足”变形分析。分析表明:立式储液罐罐壁“象足”变形主要是由罐壁纵向压应力超过临界应力而产生的局部屈曲破坏,并非强度破坏。因罐底提离导致的罐底与基础反复撞击加大了作用在罐壁上的应力,使罐壁底部“象足”变形不断发展,最终导致罐壁撕裂。在完全相同地震加速度作用下,水平地震作用比竖向地震作用罐壁更早更容易进入屈曲状态,产生“象足”变形。  相似文献   

Interactions between sediment delivery,channel change,climate change and flood risk in a temperate upland environment   总被引：1，自引：0，他引：1  

S. N. Lane  V. Tayefi  S. C. Reid  D. Yu  R. J. Hardy 《地球表面变化过程与地形》2007,32(3):429-446

This paper uses numerical simulation of flood inundation based on a coupled one‐dimensional–two‐dimensional treatment to explore the impacts upon flood extent of both long‐term climate changes, predicted to the 2050s and 2080s, and short‐term river channel changes in response to sediment delivery, for a temperate upland gravel‐bed river. Results show that 16 months of measured in‐channel sedimentation in an upland gravel‐bed river cause about half of the increase in inundation extent that was simulated to arise from climate change. Consideration of the joint impacts of climate change and sedimentation emphasized the non‐linear nature of system response, and the possibly severe and synergistic effects that come from combined direct effects of climate change and sediment delivery. Such effects are likely to be exacerbated further as a result of the impacts of climate change upon coarse sediment delivery. In generic terms, these processes are commonly overlooked in flood risk mapping exercises and are likely to be important in any river system where there are high rates of sediment delivery and long‐term transfer of sediment to floodplain storage (i.e. alluviation involving active channel aggradation and migration). Similarly, attempts to reduce channel migration through river bank stabilization are likely to exacerbate this process as without bank erosion, channel capacity cannot be maintained. Finally, many flood risk mapping studies rely upon calibration based upon combining contemporary bed surveys with historical flood outlines, and this will lead to underestimation of the magnitude and frequency of floodplain inundation in an aggrading system for a flood of a given magnitude. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

某机场振动碎石桩地基处理检测结果分析   总被引：1，自引：0，他引：1  

盛初根 《岩土工程技术》2006,20(3):151-153,158

介绍了振动碎石桩处理机场跑道地基的效果。根据钻探取样和原位测试结果,分析了碎石桩处理前后的孔隙水压力变化情况,并对比了处理前后的土层物理力学性质指标,分析了砂土地震液化可能性,得出了检测结论,可供类似工程参考。  相似文献   

朝阳露天采区水文地质特征与矿坑充水因素分析     

孟庆发 《中国煤田地质》2006,18(5):28-30

通过对朝阳勘查区露天采区的三个含水层和三个隔水层特征、地下水的补给、径流和排泄条件及含水层之间的水力联系等因素分析，认为三个含水层对矿坑均有充水影响，并预计了各含水层对矿坑的充水水量，为今后矿坑疏干排水提供了依据。  相似文献