An analytical solution for the nonlinear distribution of effective and total stresses in vertical backfilled stopes     

《Geomechanics and Geoengineering》2013,8(4):237-245

The increasing use of backfill in underground mines requires a proper evaluation of the stress state in and around the filled openings. This is, however, a relatively complex issue due, in part, to the large contrast in strength and stiffness between the backfill material and surrounding rock mass. In recent years, it has been shown that arching theory, based on limit equilibrium analysis, can be used to estimate the stress distribution in backfilled stopes. Nonetheless, many simplifications are involved in such analytical solutions and this affects the precision and significance of the calculated results. In this paper, a previously developed solution is enhanced by introducing the combined effects of non-uniform vertical stress distribution and positive pore water pressure. This leads to a more representative analytical solution, as demonstrated by successful comparisons with numerical simulations. The results indicate that the proposed solution can be used to estimate the effective and total stress state in submerged or partially submerged backfilled stopes with a simple geometry.  相似文献   

塔里木盆地凝析气田的地质特征及其形成机制   总被引：2，自引：0，他引：2  

杨海军  朱光有 《岩石学报》2013,29(9):3233-3250

塔里木盆地凝析油气资源丰富,已发现了二十余个凝析气田,包括库车坳陷的陆相油气来源的凝析气田和台盆区海相烃源岩来源的凝析气田;储层有碎屑岩,也有碳酸盐岩;时代自奥陶系至新生代均有分布。这些凝析气田的气油比分布在600~19900m³/m³,凝析油含量40~750g/m³;储层温度在78~155℃;地层压力在37~111MPa。研究认为,塔里木盆地凝析气藏的成因类型可以分为原生凝析气藏和次生凝析气藏。其中,以库车坳陷迪那2凝析气田为代表的煤系烃源岩在高演化阶段(镜质体反射率Ro为1.2%~2.0%),即凝析油和湿气生成带所形成的原生腐植型凝析气藏或煤成型凝析气藏。次生凝析气藏包括两类:陆相油气来源的多期充注,晚期干气对早期油藏发生混合改造,形成了以牙哈为代表的陆相油气成因的次生凝析气藏;以海相油气来源,多期油气充注与晚期干气气侵,造成蒸发分馏,在运移、聚集和成藏过程中烃体系分异、富化,发生反凝析作用,从而导致次生凝析气藏的形成。随着塔里木盆地勘探向深层转化,地层的温度和压力逐渐增高,烃类演化程度的升高,不同生烃阶段的烃体系混合也将更为普遍,次生凝析气藏也将更为普遍,因此,以海相油气来源的次生成因型凝析气藏将成为勘探的主体。  相似文献   

基于CFD的大通孔开闭式钻头流场研究          下载免费PDF全文

陈鱼  王义红  乔慧丽  李彦明 《探矿工程》2013,40(9):52-54

采用计算流体力学方法对大通孔开闭式钻头\[1\]的流场进行数值模拟。对不同工况下的速度场进行分析,获得了最佳钻进风量,并发现流场中存在“阻塞漩涡”。对最佳流量工况下的压力场进行分析,发现流场中还存在“抽吸压差”。获得了“阻塞漩涡”和“抽吸压差”对排渣和散热的影响机理,为钻头的优化设计提供了一些参考依据,为松软突出煤层全孔筛管护孔瓦斯抽采技术在煤矿中推广应用奠定了基础。  相似文献   

一个储量可再生的石油地质模型     

崔永强  马广宇  杨丰瑞 《化工矿产地质》2013,(3):157-161,174

最新石油地质基础研究表明,目前正在开采的油气藏可能存在大规模的油气补充,以往勘探地质模型、开发地质模型、三次采油地质模型都没有考虑到储量可增长的因素,可能需要修正。建议国家有关部门设立专项研究,以期为油气勘探开发部署和后期调整提供可靠的地质依据。  相似文献   

平顶山矿区原生结构煤和构造煤孔渗实验对比          下载免费PDF全文

郭德勇  李春娇  张友谊 《地球科学》2014,39(11):1500-1506

为了研究构造煤孔渗变化特性, 利用平顶山矿区原生结构煤和构造煤, 进行了不同围压、温度、湿度和煤体结构类型等条件下孔隙度及渗透率的实验测定, 对煤层孔渗特性在不同条件下的变化趋势进行了分析.结果表明: 围压、温度、湿度和煤体结构类型4种因素对煤的孔隙度和渗透率均有较大影响, 当温度和围压同时作用时, 围压的作用效果大于温度的作用效果.并用Origin软件对部分实验数据进行了数据拟合, 得出原生结构煤和构造煤的渗透率-孔隙度函数关系.   相似文献   

Evaluation of pile foundation response to lateral spreading   总被引：7，自引：0，他引：7  

Tarek Abdoun  Ricardo Dobry 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):1051-1058

The effects of liquefaction on deep foundations are very damaging and costly, and they keep recurring in many earthquakes. The first part of the paper reviews the field experience of deep foundations affected by liquefaction during earthquakes in the last few decades, as well as the main lessons learned. The second part of the paper presents results of physical modeling of deep foundations in the presence of liquefaction conducted by the authors and others at the 100g-ton RPI centrifuge. In the last decade centrifuge modeling has been identified as a key tool to identify and quantify mechanisms, calibrate analyses and evaluate retrofitting strategies for pile foundations. Results are presented of centrifuge models of instrumented pile foundations subjected to lateral spreading, including single pile and pile groups, 2- and 3-layer soil profiles, mass and stiffening elements above ground to incorporate the effect of the superstructure, and evaluation of proposed retrofitting strategies. Interpretations of these centrifuge experiments and their relation to field observations and soil properties.  相似文献   

Influence of the ground profile on the reduction of earthquake motion at the filled man-made islands in the Kobe harbor during the 1995 Hyogoken Nambu earthquake     

Tadahiro Fukusumi  Hitodhi Ozaki  Masao Koba   《Soil Dynamics and Earthquake Engineering》2002,22(9-12):893-899

During the 1995 Hyogoken Nambu earthquake in Kobe, the ground motion at the filled man-made islands in the Kobe harbor was not as severe as that at the mainland. The building damage was also less compared to that on the mainland. It was found by comparative study of earthquake records that the magnitude of acceleration response on the ground surface decreases at the islands as opposed to the mainland. One dimensional effective stress analysis is adopted in this study. Input data has been generated from test results, e.g. the SPT N-value by standard penetration test and shear wave velocity V_s by PS logging. Results obtained by the analyses showed good agreement with the observed records, which is an indication of the suitability of the adopted analysis procedure. From this study, the followings are concluded. By the increase of SPT N-value of the filled layers, liquefaction near ground surface is restrained and damage modes such as ejection of water and soil can be prevented. Since the ground profile at the islands is that considerably soft filled layer and marine clay layers, etc. are present and the thickness of the surface layer is large, the initial natural period of the ground is above 1 s and the natural period is elongated further under the earthquake excitation, which is deemed to be the principal reason for the reduction of the earthquake motion at the ground surface.  相似文献   

Flow and deformation failure of sandy slopes   总被引：2，自引：0，他引：2  

G. Biondi  E. Cascone  M. Maugeri 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):1103-1114

The effects of earthquake induced pore pressure on seismic and post seismic stability conditions of cohesionless slopes are investigated with reference to the infinite slope scheme. In cohesionless slopes the shear strength reduction caused by pore pressure build-up may lead the slope to a deformation failure or to a flow failure if liquefaction conditions are approached. Two critical values of the seismic induced pore pressure ratio are introduced to evaluate the effect of shear strength reduction on the slope failure mechanism. The results are given in the form of stability charts and a procedure for the evaluation of the seismic stability condition is described. The procedure gives useful information about the failure mechanism that slopes may exhibit and the displacement analysis which should be carried out.  相似文献   

高温高压实验弹性波速研究及其地球动力学意义   总被引：6，自引：2，他引：6  

马麦宁  白武明 《地球物理学进展》1999,14(1):40-55

本文在收集，整理国内外有关高温高压实验岩石，矿物弹性波速研究资料的基础上，对高温高压实验弹性波速研究的目的，内容进行了概述，并对国内外这一领域研究的历史，现状及有关实验技术方法进行了综述，其中重点介绍了我国在高温高压岩石波速研究方面的进展及所取得的成就，并对高温高压弹性波速研究的地球动力学意义进行了讨论。  相似文献   

高温高压下岩石弹性波速特征及其在深部地质研究中的意义   总被引：6，自引：2，他引：6  

刘永祥  吴福元 《地球物理学进展》1995,10(3):82-94

本文收集、整理、研究了７０年代以来的高温高压下岩石的Ｖｐ，Ｖｓ，Ｖｐ／Ｖｓ，Ｖｐ各向异性等实验资料后得出：（１）低压下岩石Ｖｐ的急剧变化是由岩石中裂纹与孔隙等引起的；（２）温度升高可增大由岩石组构引起的Ｖｐ各向异性的变化率；（３）同种岩石在不同的大地构造环境中具有不同的波速值与变化规律；（４）Ｖｐ在高地温区随温度先降低而后升高，其原因是由矿物相变造成的，与地壳中低速带的性质相当。文章最后讨论了实测波速转换为岩石类型时实验研究岩石波速的意义。  相似文献