Hydrochemistry,multidimensional statistics,and rock mechanics investigations for Sanshandao Gold Mine,China     

Hongyu Gu  Fengshan Ma  Jie Guo  Kepeng Li  Rong Lu 《Arabian Journal of Geosciences》2017,10(3):62

Prediction of bursting water in a submarine mine (Sanshandao Gold Mine) is very important. The aim of this study was to understand the water sources, mixing ratios, and flow paths in a mining region by using hydrochemistry, principal component analysis (PCA), and rock mechanics. Field observations reveal that there are unusual geothermal gradients and complicated geological conditions. Samples collected from the surface and every depth of the tunnel were analyzed for various ions and isotopes (¹⁸O and D). PCA was used to identify the most likely water sources on the foundation of hydrochemistry and a conceptual model. Four kinds of water sources were identified: (1) water mixture of surface freshwater and seawater, (2) brine derived from a deep closed environment, (3) thermal brine derived from the northwestern fault (F3), and (4) Quaternary water. The water sources were variable with time at a sampling site. The combination of water sources in a specific sampling campaign can be decided by the positive scores on principal components (PCs). The PCA results indicate that the first and the fourth kind of water source appear in the deep tunnel with the continual mining activity. Mixing ratio calculations for each sampling campaign show that the first and the fourth kind of water source constitute a small proportion of the total water. The main water sources are the second and third kinds of water. Finally, water flow paths were determined based on the PCA, and rock mechanics is used to explain the change in the water flow paths after excavation. The results show the following: (1) There are several strong water diversion zones that distribute at a certain spacing interval on the large scale and (2) “zonal disintegration” is also found in the tunnel. The fractured zone and the non-fractured zone appear in turn around the tunnel. The rock mass in these two zones represents the tensile and compressive properties, respectively. Thus, volumes of water and permeability of joints and fractures in these two zones are great different.  相似文献   

内蒙古双尖子山银多金属矿床花岗斑岩年代学、地球化学特征及构造意义   总被引：2，自引：0，他引：2  

顾玉超 《地质与勘探》2017,53(3):495-507

本文对内蒙古双尖子山银多金属矿床花岗斑岩进行了锆石SHRIMP U-Pb定年,并对花岗斑岩的主量元素、微量元素组成进行了分析研究。结果显示,双尖子山花岗斑岩加权平均年龄为(133.4±1.2)Ma,为大兴安岭南段早白垩世岩浆活动集中期产物;花岗斑岩SiO_2含量为68.81%~70.05%,低MgO、TiO_2,K_2O/Na_2O为0.97~1.27,较为富钾;A/CNK在0.94~1.12之间,属准铝-弱过铝系列;富集Rb、Th、U、K等大离子亲石元素(LILE),亏损Sr、P、Ti等高场强元素(HFSE);稀土总量ΣREE中等,δEu为0.55~0.62,Eu中等负异常。本文认为双尖子山银多金属矿床为多期次叠加的岩浆热液型矿床,160Ma和133Ma可能分别是岩浆活动的两个高峰期。花岗斑岩形成于陆内晚造山期-造山期后的伸展环境,蒙古-鄂霍次克洋俯冲板片在深部断离,引发软流圈物质上涌,这是导致大兴安岭南段早白垩世岩石圈伸展环境的主要机制。  相似文献   

Compositional dual mesh method for single phase flow in heterogeneous porous media—application to CO<Subscript>2</Subscript> storage     

Dominique Guérillot  Jérémie Bruyelle 《Computational Geosciences》2017,21(5-6):949-961

Numerical simulation of fluid flow coupled with chemical reactions has been an active field in the hydrogeology community and many formulations have been programmed into different software. In recent years, this subject has attracted increasing interest in the reservoir simulation community, partly for the application of chemical methods for hydrocarbon extraction but also for research on the geological sequestration of CO₂. In this paper, an extension to the concept of dual mesh for reactive transport modeling is presented. This approach involves two meshes, a low-resolution mesh to resolve the pressure equation and a high-resolution mesh to transport the species and to calculate the geochemical equilibrium. The main objective is to preserve the fine scale heterogeneities to reach a more accurate field behavior simulation than conventional approach which consist in performing simulations on a coarser mesh. The method is applied to a simulation of CO₂ storage in the SPE10 model that keep a high resolution of the heterogeneities.  相似文献   

Understanding the triggering mechanism and possible kinematic evolution of a reactivated landslide in the Three Gorges Reservoir   总被引：2，自引：0，他引：2  

Dong Ming Gu  Da Huang  Wei Dong Yang  Ji Liang Zhu  Guo Yang Fu 《Landslides》2017,14(6):2073-2087

More than 5000 landslides or potential landslides have been induced in the Three Gorges Reservoir (TGR) region since the impoundment in 2003, which have caused great damage and remain a huge threat to the dam and people living in the reservoir area. Understanding the deformation characteristics and failure mechanism of the landslides can be helpful in stability evaluation and landslide prediction. The primary aim of this study is to research the characteristics of the landslide motion and its relationships with environmental triggers, taking the Quchi landslide, a large, slow-moving, reactivated landslide in the TGR region, as an example. The instability clearly showed visible signs of movements since 2002, and after that, the slope has been experiencing persistent deformation. By combining 4 years of meteorological, hydrological data with displacement measurements from open fractures, deep boreholes, and surface points, as well as in situ observations, this paper reports the geological and geotechnical investigations performed to define the movement. The deformation is believed to be governed by reservoir water levels, while the precipitation has a minor effect. Seasonally, the slope movement has a very distinctive pattern with large deformation starting abruptly right after reservoir drawdown in June and lasting into late summer (September). Then there is a rapid transition to constant deformation (almost no displacement) as the reservoir level rises. The slope displacements appear to gradually increase every year, which suggests very high possibility of the large and overall failure of the slide. Both monitoring results and geomorphological observations have highlighted that the two active slide masses Q1 and Q2 would probably collapse in different kinematic evolution modes, i.e., the multistage failure and whole sliding motion.  相似文献   

四川盆地中二叠统栖霞组、茅口组岩相古地理及勘探方向     

厚刚福  周进高  谷明峰  姚倩颖  杨柳  潘立银  郝毅 《海相油气地质》2017,22(1)

通过地层剥蚀关系分析,四川盆地中二叠统沉积前的古构造格局具有"三隆一洼"的特点。基于野外剖面、岩心和薄片观察,结合录井、测井相和地震相分析,明确了栖霞组和茅口组发育镶边碳酸盐岩台地沉积,包含一级台缘带、二级台缘带、开阔台地和台盆等4种亚相以及一级台缘滩、二级台缘滩、台内滩和硅质台盆等微相。栖霞组、茅口组岩相古地理受控于沉积前古构造:一级台缘带分布于古隆起与斜坡—盆地过渡地带;开阔台地分布于古隆起区和低隆起区;台盆分布于低洼区;二级台缘带分布于开阔台地和台盆之间的过渡地带。类比上二叠统长兴组和下三叠统飞仙关组油气勘探,栖霞组、茅口组台地内部的二级台缘带可作为下一步油气勘探的有利领域。  相似文献   

Three-dimensional DEM analysis of single geogrid-encased stone columns under unconfined compression: a parametric study     

Meixiang Gu  Jie Han  Minghua Zhao 《Acta Geotechnica》2017,12(3):559-572

Three-dimensional discrete element method (DEM) was employed in this study to analyze the behavior of single geogrid-encased stone columns under unconfined compression. Four important parameters were investigated to understand and evaluate their effects on the behavior of the encased columns by seven DEM models. The biaxial geogrid used as an encasement material for stone columns was simulated using parallel-bonded particles, and the aggregate in the stone column was simulated using graded particles. Both the macroscopic responses (e.g., vertical pressure–strain curves) and the microscopic interactions (e.g., contact force, coordination number, and sliding fraction) of the columns under unconfined compression were analyzed and are presented in this paper. The numerical results show that the geogrid encasement with high tensile stiffness could provide high confining stresses and then effectively increased the bearing capacity of the column. The short column yielded quickly even though its column modulus at a small deformation was relatively high. The modulus of the column slightly decreased with an increase in the column diameter due to high circumferential strains mobilized in the geogrid encasement. The column with large aggregate was stiffer and deformed less than the column with small aggregate. Selecting aggregate with a size larger than the geogrid aperture size was an effective way to achieve better interlocking between the aggregate and the geogrid and to minimize mass loss for the geogrid-encased stone column under loading. Due to limited deformation allowed by the geogrid encasement, a coefficient of radial stress equal to half of the coefficient of passive earth pressure was suggested to estimate the ultimate bearing capacity of the geosynthetic-encased stone column.  相似文献   

Theoretical analysis of the secondary development of mining-induced surface cracks in the Ordos region     

Yuankun Xu  Kan Wu  Zhihui Bai  Zhenqi Hu 《Environmental Earth Sciences》2017,76(20):703

Prior studies have indicated that mining-induced surface dynamic cracks in eastern China only undergo one “expanding-closure” development cycle. However, field measurements from the Bulianta mines of northwestern China demonstrated that ground dynamic cracks in the Ordos region went through two “expanding-closure” cycle. Using in situ measurement data and theoretical analysis, we find that the strata control theory cannot reasonably explain this special phenomenon. In this paper, we propose a novel explanation from the perspective of soil mechanics. A comparison of two field examples in eastern and northwestern China demonstrates that our theoretical explanation is in agreement with in situ observations and therefore is a reasonable interpretation for the secondary development of ground dynamic cracks in the Bulianta mines. This study provides a theoretical basis for the mechanism of mining-induced ground dynamic cracks.  相似文献   

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谷守周  秘金钟  党亚民 《大地测量与地球动力学》2010,30(2):104-108

????XPL????Ч?????????HPL??VPL??????????????????м?????????????????????HPL??VPL??????????????HPL??VPL?????????С??9 m??12 m?????????12 m??20 m?????????????????????????????????????  相似文献   

Heritability and genetic correlation of survival in turbot (Scophthalmus maximus)   总被引：1，自引：0，他引：1  

王新安  马爱军  黄智慧  周洲 《中国海洋湖沼学报》2010,28(6):1200-1205

We analyzed the survival data of the offspring from 21 sires and 42 dams of turbot. The results show that the cumulative survival rates for turbot from 2 to 18 months range from 17.5% to 28.5%; main mortality occurred during months 2–5; and the highest survival rates of families were 97.9%, 98.8%, 99.4%, 99.7% during months 2–5, 5–6, 6–8, 8–11, and 11–18, respectively, and 99.5%, being 53.5%, 23.8%, 19.5%, 14.9%, and 13.2% higher, respectively, than the mean values in each period. In all periods, the estimated heritabilities for survival were very low without significant difference from zero (P≫0.05) (values ranged from 0.06 to 0.12), indicating low additive genetic effects. The genetic correlations of survival among families in different periods were all positive, but low in magnitude (values range from 0.03 to 0.31). Genetic correlations between long-term survival and other periods’ survival had negative values (−0.06 and −0.15) and three positive values (0.16, 0.12 and 0.14). Genetic correlations between survival and weight were all positive, except for survival at months 2–5 and weight at 18 months, which was not significantly negative (−0.18).  相似文献   

欧亚大陆及西太平洋边缘海地区瑞雷波群速度结构与各向异性分布   总被引：1，自引：0，他引：1       下载免费PDF全文

顾勤平  朱介寿  康清清  程先琼  边立恩 《地震学报》2010,32(1):12-22

根据欧亚大陆及西太平洋地区102个数字化台站记录的近万次地震事件的长周期垂直向瑞雷波资料,利用时频分析方法测量并筛选后共得到11213条质量较高的基阶瑞雷波群速度频散资料.纯路径频散的反演中同时计算方位各向异性,反演获得了欧亚大陆及西太平洋边缘海地区(10°E—150°E,10°S—80°N)8—200s共28个周期的瑞雷波群速度及各向异性空间分布图象.瑞雷波高分辨率层析成像表明,30—60s周期,以青藏高原为中心呈极低速分布;100—120s周期,速度差异幅度较大,在东亚东部及西太平洋边缘海,自北向南显示出一条宽2500—4000km,长约8000km的巨型低速异常带.相对海洋来说,欧亚大陆各向异性强度较弱且快波方向较复杂.由于受到印度板块与欧亚板块的碰撞,中国大陆西部的各向异性强度明显大于东部.  相似文献