Temporal variation in discharge chemistry and portal flow from the 8-Level adit, Lynx Mine, Myra Falls Operations, Vancouver Island, British Columbia

The Lynx mine, currently inactive, has produced copper and zinc concentrates from massive sulfide deposits on a lease within the rainy, mountainous interior of Vancouver Island. Tailings, used to back-fill a mined-out stope, are being leached by percolating groundwater and the resulting acidic, metal-laden drainage is discharging from the portal of the 8-Level adit. Temporal variations in the flow rate, specific conductance and temperature of the discharge were monitored continuously over a 2-year period while effluent chemistry was sampled weekly. Conductivity was relatively constant throughout most of the year but peaked with the first autumn storm events as accumulated soluble sulfide oxidation products were flushed from the workings. Concentrations of sulfate and most metals were closely correlated with conductivity as were low pH values as stored acidity was released along with dissolved species. Variations in pH controlled the speciation and partitioning of metals between dissolved and particulate phases.     

CM桩复合地基承载力试验结果分析

通过对“CM桩复合地基”(以下简称CM地基 )承载力试验结果的分析 ,获得了一些有益的结论 ,对其在徐州地区的推广和应用提供参考。     

利用ERT数据推求非均质多孔介质渗透系数初探

高密度电阻率成像法（ERT）能通过改变间距来对不同尺度上的地质体特征进行描述，近年来广泛地应用于地质、工程等领域。本文从电流场和渗流场的相似性出发来研究电阻率和渗透系数之间的关系，简要介绍了利用ERT技术所得的电阻率数据推求渗透系数的基本原理，并利用张家港大新和塘桥两处的ERT测量数据推求出渗透系数。与两地抽水试验结果和岩性取样分析的结果分别进行对比，结果较为吻合。     

粉质粘土中的桩承载性能分析

应用桩静载荷试验和数学分析的方法,对粉质粘土层中的桩的承载性能进行分析研究。结果显示,粉质粘土层中的桩的侧摩阻力标准值为37.6kPa,桩的端阻力标准值可达3.34M Pa,位于粉质粘土层中的桩端阻力占桩承载力的50%±,桩为端承摩擦桩,而非纯摩擦桩,且桩的承载力较高,沉降变形小,可以满足一般建筑物的荷载需求,设计时应充分挖掘该土层的潜力。     

Mercury anthropogenic loadings vs. mercury levels in fish： Baihua Reservoir as an exemplary case study

It is still disputed in the scientific community whether it is possible to trace a direct link or even proportionality between mercury （Hg） anthropogenic loadings to lake ecosystems and resulting methylmercury （MeHg） levels found in fish tissues. We present here the exemplary case of the Baihua Reservoir, located on the Maotiahoe River, near Guiyang （Guizhou, China）. Baihua was impacted for many years by Hg-contaminated effluents from industrial source. While sedimentary profiles exhibit extreme enrichment in sedimentary Hg burden, fish species harvested from the reservoir still present low Hg levels. Thus we propose here that in the case of Hg, loading does not tell it all and one must take it into account the net methylation capacity of lake ecosystems and its ability to efficiently bioaccumulate MeHg along the trophic web.     

Fluctuation responses of saturated porous media subjected to cyclic thermal loading

Normalized, coupled governing equations for one-dimensional thermal consolidation problems are established. The non-dimensional coefficients of thermal consolidation and thermal diffusivity are defined accordingly. An analytical solution is deduced by using the Laplace transform and the Gauss–Legendre method of Laplace transform inversion. The responses of saturated porous media subjected to cyclic thermal loading are studied. The evolution of temperature, pore pressure and displacement from instantaneous state to quasi-steady state, with elapsed time, are analysed. The characteristics of cyclic fluctuation and the attenuation of the field variables with increased depth are also analysed. The influences of the permeability of media on thermal responses are discussed.     

Can the diffuse double layer theory describe changes in hydraulic conductivity of compacted clays?

Observations related to modifications of the hydraulic conductivity of compacted soils as a consequence of intentional compositional variation of the percolating fluid are often attributed vaguely to calculated changes in double layer thickness. The same calculated decrease or increase in double layer thickness is interpreted differently, depending on which (unconsciously held) boundary conditions authors take into account. The interpretations of different authors seem to be paradoxical only if the boundary conditions have not been mentioned. On the basis of a literature survey and own previously published test results the different boundary conditions have been grouped and divided into classes. With this division the interpretation of changes in double layer thickness will lead to unique interpretations and predictions of changes in hydraulic conductivity.     

In Situ Pore Water Pressure Dissipation Testing of Marine Clay under Reclamation Fills

In situ dissipation tests provide a means of evaluating the in situ coefficient of horizontal consolidation and horizontal hydraulic conductivity of soft clays. Dissipation tests by means of piezocone (CPTU), dilatometer (DMT), self-boring pressuremeter (SBPT) and BAT permeameter (BAT) were utilized in the characterization of the coefficient of horizontal consolidation and horizontal hydraulic conductivity of Singapore marine clay at Changi in a land reclamation project. Dissipation tests were carried out prior to reclamation as well as after ground improvement with vertical drains to compare the changes in the coefficient of horizontal consolidation and horizontal hydraulic conductivity prior to and after ground improvement. Tests were carried out in a vertical drain area as well as in an adjacent untreated control area after 23 months of surcharge loading, for comparison purposes. The purpose of this research is to determine the horizontal consolidation parameters of Singapore marine clay prior to reclamation as well as after 23 months of surcharge loading with and without vertical drains by means of in situ dissipation tests.     

Emplaced Geotechnical Characteristics of Hydraulic Fills in a Number of Australian Mines

Hydraulic fills used in Australian mines have similar grain size distributions whilst having quite different specific gravity values, typically in the range of 2.7–4.4. When produced and distributed in slurry at 65–75% by solid content, they settle to produce fills with similar geotechnical characteristics. The fills under investigation have been found to settle, in the laboratory, to a dry density of about 0.56 × specific gravity, a saturation water content of about 17–34%, and a porosity of 37–49%. A quick estimate of the optimum water content that gives the minimum porosity may be obtained by locating the intersection of the saturation curve and minimum porosity line, which may simply be done on a water content vs. porosity plot. However, transportability of the slurry requires it to be mixed at water content substantially greater than the optimum water content. As the tailings settle out of suspension, they settle to relative density of 50–80%. This paper shows that the current empirical relationships relating relative density and N-value to friction angle for sands will significantly underestimate the friction angle of the hydraulic fills. Based on limited experimental data, a unique relationship between relative density and friction angle is proposed for hydraulic fills placed in some Australian mines.     

Hydrologic and hydraulic characteristics of the Yellow River and impact of flow and sediment diversion

In the history, the Yellow River nurtured Chinese civilization. It is respected as the ＂ancestor of the four large rivers in China＂ and praised as ＂the mother river of China＂. At the same time, the Yellow River is regarded as ＂the misery of China＂ and considered as the most complex river hard to control in the world. Today, the Yellow River is also one large river greatly influenced by human activities in the world. The safety of the Yellow River, particularly flood control, is always the most important issue for governing and developing the country. Great achievements have been made after many years of efforts for controlling the Yellow River. However, since the nineties of 20 century, some new problems occurred, such as sharp reduction of flux to sea, dry rivercourse, worsen environment, etc. Rapidly shrinking riverbed and two-level perched stream are disadvantageous to flood safety especially. The new concepts and new practices are urgently needed to control the river. Therefore, the Yellow River Conservancy Committee of Ministry of Water Resources had continuously carded out flow and sediment diversion each year from 2002 to 2005. To timely probe into the new issues produced after flow and sediment diversion, and in order to deepen the understanding of rules for the Yellow River＇s water and sediment and provide reference and experience to the researchers for other large rivers, five hydrologic and hydraulic characteristics of the Yellow River, such as lack of water, much of sediment, different resources of water and sediment, inconsistency between water and sediment and frequency of sink switching and route changing, are described. Flow and sediment diversion of the Yellow River is also reviewed. Under flow and sediment diversion,