山东省菏泽凸起地热田岩溶地热水水化学水平演化特征

在前人研究成果的基础上,选择A-A'和B-B'两条路径,采用Piper三线图解、Schoeller图解、Na-K-Mg平衡图解、饱和指数计算评价等方法,研究山东菏泽凸起地热田地热水沿路径上的循环演化特征.结果表明:沿A-A'、B-B'剖面岩溶冷水→岩溶热水,水化学类型由SO4?HCO3-Ca?Mg?Na或SO4?HCO...     

商丹断裂带(河南段)构造变形特征及其找矿意义

商丹断裂带是一条多期次活动的大型断裂带,区域上也是大型金属矿的赋存带,对金属矿产具有重要的控制作用.文章以商丹断裂带(河南段)为研究对象,在基于孔沟至寨根一带构造剖面的宏观特征和显微构造特征解析的基础上,对研究区控矿构造和机理提出了新的认识.综合研究表明,商丹断裂带(河南段)具多期活动特征,整体呈现"正花状构造"样式....     

酒东盆地地温场特征及肃州城区地热开发可行性分析

酒东盆地是典型挤压造山型盆地,在以往石油勘探和水文地质普查中已发现有地下热水存在。肃州城区一带通过可控源音频大地电磁测深探测和石油普查直流电测深资料重新解释,结合以往石油勘探成果,认为酒泉凹陷具备地热资源形成的储、盖、通、源条件,属中低温盆地传导型地热资源,具有经济开发价值。     

论直流激发极化法的视电阻率参数

直流激发极化法,计算视电阻率的一次场采集于供电方波的末端时间,从而包含了被激发形成的二次场。在高极化率地质体上,得到的视电阻率将削弱其低阻特性或放大高阻特性。为此,建议在野外工作中,应对所采集的一次场作适当的处理后,再计算视电阻率,以降低这种影响。     

Explicit integration of a porosity‐dependent hydro‐mechanical model for unsaturated soils

An adaptive substepping explicit integration scheme is developed for a porosity‐dependent hydro‐mechanical model for unsaturated soils. The model is referred to as the modified σ –Θ model in this paper, which features the employment of the subloading surface plasticity and the stress–saturation approach. On numerical aspects, convex/nonconvex subloading surfaces in the σ –Θ space may result in incorrect loading–unloading decisions during the integration. A new loading–unloading decision method is developed here to solve the problem and then embedded into the explicit integration scheme for the modified σ –Θ model. In addition, to enhance the accuracy of the explicit integration, local errors from both hydraulic and mechanical components are included in the error control for each substep. A drift correction method is also developed to ensure the state point lies on the subloading surface in the σ –Θ space within a set error level. The performance of the loading–unloading decision method for the modified σ –Θ model is discussed through comparing it with the conventional loading–unloading decision method. The importance of involving the hydraulic component in the error control is also demonstrated. The accuracy and efficiency of the proposed adaptive substepping explicit integration scheme for the modified p–Θ model are also studied via several numerical examples. Copyright © 2016 John Wiley & Sons, Ltd.     

Consolidation in spatially random unsaturated soils based on coupled flow‐deformation simulation

This paper integrates random field simulation of soil spatial variability with numerical modeling of coupled flow and deformation to investigate consolidation in spatially random unsaturated soil. The spatial variability of soil properties is simulated using the covariance matrix decomposition method. The random soil properties are imported into an interactive multiphysics software COMSOL to solve the governing partial differential equations. The effects of the spatial variability of Young's modulus and saturated permeability together with unsaturated hydraulic parameters on the dissipation of excess pore water pressure and settlement are investigated using an example of consolidation in a saturated‐unsaturated soil column because of loading. It is found that the surface settlement and the pore water pressure profile during the process of consolidation are significantly affected by the spatially varying Young's modulus. The mean value of the settlement of the spatially random soil is more than 100% greater than that of the deterministic case, and the surface settlement is subject to large uncertainty, which implies that consolidation settlement is difficult to predict accurately based on the conventional deterministic approach. The uncertainty of the settlement increases with the scale of fluctuation because of the averaging effect of spatial variability. The effects of spatial variability of saturated permeability k_sat and air entry parameters are much less significant than that of elastic modulus. The spatial variability of air entry value parameters affects the uncertainties of settlement and excess pore pressure mostly in the unsaturated zone. Copyright © 2016 John Wiley & Sons, Ltd.     

Preliminary 3–D geological model of the Kalgoorlie region,Yilgarn Craton,Western Australia,based on deep seismic‐reflection and potential‐field data

The granite‐greenstone terranes of the Eastern Goldfields Province, Yilgarn Craton, Western Australia, are a major Australian and world gold and nickel source. The Kalgoorlie region, in particular, hosts several world‐class gold deposits. To attempt to understand why these deposits occur where they do, it is important to understand the crustal architecture in the region and how the major mineral systems operate in this architecture. One way to understand these relationships is to develop a detailed 3–D geological model for the region. The best method to map the 3–D geometry of major geological structures is by acquisition and interpretation of seismic‐reflection profiles. To contribute to this aim, a grid of deep seismic‐reflection traverses was acquired in 1999 to examine the 3–D geometry of the region in an area including the Kalgoorlie mineral region and mineral fields to the north and west. This grid was tied to the 1991 regional deep seismic traverse and 1997 high‐resolution seismic profiles in the same region. The grid covers an area measuring approximately 50 km wide by 50 km long and extended to a depth of approximately 50 km (below the base of the crust in this region). The resulting 3–D geological model was further constrained by both surface geological data and geophysical interpretations, with the seismic interpretations themselves also constrained by gravity and magnetic modelling. The 3–D model was used to investigate the geometric relationships between the major faults and shear zones in the area, the relationship between the granite‐greenstone succession and the basement, and the spatial relationships between the greenstones and the granites. Interpretation of the grid of seismic lines and construction of the 3–D geological model confirmed the existence of the detachment surface and led to the recognition that the granite‐greenstone contact usually occurs at a much shallower level than the detachment. Also, west‐dipping faults in the vicinity of the Golden Mile, including the Abattoir Shear through to Boulder‐Lefroy Fault, appear to be more important than previously thought in controlling the structure of that area. An antiformal thrust stack occurs beneath a triangle zone centred on the Golden Mile. The Black Flag Group was deposited in a probable extensional setting, and late extension was also probably more important than previously thought. The granite‐gneiss domes were uplifted by the formation of antiformal thrust stacks at depth beneath them.     

Application of FY-2C Cloud Drift Winds in a Mesoscale Numerical Model

Statistical tests and error analysis of cloud drift winds(CDWs) from the FY-2C satellite were made by using radiosonde observations.According to the error characteristics of the CDW,a bias correction using the thermal wind theory was applied in the data quality control.The CDW data were then assimilated into the GRAPES-meso model via the GRAPES-3DVar.A torrential rain event that occurred in northwestern China during 1-2 July 2005 was simulated.The results indicate that the CDW data were mainly distribute...     

Response of seismically isolated structures to rocking‐type excitations

In this paper, the origin of rocking‐type excitations and their effects on the response of base isolated structures are studied. In particular, the role of kinematic interaction in the determination of the rocking excitation is highlighted. The cases of surface foundations subjected to horizontally propagating waves, as well as of embedded foundations under vertically incident shear waves are examined. The validity of the kinematic interaction based on the rigid base mat assumption is discussed. It is shown that, in the case of classical horizontal isolation, rocking input may amplify significantly the response of the lower non‐isolated modes. The examination of full three‐dimensional isolation and active and semi‐active control methods demonstrates the efficacy of these methods to improve the performance of seismically isolated structures subjected to rocking excitations. Copyright © 2009 John Wiley & Sons, Ltd.     

三峡水库汛期控制水位及运用条件

随着长江上游梯级水库的陆续建成投运，三峡水库的水文情势和功能需求与设计条件相比发生了显著变化，仍维持固定的汛限水位运行已不能适应新形势需求。本文通过辨析三峡水库设计阶段汛限水位的设置条件，挖掘流域洪水特性和洪水遭遇规律，论证三峡水库汛期运行水位动态控制的可行性。结果表明：① 三峡水库设计推求的汛限水位145 m的适用条件是应对流域性大洪水，而流域性洪水发生概率小且特征明显，可以通过水文水情分析提前预判。② 根据流域洪水类型、洪水分期和遭遇规律，预判发生区域性大洪水时，三峡水库6月初至梅雨期结束汛限水位按145 m设置，从梅雨期结束后逐渐提高水位，8月20日后过渡到155 m。③ 在考虑上游水库群联合调度和气象水文预报的配合下，正常年份三峡水库汛期运行水位可在155 m上下浮动，并考虑提前蓄水。④ 三峡水库汛期运行水位动态控制，不会增加防洪风险和库区淤积风险，对中下游江湖关系和水文情势有利，可显著提高发电、航运、生态保护和供水等综合利用效益。