Swelling behavior induced by alteration in granite and its implications on underground excavation

Granite is commonly recognized as an ideal medium for underground construction. However, in the site investigation for Heimifeng Pumped Storage Power Station project, it was found that there are swelling behaviors induced by alteration in granite and eventually causing slaking and disintegration of rock blocks. The study shows that hydrothermal alteration in granite is primarily due to the intrusion of multi-phase igneous magma. The clay minerals, such as montmorillonite, chlorite, kaolinite, are the main causes for the swelling behavior of granite. In the exploratory adits, alteration was observed to occur mainly along faults or fractures in the rock masses and resulted in roof caving if water is present. Some of the highly altered borehole cores swell and crack within 24 h in water and eventually disintegrate completely. From the testing results on the samples, the maximum axial free swelling strain is about 1.2%, while the maximum axial confined swelling strain is around 0.1% with swelling stress less than 25 kPa. Under free swelling tests, 80% of swelling is completed within 24 hours. Under confined swelling condition, swelling process is completed within 1 h for some samples, with 80% of maximum swelling strain finished within around 22 h for most of the samples. Contraction of samples occurs after swelling completed. The strength of granite, reflected by deformation and elastic moduli, shear strength, decreases due to alteration. The deformation and elastic moduli are even lower compared to highly weathered rock. The shear strength is between that for highly weathered and slightly weathered rocks. The swelling characteristics of the altered rock present great challenges for support or lining during construction and operation stages. Support or lining shall be in place immediately after excavation. Since the rock may swell when encountering water, the shotcrete shall be designed accordingly. During the construction of access tunnel and caverns, water shall be drained in time. Drainage directly from surface shall be avoided so as to prevent floor heave.     

基于RVA法的河流生态需水量研究

以河流生态水文变化的指标体系（Indicator of Hydrologic Alteration,IHA）为基础,立足整体河流水文情势的流量谱系,采用变异性范围法（Range of Variability Approach,RVA）,进行基于长系列历史流量资料的河流生态需水量估算,并以山西省5条较大河流的生态敏感断面为对象进行研究。结果表明,利用本方法估算的结果是合理的,可为河流生态需水量的估算和水资源的可持续开发利用提供科学依据。     

A Histogram Matching Approach for assessment of flow regime alteration: application to environmental flow optimization

In this paper we present a Histogram Matching Approach (HMA) for assessment of the flow regime alteration. The HMA uses the degree of histogram dissimilarity as a metric for impact assessment, which is based on the quadratic‐form distance between the frequency vectors of the pre‐ and post‐impact histograms weighted by a specified similarity matrix. The HMA is coupled with an aggregated multiobjective optimization genetic algorithm and applied to a case study on the Kaoping diversion weir (Taiwan) for determining the optimal environmental flow scheme that balances the ecosystem and human needs objectives. Two key issues are addressed in this study. First, we compare the performances of the HMA and existing Range of Variability Approach (RVA). Second, we employ three types of similarity function to investigate their effect on the outcomes of the HMA. The results reveal that the HMA consistently outperforms the RVA in preserving the natural flow variability regardless of what type of similarity function is used. No single type of similarity function can be found that would simultaneously best preserve the natural patterns of 32 Indicators of Hydrologic Alteration (IHA). For the situations where the water‐supply reliability is of critical concern, the pulse similarity is recommended because it would assure the smallest water‐supply deficit. If, however, minor degradation in the water‐supply reliability may be overlooked, the linear similarity is suggested because it would generally result in the post‐impact flows that most satisfactorily resemble to the natural flow regime. Copyright © 2008 John Wiley & Sons, Ltd.     

基于IHA/RVA法的修水流域上游大型水库影响下的枯水变异研究

根据水文变异指标法及变化范围法(IHA/RVA),对江西修水流域上游两个大型水库启用日期差异进行组合,定量计算、分析了水利工程影响下的修水流域上游枯水流量的时序变异特征,探讨了水利工程建设前后导致的水文变异程度,揭示了对河流生态系统至关重要的低流量范围内多个枯水情势高改变度的存在,为水库生态调度与河流生态保护提供了有益的参考。     

A method for operational calibration of AVHRR reflective time series data

We have developed an automatic method to monitor the AVHRR instrument sensitivity over time in the short-wave reflective channels to ensure that trends in the data series obtained by this instrument are real and not sensor artefacts.Our radiometric calibration method uses the Multivariate Alteration Detection (MAD) algorithm to statistically select invariant features over land areas from multiple image-pairs that are compared to assess changes in the instrument's calibration. This method requires no a priori regional knowledge and is globally applicable. A calibrated time series from Pseudo-Invariant Features located in central Australia are shown to have long-term trends removed. The resulting MAD-based calibration has a root mean squared error of ∼ 5-6% for both channels 1 and 2 and is in alignment with other approaches.     

设计与实现 2010年上海世博会中国馆蜕变之路

中国2010年上海世博会的中国馆从设计到建成,历经多次变更。本文试图考察中国馆在设计和建造过程中经历的若干重要变更,以反映其真实的设计实现过程。     

Permeability and alteration within the Soultz granite inferred from geophysical and flow log analysis

The 1993 stimulation tests carried out in well GPK1 at Soultz, Alsace, France, showed that out of the thousands of fractures cross-cutting the granite, only a limited number of natural fractures contributed to fluid flow. A comparison between the petrophysical properties of the rock and the interpretation of the hydraulic test results is proposed as a means of determining the distribution of the natural permeable fractures. Gamma-ray spectral logs and other geophysical logs (caliper, bulk density, P-wave slowness, and photoelectric factor) revealed some petrographical variations within the Soultz massive granite, as well as altered/fractured zones that act as preferential pathways for fluid flow as indicated by flow logs. Fluid losses during circulation tests have been estimated on the basis of statistical analysis of gamma-ray readings, and of potassium and thorium contents.     

磷矿共生含钾页岩特征及蚀变法浸钾过程

本文测试和计算了磷矿底板共生的含钾页岩的化学成分、矿物成分，并研究了钾的赋存状态。从天然浸钾过程得到启示，在热力学、晶体结构和反应动力学等三个方面研究了蚀变法的浸钾过程。浸钾后的副产品可作为优良的陶瓷原料。     

入世后的政企关系

传统上我们一直把政府视为管理者，然而，我国加入世界贸易组织以后，在经济全球化的今天，政府的职能定位发生了根本性转变，政府变成了服务的提供者，企业则是市场经济的微观主体，政府的基本职能就是为企业服务。     

因势利导合理优化--重庆大学医学研究院教学医院规划及设计侧记

以重庆大学医学研究院教学医院这一在原有建筑基础上的改建工程为例.阐述了在"因势利导,合理优化"的设计原则指导下,工程的选址、规划和建筑设计以及细部设计过程中的一些设计方法.