城市地下空间开发对地下水环境影响的初步研究

本文以南京地铁、玄武湖水底交通隧道为例,初步分析了玄武湖水底交通隧道对地下水环境的潜在影响。这种潜在影响主要表现在三个方面：阻滞地下水的排泄,引起地下水位的升降,诱发玄武湖水与古河道水的贯通。结果则是地下水污染加剧,城市生态环境的恶化。     

地下矿山工程围岩稳定性模糊动态聚类分区

针对梅山铁矿二期工程开拓设计的需要, 本文介绍了梅山地下矿山工程围岩稳定性模糊动态聚类分区的研究方法及其部分结果。该研究首先涉及分区资料的获取, 整理与分析；其次是分区因素的选取与指标确定；最后是模糊动态聚类分析方法在工程围岩分区中的应用。     

地下洞室动态开挖的三维数值分析及优化研究

针对云南锡业集团公司个旧锡矿地下采场洞室的开挖技术条件,采用非线性三维有限元法,对其动态开挖过程进行了数值模拟分析,并优化选择了地下采场洞室的开挖顺序和开挖跨距,从而得到一些有益的结论。     

偏压条件下大型地下厂房围岩变形稳定性分析

根据下坂地水库协力波斯电站工程建设实际,在现场调查和电站区勘探、测试资料基础上深入分析地下厂房地质条件,建立了能够反映厂区地形地貌、岩体结构和地应力状态的三维数值模型。根据地应力实测资料反演拟合初始地应力场背景值,采用三维弹塑性有限差分法模拟了在偏压条件下地下厂房、主变室开挖过程中围岩变形和稳定性状况,揭示了各开挖阶段应力的集中部位和围岩潜在破坏部位,这对于工程具有重要的指导意义。     

Influence of Different Redox Conditions on the Biodegradation of the Pesticide Metabolites Phenol and Chlorophenols

Abstract

The fate and behaviour of phenol and monochlorophenols during bankfiltration and underground passage with variable redox conditions were investigated. A model ecosystem was used consisting in laboratory filter columns filled with natural underground material and operated with natural aerobic and anaerobic groundwater to create different redox situations.

The test substances (phenol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol) were added continuously to the infiltrating water and their concentration in the filter effluents determined. Beside the redox conditions other factors known to affect microbial degradation processes like the substrate concentration and the underground material were varied stepwise.

Phenol was degraded under both, aerobic and anaerobic conditions. The presence of oxygen is more favourable to degradation; no lag phase was observed under aerobic conditions. In a sulfate reducing environment, phenol could only be degraded after microbial adaptation. The length of the lag phase was strongly influenced by the substrate concentration and the undergroundmaterial. Prior contact with phenol resulted in a shorter lag phase.

Monochlorophenols behaved almost persistent in the model system. Degradation could only be observed in a test filter that provided a more active microbial population due to prior adaptation to phenol and a more favourable underground material.     

加油站地下储运设备阴极防蚀之研究

加油站的地下金属结构物除地下储运设备外 (油管与油槽 ) ,地表尚有钢筋混凝土结构 ,且混凝土中的钢筋常与地下储运设备相搭接而造成彼此间的电通性 ;由于地下储运设备的包覆阻抗多大于混凝土阻抗 ,以致在进行阴极保护时 ,保护电流较易由钢筋流过 ,造成储运设备的保护电位不足 .本研究使用外加电流式阴极保护法进行加油站的阴极防蚀 ,讨论钢筋与地下储运设备搭接或未搭接时的防蚀效果 .结果显示 ,在加油站内进行阴极保护电位评估时 ,若只采用 - 85 0mV作为保护评估标准 ,可能会产生误判结果 ,应当使用电流断电器量测结构物在阴极保护下的极化量 ,方能正确判断保护效果     

分光光度法测定地表水和地下水中的6价铬

采用氯化钠、氨基磺酸、二苯碳酰二肼固体混合试剂,以分光光度法测定水中6价铬。方法检出限为0.004mg/L。对实际水样进行连续5次测定,方法精密度为4.2%—6.2%,回收率为90.0%—95.0%。经国家标准物质验证,结果与标准值相符。方法快速、准确,显色试剂可保存1年。     

An extension to rapid transit network design problem

The rapid transit network design problem consists of the location of train alignments and stations, in a context where the demand makes its own decisions about the mode and route. The originality of this study is to incorporate in the model the line locations constraints with a bounded but variable number of lines, and lines with no predetermined origins and destinations. The computational experiments show the necessity of this extension to solve large networks, principally because of its computational advantage. The project has been supported by Ministerio de Educación y Ciencia (Spain) under project TRA-2005-09068-C03-01/MODAL, and by Ministerio de Fomento (Spain) under project 2005/70029/T05.     

“Tepid” Geysers above salt cavernsGeysers tièdes au-dessus des cavités salines

The formation of a brine geyser erupting from the wellhead of a large underground salt cavern is described. In most cases, the brine outflow from an opened cavern is slow; it results from the cavern creep closure and the thermal expansion of the cavern brine. These two processes are smooth; however, the brine outflow often is bumpy, as it is modulated by atmospheric pressure variations that generate an elastic increase (or decrease) of both cavern and brine volumes. In addition, when the flow is fast enough, the brine thermodynamic behavior in the wellbore is adiabatic. The cold brine expelled from the cavern wellhead is substituted with warm brine entering the borehole bottom, resulting in a lighter brine column. The brine outflow increases. In some cases, the flow becomes so fast that inertia terms must be taken into account. A geyser forms, coming to an end when the pressure in the cavern has dropped sufficiently. A better picture is obtained when head losses are considered. A closed-form solution can be reached. This proves that two cases must be distinguished, depending on whether the cold brine initially contained in the wellbore is expelled fully or not. It can also be shown that geyser formation is a rare event, as it requires both that the wellbore be narrow and that the cavern be very compressible. This study stemmed from an actual example in which a geyser was observed. However, scarce information is available, making any definite interpretation difficult.     

A Study of the Suitable Measurement Location and Metrics for Assessing the Vibration Source Strength Based on the Field-Testing Data of Nanchang Underground Railway

Underground railway vibration source strength is one of the key values used for environmental impact assessment and the evaluation of mitigation measure’s performance. However, currently there is no international standard of measuring the underground railway vibration source strength for such purposes. The available local standards and industrial guidelines do not agree on measurement locations as well as the metrics for presenting the source strength. This has caused many confusions. This paper aims to study the suitable measurement location and metrics using the data from a large scale field-testing carried out at the Nanchang underground railway (Metro Line 1, China) in 2017. 200 passing trains were recorded during the test at two different sections of the railway line, one with the spring floating slab installed and the other without. Three locations were chosen at each section, including one in the middle of the track and two on the tunnel wall at different heights. Based on the results of statistical analysis, the maximum of z-weighted vertical vibration level (VLzmax) obtained at a lower measurement location on the tunnel wall is the best for representing the underground railway vibration source strength, which is 76.66 dB obtained from this study.