Limiting drainage criterion for groundwater of mountain tunnel

Large amount of groundwater discharging from tunnel is likely to cause destruction of the ecological environment in the vicinity of the tunnel, thus an appropriate drainage criterion should be established to balance the tunnel construction and groundwater.To assess the related problems, an limiting drainage standard ranging from 0.5 to 2.0 m3/（m·d） was suggested for mountain tunnels based on survey and comparative analysis. After that, for the purpose of verifying the rationality of the standard, a calculated formula for dewatering funnel volume caused by drainage was deduced on the basis of the groundwater dynamics and experience method.Furthermore, the equation about the relationship between water discharge and drawdown of groundwater table was presented. The permeability coefficient, specific yield and groundwater table value were introduced, and then combined with the above equation, the drawdown of groundwater table under the proposed limiting drainage criterion was calculated. It is shown that the proposed drainage standard can reach the purpose of protecting ecological environment under the following two conditions. One is the permeability coefficient ranges from 10-4 to 10-5 m/s and the specific yield ranges from 0.1 to 0.001. The other is the permeability coefficient varies from 10-6 to 10-8 m/s and the specific yield varies from 0.1 to 0.01. In addition, a majority of common geotechnical layers are involved in the above ranges. Thus, the proposed limiting drainage standard which ranges from 0.5 to 2.0 m3/（m·d） for mountain tunnel is reasonable.     

长沙某基坑支护工程设计与施工技术

分析了基坑支护几种方案的优缺点,分别介绍了长沙某办公楼深基坑支护工程的设计及施工情况,并对支护结果进行了监测和效果评价。     

Enhanced 1.32 µm fluorescence and broadband amplifying for O-band optical amplifier in Nd3+-doped tellurite glass

WO3 oxides with relatively high phonon energy and different concentrations were introduced into the Nd3+-doped tellurite-based glasses of TeO2-ZnO-Na2O to improve the 1.32 µm band fluorescence emission. The absorption spectra, Raman spectra, 1.32 µm band fluorescence spectra and differential scanning calorimeter (DSC) curves were measured, together with the Judd-Ofelt intensity parameters, stimulated emission and gain parameters were calculated to evaluate the effects of WO3 amount on the glass structure and spectroscopic properties of 1.32 µm band fluorescence. It is shown that the introduction of an appropriate amount of WO3 oxide can effectively improve the 1.32 µm band fluorescence intensity through the enhanced multi-phonon relaxation (MPR) processes between the excited levels of Nd3+. The results indicate that the prepared Nd3+-doped tellurite glass with an appropriate amount of WO3 oxide is a potential gain medium applied for the O-band broad and high-gain fiber amplifier.     

洞庭湖区软土地基加固处理方案对比研究

采用强夯法、真空预压排水固结法、动力排水固结法对洞庭湖区一场地进行了加固处理,通过对处理后场地各项参数指标的对比研究,得出动力排水固结法处理软粘土地基是行之有效的方法,达到了预期的效果。此种软基处理方案既经济又合理,同时又满足了施工工期要求,可为类似工程提供有价值的参考。     

Enhancement of 2.0 µm fluorescence emission in new Ho3+/Tm3+/Yb3+ tri-doped tellurite glasses

For enhancing the 2.0 µm band fluorescence of Ho3+, a certain amount of WO3 oxide was introduced into Ho3+/Tm3+/Yb3+ tri-doped tellurite glass prepared using melt-quenching technique. The prepared tri-doped tellurite glass was characterized by the absorption spectra, fluorescence emission and Raman scattering spectra, together with the stimulated absorption, emission cross-sections and gain coefficient. The research results show that the introduction of WO3 oxide can further improve the 2.0 µm band fluorescence emission through the enhanced phonon-assisted energy transfers between Ho3+/Tm3+/Yb3+ ions under the excitation of 980 nm laser diode (LD). Meanwhile, the maximum gain coefficient of Ho3+ at 2.0 µm band reaches about 2.36 cm-1. An intense 2.0 µm fluorescence emission can be realized .     

生物脱氮技术在处理氨氮废水的最新研究进展

文章介绍了利用微生物治理水体氮源污染的基本原理、主要工艺及其在处理氨氮工业废水的研究现状和最新研究进展。在此基础之上,针对新型的生物脱氮工艺(例如厌氧氨氧化工艺)特点,指出在处理含氨氮工业废水时需要考虑不同来源废水的水质和水量特点,选择合适的生物脱氮工艺处理水中的氮源污染。     

长沙地铁勘察水文地质条件的研究

本文通过对长沙地铁一号线某标段勘察的水文地质资料的分析,对下一步该段长沙地铁工程建设的隧道施工提出了建议。     

浅谈水泥混凝土施工质量控制的措施

水泥混凝土作为建筑材料的重要形式之一,具有强度高、经久耐用、养护费用低等优点.然而,就全国水泥混凝土的使用状况而言,仍存在许多问题.水泥混凝土最常用做路面,下面就以路面为例谈谈水泥混凝土的施工质量控制的措施.     

基于MPPT的太阳能照明控制器研究

采用四组磷酸铁锂电池作为储能元器件,提出了一种带MPPT功能的智能太阳能照明控制方法.系统以ARM7LPC2103芯片为控制核心,对四组磷酸铁锂电池巡回智能充放电,并给出了其充放电的软件控制流程图.系统采用扰动观察法对太阳能电池板进行了最大功率跟踪,并且对其建模仿真,运行结果良好,最后对系统进行了调试.系统运行结果表明,该控制器比传统的控制器拥有更好的实用价值,利用率高.