变形模量Ev2在京沪高铁路基检测试验中的应用

变形模量Ev2通过承载板和加载装置对地面进行第一次加载和卸载后再进行第二次加载,用第二次加载测得的承载板下的应力σ0和与之相对应的沉降量S计算变形模量Ev2值,可以认为第二次加载测得的沉降消除了塑性变形。测试结果更能反映路基土的真实强度。因Ev2与路基弹性模量较接近,是一种压实的理想状态,故常把其作为路基检测的一项重要指标。     

路基基床底层填筑工艺性试验

本文结合工程实例,就基床底层填料碎石物理改良进行了工艺性试验,得到了在掺入27%-30%碎石情况下,其压实标准n、Ev2、Evd、K30均能全部满足客运专线铁路路基工程施工质量验收暂行标准规定和设计要求的结果,可供相关单位参考.     

高填方路基施工强夯法关键施工技术探讨

结合昆明禄(劝)—大(松树)公路工程中一工区K25+460～K25+560处填方路段路基采用的强夯施工技术,研究其强夯工法和夯沉值控制要点,采用此法使填方土体的干密度和压实度达到规范和设计要求,可应用于填筑高填方路基施工的加固及补强。实践证明,该法对路基加固的效果较好,能避免后期发生路基变形,可为今后此类工程施工提供借鉴。     

土石混填路基连续压实质量检测

评价土石混填路基压实质量时,针对现有评价方法不足基于振动压路机与路基填料的动态相互作用原理,通过对传感器采集的压路机振动轮竖向振动信号进行处理,把压实度值(CMV)作为评价路基压实质量的指标,用于实时评价路基压实质量。采集土石混填路基不同摊铺厚和不同碾压遍数下的回弹模量和CMV数据,结合数据变化规律对数据进行筛选修正,并对比分析筛选前后CMV与回弹模量的相关性程度,结果表明,不同碾压遍数下的CMV数据具有明显的变化规律,利用其变化规律可有效筛选CMV数据。     

土石坝压实质量连续检测指标影响因素分析

为了提高土石坝碾压中连续压实控制技术的适用性,设计并开展了3项现场试验,研究了振动碾压时的激振力、行进速度引起的连续检测指标CMV、CCV、Ks和VCV的测值偏差,采用线性回归分析方法研究了强、弱振工艺对不同类别连续检测指标相关性校验的影响规律,并分析了连续检测指标测值与碾压遍数之间的相关性,进而给出了土石坝连续压实检...     

高液限土路基掺沙改良路用特性试验

为了研究高液限土路基掺沙改良的长期水稳定性和强度特性,以最大干密度、界限含水率、浸水CBR强度值作为路用特性分析的控制参数,进行室内试验和现场试验。依据不同掺沙量和压实度条件下各控制参数的变化规律确定最优掺沙比;在最优掺沙条件下,进一步分析路用水稳定性与施工控制参数,即含水率、压实度、击实功的变化规律,获得水稳定性和强度兼顾的施工参数最佳组合。试验表明,以空气率和饱和度作为路基施工质量检测双指标控制方法,可以弥补现行规范仅以压实度作为单一质量评价标准的不足。     

马平高速公路路基土承载比（CBR值）试验及质量控制

青海省马平高速公路路基施工过程中成功的运用了CBR值试验技术,此技术与传统的压实度控制路基施工质量相比,采用通过试验,提前掌握土的压实度与土的承载力间的关系,应用于施工中,取得了较好的效果。     

水电工程进场公路路基压实质量实时监控系统

针对水电工程进场公路路基碾压质量控制的要求,研制开发了基于GPS技术、GPRS技术和计算机网络技术的进场公路路基压实质量实时监控系统。通过在压路机上安装高精度GPS接收机和压实及振动监测装置,在碾压过程中自动采集压路机位置坐标、振动频率及压实监测值(CV),在监控客户端实时绘制、显示和查询碾压轨迹、振动频率和CV值,当振动状态不达标时,实时报警。该系统克服了人为粗放控制的弊端以及事后有限抽检存在的偏差,实现了施工过程中对碾压轨迹的精细控制。     

地基系数K30在京沪高铁中的应用

地基系数K30是表示路基表面在平面压力作用下产生的可压缩性的大小。K30作为一种抗力指标,能够直观地表达路基刚度和承载能力,物理意义明确,与传统的物理指标相比具有明显的优越性。     

水电站公路路基施工技术

一、路基填料与压实 公路路基的强度和稳定性很大程度取决于路基填料的性质及其压实的程度。从现有条件出发,改进填料要求和压实条件是保证路基质量最有效和最经济的方法。路基填料。规范规定了对路基填料应有条件的选用。对路基填料的最小强度和最大粒径给了量化的标准,     

偏最小二乘回归与灰色模型耦合预测城市用水量

 影响城市用水量的各个因素,存在多重相关性,采用传统最小二乘回归法建模,其估计参数存在较大误差,预测精度降低。运用偏最小二乘回归法建立城市用水量的预测模型可以克服变量间的多重相关性影响,并可以很好地解释因变量;采用GM（1,1）建立的城市用水量预测模型,能够克服参数的非线性干扰,进行中长期预测。结果和实际符合,将两者进行耦合,充分利用了两种模型的优点,预测结果更为合理可靠。     

渭河源区水文气象要素演变趋势及阶段性分析

研究渭河源区水文气象要素变化特征,并进一步分析各个要素之间的相互关系,为渭河源区水资源的合理开发利用提供科学依据与技术支撑。采用坎德尔秩次相关、斯波曼秩次相关、线性趋势回归检验法对渭河源区水文气象要素变化趋势进行检验,利用M-K检验法找出各要素的突变年份,运用多元线性回归分析法分析不同阶段降雨、蒸发量对径流量的影响程度。结果表明:近30年来渭河源区年降水量与四季降水量均呈不显著减少趋势,年蒸发量与春、夏季蒸发量呈显著增加趋势,年径流量与夏季径流量呈显著减少趋势,冬季径流量呈不显著增加趋势。年降水量和年径流量均在1993年发生显著性突变,年蒸发量在1990年发生显著性突变。分析得出:1981-1993年年径流量变化主要受降水量变化影响,1994-2010年径流量变化主要受蒸发量变化影响。     

Pre-processing data to predict groundwater levels using the fuzzy standardized evapotranspiration and precipitation index (SEPI)

Due to sudden declines in groundwater levels in Neyshabur Plain, one of the most important parts of water supply management programs at the catchment scale is to accurately predict the groundwater level fluctuations. In this paper, the rainfall data from 22 rain gauges and evapotranspiration stations during the period of 1974–2015 were used to find the cumulative effects of rainfall and evapotranspiration on fluctuations in groundwater levels. First, using the Hargreaves-Samani method, the modified evapotranspiration was calculated on the plain. Using the Kriging method, the average amount of precipitation and evapotranspiration of the reference plant was also calculated. Then, employing the fuzzy logic, the fuzzy standardized evapotranspiration and precipitation index (SEPI) was produced. The correlation results between SEPI indicator and fluctuations in groundwater levels showed that the long-term time scales had greater correlations. Thus, the correlations for the time scales of 30, 36, 42, 48, 54 and 60 months were respectively obtained as 0.56, 0.68, 0.71, 0.69, 0.59 and 046. These six parameters were used for principal components analysis (PCA) and the selection criteria (SC) index was used to select the properties affecting every component. The ranking results of testing local linear regression with PCA (LLR-PCA) and dynamic local linear regression with PCA (DLLR-PCA) models, Broyden, Fletcher, Goldfarb, Shanno algorithm with PCA (BFGS-PCA) neural network and Conjugate Gradient-PCA indicated that the DLLR model with three main components had the best performance so that the values of R², RMSE, MBE and MAE were obtained as 0.84, 0.215, 0.028 and 0.162, respectively. The results generally showed that due to severe linearity between SEPI indicator and its time scales, the use of PCA is essential for simulating fluctuations of the groundwater levels.     

Monitoring of COD as an organic indicator in waste water and treated effluent by fluorescence excitation-emission (FEEM) matrix characterization.

The fluorescence excitation-emission matrices (FEEM) of domestic waste water, treated effluent of a waste water treatment plant and receiving river water were analyzed to select wavelengths for the monitoring of organic contents as COD. Excitation/emission wavelengths of 220/350 nm and 270/350 nm for protein-like fluorescence and 240/450 nm and 340/450 nm for humic-like fluorescence were suggested as fluorescence peak emitting wavelength pairs, respectively. Without any pre-treatment, the protein-like fluorescence peaks showed better correlation between COD values and fluorescence intensities than the humic-like fluorescence peaks. No enhanced correlation was observed by removing the suspended solids from the samples using filtration. However, statistical multiple regression methods, using the fluorescence intensities from each peak and the light scattering intensity at 633 nm as variables, resulted in an enhanced correlation, with r2 > 0.9 for the measured and predicted COD values.     

华中地区土壤可蚀性因子研究

以全国第2次土壤普查数据为基础,利用 EPIC模型估算华中地区主要土壤可蚀性因子K 值,结合该区土种分布图,分析各主要土壤类型可蚀性K 值分布特征。结果表明：该区土壤可蚀性因子K值主要分布在 0.09～0.39 之间,高值区主要分布在河南省的东部、西部区域,低值区则主要分布在湖南省的南部、湖北及河南交界的中部及东部地区。依据华中地区土壤图,全区共分布有土类 25 种。其中,K 值最大的为褐土,约为0.34 ;红黏土的K 值次之,为0.31;粗骨土的可蚀性最低,约为0.19。华中地区红壤、水稻土、潮土、黄壤、黄棕壤等土类所占面积较大（约占全区总面积的 72.63% ）,其土壤可蚀性因子K 值分别为：0.250 , 0.253 ,0.287 , 0.225 ,0.244,可基本反映华中地区的土壤抗侵蚀情况。     

An analysis of characteristic discharges for the Adaim River (Iraq) in multiyear period

A major River Tigris tributary in Iraq, the Adaim River, has a Mediterranean river flow regime with a total basin area of 12,482 km². The river catchment responds almost immediately to rainfall with apparently minimum storage (i.e. flashy stream). The river daily hydrograph showed a daily peak flow of 1,476 m³/s with substantial seasonal and random variability; the flow duration curve followed the two‐parameter lognormal probability distribution. Gamma and the two‐parameter Weibull probability distributions fitted the monthly mean river discharge for the period 1937–2012 well. Normal and gamma probability distributions were found to appropriately describe the distribution of the annual mean river discharge for the same period. Gumbel extreme value, Log Pearson type III, and the two‐parameter lognormal distributions gave a reasonable fit to the annual maximum discharge record for the river. A regression formula was used to fit the annual minimum discharge record, which has a significant number of zero values. There was a positive and significant correlation (r = 0.77) between the annual mean discharge at the measuring site and seasonal rainfall measured at Karkuk meteorological station located in the north central part of the basin. The rainfall record at Karkuk showed a significant decline in seasonal rainfall after 1993.     

微生物吸附低温水体中Cr(Ⅵ)、Cd(Ⅱ)离子研究

利用从活性污泥中分离、纯化、筛选得到的霉菌,进行吸附水体中Cr(Ⅵ)、Cd(Ⅱ)离子研究。结果表明:在Cr(Ⅵ)、Cd(Ⅱ)质量浓度分别为300mg/L时,菌种生长良好。吸附水体中Cr(Ⅵ)、Cd(Ⅱ)的最佳条件:pH值5.0,时间1h,温度10℃。吸附规律符合Langmuir等温吸附模型,由回归方程得到Cr(Ⅵ)的表观最大吸附量为14mg/g;Cd(Ⅱ)的表观最大吸附量为52mg/g。对菌种吸附低温水体中两种重金属离子时pH值变化影响及其吸附动力学进行了研究。证明该菌可以有效地去除低温水体中Cr(Ⅵ)、Cd(Ⅱ)离子。     

Biosorption of As(V) from aqueous solutions by living cells of Bacillus cereus

In this work, the biosorption of As(V) from aqueous solutions by living cells of Bacillus cereus has been reported. The batch biosorption experiments were conducted with respect to biosorbent dosage 0.5 to 15 g/L, pH 2 to 9, contact time 5 to 90 min, initial concentration 1 to 10 mg/L and temperature 10 to 40 °C. The maximum biosorption capacity of B. cereus for As(V) was found to be 30.04 at pH 7.0, at optimum conditions of contact time of 30 min, biomass dosage of 6 g/L, and temperature of 30 ± 2 °C. Biosorption data were fitted to linearly transformed Langmuir isotherms with R(2) (correlation coefficient) >0.99. Bacillus cereus cell surface was characterized using AFM and FTIR. The metal ions were desorbed from B. cereus using both 1 M HCl and 1 M HNO(3). The pseudo-second-order model was successfully applied to predict the rate constant of biosorption.     

Regression and Weighted Averaging Models Relating Surficial Sedimentary Diatom Assemblages to Water Depth in Lake Ontario

Diatom assemblages in surface sediment samples in depth profiles from Lake Ontario and from East Lake, a shoreline lake, were analyzed for the purpose of describing the relationship between species distribution and water depth. At both sites species composition varied markedly with sample depth. In East Lake a multiple regression of four habitat groups: benthic, epiphytic, tychoplanktonic, and euplanktonic, against water depth (30 cm–8 m) produced a relationship with a standard error (SE) of 1.5 m. An analysis of the ratio of euplanktonic diatoms to periphytic diatoms over a transect from 3 m to 150 m in Lake Ontario produced a multiple regression with an SE of 11.8 m. In another approach, water depth optima for 91 diatom taxa were developed using a weighted averaging (WA) technique. A good correlation (r² > 0.9) was found between measured and inferred water depth over the range 3 m to 30 m using a unimodal WA regression model. The transfer functions offer the possibility of inferring Holocene water level changes in Lake Ontario from fossil diatom assemblages in sediment cores.     

污水灌溉区土壤镉的高光谱遥感监测研究

以石家庄多年污水灌溉区为对象,通过对污灌土壤的可见-近红外波段光谱信息进行测量和处理,利用相关分析和多元逐步回归分析,建立土壤镉含量与反射光谱变量之间的回归模型。结果表明,土壤镉在研究区土壤中有一定程度的积累,镉含量与其原始光谱、倒数对数光谱在多数光谱波段达到极显著相关水平,与连续统去除光谱相关性不显著。逐步回归模型中,倒数对数模型拟合精度最高,均方根误差为0.020,预测精度达到92.71%,说明倒数对数光谱变量模型可有效预测土壤镉含量,是估算研究区土壤镉含量较理想的预测模型。