Application of subsurface wastewater infiltration system to on-site treatment of domestic sewage under high hydraulic loading rate

In order to enhance the hydraulic loading rate （HLR） of a subsurface wastewater infiltration system （SWIS） used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results show that the intermittent operation mode contributes to the improvement of the HLR and the pollutant removal rate. When the wetting-drying ratio （RwD） was 1.0, the pollutant removal rate increased by （13.6 ± 0.3）% for NH3-N, （20.7 ± 1.1）% for TN, （18.6± 0.4）% for TP, （12.2 ± 0.5）% for BOD, （10.1 ± 0.3）% for COD, and （36.2 ± 1.2）% for SS, compared with pollutant removal rates under the continuous operation mode. The pollutant removal rate declined with the increase of the HLR. The effluent quality met The Reuse of Urban Recycling Water - Water Quality Standard for Scenic Environment Use （GB/T 18921-2002） even when the HLR was as high as 10 cm/d. Hydraulic conductivity, oxidation reduction potential （ORP）, the quantity of nitrifying bacteria, and the pollutant removal rate of NH3-N increased with the decrease of the RWD. For the pollutant removal rates of TP, BOD, and COD, there were no significant difference （p 〈 0.05） under different RwDS. The suggested RWD was 1.0. Relative contribution of the pretreatment and SWlS to the pollutant removal was examined, and more than 80% removal of NH3-N, TN, TP, COD, and BOD occurred in the SWIS.

Dynamic monitoring of soil bulk density and infiltration rate during coal mining in sandy land with different vegetation

To investigate the effects of coal mining on soil physical properties,sandy lands with three major vegetation types(Salix psammophila,Populus simonii,and Artemisia ordosica)were investigated by the ring knife method and double-ring infiltrometer.Specifically,variations in soil bulk density and water infiltration rate and the influences of coal mining and vegetation type on the properties during different subsidence stages were studied at the Shendong Bulianta mine.The results showed that,in the period before mining,soil bulk density occurred in the order A.ordosica>P.simonii>S.psammophila,with a negative correlation between the initial infiltration rate and steady infiltration rate being observed.In the period during mining and 3 months after mining,there were no significant differences in soil bulk density and water infiltration rate among vegetation types.At 1 year after mining,the soil bulk density occurred in the order A.ordosica>S.psammophila>P.simonii,having a negative correlation with the steady infiltration rate.The water infiltration depths of the S.psammophila,P.simonii and A.ordosica were 50,60,and 30 cm,respectively.The infiltration characters were simulated by the Kostiakov equations,and the simulated and experimental results were consistent.Linear regression revealed that vegetation types and soil bulk density had significant effects on soil initial infiltration rate during the four study periods,and the infiltration rate of the period 1 year after mining was mainly influenced by the soil bulk density of the period before mining.The results indicated that vegetation types had significant effects on soil bulk density,and that the tree-shrub-grass mode was better than one single plantation for water conversation and vegetation recovery in sandy land subjected to mining.

Estimation and inter-comparison of infiltration models in the agricultural area of the Mitidja Plain, Algeria

Infiltration is an important part of the hydrological cycle, and it is one of the main abstractions accounted for in the rainfall-runoff modeling. The main purpose of this study is to compare the infiltration models that were used to assess the infiltration rate of the Mitidja Plain in Algeria. Field infiltration tests were conducted at 40 different sites using a double ring infiltrometer. Five statistical comparison criteria including root mean squared error(RMSE), normalized root mean squared error(NRMSE), coefficient of correlation(CC), Nash-Sutcliffe efficiency(NSE), and Kling-Gupta efficiency(KGE) were used to determine the best performing infiltration model and to confirm anomalies between predicted and observed values. Then we evaluated performance of five models(i.e., the Philip model, Kostiakov model, Modified Kostiakov model, Novel model, and Horton model) in simulating the infiltration process based on the adjusted performance parameters cited above. Results indicated that the Novel model had the best simulated water infiltration process in the Mitidja Plain in Algeria. However, the Philip model was the weakest to simulate the infiltration process. The conclusion of this study can be useful for estimating infiltration rate at various sites using a Novel model when measured infiltration data are not available and are useful for planning and managing water resources in the study area.

Threshold pressure and infiltration behavior of liquid metal into fibrous preform

A dynamic measuring apparatus was developed to investigate the infiltration process of liquid metal into the fibrous preform. 10% （volume fraction） chopped carbon fiber preforms were infiltrated with magnesium alloy under different infiltration pressures. The threshold pressure and flow behavior of liquid metal infiltrating into the preforms were calculated and measured. The microstructure of obtained Ct4Mg composites was observed. The results indicate that the measured threshold pressure for infiltration was 0.048 MPa, which was larger than the calculated value. The infiltration rate increased with the increase of infiltration pressure, but the increase amplitude decreased gradually. The tiny pores in the composites could be eliminated by increasing the infiltration pressure. When the infiltration pressure rose to 0.6 MPa, high quality C1/Mg composite was obtained.

Comparison of models to predict air infiltration rate of buildings with different surrounding environments

The air infiltration rate of buildings strongly influences indoor environment and energy consumption.In this study,several traditional methods for determining the air infiltration rate were compared,and their accuracy in different scenarios was examined.Additionally,a method combining computational flow dynamics(CFD)with the Swami and Chandra(S-C)model was developed to predict the influence of the surrounding environment on the air infiltration rate.Two buildings in Dalian,China,were selected:one with a simple surrounding environment and the other with a complex surrounding environment;their air infiltration rates were measured.The test results were used to validate the accuracy of the air infiltration rate solution models in different urban environments.For the building with a simple environment,the difference between the simulation and experimental results was 0.86%–22.52%.For the building with a complex environment,this difference ranged from 17.42%to 159.28%.We found that most traditional models provide accurate results for buildings with simple surrounding and that the simulation results widely vary for buildings with complex surrounding.The results of the method of combining CFD with the S-C model were more accurate,and the relative error between the simulation and test results was 10.61%.The results indicate that the environment around the building should be fully considered when calculating the air infiltration rate.The results of this study can guide the application of methods of determining air infiltration rate.

Fuzzy Analytical Solution to Vertical Infiltration

In this article, we examine the solution of the fuzzy linear vertical infiltration equation, which represents the water movement in porous media in that part which is called the vadose zone. This zone is very important for semi-arid areas, due to complex phenomena related to the moisture content in it. These phenomena concern the interchange of moisture content between the vadose zone and the atmosphere, groundwater and vegetation, transfer of moisture and vapor and retention of moisture. The equation describing the problem is a partial differential parabolic equation of second order. The calculation of water flow in the unsaturated zone requires the knowledge of the initial and boundary conditions as well as the various soil parameters. But these parameters are subject to different kinds of uncertainty due to human and machine imprecision. For that reason, fuzzy set theory was used here for facing imprecision or vagueness. As the problem concerns fuzzy differential equations, the generalized Hukuhara (gH) derivative was used for total derivatives, as well as the extension of this theory for partial derivatives. The results are the fuzzy moisture content, the fuzzy cumulative infiltration and the fuzzy infiltration rate versus time. These results allow researchers and engineers involved in Irrigation and Drainage Engineering to take into account the uncertainties involved in infiltration.

Clogging Process Caused by Organic Particle Accumulation and Biofilm Growth in Subsurface Wastewater Infiltration System

Substrate clogging is the worst operational problem for subsurface wastewater infiltration system （ SWIS ）, nevertheless quantitative understanding of the clogging process is currently very limited. In this study, the developing process of clogging caused by organic particle accumulation and biofilm growth was investigated in two groups of lab-scale SWIS, which were fed with glucose （dissolved organic matter） and starch （particulate organic matter） influent and filled with the same substrate made of 50% brown soil and cinder at a weight of 50%. Results showed that in glucose-fed systems the growth of biofilm in the substrate pores certainly caused remarkable reduction of effective porosity, especially for the high concentration organic wastewater, whereas its influence on infiltration rate was negligible. In comparison with biofllm growth, organic particles accumulation could rapidly reduce infiltration rate and the clogging occurred in the upper layer in starch-fed systems and the most important contribution of biofilm growth to clogging was accelerating the occurrence of clogging.

Effects of Organic Compound Fertilizers on Soil Water Infiltration Characteristics

In order to study the effects of organic compound fertilizers on soil water infiltration characteristics,an indoor one-dimensional soil column water infiltration test was carried out.Six soil sample treatment groups were set,namely marshy solonchak(control check,CK for short),bamboo charcoal-mixed marshy solonchak,Difuyuan-mixed marshy solonchak,salined flavo-aquic soil(CK),bamboo charcoal-mixed salined flavo-aquic soil and Difuyuan-mixed salined flavo-aquic soil.After 120 min of infiltration,compared with the CK groups of marshy solonchak and salined flavo-aquic soil,the cumulative infiltration volumes of the bamboo charcoal and difuyuan treatment groups increased by -18.78%,-3.93% and 25.77%,6.53%,respectively;and the displacement increased by -18.93%,1.64% and 22.6%,12.5%,respectively.The relationship between the wetting front displacement and time conformed to a linear function.The effects of organic compound fertilizers on the initial infiltration rates of marshy solonchak and salined flavo-aquic soil were significant,and the relationship between infiltration rate and time conformed to a power function.The vertical distribution of soil moisture under the application of organic compound fertilizers showed that the moisture content changed relatively small within 5 cm of the surface soil layer,then decreased slowly within 5-10 cm of the soil layer,and decreased drastically below 10 cm of soil layer;and relative to the CK group,the application of organic compound fertilizers was beneficial to increase the moisture content of salined flavo-aquic soil.The organic compound fertilizers reduced the water infiltration capacity of marshy solonchak and improved the water infiltration capacity of salined flavo-aquic soil.Compared with Difuyuan,bamboo charcoal reduced the water infiltration capacity of marshy solonchak better and improved the water permeability of salined flavo-aquic soil more significantly.

W-OH固化剂对高寒矿区煤矸石水分入渗的影响及模型拟合

采用室内积水条件下煤矸石柱水分入渗模拟试验,研究了不同浓度W-OH(0%、1.5%、2.5%和3.5%)喷施处理对高寒矿区煤矸石水分入渗的影响,同时采用Philip、Kostiakov和Horton 3种入渗模型对入渗过程进行拟合,利用一维代数模型预测煤矸石剖面体积含水率分布特征,并评价模型适用性。结果表明:(1)累计入渗量和湿润锋前进距离随入渗时间的增加而逐渐增加且与WOH浓度存在负相关性。同一入渗时刻,W-OH浓度越大,入渗率和湿润锋前进速率越小,与对照(0%W-OH)相比,3种W-OH浓度(1.5%、2.5%、3.5%)处理的初始入渗率分别降低了1.12%、3.59%和9.64%,稳定入渗率分别降低了16.92%、78.46%和89.23%,平均入渗率分别降低了11.35%、58.26%和71.02%。(2)3种入渗模型都能较好地拟合不同浓度W-OH处理煤矸石水分入渗过程,Philip、Kostiakov和Horton模型的决定系数(R2)均值分别为0.962、0.957和0.967,其中Horton模型的拟合效果较好。(3)积水入渗过程中同一W-OH浓度,埋深越大,水分入渗至各监测点所需的时间越长,同一深度,W-OH浓度越大,水分入渗至各监测点所需的时间也越长。(4)一维代数模型可以较好地模拟入渗结束后煤矸石剖面体积含水率分布特征,模拟值与实测值间的均方根误差(RMSE)和平均绝对误差(MAE)分别在2.574%~3.326%之间和2.308%~2.707%之间,符合度指数(D)均在0.92以上。研究结果可以为W-OH固化剂在高寒矿区煤矸石山冻土剖面重构中的应用提供理论指导。

模拟降雨条件下重构阻水层对坡面风化煤矸石产流产沙的影响

[目的]为缓解水分因子对高寒矿区扰动土体无法形成冻土带来的不利影响,研究提出扰动土体下方添加高阻水性材料亲水性聚氨酯(W-OH)重构底部阻水层(近似无缝隙的不透水层)的设计方案,分析重构阻水层后高寒矿区风化煤矸石坡面入渗、产流和产沙的变化特征,为高寒矿区扰动坡面冻土重现以及重构阻水层的坡面水土流失防治提供理论支撑。[方法]通过人工模拟降雨试验,研究在60和90 mm/h降雨雨强条件下,重构阻水层(添加W-OH浓度0%,1.5%,2.5%,3.5%,4.5%)后不同坡度条件的(3种坡度5°,15°,25°)的风化煤矸石坡面入渗特性和水土流失变化规律。[结果]①重构阻水层后的煤矸石坡面稳定入渗率较自然坡面明显降低,且与W-OH添加浓度呈负相关关系;②煤矸石坡面产流率随时间变化呈现先快速上升后逐渐平稳的变化趋势,平均产流率与W-OH添加浓度呈现正相关关系,添加浓度为1.5%,2.5%,3.5%,4.5%W-OH的煤矸石坡面平均产流率较自然状态增加26.75%,38.02%,46.90%,63.23%;③坡面平均流速与降雨雨强、W-OH添加浓度和坡度均呈正相关关系,影响程度表现为:降雨雨强>坡度>W-OH添加浓度。④坡面产沙率随时间变化曲线多为“单峰”曲线,呈现先迅速上升随后缓慢下降最终趋于稳定的变化趋势,添加浓度为1.5%,2.5%,3.5%,4.5%W-OH的煤矸石坡面平均产沙率较自然状态增加26.98%,49.48%,71.64%,94.01%。[结论]重构阻水层对坡面风化煤矸石渗透性能降低明显,能有效帮助高寒矿区扰动坡面的冻土恢复和形成,但入渗率的降低使坡面更容易产生径流,增加了地表的产流产沙,可配置一定的水土保持措施。

磁化微咸水对南疆盐渍土壤水分入渗及盐分淋出特征的影响

为探究磁化微咸水灌溉对南疆盐渍土入渗及盐分离子迁移特征的影响,采用恒定磁场强度400 mT对矿化度分别为0、2、3、5 g/L微咸水进行磁化处理,以未磁化处理为对照,对比分析各处理累积入渗量、湿润锋运移距离和淋洗后不同土壤剖面总盐、脱盐率、盐分离子和SAR的影响规律。结果表明:磁化微咸水入渗减小了相同时间内的累积入渗量和湿润锋深度,降低了Philip入渗模型吸渗率,土壤含水率比未磁化微咸水提高5.00%~6.29%;磁化处理显著降低了土壤含盐量,对0~50 cm土壤内总盐含量磁化处理较未磁化降低11.79%~41.64%,在同一磁化强度下,土壤含盐量随矿化度的增加而增加,脱盐率随矿化度的增加而降低。在同一矿化度下,磁化处理含盐量低于未磁化处理,脱盐率高于未磁化处理。磁化微咸水灌溉有利于降低土壤中盐分离子含量,0~50 cm土层K^(+)、Na^(+)、Ca^(2+)、Mg^(2+)、HCO_(3)^(-)、Cl^(-)、SO_(4)^(2-)含量磁化较未磁化处理降低16.90%~25.97%、43.62%~64.68%、11.15%~31.44%、-8.12%~49.07%、-74.14%~13.43%、21.46%~52.81%、6.66%~13.10%。磁化微咸水灌溉处理显著降低0~50 cm土层深度处土壤SAR。

横坡垄作措施下层状棕壤的积水入渗特征及其模拟

横坡垄作系统中雨水/灌溉水易在垄沟低洼处积聚,诱发积水入渗,使入渗特性有别于传统耕作系统。基于横坡垄作垄沟内积水特征,采用室内土柱供水实验,以层状棕壤为研究对象,分析5个积水深度(2、4、6、8和12 cm)下入渗率、湿润锋运移动态变化,并利用修正的Gree n-Ampt模型对积水入渗过程进行模拟。结果表明:1)耕层阶段,入渗率呈急剧下降后趋于稳定趋势;过渡阶段,入渗率稳定一定时段后逐渐降低;犁底层阶段,入渗率趋于稳定;2)积水深度的增加均促进湿润锋的运移,但未改变湿润锋运移过程;3)初始入渗率、稳定入渗率、平均入渗率、累积入渗量等入渗参数均随积水深度增加呈幂函数增大,其中积水深度12、8、6和4 cm下的平均入渗率较积水深度2 cm分别增加120.5%、65.4%、39.4%和29.9%;4)在解析积水深度(h)与饱和导水率(K_(s)(h))间呈线性正相关关系基础上(K_(s)(h)=0.092h+0.76),结合湿润锋处土壤吸力(25.61 cm),构建模拟积水入渗过程的修正Green-Ampt模型。积水深度的增加加快土壤水分入渗,可利用修正Green-Ampt模型对积水入渗过程进行模拟。研究结果可为横坡垄作措施下水分高效利用、水资源调控提供科学依据。

北方土石山区坡面水土流失特征研究

[目的]揭示北方土石山区坡面水土流失规律,为山区土壤侵蚀防治和生态建设提供科学依据。[方法]利用1988—1991年坡面径流小区观测数据,运用统计和相关分析等方法,对不同下垫面条件下坡面水土流失特征进行了分析,并探讨了坡面径流深度、土壤侵蚀模数、土壤入渗率与有效降雨量、平均降雨强度、降雨历时、降雨等级的关系。[结果](1)在5°08′~24°08′坡度范围内,坡面径流深度随坡度增加逐渐减小,土壤侵蚀模数和土壤入渗率随坡度增加逐渐增大;(2)在2.18~33.19 m坡长范围内,坡面径流深度随坡长增加逐渐减小,土壤侵蚀模数和土壤入渗率随坡长增加呈现先增后减的变化趋势,存在临界坡长;(3)随着植被覆盖度增加,坡面径流深度、土壤侵蚀模数迅速减小,土壤入渗率逐渐增加;裸地的坡面径流深度和土壤侵蚀模数显著高于30%植被覆盖度坡面,但植被覆盖度由30%增加到60%,90%时,坡面水土流失过程的影响差异并不明显,说明在水土流失治理中存在临界植被覆盖度;(4)坡面径流深度、土壤侵蚀模数主要受到有效降雨量和平均降雨强度影响,且均呈显著正相关;而土壤入渗率主要受到平均降雨强度和降雨历时影响,与平均降雨强度呈显著正相关,与降雨历时呈显著负相关;随降雨等级的增加,坡面径流深度和土壤侵蚀模数呈增加趋势而土壤入渗率呈先增加后减少的趋势。[结论]下垫面条件和降雨因素对北方土石山区坡面水土流失过程产生了重要影响。未来应结合室内试验和模型模拟,进一步加强该区域不同自然因素和人类活动对坡面水土流失过程和影响机制的研究。

多裂肌脂肪浸润的Goutallier分级与腰椎融合术后相邻节段退变的相关性分析

目的探讨多裂肌脂肪浸润Goutallier分级与腰椎融合术后邻近节段退变(ASD)的相关性。方法选择2017年1月至2020年6月在该院接受经椎间孔腰椎椎间融合术(TLIF)治疗的168例L 4腰椎滑脱患者资料进行回顾性分析,根据轴向T1加权MRI图像,采用Goutallier分级对L 3、L 4、L 5节段的多裂肌脂肪浸润情况进行评估。观察术后ASD发生率,观察是否ASD患者术前多裂肌的Goutallier分级,以及患者术前多裂肌的Goutallier分级与术后发生ASD的关系。结果随访期间共有41例出现ASD,发生率24.40%。ASD组L 3、L 4、L 5节段的多裂肌脂肪浸润程度均显著高于非ASD患者,差异均有统计学意义(P<0.05)。ASD组患者年龄、骨盆倾斜角(PT)、腰椎前凸角(LL)、术前邻近节段退变的占比高于非ASD组,骶骨倾斜角(SS)低于非ASD组,差异均有统计学意义(P<0.05);ASD和非ASD患者的性别和体质量指数差异无统计学意义(P>0.05)。多因素Logistic回归分析显示,控制混杂因素后,术前多裂肌的Goutallier分级是ASD的风险因素,L 3节段多裂肌的Goutallier分级与ASD的OR值最高。结论术前多裂肌Goutallier分级是退行性腰椎滑脱患者行TLIF术后发生ASD的风险因素。

Creep property research of new martensite heat-resistant steel G115

G115 steel was jointly developed by China Iron & Steel Research Institute Group Co.,Ltd.and Baosteel for usage in 600-650 ℃ ultrasupercritical boiler tubes.Using a hot extruded G115 tube,creep tests were conducted under a constant stress of 130 MPa and temperatures of 625,650 and 675 ℃.Comparing creep curves under different temperatures,it is observed that the creep performance of a G115 tube is more sensitive to temperature than stress.Steady-state creep rates of creep specimens are significantly increased by enhancing the temperature.A micro-structural analysis of ruptured creep specimens under a stress of 130 MPa and temperatures of 650 ℃ and 675 ℃ was performed;the fracture mechanism of creep specimens under these two temperatures mainly included the appearance of creep holes on the grain boundary and a decrease in the martensite lath density.

石灰与水泥改良粉质黏土的水稳定性试验研究

为探究粉质黏土采用石灰和水泥改良后的水稳定性,设计并制作了不同石灰和水泥掺量的改良粉质黏土试样,并通过自制的崩解仪开展了崩解试验。试验结果表明,未掺加改良剂的素粉质黏土试样浸水后会迅速崩解,且崩解过程具有明显的阶段性。当石灰掺量小于6%时,改良粉质黏土试样在水中发生崩解,但其耐崩性会随石灰掺量和压实度的增加而提升。当石灰掺量达到6%、水泥掺量达到2%时,改良粉质黏土试样在水中未发生崩解,但水仍会渗入试样内部,此时可采用入渗率描述试样的水稳定性。改良粉质黏土试样的入渗率会随压实度的增加而降低;相同压实度下改良粉质黏土试样的入渗率随改良剂掺量的增加而降低。相同掺量下水泥改良粉质黏土的水稳定性提升效果优于石灰改良粉质黏土,且水泥的改良效果相当于多掺2%的石灰,但水泥掺量不宜低于2%。

生物炭与化肥配施对紫色土坡耕地侵蚀性耕层土壤水分及入渗特性的影响

土壤水分及入渗是坡耕地降雨径流侵蚀的关键环节.采用铲土侵蚀模拟法,建立5种侵蚀程度的坡耕地原位试验,开展不施肥(CK)、单施化肥(F)、生物炭与化肥配施(BF)的对比试验,分析不同施肥措施与侵蚀程度下土壤水分及入渗性能变化.结果表明:①在不同施肥措施下,BF提高了土壤中粉粒占比,显著降低了土壤容质量,增大了毛管孔隙度,提高了土壤自然含水率;而随着侵蚀强度加剧,土壤容质量总体呈现上升趋势,总孔隙度则呈相反规律,自然含水率也随之下降.②坡耕地耕层土壤稳定入渗率从大到小依次为:CK,F,BF,对施肥措施响应显著,但土壤侵蚀强度对入渗特征作用不显著;Philip模型对施肥措施下坡耕地侵蚀性耕层土壤水分入渗过程模拟效果最佳,Horton模型能较好地反映低侵蚀强度下耕层入渗规律,而高侵蚀强度下则以Philip模型拟合效果更优.③冗余分析(RDA)结果显示,BF、土壤侵蚀厚度20 cm(S-20)、F、CK、土壤侵蚀厚度15 cm(S-15)是引起耕层土壤物理性能与入渗参数发生变化的主要因素(p<0.05);土壤孔隙度以及水分指标与砂粒、粉粒均呈正相关,与黏粒、容质量呈负相关;土壤容质量与黏粒、入渗特征存在正相关关系;同时,15 cm侵蚀厚度(S-15)是该研究区紫色土坡耕地侵蚀性耕层土壤的承受阈值.

典型引黄灌区包气带与地下水动态响应试验

【目的】开展银川平原引黄灌溉引起的包气带和地下水的动态响应试验,研究“灌溉水-包气带水-地下水”的转换过程和规律。【方法】以典型引黄灌区水田为研究对象,运用水文地质学、土壤水动力学等学科理论对原位试验观测资料数值分析,借助Origin、SPSS等统计分析软件进行数据处理,利用Hydrus-1D、Surfer等数值模拟软件进行拟合和插值分析。【结果】结果得出,灌溉过程中包气带各埋深层位的水分和负压变化呈显著相关性,相关系数达0.9以上;运用Hydrus-1D拟合田间土壤水分特征曲线,发现叠加各埋深层位可得到较连续的拟合曲线;在多次灌溉入渗试验中,第1次灌溉入渗引起的地下水动态响应最快,灌溉后响应时间为388.8 min;运用地下水灌溉响应法定量测算灌溉入渗能力,算得田间灌溉入渗系数均值为0.202;对地下水位动态进行插值分析,发现回灌逐步形成“水丘”中心,地下水流场也随之发生变化;通过地下水补给源项分析,引黄灌区内灌溉水对地下水的年灌溉补给贡献率达79%。【结论】通过原位田间试验,进一步厘清引黄灌区的包气带特性和地下水响应过程,发现引黄灌溉对灌区地下水的补给和流场特征有着决定性的作用,为提高引黄水量利用率和包气带-地下水资源评估、管理及调控提供一定科学支撑。

低合金化对钢筋耐氯离子腐蚀性能的影响

通过电化学开路电位、动电位极化曲线、阻抗谱和周期浸润试验方法,对普通HRB400钢筋和两种低合金化耐蚀钢筋在0.34 mol/L NaCl溶液中的腐蚀行为进行了研究。与普通HRB400钢筋相比,实验结果显示低合金化耐蚀钢筋有以下特点:开路电位值呈正移趋势,表现出较高的热力学稳定性;自腐蚀电位较为正向,自腐蚀电流密度较低,并且极化电阻显著增加;相对电化学腐蚀速率仅为58%和68%;相对失重率仅为63%。添加少量合金元素能够显著降低钢筋的腐蚀速率。

伊犁黄土水分入渗规律试验研究

为了了解伊犁黄土水分入渗规律,在伊宁市北岸干渠边坡采样,进行了一维土柱积水入渗、变水头测定黄土渗透系数试验。结果表明,黄土湿润锋前进距离、累积入渗量随时间呈幂函数递增关系,入渗率随时间呈幂函数递减关系,用Kostiakov公式建立了伊犁黄土入渗模型。随着黄土干密度增大,累积入渗量加大,湿润锋运移速率减弱,到达渗透阶段时间延长,入渗率减小且逐渐趋于稳定,干密度较大的黄土稳渗率较小。采用TST-55型渗透仪通过变水头试验得到了伊宁市北岸干渠黄土饱和渗透系数在2.25×10^(-4)~2.32×10^(-5)cm/s,拟合了干密度与饱和渗透系数的关系式,表明干密度与饱和渗透系数呈负指数函数关系。