国际期刊导读

双侧延伸端板半刚性组合节点的抗震性能（1）：试验研究;双侧延伸端板半刚性组合节点的抗震性能（2）：抗震模拟;碳钢和不锈钢管状支撑构件循环试验和数值模型。     

中应变率下动静组合加载岩石的本构模型

阐述动静组合加载岩石的本构模型研究意义，并对国内外关于岩石动态本构模犁的研究方法进行分类。采用组合模型研究方法，将统计损伤模型和黏弹性模型相结合，分别建立中应变率下二维和三维受静载荷作用岩行在动载荷作用下的本构模型（动静组合加载本构模型）。对一维动静组合加载本构模掣用不同静应力的相关试验进行验证，其结果表明，利用该模型计算得到的本构曲线与试验结果具有较好的一致性。对于三维动静组合加载本构模型，采用动力三轴试验机加围压时对应的岩石动载本构关系进行验证。     

重金属污染土电阻率影响因素的试验研究

为探究重金属污染物浓度、含水率、土类型等因素对重金属污染土电阻率的影响,为电阻率法在重金属污染场地中的应用提供理论依据,采用标准的3因素3水平的正交试验表制定试验方案进行正交试验,为了更加明确三因素对土电阻率的影响,进行不同类型土分别在不同重金属污染物浓度和不同含水率下的土电阻率测试试验,用自制室内电阻率测试装置进行测试。结果表明:在软土地区,当土体受重金属污染时,影响重金属污染土电阻率变化的主次因素依次是重金属污染物浓度、含水率、土的类型。土的电阻率随着含水率的增加而呈指数减小,重金属污染土的电阻率随着重金属污染物浓度的增加而呈指数减小,在同一超标倍数下,不同类型土电阻率变化率由大到小的顺序为:粉质粘土﹥淤泥质粉质粘土﹥淤泥质粘土。     

重金属污染土强度特性试验研究

通过将重金属冶炼企业的尾矿库、废料堆填区采取重金属尾矿样品,与无污染净土进行混合,制作不同重金属污染物含量的土样,进行物化分析、直接剪切试验与无侧限抗压强度等试验,研究了重金属污染物的不同含量对土体强度特性的影响。试验结果表明,重金属污染物对土体强度特性有较大影响,随着污染物浓度的增加,其粘聚力增大,则内摩擦角呈降低趋势。在同一含水量的情况下,随着重金属污染土含量的增加,其强度总体上有减小的趋势。强度随着重金属污染土掺入比的增加,其降低量也逐渐增加,降低量约为35%~60%。重金属污染物通过土颗粒间双电层与水膜厚度与表面性质,打破颗粒间的电离平衡,从而改变土体的强度性质。     

人工冻结黏土单轴蠕变本构关系研究

通过对黏土进行重塑,在不同温度与应力的条件下对其进行单轴蠕变试验并获得应变与时间的关系曲线;再对常用元件模型进行添加删除元件,组合出适用于工程实践的模型,由此推出应变与时间的对应函数;最后,在origin中对试验曲线进行拟合。拟合结果表明:所得函数能够较好地反映试验结果,可用于工程实践。     

水泥固化重金属铅污染土的强度特性研究

污染场地中开挖出来的污染土利用水泥固化处理（S/S法）后,其污染物质的淋滤特性和土体的强度得到改善,可用于场地的回填和堤坝的填筑等。针对该项技术,对水泥固化稳定后的重金属铅污染土的强度特性进行了研究。试验所用的铅污染土通过将硝酸铅溶液加入干土中人工制备而成,并考虑了不同铅离子含量和水泥掺量对水泥固化污染土强度特性的影响。试验结果表明：水泥固化污染土的无侧限抗压强度随着水泥掺量以及龄期的增长而提高;与常规水泥土（不含重金属污染物）强度相比,污染土中铅离子含量较低时,强度略有提高,铅离子含量较高时,强度显著降低;不同铅含量水泥土试样的应力应变关系均表现为强度越高,破坏应变越小;试样28 d龄期的变形模量与强度呈较好的线性对应关系。     

沪通铁路长江大桥主梁新细节疲劳性能试验研究

为了研究沪通铁路长江大桥主梁桁架斜腹杆过焊孔焊接细节的疲劳性能,根据相似理论设计了疲劳试验 模型,并完成了3组（9个）试件的疲劳试验研究。试验中测得了各个试件在不同应力幅值下的疲劳寿命与应变状 态;并建立试件的有限元模型对比分析试验结果。试验结果表明：疲劳试验中每个试件的裂纹扩展与破坏模式具 有一致性;有限元计算结果与试验测试结果吻合良好,且误差均在15%以内;通过试验数据拟合得到过焊孔构造 细节的S-N曲线,其斜率为1/2.66,与Eurocode3的71焊接细节S-N曲线存在一定的差异;失效概率为2.3%的200万 次对应的该焊接细节疲劳应力幅值为37.89MPa。     

粉砂质泥岩三轴压缩应力松弛特性试验研究

 采用RLJW–2000型岩石三轴流变伺服仪,在分级加载条件下完成饱和粉砂质泥岩的三轴压缩应力松弛试验。基于试验结果,划分岩石的应力松弛阶段,分析岩石的应力松弛特征,研究不同应变水平下岩石的应力松弛速率、径向应变、体积应变以及松弛模量随时间的变化规律,探讨岩石应力–应变等时曲线特征,系统地揭示粉砂质泥岩三轴压缩应力松弛特性。选取Burgers模型来描述粉砂质泥岩的应力松弛特性,采用LM-NLSF法对模型参数进行辨识。对比模型拟合曲线与试验曲线,二者吻合较好,表明Burgers模型可以较好地描述粉砂质泥岩的应力松弛特性,辨识得出的模型参数具有一定的实用价值。     

重金属污染对土压实性及抗剪强度影响的试验研究

通过在实际重金属冶炼企业的尾矿库、废料堆填区采取重金属尾矿样品,与代表性净土进行掺和,配制了不同压实度、不同龄期、不同掺和比的重金属污染土样;在各自的最优含水量下,进行击实和直接剪切等物理力学试验,研究重金属污染对土的压实特性与抗剪强度的影响规律。试验表明:1)重金属污染对土体击实特性的影响,金属Mn的影响不大,Pb、Zn、Cd、Cr影响较大,后者表现为随掺和比增大,最优含水量减小,土的最大干密度增大;2)随着重金属污染土体压实度的增大,土的黏聚力C逐渐增大的,内摩擦角φ值逐渐降低,污染土的强度指标明显低于重塑净土的抗剪强度指标;3)重金属污染的作用效应是一个缓慢的过程,随着重金属污染物作用时间的延长,土的黏聚力c值下降,内摩擦角φ值上升;4)随着污染浓度的增加,土的黏聚力c值增大,则φ值呈降低趋势。     

基于变参数的含水岩石弱化流变模型研究

基于不同含水率的岩石蠕变试验,分别考虑岩石时效劣化效应和含水弱化效应,分析不同应力状态下和不同含水率状态下的蠕变曲线。根据试验蠕变曲线得到岩石弹性模量随时间和含水率的变化关系,拟合得到岩石的时间衰减指数和含水衰减指数。在假设岩石时效损伤和含水损伤为各向同性损伤的基础上建立了岩石时效蠕变损伤模型,并对不同含水率下的岩石蠕变损伤开展了数值模拟研究。数值模拟结果同岩石蠕变试验曲线很好地相吻合,模拟结果表明了该蠕变损伤模型的合理性。本文所开展的岩石时效劣化和含水弱化蠕变损伤模型的研究工作,将为岩石流变特性的研究提供一定的理论依据。     

某金矿河水与底泥中重金属含量的相关性研究

通过研究水质与沉积物中重金属含量的相关性,分析了其受污机理,确定了各种污染物的不同来源,进而得出相关方程,从而达到结合矿区其他河段已知介质中的含量,推断对应的另一种介质污染情况的目的.     

Phosphate sources and their suitability for remediation of contaminated soils

Phosphate minerals and specifically apatite show promise for environmental cleanup because they can form stable compounds with a wide range of cationic contaminants. However, phosphate minerals naturally accumulate some heavy metals that may cause additional contamination of the environment if used improperly. Nine commercially available phosphate materials were evaluated for remediation of contaminated soil based on solubility, concentration of metal/metalloid impurities, and leachability of impurity metal/metalloids. The phosphate materials consisted of three groups: processed (i.e., fertilizers), mined (rock phosphates from different formations), and biogenic (ground fish bone). Processed and mined rock phosphates contained relatively high total concentrations of As, Co, Cr, and Cu but did not exceed the RCRA toxicity characteristic leaching procedure (TCLP) limits. Biogenic apatite contained much lower metal concentrations than processed and mined rock phosphate and was appreciably more soluble. By combining biogenic and mined phosphate it is possible to obtain a wide range of phosphate release rates, permitting rapid immobilization of contaminants while providing a slow release of phosphate for continued long-term treatment.     

Cadmium adsorption by sediment in a turbulence tank.

The mechanism sediment motion that affects cadmium (Cd) adsorption on sediment particles was studied in a turbulence tank in the presence (and absence) of bed mud. The experimental results were verified by a mathematical model for heavy metal transport-transformation developed for the turbulence tank. The mathematical model includes the equations of water flow, sediment motion, heavy metal transport-transformation, heavy-metal reaction kinematics and equations for prescribing the initial conditions and boundary conditions for the experiment. The model conforms the transport-transformation of heavy-metal pollutants in surface waters to following the law of convective-diffusive of common tracers and the characteristics of fate and transport of sediment motion. Variations of dissolved Cd concentrations and suspended particulate Cd concentrations with time and in the water column were measured and computed. The experimental measurements correspond with the computed results. Both the experimental measurements and computed results show that it takes about 6 h to reach equilibrium condition for cadmium adsorption by sediment particles. This is different from the result obtained from experiments conducted in continuously stirred tank reactors (or batch reactors) in which adsorption equilibrium can be achieved in about 20 min. Determination of the model parameters for sediment adsorption-desorption of metals in the tank is discussed. The experimental and computed results obtained in this study are useful to solve practical engineering problems in surface waters.     

Disposal of heavy metal‐contaminated sediment from Ulsan Bay,South Korea: treatment processes and legal framework

The effectiveness of two different management schemes to dispose of heavy metal‐contaminated sediments from Ulsan Bay, South Korea, soil washing and solidification/stabilization, were evaluated through a series of analyses. NaOH proved to be an effective washing reagent for As, extracting 75% of the As in sediment samples. EDTA was found to significantly enhance the extraction of Cu, Pb and Zn. However, complete removal of any metals was not achieved even after application of 100 mM concentrations of washing reagents. Therefore, a solidification/stabilization technique was applied to dredged sediment samples using ordinary Portland cement (1–40%) and fly ash (～20%). Solidified sediments did not release meaningful amount of the metals via leaching tests. Our results suggest that solidification/stabilization is a better option for effective disposal of heavy metal‐contaminated sediments than soil washing. A legal framework for the treatment of hazardous wastes and contaminated soils in Korea is discussed.     

水泥固化/稳定化场地污染土的效果分析

针对目前原位固化/稳定化技术的长效性以及不同污染场地对固化/稳定化处理效果影响的不确定性,通过对比水泥-粉煤灰固化剂处理的污染土在不同固化剂配比下的强度、pH和重金属的浸出随时间的变化情况,研究对比了其在英国两个实际场地修复项目之间的处理效果。涉及的两个污染场地分别位于英国的密德萨斯地区和Castleford,Yorkshire地区,均不同程度地被重金属(Cu、Ni等)和有机物所污染。通过实测现场固化污染土不同时间点的无侧限抗压强度和两种标准(TCLP和BSEN 12457)下的浸出液污染物浓度,给出了两个项目中水泥-粉煤灰固化污染土的强度和pH随时间变化的曲线;计算得出了不同时间点Cu和Ni的固定效率。现场试验结果表明,两种重金属在所有水泥-粉煤灰固化污染土0.08~17 a间的时间点上的固定效率均超过99.4%;最后,通过比较两个项目中在不同时间点所测得的强度、浸出等数据,验证了水泥固化污染土在工程实例中长达17 a的有效性。     

冻融作用下特定污染物的清洗试验研究

抽出处理法是目前修复土壤污染常用的方法之一,为了解决抽出处理法中对渗透性差的土中污染物和低浓度污染物效率低的问题,利用土体冻结过程中在一定的温度梯度和水分条件下未冻土侧水分(溶质)向冻结锋面迁移和冻融作用导致渗透性增强的特性,开展了基础试验。试验将混有模拟污染物NaCl溶液的粘土作为研究对象,结合传统的抽出处理法,实施了单向冻融试验和污染物清洗模型试验,探索了利用冻融现象清洗污染土壤的可行性。结果表明,冻融作用有助于提高污染物的抽出效率。     

水泥固化稳定重金属污染土的工程性质试验研究

随着社会的快速发展,因工业生产以及人类活动引起的地基土重金属污染现象越来越严重。地基土受到重金属污染后,其工程性质会发生改变。固化稳定法是处理重金属污染土地基的常用方法之一。以人工制备的铅或锌重金属污染土为研究对象,通过系统的室内试验,着重研究水泥固化稳定重金属污染土的工程性质。试验结果表明,土体受到污染后,其强度降低;掺入水泥固化稳定的重金属污染土的强度随水泥掺入量以及养护龄期的增加显著增大。通过试验还发现,较低浓度重金属离子的存在可以促进水泥固化土抗剪强度的提高。     

水泥固化重金属污染土干湿循环特性试验研究

水泥固化/稳定法是修复污染土地基的常用方法,修复后的固化土在外界环境干湿循环作用下的稳定性如何是事关修复成败的关键所在。通过系统的室内试验,着重研究了水泥固化Pb²⁺、Zn²⁺污染土在干湿循环作用下的强度特性、淋滤特性以及微结构变化规律,揭示了水泥固化重金属污染土的微观作用机制。试验结果表明,固化土体的强度及淋滤特性随着水泥掺量的增加得到了显著改善。固化重金属污染土的无侧限抗压强度随干湿循环次数的增加先增大,达到峰值后,随干湿循环次数的继续增大而减小。污染物掺量较低时,重金属离子的滤出浓度在干湿循环作用初期略有降低,此后则有所增加,但变化幅度较小;高污染物掺量时,滤出液中的重金属离子浓度较高,且随着干湿循环次数的增加而不断增大。低污染物掺量下,水泥对Pb²⁺及Zn²⁺固化效果相差不大;高污染物掺量下,水泥对Zn²⁺的固化效果较好。经过干湿循环作用后的固化土的扫描电镜试验结果与与其宏观力学及淋滤特性指标变化规律一致,从微观角度揭示了固化土工程性质的变化机制。     

Retention and release of Zn and Cd in spodic horizons as determined by pH(stat) analysis and single extractions

In the northern Campine in Belgium, large areas are contaminated by heavy metals such as Zn and Cd due to the (former) non-ferro metal industry. In the sandy soils, the heavy metal adsorption/attenuation in the spodic horizon represents the main retention mechanism of leached pollutants from the contaminated topsoils. In this study, the pH-dependent behaviour of the elements in these spodic horizons was tested by pH(stat) experiments and compared to sandy loam soils. Extractions with CaCl(2) 0.01 M and EDTA 0.05 M provided a further insight into the binding mechanisms. The results indicate that organic matter is the main factor responsible for the mobility of Cd, Zn and Ca in the spodic horizons. The binding of elements is not very strong, however, and highly dependent on pH. A slight decrease in pH can cause a significant release of metals from the spodic horizons, with up to 60% of Cd and 90% of Zn being released within a 1.5 unit change in pH (starting from the naturally occurring pH). This pH change can happen rapidly in these soils, due to the low buffering capacity, and is realistic given the acidification in Flanders. For the sandy loam soils, a pH decrease of 3 units is needed to release 40% of Cd and 20% of Zn, and the acid neutralization capacity is exhausted more gradually, suggesting that slower buffering mechanisms take place. For the sandy loam soils, Cd retention is mainly governed by organic matter, while for Zn other factors such as the clay minerals also play an important role. Despite the high potential mobility and pH dependence of the heavy metal retention in the spodic horizons, the actual risk for groundwater pollution is limited. For the diffusely contaminated areas, where traditional remediation is not an option, spodic horizons may therefore contribute to a natural attenuation of the soil contamination.