温度对混凝土力学性质影响的颗粒流模拟研究

为探索混凝土在热力耦合作用下的宏观力学性质和微裂纹的变化规律,采用PFC软件中的热模块,对5种温度下的混凝土试块进行了数值模拟分析。研究结果表明:(1)温度和峰值强度呈现负相关关系,单轴抗压强度和弹性模量随温度的变化服从幂函数关系,且温度对于强度和变形参数的影响不同,强度相较于变化参数而言,对温度更加敏感。(2)随着温度的升高,由热破裂所造成的损伤不断增加,热损伤集中在界面过渡区。随着温度的升高,混凝土的破坏模式由剪切破坏逐渐转变为劈裂破坏。(3)600℃属于临界温度,在600℃之前,宏观力学性质和微裂纹扩展均变化剧烈;超过600℃以后,宏观力学性质的劣化和微裂纹的发展均放缓。     

不同降雨入渗条件下预应力锚索加固边坡稳定性分析

为了研究不同降雨条件下边坡安全系数及预应力锚索轴力变化规律,以省道S303沿线某边坡为研究对象,考虑土体饱和-非饱和渗流与非饱和强度理论,基于有限元分析,对不同降雨工况下的孔隙水压分布、锚索轴力及采用强度折减法计算的边坡安全系数变化规律进行了研究。结果表明: 降雨量一定时,降雨入渗范围随雨强增大而减小,暂态饱和区域随雨强增加而增大; 边坡在加固前后的安全系数均随降雨量增加而不断减小,采用预应力锚索加固能有效提高边坡安全系数,并减小降雨对边坡稳定性的影响; 随着降雨量增加,各锚索轴力均增大,当降雨量一定时,雨强越小,对应的锚索轴力提升幅度越大,靠近底部的锚索轴力对降雨最为敏感。     

Synthesis and characterization of geopolymers containing blends of unprocessed steel slag and metakaolin: The role of slag particle size

The present research deals with the production and characterization of geopolymers prepared by mixing metakaolin with a steel slag from the production of chromium-manganese steel, a commercial sodium silicate solution and a sodium hydroxide solution. Different specimens were prepared by mixing metakaolin with different proportions of steel slag (20, 40, 60, 80 wt%) characterized by different maximum particle size. Specimens containing just metakaolin and steel slag alone were also prepared for comparison. All specimens have been characterized regarding their compressive strength, specific surface area, water absorption and microstructure. It has been observed that the use of fine steel slag powders leads to increases the performances and that the specimens containing 40 wt% steel slag and 60 wt% metakaolin revealed the best overall behaviour.     

薄壁管高温爆破试验装置研制及应用

为获得燃料组件及燃料相关组件用包壳管的高温爆破性能，研制了薄壁金属管高温爆破试验装置，主要由高压气源单元、试验气氛单元、加热单元、试验台架及测控单元组成。该装置可实现的最高试验温度为1 200 ℃、最高升温速率为10 ℃/s、最大试验压力为100 MPa；可完成压水堆运行工况下的等温高温爆破及模拟事故工况下的瞬态加热高温爆破两种试验。利用该装置完成了316L不锈钢薄壁管的瞬态加热高温爆破试验，获得了600~1 200 ℃、升温速率为5 ℃/s条件下的高温爆破强度（极限环向应力）和周向延伸率数据。试验装置的验证及不锈钢薄壁管的高温爆破试验表明，研制的薄壁金属管高温爆破试验装置满足试验要求，试验灵活方便、控制精度高。     

Assessment of plastic damage in high strength structural steel using electromagnetic technique

ABSTRACT

High strength structural (HSS) steels are widely used in many construction equipment and infrastructures. Currently, there is a substantial demand of Non-Destructive Testing of these steel structures. In this research, the electromagnetic technique was utilised to assess the plastic damage in a typical HSS steel (i.e. Q690 steel). The results showed that the magnetic hysteresis loop of this material changed apparently after the tensile deformation, and the relevant magnetic parameters such as coercivity, remanence, and maximum permeability were sensitive to the cumulative plastic strain. The results demonstrated that there is a good coherence between the plastic damage evolution and the magnetic parameters variation, which indicated that the electromagnetic technique is an effective method to assess the plastic damage of HSS steel.     

塔山矿新型27 mm高强玻璃钢锚杆技术应用

由于塔山矿回采巷道均为放顶煤开采，矿压显现明显，巷道断面大，在回采过程中尾顺槽围岩变形量大，致使使用传统普通玻璃钢锚杆支护时出现杆体被拉断、杆体尾部被剪断等支护失效现象。为了解决上述问题，采用新型27 mm高强玻璃钢锚杆对塔山矿8112工作面进行试验。试验结果表明，在保证采掘安全的前提下，使用新型锚杆取代普通锚杆，可以大大提高巷道支护的稳定性，节约巷道支护成本，保证施工工期正常完成，同时提高工作面回采效率。采用新型锚杆后，使巷道支护兼具安全、经济双重效益，同时对全矿井以及其他所有同类型矿井类似回采巷道，具有积极的推广和借鉴意义。     

Nonwoven geotextiles from nettle and poly(lactic acid) fibers for slope stabilization using bioengineering approach

This article deals with needle-punched nonwoven geotextiles prepared from nettle and poly(lactic acid) fibers in different weight proportions for potential slope stabilization application using bioengineering approach. The geotextiles were tested for tensile strength, biodegradability, and enhancement of soil fertility. The tensile strength of the geotextiles was found to decrease with addition of stronger nettle fibers. This apparently surprising behavior was explained in the light of theoretical tensile mechanics of nonwovens. Further, the nettle fibers displayed higher biodegradability than the poly(lactic acid) fibers, and when buried under soil, all the geotextiles exhibited a loss in tensile strength. Interestingly, the fertility of the soil was remarkably improved after biodegradation of poly(lactic acid) fibers. Overall, the nonwoven geotextiles prepared in this work were found to be promising for slope stabilization application.     

孔隙水压对充填体性能的影响

为探究大水矿山充填体的力学性能变化,将充填体试块置入高压水体中使其内部形成孔隙水压,研究孔隙水压下充填体的抗压强度、抗拉强度和含水量等指标的变化。试验以孔隙水压、浸入时间、充填配比和料浆浓度为主要影响因素,开展29组充填体强度试验。方差分析表明,料浆浓度和充填配比对充填体抗压强度影响极显著,孔隙水压影响显著;浸入时间对充填抗拉强度影响显著。相同充填配比和料浆浓度下的充填体抗压和抗拉强度随孔隙水压和浸入时间增长而下降,其中抗拉强度下降幅度较大。充填体含水量随孔隙水压增大而增大,增长趋势和充填体强度增大趋势相吻合。     

全尾砂和废石联合胶结充填体最佳配比及应用

针对红岭铅锌矿分级充填骨料来源不足、地表废石堆积污染环境的情况,提出将该矿选厂产生的全尾砂和地表废石作为充填骨料的联合胶结充填方案。分别测试了全尾砂和地表废石的物理化学性质,验证了碎石和全尾砂作为联合充填骨料的可行性。通过充填配比试验,分析了不同配比全尾砂废石充填体强度特性,得出了最佳充填配比。结果表明,充填试块的强度随灰砂比减小而减小,随养护龄期增加呈增大趋势,随充填料浆质量浓度增大而增大,最佳配比为: 胶结充填灰砂比1∶8、普通充填灰砂比1∶12,全尾砂∶废石配比4∶6,质量浓度78%。根据研究结果,在红岭铅锌矿进行了全尾砂废石充填技术工业应用,证实该技术可行。     

Characterization and actuation behavior of SPS/SGO ion exchange polymer actuator based on PEDOT: PSS/SGO composite electrode

ABSTRACT

This paper studied the fabrication of new hybrid-type poly(3,4- ethylene dioxythiophene) (PEDOT)/sulfonated graphene oxide electrode-based polymer actuator produced by film casting method. Sulfonated Poly(1,4-phenylene ether-ether sulfone) (SPS) ion-exchange polymer membrane-based ionic polymer composite actuators were fabricated using the different concentration of SGO. The characterization and actuation were demonstrated. By altering SGO concentration, four different SPS based membrane actuators were analyzed. The effects of SGO concentration on the morphology, proton conductivity, ion exchange capacity, and water uptake capability were studied. The maximum tip displacement and force by varying concentration of SGO were evaluated for the actuation performance.