共查询到19条相似文献，搜索用时 218 毫秒
1.
开展沸石掺量对土体强度、变形和渗透性影响的力学试验研究。选取相同质量但不同粒径的沸石制备泥质含气沉积物样品,基于CT扫描探讨沸石法制备含气样品的效果。结果表明：沸石掺量低于10%时,沸石对土体的抗剪强度、变形特性、渗透特性不会造成显著的影响;沸石吸附氮气条件下,掺入沸石的平均粒径与所产气泡的平均直径呈线性关系,且沸石产生的气泡平均等效直径约为土颗粒d50的30～40倍;沸石法制样前应对掺入的沸石进行优选。 相似文献
2.
《安徽科技学院学报》2020,(2)
目的:利用NaOH溶液改性人造沸石制成改性沸石处理氨氮废水。方法:投加量、吸附时间、氨氮浓度、共存阳离子为指标,在单因素试验的基础上,采用正交试验对氨氮吸附效果进行优化。再对数据进行吸附等温线实验以及吸附动力学实验。结果:当投入沸石4.0 g时,氨氮废水的去除率为70.25%;处理时间在60 min的时候,氨氮废水的去除率达到了85.70%;当初始氨氮浓度为80 mg/L时,去除率算得为58.46%;当投入AlCl_3时,得到得氨氮去除率为68.73%;最佳综合处理条件为:处理时间为60 min,氨氮浓度为60 mg/L,高岭土投加量为5.0 g,共存阳离子为Mg~(2+)。在一定条件下,改性沸石可以较好地处理氨氮废水。结论:NaOH溶液改性人造沸石的方法简便、易行,可以较好地处理氨氮废水。 相似文献
3.
胡翱翔 《深圳职业技术学院学报》2022,(5):47-53
为研究超高性能混凝土（UHPC）单轴受压力学性能,进行了6组UHPC棱柱体轴心受压力学性能试验,研究纤维掺量对试件破坏形态、轴心抗压强度、受压变形能力、弹性模量以及泊松比的影响．基于试验数据,建立了轴心抗压强度与立方体抗压强度、弹性模量与立方体抗压强度、泊松比与纤维掺量之间的关系,以及考虑损伤阈值影响的UHPC单轴受压损伤本构方程,理论曲线与试验曲线吻合较好．研究结果可为UHPC工程应用提供参考． 相似文献
4.
5.
为研究高掺量胶粉对胶粉-SBS复合改性沥青流变性能的影响,首先采用三大指标和布氏旋转黏度确定了高掺量胶粉-SBS复合改性沥青的最佳胶粉掺量,再采用动态剪切流变(dynamic shear rheology, DSR)试验和弯曲梁流变(bending beam rheometer, BBR)试验评价了高掺量胶粉-SBS复合改性沥青在高低温条件下的流变性能,最后通过红外扫描试验和荧光显微镜试验分析了高掺量胶粉-SBS复合改性沥青的微观特征。结果表明：高掺量胶粉-SBS复合改性沥青在胶粉掺量为42%时的流变性能最佳;高掺量胶粉可以提高胶粉-SBS复合改性沥青的复数剪切模量、车辙因子和蠕变劲度,降低相位角和蠕变速率,使其高低温流变性能得到明显改善;胶粉-SBS复合改性在沥青中的改性过程主要为物理改性,并且胶粉脱硫后,其内部交联减少,在沥青中的分散效果更为均匀,可以使得高掺量胶粉与SBS在沥青中形成更为致密的交联结构,增强复合改性沥青的流变性能。 相似文献
6.
《东南大学学报》2015,(3)
采用动态剪切流变仪(DSR)在16~40℃中等温度下测试、分析了基质沥青及其温拌沥青的复数剪切模量G*、相位角δ等流变性能,进而建立了疲劳因子G*sinδ与基质沥青性质、试验温度和拌剂掺量的关系模型.结果表明,复数剪切模量G*随温度升高而减小,而相位角δ随温度升高而增大;温拌剂掺量越高,复数剪切模量G*越大,相位角越小;疲劳因子G*sinδ随着温度升高呈指数减少,随温拌剂掺量增加呈线性增大;在较低温度和较高掺量下,疲劳因子的变化幅度更大;基质沥青复数模量越小,温拌剂对温拌沥青流变性能的影响更为显著,而老化对基质沥青性能的影响高于对沥青-温拌剂相互作用的影响;掺量越高的温拌沥青结合料,越容易疲劳开裂. 相似文献
7.
翁晴 《福建工程学院学报》2012,(3):214-217
以表面活性剂十二烷基硫酸钠(SDS)对沸石进行改性,改性后的沸石对亚甲基蓝溶液进行吸附,以紫外可见分光光度计分析最佳吸附条件。实验结果表明:SDS改性沸石吸附亚甲基蓝的最佳投入量为0.2 g;平衡时间为25 min;随着亚甲基蓝溶液的初始浓度增大,吸附量增大;溶液中其他阳离子存在竞争吸附。吸附过程可用伪二级反应动力学方程来描述,吸附活化能较小,主要为物理吸附过程。 相似文献
8.
王德奎何仕庄金平林晗绯 《福建工程学院学报》2021,(1):51-55
浇筑了13批次共123个标准试块分别进行7、28、60、90d龄期的抗压试验。试验结果表明:橡胶的掺入改善了自密实混凝土脆性破坏形态,降低了各龄期强度,同掺量下掺橡胶粉强度最低,掺1~2mm橡胶颗粒的强度最大;7d龄期强度可达60d龄期强度的65%~80%;橡胶掺量不大于30%的试件,60d龄期强度已经趋于稳定,橡胶颗粒掺量40%的试件28d龄期强度已趋于稳定;拟合了橡胶粒径、掺量与强度的预测公式,7d龄期与后期强度的经验公式,与试验结果对比吻合较好。 相似文献
9.
《赤峰学院学报(自然科学版)》2016,(21)
以粉煤灰为主要原料,负载Fe_3O_4为磁核,采用水热合成法制备磁性沸石,并将其用于对亚甲基蓝的吸附研究,考察了pH、吸附剂的用量、吸附时间、初始浓度等对吸附效果的影响.结果表明,磁性粉煤灰基沸石对亚甲基蓝具有较好的吸附能力,脱出率在90%以上;在pH=5时的吸附量最大;吸附时间在4min内基本上达到吸附平衡. 相似文献
10.
沸石微波改性及对废水中甲基橙的吸附性研究 总被引：1，自引：0，他引：1
采用微波辐射技术和盐酸对天然沸石进行活化改性处理,研究了改性沸石对废水中甲基橙的吸附性能及影响因素。结果表明：改性沸石明显提高了沸石对甲基橙的吸附能力。当溶液pH值为2．0、常温、振荡时间为60min、改性沸石用量为25g／L时,改性沸石对浓度为7．685mg／L的甲基橙的去除率达99．58％。改性沸石对甲基橙的吸附规律较好地符合Freundlich吸附等温式。 相似文献
11.
In-situ vane shear test is frequently performed to determine shear strength for slope stability analysis in Tianjin New Harbor. However,the soil shear strength varies with the shear plane orientation. A possible means to reduce the effect of directional dependency of shear strength is to convert the in-situ vane shear strength into undrained shear strength parameters. A method of converting in-situ vane shear strength into undrained shear strength parameters is presented. The shear strength parameters determined for all of the in-situ vane shear strengths are subjected to statistical regression analysis to take into consideration the possible effect of non-homogeneity in the soft clay deposit. Using the regressed shear strength parameters, slope stability analyses are performed for five existing soil slopes. The results of stability analyses indicate that the safety factors obtained from the converted parameters reflect the state of the slopes analyzed much better than those obtained from in-situ vane shear strength and laboratory consolidated-undrained and unconsolidated-undrained strength parameters. It is concluded that the presented methsod of determining undrained shear strength parameters for in-situ vane shear strength is effective. 相似文献
12.
INTRODUCTION Adequate information on dynamic soil proper-ties, especially dynamic shear modulus and dampingratio, is essential for accurate computations of groundresponse and soil-structure interaction problems.Many experimental investigations carried out onsandy soils through resonant column test or improvedcyclic triaxial test in early studies (Hardin and Richart1963; Hardin and Black, 1968; Drnevich and Richart,1970; Seed and Idriss, 1971; Kokusho, 1980) showedthat the small … 相似文献
13.
Undrained anisotropy and non-coaxial behavior of clayey soil under principal stress rotation 总被引：2，自引：0，他引：2
In this study, a series of undrained tests were conducted on both intact and reconstituted clay using an automatic hollow cylinder apparatus. Monotonic shearing tests with fixed principal stress directions were carried out, pure and cyclic prin- cipal stress rotation tests were also performed. The non-coaxiality, defined as the non-coincidence of the principal plastic strain increment direction and the corresponding principal stress direction, of clayey soil was studied experimentally. The effects of the intermediate principal stress, shear stress level, and inherent anisotropy were highlighted. Clear non-coaxiality was observed during pure principal stress rotation, in both intact and reconstituted clay. The influence of the intermediate principal stress pa- rameter, shear stress level, and inherent anisotropy on the non-coaxial behavior of the clayey soil was found to be insignificant when compared with the sand. The non-coaxial behavior of the clayey soil depended more on the stress paths. Under undrained conditions, the contribution of elastic strain to the direction of the total principal strain increment cannot be ignored. 相似文献
14.
温室气体及其排放的研究 总被引：5，自引：0，他引：5
张秀君 《沈阳教育学院学报》1999,1(2):103-105,108
本文对主要的温室气体及其源、汇、环境效应、减排措施进行了研究。温室气体主要指CH4、CO2、N2O、CFCs等,其中CH4、N2O和CFCs不仅是温室气体,而且在平流层中会玻坏臭氧层。自工业革命以来,大气中温室气体排放源的增加及汇的降低导致了全球气候变暖,严重地威胁着人类赖以生存的环境——地球。 相似文献
15.
Soil liquefaction can cause disastrous consequences to buildings and human lives. Regular countermeasures against soil liquefaction are often overly expensive for normal buildings and structures. This could be the major reason that liquefaction induced damage is still widely encountered in large- and mid-size earthquakes in recent years. In this paper, a new method for the mitigation of soil liquefaction using the microbially induced soil desaturation is proposed and tested. The desaturation effect in soil is achieved by the generation of nitrogen gas produced from the microbial denitrification process. Some major issues related to this method are experimentally investigated. These include soil desaturation procedures, shapes and distribution of gas bubbles in soil, mechanical responses and liquefaction resistance of desaturated soils, and stability of gas in soils. The desaturation treatment of soils is made simply by introducing denitrifying bacteria and a desaturation solution into soil pores by mixing, flushing, or injection. The degree of saturation can be reduced as the microbial reaction proceeds. Experimental results show that the final degree of saturation is related to the initial nitrate concentration added to the soil: the higher the concentration of nitrate in the desaturation solution, the lower the degree of saturation that can be achieved. The existence of gas bubbles in soil is evidenced by computer tomography (CT) technology. The CT images reveal that gas is in the form of small pockets which has a size a little larger than the mean size of sand grains. It is shown in the shaking table tests that microbially induced desaturation can effectively improve the liquefaction resistance of soil by showing a much lower pore pressure generation, much smaller volumetric strain, and much smaller settlement of the structure in desaturated soil, as compared with those in saturated soil. Triaxial consolidated undrained tests reveal that the desaturation treatment of soil can improve the undrained shear strength of loose sand. The stability of gas is tested under hydrostatic and water flow conditions. The gas phase is stable under the hydrostatic condition, but unstable under water flow conditions. So measures ought to be taken to prevent steady flow in practice. 相似文献
16.
Correlation of liquefaction resistance with shear wave velocity based on laboratory study using bender element 总被引：1，自引：0，他引：1
INTRODUCTION Evaluation of soil liquefaction resistance is an important aspect of geotechnical engineering practice, and several types of evaluating procedures have evolved over the last three decades. The well known “simplified procedure” originated by Seed and Idriss (1971) can be used to evaluate liquefaction resistance based on standard penetration test (SPT) blow counts. Over the years, the simplified procedure has been modified and updated with additional data, and has become th… 相似文献
17.
陈三姗陈峰 《福建工程学院学报》2021,(1):61-67
从粉煤灰-水泥相互作用、粉煤灰-淤泥质土相互作用两个方面开展一系列试验,研究粉煤灰对水泥和淤泥质粘土的强度及固化过程的影响,然后通过扫描电镜(SEM)试验,观察粉煤灰水泥土的微结构变化以探究其机理。粉煤灰水泥石强度试验表明粉煤灰能使水泥石28d及以上龄期的强度提高,粉煤灰淤泥质土的含水率试验和固结不排水试验表明,粉煤灰使淤泥土的硬度变大,X射线衍射(XRD)试验表明粉煤灰能细化水泥中Ca(OH)2晶粒,SEM试验结果表明粉煤灰可以使水泥土的微结构更加密实。 相似文献
18.
ZHANG Jia-yuan ZHOU Jie-min 《重庆大学学报(英文版)》2007,6(3):155-160
Steam-reforming is an effective approach for upgrading methane and hydrocarbon of coke-oven gas into CO and H2, but the kinetic behavior needs more study. We investigated the conversion of methane in coke-oven gas by steam reforming process in an electric tubular flow at 14 kPa with temperature varying from 500 °C to 950 °C, and developed a kenetic model for , ignoring the effects of adsorption and diffusion. The optimal dynamic conditions for methane conversion 14 kPa are as follows:the ratio of the amount of water to the amount of methane is from 1.1 to 1.3;the reaction temperature is from 1 223 K to 1 273 K. The methane conversion rate is larger than 95% when the ratio of the amount of water to the amount of methane is 1.2 at a temperature above 1 223 K with the residence time up to 0.75 s. 相似文献
19.
利用公式△H=-0．1196n／A计算了乙醚和丙酮分别在氧气和空气中燃烧反应的温度,并推测了乙醚和丙酮燃烧反应的机理．乙醚在氧气中燃烧反应的火焰温度理论值为3272K,与测定温度3134K接近,误差为4．40％．丙酮在空气中燃烧反应的火焰温度理论值为1292K,与测定温度173K接近,误差为1．49％．根据乙醚和丙酮燃烧反应的火焰温度,推测乙醚和丙酮燃烧反应机理为：（1）O2＋hv→2O·;（2）（C2H5）2O→4C＋4H2＋H2O（乙醚）,CH3COCH3→3C＋2H2＋H2O（丙酮）;（3）H2＋O·→H2O＋hv;（4）C＋O·→CO＋hv;（5）2CO＋O2→2CO2． 相似文献